Huge N.J. forest fire expands to 11,000 acres, could be largest wildfire in 15 years

June 23, 2022 · 3 minute read
Huge N.J. forest fire expands to 11,000 acres, could be largest wildfire in 15 years

Updated: Jun. 21, 2022, 12:25 p.m. | Published: Jun. 20, 2022, 11:25 a.m.

Firefighters on Monday continue to battle a massive forest fire in Wharton State Forest that has grown to 11,000 acres but is now 50% contained.

The New Jersey Forest Fire Service said backfiring operations will continue all day to help contain the blaze in the Pine Barrens, which is burning in Washington, Shamong, Hammonton, and Mullica townships in South Jersey.

The fire could consume as much as 15,000 acres before it is fully under control, said Greg McLaughlin, the Chief of the NJ Forest Fire Service at a Monday afternoon press conference.

No one has been hurt, though 50 people who aren’t residents have been evacuated from the area. Two roads remain closed, Route 206 from Chew Road to Atsion Road and Route 542 from Green Bank Road to Columbia Road. The fire’s cause remains under investigation, though natural cause have been ruled out, officials said.

“We can be looking at the largest forest fire in New Jersey in 15 years,” state Department of Environmental Protection commissioner Shawn LaTourette said.

The last fire that was at least 15,000 acres was a 2007 blaze that consumed 17,000 acres of woods in southern Ocean and Burlington counties, forcing thousands of residents to evacuate.

Forecasters say Monday’s weather conditions — still dry but less windy than Sunday — should help firefighters somewhat.

Wharton State Forest fire
At least 7,200 acres at Wharton State Forest in South Jersey have burned as of late Monday morning since a fire broke out on Sunday, June 19, 2022.New Jersey Department of Environmental Protection

“The winds are definitely not as bad as (Sunday),” said Jonathan O’Brien of the National Weather Service in Mount Holly. “(Sunday) was the kind of day that favors rapid fire spread with strong, gusty northwest winds.”

No rain is in the forecast for the rest of the day or at night but there’s a chance of showers Tuesday night, forecasters say.

Gov. Phil Murphy said Monday evening rain could be “a huge boost.”

Eighteen structures are threatened; six were in jeopardy when officials provided their previous update at 11 p.m Sunday. Volunteer fire departments from Atlantic, Burlington and Ocean counties are protecting those buildings.

Murphy also said it appears there is “no threat to lives or private property.”

Batsto Village and all associated hiking and mountain bike trails are closed to visitors. The Mullica River Campground, Mullica River Trail and boat launches along the Mullica River are closed from the Atsion Recreation Area to Batsto Village. Pinelands Adventures has suspended kayak and canoe trips.

Some area police departments, including Galloway, have told residents that they might find ash around their towns.

“At this time, we know that there is a strong odor of wood burning present throughout town, similar to one you would have when standing adjacent to a campfire,” Galloway police said Monday.

The smell of smoke was present at least 40 miles away in Atlantic City and Brigantine Monday morning, with a haze cast over the Jersey Shore towns.

At 7:25 p.m. Sunday, the fire had burned about 600 acres and was 10% contained. A new update on the fire should be available around 10:30 a.m. Monday, officials said. By 11 p.m. it had grown to 2,100 acres but was 20% contained.

According to the state parks department, Wharton is the state’s largest single tract of land within the New Jersey State Park System, occupying 122,800 acres of pine forest, meadows, lakes and rivers within the Pinelands National Reserve in Burlington and Atlantic counties.

The forest fire is currently the largest in New Jersey since the Spring Hill wildfire in Penn State Forest in Burlington County burned more than 11,000 acres in the spring of 2019.

Murphy on Monday praised the “heroic work” by state firefighters, as well as county and local responders.

“This is increasingly, sadly, the world we’re in, with climate change,” Murphy said during his regular television show on News 12 New Jersey. “This went from 2,000 acres to 11,000 in a very short amount of time.”

NJ Advance Media freelance photographer Dave Hernandez and staff writer Brent Johnson contributed to this report.

Bernheim Forest sensory garden reopens with more accessible attractions

June 23, 2022 · 1 minute read
Bernheim Forest sensory garden reopens with more accessible attractions

June 20, 2022

Bernheim Forest’s newly expanded sensory garden invites visitors to experience nature through more than just their eyes.

The installation reopened last week after undergoing major renovations. These changes aimed to make it more accessible for visitors with sensory sensitivities or challenges — those who are blind, visually impaired or have Autism Spectrum Disorder.

“We were founded in 1929 as a place that welcomes everyone, and our philosophy is it’s not enough to put out a sign that says ‘everyone welcome’ — it’s an ongoing work in progress,” Director of Education Kristin Faurest said. 

The garden includes plant beds catered to each of the five senses. Visitors can see, feel and smell a variety of species, each categorized by the sense they appeal to most.

“By focusing on each sense individually, it’s a kind of mindfulness and connection that keeps you from feeling overwhelmed, which is something that not just people with Autism Spectrum Disorder can experience,” Faurest said. “[The garden] is a place to focus, center yourself and calm down.”

The garden also features a quiet space surrounded by small evergreens, creating a secluded spot to step away. The plants are arranged in an infinity symbol — often used to represent Autism support.

Renee Frith, Bernheim’s director of Horticulture and Sustainable Landscapes, said the garden will likely continue expanding in the coming years. She said they’re looking at adding an audio installation and ways to further improve accessibility.

“Gardens are ever-growing, ever-changing. The natural environment is that way as well,” Frith said.

Funding was obtained through the Crusade for Children, the Kentucky School for the Blind Charitable Fund and Kosair Charities. Numerous advocacy and charity groups that focus on sensory sensitivity and impairment aided in the design process.

“All of these groups spent so much time coming out and volunteering and working with us — telling us what to design, how to do it, how we can do it better,” Frith said. “We don’t have all the answers, and we aren’t afraid to say we don’t know, because that’s how you learn. This whole garden has been a great experience in learning about different communities and how they experience nature.”

Deadly Jewels of Virginia forests

June 15, 2022 · 2 minute read
Deadly Jewels of Virginia forests

The vibrant, metallic green of an emerald ash borer (EAB) makes it look like royalty of the forest. But this beautiful, invasive insect is also deadly. Just one beetle can lay 40-70 eggs on the bark of its preferred host: ash trees. The growing larvae disrupt the flow of water throughout the tree, which will ultimately kill the tree. A healthy ash tree can be killed in just three years from the first symptoms of decline. This insect has devastated the population of ash trees in North America and will continue to survive and multiply as long as there are still host trees available. Due to the high price of control and removal, the EAB is one of the costliest invasive forest insects in U.S. history.

Counties in which EAB have been found as of August 2020.

The EAB has been located and confirmed in almost every county in Virginia. Only counties in the easternmost part of the state have yet to confirm the suspected presence of EAB. Because it is an invasive insect, native trees do not have natural resistance that keep the insect at bay. The insects move naturally to search for new host trees, but the biggest factor in the spread of EAB is the movement of wood by humans, for purposes such as firewood.

The indicative “s-shaped” galleries of EAB

EAB emerge as adults from mid-May to their peak in June. Landowners should be aware that any living ash trees on their property can be a host to EAB. Symptoms of this deadly insect include a thinning tree canopy, epicormic branching (sprouts from the main trunk), serpentine galleries under bark, and D-shaped exit holes on the bark. Another indicator of EAB presence is increased woodpecker activity in the winter, when ash trees can be full of EAB larvae.

There are, however, several options to help manage an infestation and keep trees alive and healthy. An annual soil drench or bark spray is a less costly, but also less effective, method. The best treatment for EAB is a direct trunk injection of the insecticide emamectin benzoate to trees with a live crown of at least 70%. These injections have been shown to keep ash trees alive and healthy for up to three years. This method is fairly costly, thanks to the price of the chemical and the need for specialized equipment.

The Virginia Department of Forestry recognizes that treatment can be a financial burden for landowners and organizations. To help offset the price of treatment, VDOF’s Emerald Ash Borer Cost-Share program can financially assist those who are eligible. This year’s program is open to landowners in the eastern part of the state and to organizations statewide.

Infected ash trees that may not be worth treating can still be utilized as firewood in the same county they are downed, or upcycled into quality wood products. Please remember when you go on a trip to buy firewood at your destination. EAB and other invasive forest pests are often transported in infested firewood, and you may inadvertently spread these pests to more trees and forests.

The emerald ash borer is a devastating invasive pest that can cause widespread damage to single ash trees and acres of forest alike. Through sound management practices, treatment of trees, and monitoring for signs of EAB, this jeweled insect can be a threat of the past.

Cover image: An adult emerald ash borer. Credit Leah Bauer, USDA Forest Service Northern Research Station,

Sniffing out forest fungi

June 15, 2022 · 1 minute read
Sniffing out forest fungi

Field mycologist Željko Zgrablić works with his dog to track how climate change affects truffles.

Truffles are socially and economically important in parts of Croatia. They can be worth up to €5,000 (US$5,300) per kilogram. The truffle industry and related tourism provides jobs, supplements incomes and boosts local economies. It’s not just about money, however; many people just love being out in the forest looking for them.

My fascination with fungi began at the age of six, when my father and grandfather began taking me out to hunt for game and to collect mushrooms near our home in Istria. Today, I focus mainly on truffles and other hypogeous fungi, which produce their fruiting bodies underground. I spend 50–100 days a year in the field with my dogs, collecting samples and data on the life cycles, ecology and geographical spread of fungi across Croatia. Here, I’m with my dog Masha. I love the work.

Thirty years ago, rainfall used to be more predictable across the year in Istria. Now, the climate is more extreme, and includes droughts. Truffles require a specific amount of water to grow. And warm winters have increased the population of wild boars, which damage the soil and eat the truffles. The truffles are becoming harder to find.

Truffle plantations could take the pressure off natural habitats. There, the soil water content can be controlled, agricultural methods can be used to enhance production and boars can be kept out. We’re studying the viability of farming black truffles, in part by experimenting with different ways to inoculate tree seedlings with their spores.

We’re using DNA barcoding to identify fungi in soil from their spores and root-like mycelium in protected areas. We’re finding that there are often many more species present than previously thought.

Our comparisons of areas with and without truffles could help to reveal why they grow in some areas but not others. Our work is also helping to show the importance of biodiversity in places such as the Adriatic islands of Brijuni National Park.

Nature 606, 616 (2022)


Indigenous knowledge reveals history of fire-prone California forest

June 9, 2022 · 5 minute read
Indigenous knowledge reveals history of fire-prone California forest

A collaboration between scientists and Native American tribes finds tree density in parts of the Klamath Mountains is at a record high, and at risk of serious wildfires.

Controlled fires can be used to reduce the risk of wildfires. Credit: David Hoffmann/Alamy

Indigenous oral accounts have helped scientists to reconstruct a 3,000-year history of a large fire-prone forest in California. The results suggest that parts of the forest are denser than ever before, and are at risk of severe wildfires1. The research is part of a growing effort to combine Indigenous knowledge with other scientific data to improve understanding of ecosystem histories.

Wildfires are a substantial threat to Californian forests. Clarke Knight, a palaeo-ecosystem scientist at the US Geological Survey in Menlo Park, California, and her colleagues wanted to understand how Indigenous communities helped shape the forest by managing this risk in the state’s lush western Klamath Mountains. Specifically, they studied Indigenous peoples’ use of cultural burning — small, controlled fires that keep biomass low and reduce the risk of more widespread burning. The results are published in the Proceedings of the National Academy of Science.

“When I was a little kid, my grandmother used to burn around the house,” says Rod Mendes, fire chief for the Yurok Tribe fire department, whose family is part of the Karuk Tribe of northern California. The Karuk and Yurok tribes have called the Klamath Mountains home for thousands of years. “She was just keeping the place clean. Native people probably did some of the first prescribed fire operations in history,” says Mendes.

Understanding how Indigenous tribes used fire is essential for managing forests to reduce wildfire risk, says Knight. “We need to listen to Native people and learn and understand why they managed the landscape the way they did,” adds Mendes.

Collaboration for corroboration

To map the region’s forest history, the team drew on historical accounts and oral histories from Karuk, Yurok and Hoopa Valley Tribe members collected by study co-author Frank Lake, a US Forest Service research ecologist in Arcata, California, and a Karuk descendant, as part of his PhD thesis in 2007. These accounts described the tribes’ fire and land use. For instance, members lit small fires to keep trails clear; this also reduced the amount of vegetation, preventing expansion of wildfires from lightning strikes. Larger fires, called broadcast burning, were used to improve visibility, hunting and nut-harvesting conditions in the forest. The effects of fire on the vegetation lasted for decades.

Knight says that it was important to collaborate with the tribes given their knowledge of the region. The Karuk Resources Advisory Board approved a proposal for the study before it began. “In a way, it’s decolonizing the existing academic model that hasn’t been very inclusive of Indigenous histories,” says Lake.

The researchers also analyzed sediment cores collected near two low-elevation lakes in the Klamath Mountains that are culturally important to the tribes. Layers of pollen in the cores were used to infer the approximate tree density in the area at various times, and modeling helped date the cores so they could estimate how that density changed.

The team also measured charcoal in the cores’ layers, which helped to map fluctuations in the amount of fire in the region. Burn scars on tree stumps pointed to specific instances of fire between 1700 and 1900. Because the stumps’ rings serve as an ecological calendar, the researchers were able to compare periods of fire with corresponding tree-density data. They then pieced together how this density fluctuated with fire incidence. Although these empirical methods could not specifically confirm that the fires were lit by the tribes, patterns suggested when this was more probable, says Knight. For instance, increased burning in cool, wet periods, when fires caused by lightning were probably less common, suggested a human influence.

Combining multiple lines of evidence, Knight and her team show that the tree density in this region of Klamath Mountains started to increase as the area was colonized, partly because the European settlers prevented Indigenous peoples from practicing cultural burning. In the twentieth century, total fire suppression became a standard management practice, and fires of any kind were extinguished or prevented — although controlled burns are currently used in forest management. The team reports that in some areas, the tree density is higher than it has been for thousands of years, owing in part to fire suppression.

Healthy forest

A dense forest isn’t necessarily a healthy one, says Knight. Douglas firs (Pseudotsuga menziesii), which dominate the lowland Klamath forests, are less fire resilient and more prone to calamitous wildfires. “This idea that we simply should let nature take its course is just not supported by this work,” she says. She adds that one of the study’s strengths is the multiple lines of evidence showing that past Indigenous burning helped to manage tree density.

Fire ecologist Jeffrey Kane at the California State Polytechnic University Humboldt in Arcata says that the study’s findings of increased tree density are not surprising. He has made similar observations in the Klamath region. “There’s a lot more trees than were there just 120 years ago,” he says.

Dominick DellaSala, chief scientist at forest-protection organization Wild Heritage in Talent, Oregon, points out that the results suggesting record tree densities cannot be applied to the entire Klamath region, owing to the limited range of the study’s lakeside data.

Knight, however, says that the results can be extrapolated to other similar low-elevation lake sites that have similar vegetation types.

More Indigenous voices

Palaeoecology studies are increasingly incorporating Indigenous knowledge — but there’s still a long way to go, says physical geographer Michela Mariani at the University of Nottingham, UK. In Australia, Mariani has also found that tree density began to increase after British colonization hampered cultural burning. “It’s very important that we now include Indigenous people in the discussion in fire management moving on,” Mariani says. “They have a deeper knowledge of the landscape we simply don’t have.”

Including Indigenous voices in research is also crucial for decolonizing conventional scientific methods, Lake emphasizes. It “becomes a form of justice for those Indigenous people who have long been excluded, marginalized and not acknowledged”, he says.



  1. Knight, C. A. et al. Proc. Natl Acad. Sci. USA 119, e2116264119 (2022).PubMed Article Google Scholar 

The ‘Extinct’ Ivory-Billed Woodpecker Not Extinct After All

June 8, 2022 · 1 minute read
The ‘Extinct’ Ivory-Billed Woodpecker Not Extinct After All

Since 1944, nobody—in a way that can be verified, anyway—has seen an ivory-billed woodpecker alive. Once common from the Carolinas to Texas, the US Fish and Wildlife Service recommended last year the bird be removed from the Endangered Species List because it was extinct. Meanwhile, a group of scientists was climbing through humid Louisiana forests, chasing whispers the big bird—the largest woodpecker in North America—still lived there.

Trail cameras, drone cameras, audio recordings, and, just as importantly their own eyes and ears, confirmed to members of the study the ivory-billed woodpeckers had survived in small numbers after all. They published their findings in a recent and not yet peer-reviewed paper.

Photos from the cameras were enough to give an indication of size, as well as distinctive markings that are, nevertheless difficult to distinguish, even for experts, from other woodpeckers that have similar colorings. Even better, the use of video allowed the scientists to make detailed observations of how the birds foraged for food and interacted socially, adding further differentiation that these were indeed the elusive ivorybills.

Steve Latta, who led the research team, had one particularly memorable encounter with the bird. “It flew up at an angle and I watched it for about six to eight seconds, which was fairly long for an ivory-billed woodpecker,” Latta told The Guardian. “I was surprised. I was visibly shaking afterward. You realize you’ve seen something special that very few people had the opportunity to see.”

Many ornithologists had a hunch the swampy forests of the southeast held a small population of the shy birds.

“No one has held a camera and got a picture of one in years because it’s a scarce bird in tough swampy habitat and they don’t want people close to them because they’ve been shot at for 150 years,” said Geoffrey Hill, a biologist who unsuccessfully tried to spy the bird in Florida in 2005.

“They have better eyes than we do, they are high in the trees and actively flee people. They aren’t great thinkers but they have developed a pretty simple strategy to avoid people.”

Clearly, that strategy might need some tweaking.

A California redwood forest has officially been returned to a group of Native tribes

June 2, 2022 · 4 minute read
A California redwood forest has officially been returned to a group of Native tribes

Save the Redwoods League has donated more than 500 acres of redwood forestland to the InterTribal Sinkyone Wilderness Council, a coalition of Native tribes that have been connected to the land for thousands of years.

Max Forster/Save The Redwoods League

A conservation group is returning guardianship of hundreds of acres of redwood forestland to a coalition of Native tribes that were displaced from the land generations ago by European American settlers.

Save the Redwoods League purchased the 523-acre area (known as Andersonia West) on the Lost Coast of California’s Mendocino County in July 2020. It announced on Tuesday that it had donated and transferred ownership of the property to the InterTribal Sinkyone Wilderness Council, a consortium of 10 Northern California tribal nations focused on environmental and cultural preservation.

The forest will be renamed “Tc’ih-Léh-Dûñ” — which means “fish run place” in the Sinkyone language — as “an act of cultural empowerment and a celebration of Indigenous resilience,” the league said in a release. The tribal council has granted it a conservation easement, meaning use of the land will be limited for its own protection.

“Renaming the property Tc’ih-Léh-Dûñ lets people know that it’s a sacred place; it’s a place for our Native people. It lets them know that there was a language and that there was a people who lived there long before now,” said Crista Ray, a tribal citizen of the Scotts Valley Band of Pomo Indians and a board member of the Sinkyone Council. She is of Eastern Pomo, Sinkyone, Cahto, Wailaki and other ancestries.

How the transaction played out

The league’s 2020 purchase of the forest cost $3.55 million and was fully funded by Pacific Gas & Electric Company (the utility, which has been behind multiple deadly wildfires, supports habitat conservation programs to mitigate other environmental damage it has caused).

PG&E reimbursed the league and council for “transactional cost and management plan preparation,” the statement adds, and contributed a $1.13 million endowment to support ongoing stewardship of the area.

National Parks Should Be Controlled By Indigenous Tribes, One Writer Argues

Establishing Tc’ih-Léh-Dûñ supports meeting the power company’s 30-year conservation goals, which the league says were developed alongside the U.S. Fish and Wildlife Service. The agency also approved the long-term management and stewardship plan for the property.

What their conservation efforts will entail

Tc’ih-Léh-Dûñ is home to ancient trees, important bodies of water and a variety of endangered species.

It consists of 200 acres of old-growth coast redwoods and 1.5 miles of Anderson Creek, a stream and tributary of the South Fork Eel River.

“Second-growth redwoods, Douglas-firs, tanoaks and madrones also tower over a lush understory of huckleberries, elderberries, manzanitas and ceanothuses,” as the league describes it. This habitat supports endangered species like the northern spotted owl, steelhead trout, coho salmon, marbled murrelet and yellow-legged frog.

The council and the league say their partnership will protect the environment by preventing habitat loss, commercial timber operations, construction and other development.

They plan to rely on a mix of Indigenous place-based land guardianship principles, conservation science, climate adaptation and fire resiliency concepts to heal and preserve the area.

“We believe the best way to permanently protect and heal this land is through tribal stewardship,” said Sam Hodder, resident and CEO of Save the Redwoods League. “In this process, we have an opportunity to restore balance in the ecosystem and in the communities connected to it, while also accelerating the pace and scale of conserving California’s iconic redwood forests.”

Why Indigenous guardianship matters

People involved with the partnership stress that it’s not just the protection of the land that matters — it’s also the restoration of the property to descendants of its original inhabitants.

Notably, the Sinkyone Council has designated Tc’ih-Léh-Dûñ as a tribal protected area.

“This designation recognizes that this place is within the Sinkyone traditional territory, that for thousands of years it has been and still remains an area of importance for the Sinkyone people, and that it holds great cultural significance for the Sinkyone Council and its member tribes,” said Priscilla Hunter, a tribal citizen of the Coyote Valley Band of Pomo Indians and chairwoman of the Sinkyone Council who is of Northern Pomo and Coast Yuki ancestries.

Returning farmland to Yakama Nation is a step toward self-sufficiency tribes once had

It joins another 180,000 acres of conserved lands along the Sinkyone coast, the release notes. The council hopes that the acquisition will continue expanding the network of adjacent protected lands with similar ecosystems and cultural histories.

That will enable the tribes to “achieve larger landscape-level and regional-level protections informed by cultural values and understandings of these places,” according to Hawk Rosales, a former executive director of the council who is of Ndéh (Apache) ancestry.

The land donation can be contextualized as part of the broader “land back” movement, an intersectional effort to return Indigenous lands — and autonomy — to Indigenous communities, especially public lands like national parks. Research shows that forced relocation and the loss of historical lands has made Native Americans more vulnerable to climate change.

And this isn’t the first time the league has donated land to the Sinkyone Council — it donated a nearby 164-acre plot of redwoods back in 2012, marking the first time Save the Redwoods entered into a conservation agreement with a tribal entity.

Indigenous people worldwide play a key role in environmental stewardship. According to a 2021 United Nations policy brief, they represent some 5% of the world’s population, but effectively manage roughly 20% 25% of the Earth’s land. Much of their land is in areas that hold 80% of the planet’s biodiversity and about 40% of protected lands.

This story originally appeared in the Morning Edition live blog.

The hybrid tree that conquered the world

June 2, 2022 · 13 minute read
The hybrid tree that conquered the world

The world’s cities have always been radically hostile environments for trees – but there’s one variety that’s proved to be remarkably resilient.

In an unremarkable corner of London’s Cheapside district, tucked away behind black wrought-iron fencing, is one of the city’s oldest residents. With a towering frame and slightly stooped posture, capped with a broad thatch of leathery, star-shaped leaves, this venerable giant is thought to have presided over the city since at least the 18th Century.

Over its lifetime, the Cheapside tree has lived through countless dramas and innovations – slowly inching its way upwards while stonemasons toiled away erecting early coffee houses and banks, then gradually broadening its shoulders as the first electric hackney carriages rolled along the streets below, and later, shading the cars that replaced them. It’s been a stoic witness to the infamous cholera outbreak of 1854 – which led to the introduction of modern sanitation – the 1918 flu pandemic, and the horrors of the Blitz.

But life for this Londoner has not been easy. Hemmed in on one side by buildings and the other by a road, it inhabits one of the most polluted parts of the city. And like most urban trees, when it rains it’s either inundated with runoff or left thirsty. Its roots are squashed into heavily compacted, alkaline soil – with little space to stretch out their tendrils without bumping into concrete. The City of London may be an urban jungle, but it’s hardly an idyllic environment for a tree.ADVERTISEMENT

In fact, there’s emerging evidence that urban trees share many of the burdens of other city residents – often living in cramped conditionsriddled with infectious diseases, and suffering from chronic stress. In this unnatural setting, they tend to live fast and die young – research has found that they have mortality rates nearly twice as high as those in rural areas, with fewer surviving trees every year.  

“Street trees are typically not getting older than 30 to 40 years,” says Cecil Konijnendijk, professor of urban forestry at the University of British Columbia in Canada. As we speak, he’s surveying the health of the trees he can see from his hotel room during a visit to Brussels. “I can see already in a line of six trees one or two that don’t look healthy,” he says.

The Cheapside London plane tree has barely changed for hundreds of years (Credit: Alamy)

The Cheapside London plane tree has barely changed for hundreds of years (Credit: Alamy)

Though it can be easy to think of them as little more than city furniture, urban trees are very much alive – and their struggle to survive is only becoming more extreme. Without a radical rethink of the living conditions of this long-overlooked community, some experts are concerned that our cities could soon lose much of their greenery altogether.

How have some trees survived in these dystopian environments for so long? And what can be done to save the others?

A secret tryst

It all started in the 17th Century. As global trade took off between Western countries and their colonies, among the endless crates of imported spices, silks, ancient artifacts and tea were millions of tiny guests – seeds. Explorers and merchants sent these tiny souvenirs back from wherever they traveled – so as the map expanded, so did the plants available in Britain. Soon English gardens were transformed into showrooms for the flora in the furthest reaches of the planet.

It was around this time that the London plane tree came into being. To this day, its origins remain a mystery. But somehow, amid the chaotic meeting of the so-called New World and the Old, two plants from continents thousands of miles apart – an American sycamore and an Oriental plane – met and reproduced.

One possibility is that the two strangers may have coexisted on the grounds of the Oxford Botanical Garden, where one botanical thing led to another. An alternative theory is that they hooked up in Spain, where their offspring was first described. Either way, the result was a large, strikingly beautiful tree with a fast growth rate and an unusually robust constitution, able to survive in one of the harshest environments on Earth – human cities. It didn’t take long for the London plane to be a hit.

Within a century these noble plants could be found scattered across London. The exact age of the Cheapside tree is hotly disputed – some say it belongs to this first generation, making it up to 300 years old, while the City of London asserts that it was planted in 1820 at a cost of sixpence.

For regular trees, these early additions are still just youngsters. But for city trees, they’re positively ancient.

Gingko trees have barely changed since they first appeared on the planet 200 million years ago – but they happen to make remarkably good city residents (Credit: Getty Images)

Gingko trees have barely changed since they first appeared on the planet 200 million years ago – but they happen to make remarkably good city residents (Credit: Getty Images)

In the 19th Century, London plane trees were used to transform the city’s layout, turning previously naked streets into familiar leafy boulevards – inspired by the same trend in Paris. (One particularly broad specimen in London’s Mayfair, dating back to the Victorian era, was valued at £750,000 by tree officers from the local authority in 2008.)

Even as the harsh living conditions of the Industrial Revolution began to take hold, London plane trees continued to cling on where others got sick. In addition to being unusually hardy, the hybrid giants had some quirky features that helped them adjust to city life, such as the ability to slough off the outer layers of their smog-coated trunks to reveal a fresh patchwork of green and white bark beneath.

By the 1920s, the London plane represented 60% of their city namesake’s trees, and their almost-cartoonishly straight trunks and fluffy crowns had become a regular fixture in many other urban centres around the globe, from Sydney to New York City. They were soon joined a handful of other species, such as the common lime (also known as the linden tree), which currently makes up 45% of the canopy in the Finnish capital Helsinki.


From working with contaminated city soil to reconsidering weeds, pests and even lawns, gardening is changing as we adapt it to the realities of modern life. This series takes a look at its future in the 21st Century – and explores how it can be updated to fit with modern sensibilities and challenges, such as environmental awareness and pollution.

An unappealing prospect

Today the London plane is not as dominant as it once was – or quite as robust. Research in the Czech Republic has found that the trees’ health has been steadily deteriorating, and in any given year, the proportion of sickly individuals can be up to 97.5%. It’s widely accepted that when trees are stressed out by their local environment – such as warming cities or life in a concrete street box – they become particularly susceptible to a range of diseases. And this variety has been catching a new kind of fungal infection that causes characteristic sores, or “cankers” on the trunk.

Even for the long-suffering London plane, the conditions in modern cities are a step too far.

While other city trees' bark used to get choked up with smog, London plane trees simply sloughed theirs off (Credit: Getty Images)

While other city trees’ bark used to get choked up with smog, London plane trees simply sloughed theirs off (Credit: Getty Images)

“One of the greatest challenges [for trees in city environments] is just space,” says Andy Hirons, a senior lecturer in Arboriculture at Myerscough College in Lancashire, pointing out that large trees in the wild have vast root structures, often sprawling out nearly as far as their branches do. But in cities, the spaces we carve out for them are “often woefully inadequate for the size of the tree and the ambition those planting the tree have for it”, he says.

These confined conditions then lead to other issues, such as localised droughts – a common problem, as a tree’s roots can quickly mop up the water in its little pocket of land. “A tree with a smaller working environment will cause it to dry out much quicker, so they’ll experience drought cycles,” says Hirons. “And, you know, if a tree is always living on the edge of that sort of stress, they become more vulnerable to pathogens, pests, etc, just like us.”

Not only are city trees imprisoned in small slivers of soil, the soil itself is the equivalent of junk food – without the acidic organic matter that would usually cover the forest floor, the root environment tends to be alkaline, hindering their ability to absorb nutrients.

Even the soil’s structure is all wrong: where there should be pockets of air, the soil is compacted into dense clumps. “This means that it’s physically much more difficult for the roots to grow through and expand,” says Hirons. Eventually this limits their distribution and scale, further limiting their underground world.

Then there’s the pollution. This is ubiquitous – in the soil, there are heavy metals, as well as salt from the de-icing of roads and chemical contaminants from building materials. In the air, particulates block up microscopic pores in city trees’ leaves and smother delicate structures on the surface of the trunk – which plays a surprisingly important role in gas exchange and photosynthesis – while nitrogen oxides are absorbed by the leaves, leading to potentially toxic accumulations.

Finally, there’s the trees’ human neighbours.

Cities tend to trap more heat than the surrounding countryside, forming "heat islands" – so the best city trees can withstand high temperatutes (Credit: Getty Images)

Cities tend to trap more heat than the surrounding countryside, forming “heat islands” – so the best city trees can withstand high temperatutes (Credit: Getty Images)

“There are big problems with the ways we interact with trees,” says Hirons. He lists off some common crimes humans commit against their woody bystanders – resting bikes on them, using their protective enclosures as litter bins, encouraging pets to urinate all over their trunks, which alters the ground chemistry. Perhaps most bizarrely, some people even train their dogs to bite living branches. “[It’s] just crazy. Once that bark is lost, it’s devastating for the tree – it’s like losing your skin,” he says.

Crucially, many of the oldest urban trees will have spent the majority of their lives in conditions that were significantly less desperate. While in human terms the invention of tarmac in 1902 may seem like the distant past, for a three-century-old tree the era of these impermeable surfaces – which allow precious water to flow off into drainage channels rather than percolating down into the ground where it can be accessed – is relatively new.

“Effectively what you’re doing [with hard street coverings like tarmac and paving] is decoupling the climate, in terms of precipitation, from the experience of the tree,” says Hirons. Today city trees in some of the wettest parts of the planet are effectively inhabiting miniature deserts. They’re also suffocating.

“Impermeable surfaces really reduce the gas exchange between the root system and the atmosphere as well,” says Hirons. Just like humans, trees need to breathe – they must be able to absorb oxygen through their roots in order to release the energy from their food.

“They had much, much better rooting environments [in the past] in many ways,” says Hirons, who explains that 200 years ago pavements were wider and trees weren’t competing with fibre optic broadband cables for space. “And it’s difficult to see how that’s going to be pulled back.”

In short, just because old trees have made it this far, there’s no guarantee they’ll survive another century.

Many of London's oldest street trees were planted centuries ago, before the invention of the things that can make their lives difficult today – like tarmac (Credit: Alamy).

Many of London’s oldest street trees were planted centuries ago, before the invention of the things that can make their lives difficult today – like tarmac (Credit: Alamy).

A tricky brief

Enter the next generation of city trees, which experts are struggling to recruit.

One challenge is the new awareness of the importance of biodiversity, both for its ecological benefits and as an insurance against new diseases or pests that could wipe out whole species. When Dutch elm disease swept around the globe in the 1960s and 70s, it killed off around 25 million trees in Britain alone. By 1976, the United States had already lost around 38 million trees – few survived. 

All this means that city planners can no longer rely on an elite pool of high-performing trees, such as the London plane. Instead, they’re on the lookout for a more varied supply which can thrive in the increasingly harsh conditions urban forests have to offer. And it hasn’t been easy.

According to one estimate, there are currently around 800,000 street trees in London, with the ones that end up on pavements carefully selected by developers and city arborists. But even once they’ve identified a species that could work, getting hold of enough of these trees to populate a city is a huge challenge. There’s often little incentive for plant nurseries to invest the time and money it takes to grow young trees unless they know there’s going to be a market for them in 10 years’ time – and at the moment, most demand is for a narrow selection of small trees like silver birches.

“Frankly, just sticking in really small rowans or birches is not really going to deliver what we want in the future,” says Hirons. “You take away those last statuesque plane trees, and that’s what you’re left with.”


For more stories about plant life and the role it plays on our planet, please visit Our Green Planet, a digital initiative from BBC Earth in association with The Moondance Foundation. It aims to raise awareness of the beauty and fragility of our planet’s green ecosystems, forging a deeper understanding of the important role that plants play in biodiversity.

Next there’s the surprisingly high mortality rate for young trees, which are particularly vulnerable in the years it takes for them to establish in their new home. Hirons says this is currently around 13% – but in some situations it’s significantly higher. Nearly 50% of the new trees added to one street in Toronto, Canada were dead within three years.

However, Hirons is optimistic that cities can solve these problems.

One important change will be to make it clear to growers that there is demand for certain larger tree species, in advance of when they’re needed. But even more vital is designing the spaces they will inhabit with their physiological requirements in mind – ideally, larger pockets of land where they can develop healthy root systems.

Trees whose roots are smothered by hard surfaces like concrete, tarmac or paving slabs can be chronically stressed (Credit: Getty Images)

Trees whose roots are smothered by hard surfaces like concrete, tarmac or paving slabs can be chronically stressed (Credit: Getty Images)

And support in their early years is also crucial. “It’s like with human children – if you don’t have a good start, you will get the consequences later in your life,” says Konijnendijk. “It means we need to help them along the way, basically.” This includes things like “mulching” – adding organic matter to the root surface to seal in moisture – watering, and making sure they’ve got enough space, above and below ground.

If urban planners get it right, over the next few decades cities across the globe may soon break away from the monoculture aesthetic that London plane trees have lent them for centuries – and pioneer something more colourful. Hirons is rooting, quite literally, for more gingkos (ancient trees that once lived alongside dinosaurs) which are currently popular in Japan.

“I do like gingkos,” says Hirons. “I think they’ve got a lot of character they become sort of more and more on unweildy and wild as they get older. They’re really resilient, and they also can deliver just fantastic yellow-gold autumn colour as well.” Of course, what he’d really like to see are baobabs – strange, bulbous trees that flourish in the Sahel region of Africa on the edge of the Sahara desert – “but then we really would be in the realm of serious climate change…” he says.

Zaria Gorvett is a senior journalist for BBC Future and tweets @ZariaGorvett

See how Minnesota fire towers help preserve a 5,000-year-old bog

May 25, 2022 · 10 minute read
See how Minnesota fire towers help preserve a 5,000-year-old bog

The rich pine forest surrounding Pine Lake Forest Road in Hubbard County, Minnesota. Hubbard County is located in the Heartland Lakes region of northern Minnesota. There were once nearly 150 fire towers standing guard over the state’s forests as protection against unwanted fires. Today, only a handful of towers exist. Sarah Stacke

In northern Minnesota, not much can beat the pristine view ­­– and the rush – of climbing a fire tower. Reaching 100 feet into the sky, there were once nearly 150 of these steel lookouts guarding the state’s fire-prone forests.

Today, only a handful of climbable towers exist and they remain on the front lines of fire prevention through education and an innate human desire to perch above the treetops.

Most fire towers in the U.S. were built in the 1930s. Staffed by generations of women and men trained to locate the first wisps of smoke, they were relied upon for over two decades as a critical line of defense against forest fires. In the 1950s, lookouts were replaced by airplanes.

Now a relic of history, the steep staircases of the fire towers in Minnesota’s Itasca State Park and Big Bog State Recreation Area are tackled by thousands of people every year. On their way to the top, they learn about the land, its history, and the importance of preventing unplanned forest fires.

LEFT: The 100-foot Aiton Heights Fire Tower in Itasca State Park is open to the public during the spring, summer, and fall. RIGHT: Kasey Lake is on the trail that leads to Aiton Heights Fire Tower, a popular tourist attraction in Itasca State Park. Sarah Stacke

Errol Sleeper, 7, takes in the view from the cab of the Aiton Heights Fire Tower in northern Minnesota’s Itasca State Park. After climbing to the top of the 100-foot tower, Sleeper officially became a member of the Ancient and Honorable Order of Squirrels, a national fire tower club founded in 1927 by an Itasca Park Ranger to educate youth and adults about fire prevention and forest health. Sarah Stacke

Nearly 100% of unwanted fires burning through woodlands, prairies, and neighborhoods today are preventable. “Thanks to the fire tower, we have the opportunity to educate hundreds of children plus adults on forest stewardship and fire prevention,” says Dawn Jensen, who works for the Minnesota Department of Natural Resources at Big Bog State Recreation Area, an over 9,000-acre area located on the shores of Upper Red Lake.Sponsor Message

In 2011, an out of service fire tower was refurbished and moved to the visitor center at Big Bog to serve as a tourist attraction and educational resource. The idea worked. About 10,000 people visit Big Bog annually and the majority climb the tower, reports Jensen. Through interpretive signs, school tours, and conversations with staff and local fire historians, visitors learn about the surrounding ecosystems, specifically the massive bog and Red Lake, and why protecting them is critical.

Formally titled the Red Lake Peatlands, the big bog from which Big Bog State Recreation Area takes its name, covers upwards of 500 square miles and is the largest bog in the lower 48 states. A mile-long boardwalk allows a relatively close-up look at this natural masterpiece.

In a clever twist, the bog’s inhospitable moss and peat-covered landscape accommodates several rare and endangered fauna and flora, as well as moose, deer, bears, foxes, wolves, and an abundance of birds. “For centuries,” reads an interpretive sign along the boardwalk, “North American native peoples have ventured into the bog to hunt and trap game and to harvest the plants and berries. Bog plants have been used for food and medicines, and to make baskets, mats, dwellings, and canoes.”

Carnivorous pitcher plants grow in Big Bog. The plants attract and drown their prey with nectar. The Red Lake Peatlands have been called Minnesota’s last true wilderness. Sarah Stacke

The swimming beach at Big Bog State Recreation Area in northern Minnesota is on the shores of Upper Red Lake. Big Bog park was established in part to create a sustainable tourist attraction is Waskish, Minnesota, after the local economy was devastated when the walleye population of the lake crashed in the 1990s. Sarah Stacke

When dry, peat ignites easily and can burn for days, weeks, even years if smoldering underground. Peat fires can travel underground, making them infamously difficult to extinguish, as well as unpredictable and hard to control. Sarah Stacke

Since it began developing around 5,000 years ago, the bog has remained one of the most intact and undisturbed ecosystems in Minnesota. The views of Red Lake and the bog from the fire tower and boardwalk are largely what humans would have seen thousands of years ago.

“Fire towers are a lighthouse in the wilderness,” says Jensen, a constant reminder of the beauty of the ancient forests and the destruction wildfires can cause.

The bog’s relationship to fire is both indispensable and infamous. The ecosystem depends on periodic fires for survival, but uncontrolled fires can be devastating to the bog’s animals and nearby humans.As the bountiful layers of sphagnum moss decay, peat is formed. Though typically wet and spongy, when dry, peat ignites easily and often burns unnoticed for days, weeks, and even years. Peat fires, which can smolder underground, are notoriously difficult to extinguish, says Lyle Fenske, a retired forester who lives in the area.

Two of the top three deadliest fires in U.S history were in Minnesota. The second deadliest was the Cloquet Fire, which in 1918 killed 453 people, displaced or injured 52,000 more, and burned 1.2 million acres. The third deadliest was the Great Hinckley Fire of 1894, which claimed the lives of 418 white people and an unknown number of Native Americans. Their deaths weren’t counted in the toll.

In response to the state’s fires, many caused by logging practices, the Minnesota forestry service was established in the early 1900s, creating the foundation for a statewide system of fire towers. Over the decades, policies surrounding fire suppression and land management have been greatly debated. As Connie Cox of the Minnesota DNR explained, through research conducted in Itasca State Park and elsewhere, it is now understood that fires are a natural and needed process for the regeneration of nature, in particular the pine forests. Prescribed burning, used as a resource management tool, begins the process of reintroducing fire on the landscape and officials are increasingly looking at the ways Native communities have historically used controlled fires to rejuvenate the land and clear underbrush that contributes to extreme wildfires.

The fire tower at the DNR Forestry Station in Nimrod, Minnesota, is one of the only towers in the state still used to detect fires. Built in 1928, a 94-foot ladder leads to the tower’s cab. Sarah Stacke

LEFT: The fire tower at the DNR Forestry Station in Nimrod, Minnesota, is one of the only towers in the state still used to detect fires. RIGHT: Inside the DNR Forestry Station in Nimrod, Minnesota, a map identifies the location of the area’s fire towers. Information provided by lookouts in each tower is used to triangulate the exact location of a fire. Sarah Stacke

An Osborne Fire Finder, a type of alidade tool used to locate fires, inside the cab of the fire tower at the DNR Forestry Station in Nimrod, Minnesota. The tower in Nimrod is one of the only fire towers in the state still actively used for fire detection. Sarah Stacke

There is one fire tower in northern Minnesota that reserves itself for lookouts only, not thrill seekers. At the DNR Forestry Station in Nimrod, a 94-foot ladder leads skyward to the bright red octagonal cab of a fire tower.

Inside, a stool is positioned alongside an Osborne Fire Finder, a type of alidade tool developed in the 1920s to enable lookouts to pinpoint the exact location of a fire. The Nimrod tower, built in 1928, is staffed regularly during Minnesota’s fire season. An airplane is also deployed to monitor the forests, but is tasked with covering a large area.

“The tower can be a quicker way to spot smoke,” MN DNR Forester Jordan Griffing told me. With a fire, a lot can happen in an hour.

Itasca State Park, home to the headwaters of the Mississippi River and Aiton Heights Fire Tower, has long recognized the many ways official and makeshift towers play a role in fire prevention and education. Roughly a decade after the park was established in 1891, the Mississippi River Commission built six simple timber platforms above the treeline to map the Lake Itasca Basin.

Courageous visitors climbed to the top of the structures and, unexpectedly, the platforms proved themselves to be “very important in locating fires,” says Connie Cox, the MN DNR Lead Interpretive Naturalist at Itasca. The park immediately realized the platforms served the dual purpose of detecting fires and providing an “opportunity to educate people about the Itasca landscape,” added Cox.

By the 1920s, when the park’s wooden towers gave way to steel, Itasca had already set in motion a fire prevention program that employed the ascent of the towers as an educational tool.

“That’s why we keep our fire tower open,” Cox told me. It ushers an “appreciation of the forest…and if you want to protect something you have to develop an appreciation for it.”

LEFT: Fire tower historian David Quam, 82, founded the Forestry Education Center at the Beltrami County Fairgrounds in Bemidji, Minnesota. Quam led the effort to restore and preserve the Pinewood Fire Tower, now located on the fairgrounds. RIGHT: Connie Cox is the MN DNR Lead Interpretive Naturalist at Itasca State Park. Sarah Stacke

Fire scars remain on red pines in Preacher’s Grove from a fire that burned through the park in the 1860s. Prior to the fire suppression efforts that began in the 1900s, the park would have had a natural fire every 22 years on average. Fire creates favorable conditions for the growth and survival of pines and they depend on it for reproduction. Sarah Stacke

Itasca State Park, Minnesota: Fire scars remain on red pines in Preacher’s Grove from a fire that burned through the park in the 1860s. Since fires were nearly eliminated from the park a century ago, trees such as spruce, fir and maple have been allowed to dominate the ecosystem instead of pines. The park now facilitates controlled burns as part of its forestry management techniques. Sarah Stacke

Over half a million people visit Itasca annually. While the headwaters are what draw most people, the Aiton Heights tower is a close second. A “good chunk” of visitors climb it to connect with the natural landscape, “not a manicured forest,” says Cox.

Itasca was founded to protect thousands of acres of old-growth pines from logging, which in turn protect the headwaters. Large stretches of the park haven’t been interfered with since explorer Henry Rowe Schoolcraft was led to the headwaters by an Ojibwe guide, Ozawindib, in 1832.

Similar to the experience in Big Bog, from the top of the Aiton Heights tower, the dense quilt of emerald trees and cobalt lakes looks nearly the way it did before European settlers, when only the Dakota and Ojibwe inhabited the land.

Cox likes to say Itasca’s visitors “come for the river and return for the pines,” a nod to the magnetism of a forest that has long been conserved and protected from the devastation of unwanted fires.

The Red Lake Peatlands have been called Minnesota’s last true wilderness. The 500-square-mile Big Bog State Recreation Area is the largest in the lower 48 states. The bog has long been a source of medicinal plants to the land’s original inhabitants, the Ojibwe. The bog’s ecosystem benefits from periodic fires, but uncontrolled fires can be devastating to the bog’s animals and nearby humans. Sarah Stacke

The 100-foot fire tower in Big Bog State Recreation Area offers views of Upper Red Lake and portions of the Red Lake Peatlands. About 100,000 people come to the park annually and the majority climb the tower, according to the park’s staff. Interpretive signs at the base of the tower educate visitors about fire prevention and the history of the region’s forests. Sarah Stacke

A bird’s-eye view of the forests covering Itasca State Park from Aiton Heights Fire Tower, a popular attraction in the park. The tower is used to educate visitors about fire prevention and the forest. Sarah Stacke

Sarah Stacke is a freelance photographer and archive investigator based in Brooklyn, N.Y. She is also one of the founders for the 400 Years Projects. Follow her on Instagram @sarah_stacke.

Scientists discover an ancient forest inside a giant sinkhole in China

May 25, 2022 · 2 minute read
Scientists discover an ancient forest inside a giant sinkhole in China

An aerial photo taken in April 2020 shows the scenery of a giant karst sinkhole in China’s Guangxi Zhuang Autonomous Region. A similar sinkhole was found earlier this month with an ancient forest at the bottom with trees towering over 100 feet tall. Xinhua News Agency/Getty Images

Cave explorers stumbled upon a prehistoric forest at the bottom of a giant sinkhole in South China earlier this month. Sinkholes such as these are also known in Chinese as Tiankeng, or “Heavenly pit.”

At 630 feet deep, the sinkhole would hide the Washington Monument and then some. The bottom of the pit holds an ancient forest spanning nearly three football fields in length, with trees towering over 100 feet high. And according to the Chinese government, it is one of 30 enormous sinkholes in the county.

The sinkhole was discovered by cave explorers outside Ping’e village in Leye County, South China’s Guangxi Zhuang Autonomous Region. A team of explorers descended into the pit on May 6, where they found ancient trees and other plant life, according to a Guangxi news release.

Karst is a type of topography, ideal for geological wonders like the sinkhole in Leye County, created by groundwater dissolving the limestone rock beneath the surface, according to the U.S. Geological Survey. About 20% of the United States is made up of karst landscapes, including attractions such as Carlsbad Caverns in New Mexico and Mammoth Cave in Kentucky.Sponsor Message

About 13% of China is covered by karst topography, according to NASA, with the Guangxi region being a prime example of its beauty.

Karst landscapes vary in size and shape depending on the surrounding climate, George Veni, executive director of the National Cave and Karst Research Institute, told Live Science.

“In China, you have this incredibly visually spectacular karst with enormous sinkholes and giant cave entrances and so forth,” Veni said. “In other parts of the world you walk out on the karst and you really don’t notice anything. Sinkholes might be quite subdued, only a meter or two in diameter. Cave entrances might be very small, so you have to squeeze your way into them.”A stone spire forest in the middle of nowhere

Veni’s institute is the sister organization of the team that discovered the new sinkhole, the Institute of Karst Geology of the China Geological Survey. Chen Lixin, who led the Guangxi cave expedition team, said the prehistoric trees at the bottom of the pit are almost 130 feet high and the dense brush on the forest floor stands shoulder-high, according to the Guangxi news release.

Could we learn to love slugs and snails in our gardens?

May 19, 2022 · 5 minute read
Could we learn to love slugs and snails in our gardens?

Before you squash or poison the next slug or snail you see in your garden, consider this: The British Royal Horticultural Society no longer classifies these gastropods as pests. Why on earth would a leading gardening organization do that, you might wonder. After all, slugs and snails are usually seen as a problem, given their eagerness to devour the plants you’ve lovingly nurtured.

The issue is that they are part of nature. Slugs and snails play a key role in healthy ecosystems, acting to break down organic material as well as providing a source of food for blue-tongued lizards, frogs, and kookaburras.

So can we learn to live with slugs and snails? Yes, if we reframe how we see these invertebrates. After all, the definition of “pest” is based on our perception and can change over time. By rejecting the “pest” status of many invertebrates and advocating planet-friendly gardening, the horticultural society directly connects the local actions of gardeners to our global biodiversity crisis.

Their principal entomologist, Andrew Salisbury, has argued that “now is the time to gracefully accept, even actively encourage, more of this life into our gardens”.

This doesn’t have to mean letting them destroy your lettuces. Nature can help. Enticing lizards, frogs, and birds to your garden can help control slugs and snails and boost biodiversity.

Kookaburra and magpie
Attracting birds like kookaburras and magpies to your garden can keep slugs and snails in check. Shutterstock

Are these ‘pests’ actually legitimate garden inhabitants?

Gardening increased in popularity during the pandemic. With widespread rainy weather across Australia’s east coast, gardeners are more likely to see – and potentially be annoyed by – slugs and snails.

So should Australian gardeners follow the UK’s example? Should we try to welcome all species into the garden? Responses to these questions typically describe slugs and snails as “pests”, invoke the idea of a native/non-native species divide or describe the perceived damage done by invasive species.

Let’s tackle the pest argument first. We define pests based on perception. That means what we think of as a pest can change. The garden snail is a good example. Many gardeners consider them a pest, but they are cherished by snail farmers who breed them for human consumption.

By contrast, many scientists consider the concept of an invasive species to be less subjective. Australia’s environment department defines them as species outside their normal distribution (often representing them as non-native) which “threaten valued environmental, agricultural or other social resources by the damage it causes”. Even this definition, however, is a little rubbery.

In recent decades, researchers in the humanities, social sciences, and some natural sciences have shown our ideas of nativeness and invasiveness also undergo change. Is the dingo a native animal, for instance, after being introduced thousands of years ago? Would it still be considered a native if it was introduced to Tasmania where it does not occur?

Despite these questions over their worth, the ideas of “pest” and “invasive species” have proven remarkably persistent in ecological management.

Red triangle slug on gum tree
Australia has a wealth of native land gastropods like this red triangle slug, found up and down the east coast. Shutterstock

What exactly are the slugs and snails we find in our gardens?

Australia has a huge diversity of land snails, with many species yet to be described. Many species are in decline, however, due to introduced predators and loss of habitat, and now require conservation efforts.

Does that include our gardens? Well, most snails and slugs found in gardens are considered non-native species which were introduced accidentally. The ability of snails to spread far and wide means these humble gastropods are listed on Australia’s official list of priority pests. We already have biosecurity measures in place to avoid unwanted introduction of new snail species.

The common garden snail, which hails from the Mediterranean, has now spread to every state and territory. But other species are still spreading, such as the Asian tramp snail on the east coast or the green snail, which is currently limited to Western Australia. So if we accept the existence of all kinds of snails and slugs in the garden, we could be undermining efforts to detect and control some of these species.

Asian tramp snail
The Asian tramp snail is regarded as a serious pest. Andrew Hardacre, FlickrCC BY

While slugs and snails don’t usually seriously threaten our home gardens, some species are known agricultural pests. The common garden snail can cause major damage to citrus fruit and young trees, while slugs such as the leopard slug or the grey field slug can devastate fields of seedlings. The damage they can do means farmers and their peak bodies would feel uneasy about changing how we think of these land mollusks.

Some snails can also carry dangerous parasites like the rat lungworm or the trematode worm Brachylaima cribbi. These can hurt us, particularly if a snail is accidentally eaten, or if vegetables in the garden are contaminated. If we let snails move around unhindered, we could increase the number of infections. Pets and children are the most at risk.

So should we follow the UK’s example?

It is not straightforward to rethink how we view and respond to creatures typically considered pests in the garden. But it is worthwhile thinking this through, as it requires appreciating how humans and nonhumans are interdependent. And we can gain a better understanding of how our simple actions in our gardens can scale up to affect human and planetary health and well-being.

The world’s ongoing loss of biodiversity and the steadily changing climate must inform how we relate to and care for the nonhuman life – from mycelium in the soil to gastropods – that enliven our gardens.

This does not mean everything must have an equal opportunity to flourish. But it does require us to pay attention. To observe, to wonder, and to be curious about our entangled lives. This kind of attention could help us take a more ethical approach to the everyday life and death decisions we make in our patch.

What does that look like? By understanding gardens as interconnected natural and cultural spaces, we can work to limit our resident slug and snail population and promote biodiversity. A perfect way to start is to design a lizard, frog, and bird-friendly site.

Eric’s Heroes: The Tree of Life

May 19, 2022 · 4 minute read
Eric’s Heroes: The Tree of Life

OLYMPIA, Wash. — In a state that has millions and millions of trees, there is one that has become a kind of symbol to a lot of people.

It’s been around for hundreds of years, and as strange as it sounds, this tree is actually inspiring.

On the outermost edge of the state of Washington, out on the Olympic Peninsula is a coarse and raw place. Unforgiving.

The rain comes in sheets.

The wind wallops and wails.

The sea batters the coast with a watery fist that never tires.

To survive here is no easy thing for any living thing.

There are bluffs along ruggedly beautiful Kalaloch beach and on the bluffs are trees that have weathered bitter storms for hundreds of years.

But on one bluff there is one Sitka spruce that is special.

From the beach, down below its canopy, there is a story to be told. A story of survival.

This is no tree. This is a metaphor for life.

“It makes me think about life and how we really are just hanging by a thread,” said Susan Chilton from Spring, Texas. This week’s installment profiles a tree that is inspiring others.

“It is very powerful, it’s a very powerful symbol, and a beautiful illustration of what nature can do with and without our help, right?”

Nobody knows how old it is. How long its been straddling like this.

It has come to be known in these parts as “The Tree of Life”.

People look at the tree called the tree of life near Kalaloch beach

“Somehow it’s surmounted some of the obstacles that were here before it, and it has outlasted them,” said Jennifer Ding from Cambridge, Massachusetts.

Brian Conway says, “For me a little bit of hope. That no matter how tough things can get, how the typical things in life that you depend upon might not be there, you can still get through it.”

There is a waterfall behind it and with the frontal assault of the tides, its foundation is under assault from front and back.

Each storm could be it’s last.

Becca Pifer “I think it’s touching. I think it’s a reminder that things we think are permanent are transient, and we can’t really rely on anything to stay the same for quite too long.”

This is Mathew Nichols. He’s a local who so admires the plight of the “Tree of Life” that he has taken to documenting it.

Mathew Nichols says, “Every year I prepare myself that it’s going to come down, and every year I think this winter’s the winter. But it continues to surprise me and I’ll just accept it surprising me every year.”

He’s there every couple of weeks. Taking his pictures. Hoping that the inevitable doesn’t happen. Knowing that, in the end, it will.

La Push waterfall (Mathew Nichols Photography)

His photos dazzle. They speak to a profound mystery that the tree seems to know the answer to.

They make us ponder, reflect, and feel small.

Mathew Nichols is a local photographer who has taken to documenting the tree of life

Mathew Nichols says, “You know to me it symbolizes the ability to go on, you know. No matter what’s thrown at it, it continues to thrive.”

Tourists come here now. Attracted by the tree’s quest for immortality.

Down the road a ways, Lissy Andros is with the chamber of commerce for the city of Forks.

Lissy Andros says, “We tell people that the Tree of Life, it’s a tree that’s basically on the bluff, and roots are exposed. And we don’t know how it’s staying alive.’

“I’m going to be super sad when it’s not here anymore. But it could outlive me. I don’t know.”

It’s like a high wire artist doing the splits over certain death below.

Some of its roots cling desperately to sandstone and clay.

Others dangle helplessly, straining and grasping for terra firma.

The big ones – old and time-tested – seemingly levitate. Gnarled and twisted. Dancing above the fray.

Day after day, the tree, nearly adrift, but hardwired to survive, strives to exist. It clings to life.

That’s what we do, isn’t it?

We cling to life.

The tree of life near Kalaloch beach

Dave Daltorio says, “It is symbolic of life right? You go through different phases in your life and sometimes you’re hanging by a thread just like this tree is. But it survives.”

Karen Daltorio says, “I’m happy that it’s living and I’m going to be optimistic that it’s going to be around for quite a while longer.”

Keith Kriegel says, “It’s had a hard life but it’s hanging in there and it’s doing the best it can with what it has to work with.”

Becca Pifer “For now it’s a joy, it’s beautiful, and it’s nature at its best.” “

And so this mirror on the beach endures. Untethered. But grounding us. Reflecting back on how precious life is. How life persists until it can’t anymore.

And somehow, it lives. Against all odds. Against the laws of gravity and nature, it lives.

And for now, anyway, for people like Mathew Nichols, who is drawn to it again and again, and countless others, it inspires and somehow teaches.

Because the Tree of Life’s story is all of our stories.

This is no tree. This is a metaphor for life.

Healthy Soils for Healthy Trees

May 11, 2022 · 0 minute read
Healthy Soils for Healthy Trees

Join the Chesapeake Bay Foundation to learn the basics of
improving soil health in urban environments.

Lara Johnson of the Virginia Department of Forestry will provide an overview on how to rehabilitate highly compacted soils. Lara will demonstrate how to test for compaction and how to amend the soil to bring back biological processes so it can support healthy tree growth.

The program will begin indoors before moving outside where you will have an opportunity to perform the demonstrated skills firsthand with guidance from our workshop experts.

All tools will be provided. This workshop is free, but registration is required. We have limited registration for this event to ensure that physical distance can be maintained. CBF requires volunteers to wear a CDC-approved mask while indoors.

This event is hosted in partnership with the Virginia Department of Forestry and Richmond Parks and Recreation Department.

Unlocking the secrets of maple syrup, one molecule at a time

May 11, 2022 · 4 minute read
Unlocking the secrets of maple syrup, one molecule at a time

Nature conceals a phenomenal number of molecules as varied as they are imperceptible. The plant kingdom is particularly chemically complex.

Plant evolution has taken place over hundreds of millions of years, giving plants the ability to respond to various environmental stresses and threats. Several species have developed an arsenal of molecules allowing them to adapt and to protect themselves against competitors and predators. Some of these molecules also have health benefits for the animals that consume them.

Advances in food science over recent decades show that many plants provide a wealth of benefits that, until recently, were largely unknown. Taken together, these discoveries support more than ever the fact that a varied and balanced diet offers benefits that go beyond simple energy intake. As a result, consumer demand for plant-based foods with higher nutritional value is currently at record highs. This trend has yet to run out of steam. At the same time, sugary foods are increasingly marginalized and categorized as unhealthy.

But in the realm of sweets, maple syrup is finally claiming its rightful place! Maple syrup is no longer only the jewel of Canada’s culinary heritage, its nutritional reputation is also improving. Because of its unique natural source and manufacturing processmaple syrup contains bioactive molecules whose benefits go far beyond the simple pleasure of a sweet treat.

Benefits that go beyond energy intake

In eastern Canada, March and April herald maple sugaring time. Higher temperatures cause maple trees to convert their energy reserves (stored as complex carbohydrates) into soluble sugars that mix with the water in the tree. Producers collect the flavored sap by drilling holes in the trees.

The sap is approximately 98 percent water, and it takes about 40 liters of this maple water to generate one liter of syrup. During this concentration process, the levels of sugars and nutrients increase substantially. The high temperature that comes from boiling the sap causes a series of chemical reactions as the excess water evaporates.

The main components of maple syrup are sucrose and water. Glucose and fructose also contribute to the sweet taste of the syrup, but to a lesser extent. While these three simple carbohydrates are sources of energy, maple syrup is also an excellent source of manganese and riboflavin (vitamin B2), as well as a significant source of other vitamins and minerals (zinc, potassium, calcium and magnesium).

The composition of phenolic compounds of maple syrup is even more impressive. Since the beginning of the 20th century, researchers have discovered more than 100 of these molecules in plants. Many of them are antioxidants and contribute to the taste, aroma, color of maple syrup. They are primarily responsible for its recent superfood status.

One of the most promising phenolic components (in terms of biological activities) is a molecule found nowhere other than in Canada’s most famous product.

Unlocking the secrets of maple syrup, one molecule at a time
Structure of quebecol [2,2,3-tris(4-hydroxy-2-methoxyphenyl)propan-1-ol], a molecule exclusively found in maple syrup whose secrets are just beginning to be revealed. Credit: Sébastien Cardinal

A molecule worthy of national pride

Quebecol—named after the province where the majority of the world’s maple syrup production originates—is a polyphenolic compound (carrying several phenol groups), first isolated in 2011 by a team led by Navindra Seeram at the University of Rhode Island. This compound is so exclusive to maple syrup that it is not even present in raw maple sap! Rather, current knowledge suggests that it is the product of chemical reactions that occur during the transformation of sap into syrup.

Early laboratory studies, quebecol inhibited cell proliferation of breast cancer and colon cancer cells. But only a small quantity of polyphenol could be isolated, and these tests didn’t go beyond the preliminary stage. More than 20 liters of maple syrup is needed to isolate less than a milligram of quebecol.

Judging that this syrup would be of better use in kitchens than in laboratories, Normand Voyer, a chemistry professor at Laval University, and I (Sébastien) decided to tackle this supply problem. When I was a Ph.D. candidate in 2013, we published a chemical synthesis pathway to build this natural molecule much more efficiently in the laboratory from simple precursors. As this work made quebecol much more accessible, the investigation of its properties continued and deepened.

In particular, Normand Voyer, Daniel Grenier and their teams, in the faculty of dentistry of Laval University, published two studies demonstrating the molecule’s anti-inflammatory properties. This research also made it possible to determine the active portion of the molecular structure.

A compound still relevant today

Our 2021 study showed that quebecol’s anti-inflammatory properties may benefit periodontal disease, a severe infection of the gums. We expect additional studies to be published this year, including one showing that quebecol might help with the treatment of a skin condition.

Although the evidence of biological activity of quebecol has been limited to in vitro experiments, these results certainly encourage further study in more complex systems. It is also important to note that the results came from using the isolated pure molecule.

These studies do not propose using pure maple syrup as a medicinal agent against different conditions. Given the quantity of maple syrup one would have to eat to get the necessary dose of quebecol, the harms from a massive ingestion of sugar would obscure any benefit. It’s also difficult to establish the distribution of the molecule in the human body when it’s taken orally.

In any case, these discoveries once again highlight the uniqueness of maple syrup and help to strengthen its status as a singular food. Perhaps it contains other equally promising molecules just waiting to be discovered. Let’s bet that this local treasure has not yet revealed all its secrets!

Why trees on farms make a win-win for people and nature

May 5, 2022 · 4 minute read
Why trees on farms make a win-win for people and nature

Photo caption: A woman arranges a kacang panjang (long bean) bush in Indonesia. CIFOR/Icaro Cooke Vieira

Trees on or around farms can improve soil health, regulate microclimates, enhance carbon sequestration, and improve biodiversity at multiple scales. However, the ways in which tree-based farming systems affect the diets of rural populations is less well understood.

Today we are producing more food than ever before in history, and yet malnutrition is still the leading cause of poor health globally – a problem that has only been exacerbated by the recent COVID-19 pandemic.

Although technological advances in industrial agriculture have decreased global hunger in recent decades, the increase in food production has not necessarily resulted in healthier diets. In fact, agricultural expansion has increased global dependence on maize, rice and wheat, which are rich in calories but relatively low in micronutrients. Although humans can eat about 7,000 different plants for food, these three staple crops account for 50 percent of plant-based food intake.

Smallholder farmers in low-and middle-income countries produce much of the world’s food, yet these farming households also disproportionately suffer from poor diets. Food security and nutrition policies in these regions often focus on increasing agricultural production, either through intensification of existing production systems or expansion of cultivated land at the expense of forests and other biodiverse ecosystems. Yet, wild foods from forests and fallows can be an important source of micronutrients for smallholder farmers in these regions.

Although far from a new farming technology, researchers and policymakers are increasingly considering the integration of trees on and around farming systems as a potential “win-win” solution for supporting dietary quality and the natural environment. The evidence on associations between tree-based farming systems and positive ecological outcomes is well documented: trees on or around farms can improve soil health, regulate microclimates, enhance carbon sequestration and improve biodiversity at multiple scales.

However, the ways in which tree-based farming systems affect the diets of rural populations is less well understood.

To contribute to this developing field, a team of researchers from Denmark’s University of Copenhagen and the Center for International Forestry Research and World Agroforestry (CIFOR-ICRAF) reviewed papers that assess the dietary quality of populations practicing tree-based farming in low- and middle-income countries.

The researchers identified 36 papers that together highlight three distinct pathways through which trees on or around farms support people’s diets:

  1. Providing edible products such as fruits, nuts, and leaves – the most direct link
  2. Providing marketable products, where people can use the money to buy food – the indirect income link
  3. Improving agricultural production of other crops through ecosystem services (e.g. increased pollination, microclimate regulation), where people either consume or sell the additional harvest – the indirect agroecological link

Taken together, most of the reviewed studies indicate positive associations between tree-based farming systems, household income and improved dietary quality. Yet, the relative benefits for income and diet quality depend on the type of tree-based farming system in place: (a) home gardens/trees on farms; (b) shifting cultivation systems; (c) timber/plantation tree crops or (d) forest-edge farming.

In general, the studies show that maintaining diversity within tree-based farming systems can provide households with more means to diversify their diets with foods from the farm and market. Additionally, preserving biodiversity within and around tree-based farming systems may also increase the availability of micronutrient-rich foods in the wild. Finally, the cultivation of multiple tree species can serve as important safety net for households in the face of uncertain climatic or economic conditions, improving access to nutritious foods year-round.

The types of species and arrangement of trees within different farming systems could be another important factor that affects the benefits for diets. However, from the small number of studies published to date, it was not possible to identify which types of tree-based farming system configurations are best for improving dietary quality.

A further development of tree-based farming system classifications with a distinct consideration of food (i.e. home gardens or trees on farm, shifting cultivation, timber or plantation tree crops, and forest-edge farming) could be a first step to making better empirical comparisons across disparate cultural and geographical contexts.

The extent to which any tree-based farming system can influence diets also depends on factors outside the farming system itself. Policies and institutions at the national scale, bioclimatic and geographical aspects at the landscape scale, as well as socio-economic aspects at both the landscape and household level, such as market access, education, and/or gender-driven power dynamics play an important role in determining how tree-based farming affects household diets.

These various influences are difficult to tease apart and have yet to be thoroughly investigated.

While a general positive association is found, the synthesis highlights the complexity of drawing links between trees, farming systems, and dietary quality.

Improved visibility and understanding of the role that trees play in promoting more ecologically sustainable and nutritious diets is key to designing more sustainable landscapes for people and the planet.

Plant this, not that: Native alternatives to invasive plants

May 4, 2022 · 5 minute read
Plant this, not that: Native alternatives to invasive plants
This combination photo shows purple loosestrife (Lythrum salicaria), left, and a Liatris spicata, commonly called blazing star or gayfeather. Purple loosestrife is an invasive plant that threatens wetlands and chokes out food sources and habitat for wildlife. Liatris spicata is a recommended alternative for invasive purple loosestrife. Chicago Botanic Garden via AP, left, and Jessica Damiano via AP

When my family moved into a new home in the spring of 2005, the only plants growing in the garden were a rhododendron by the front door and a few scattered daffodils and ferns. I was delighted to see a stunning perennial pop up a month later.

Being little more than a fledgling gardener then, I didn’t know what the plant was, and to be honest, it didn’t matter: I was in love with my new purple beauty.

Two years later, after graduating from Cornell University’s master gardener program and working as a gardening columnist for my local paper, I sadly knew better: My favorite plant, purple loosestrife (Lythrum salicaria), was considered invasive in my home state of New York.

“But it’s not spreading on my property,” I whined to no one in particular. “It’s actually well-behaved.”

Further research revealed that, although some plants make their invasive nature known at home (looking at you, mint), others are wolves in sheep’s clothing. They seem well-contained in the garden but become downright thugs when their seeds are eaten by birds and dispersed elsewhere.

Those seeds grow into plants that outcompete native vegetation because they aren’t recognized as food by much of the local wildlife, which would otherwise keep them under control. Unchecked, they grow larger and eventually choke out native plants that provide food, nesting material, and shelter for birds, pollinators, and small animals. This disrupts the entire ecosystem.

This image provided by Chicago Botanic Garden shows purple loosestrife (Lythrum salicaria), an invasive plant that threatens wetlands and chokes out food sources and habitat for wildlife. Chicago Botanic Garden via AP

Many state environmental agencies prohibit the sale and use of plants deemed harmful to human or ecological health. But some invasives are not officially designated, and others may be listed by one state but not another. To complicate matters further, some invasives continue to be sold at the retail level.

So what’s a gardener to do?

For starters, avoid any plant advertised as “vigorous,” “fast-spreading,” “quick-climbing” or a “rapid self-sower,” which are marketers’ code words for invasive. Next, familiarize yourself with your state’s list of locally invasive plants (those website addresses are compiled by the U.S. Environmental Protection Agency at

Shown here is Liatris spicata, commonly called blazing star or gayfeather. The plant is a recommended alternative for invasive purple loosestrife (Lythrum salicaria). Jessica Damiano via AP

Yes, I yanked out that purple loosestrife, which the EPA warns “clogs rivers and lakes, grows into mats so thick that boats and swimmers can’t get through and destroys food and habitat for our fish and water birds.” I replaced it with the tame but equally beautiful Liatris spicata, which has been a respectful resident of my garden for the past 15 years.

Here are seven other garden bullies and suggestions for mild-mannered alternatives to plant.


INVASIVE: Butterfly bush (Buddleia davidii) sounds like a butterfly-friendly plant, but don’t let the name fool you. Although your butterfly bush may, indeed, be covered in butterflies, the food source it provides them is less than ideal. In addition, it forms large thickets that displace native species in the wild.

NATIVE ALTERNATIVES: California lilac (Ceanothus) is an evergreen shrub with deep blue flowers that grows well in zones 8-10, or try the white-blossomed wild hydrangea (Hydrangea arborescens) in zones 3-9.


INVASIVE: Scotch broom (Cytisus scoparius), a nitrogen-fixing legume, is easily established even in the worst growing conditions, and its seeds can remain viable in the soil for decades. According to the EPA, it has “invaded most of the remaining Garry oak savannah ecosystems in Oregon, Washington, and British Columbia (and) is considered to be a threat to the native plant community.”

NATIVE ALTERNATIVES: For similar loose-looking shrubs with small yellow flowers, consider Mormon tea (Ephedra) in zones 3-6 or California flannel bush (Fremontodendron californicum) in zones 8-10.


INVASIVE: Rugosa rose (Rosa rugosa) is ubiquitous on beach dunes along the entire Northeast coast, as well as in coastal areas of the Pacific Northwest and parts of Minnesota, Wisconsin, Michigan, Alaska and elsewhere. It is considered noxious for its ability to displace desirable vegetation.

NATIVE ALTERNATIVES: Arkansas rose (Rosa arkansana), California wild rose (Rosa californica), Carolina rose (Rosa carolina), Rosa virginiana (Virginia rose), Rosa woodsii (Western wild rose) and prairie rose (Rosa setigera) are suitable stand-ins. Choose the native rose named for the region nearest you.


INVASIVE: Both Chinese wisteria (Wisteria floribunda) and Japanese wisteria (Wisteria sinensisuse) are aggressive vining plants that threaten native species, including large trees.

NATIVE ALTERNATIVE: Seek out the fragrant, stunning American wisteria (Wisteria frutescens) in zones 5-9.


INVASIVE: Japanese barberry (Berberis thunbergii) forms large thickets and serves as a habitat for deer ticks and black-legged ticks, which transmit Lyme disease and other illnesses.

NATIVE ALTERNATIVES: For eye-catching berries that provide winter interest, consider American beautyberry (Callicarpa americana) in zones 6-10, winterberry holly (Ilex verticillata) in zones 3-9, or red barberry (Mahonia haematocarpa) in zones 5-9.


INVASIVE: Winged burning bush (Euonymus alatus) produces an abundance of seeds that root easily around the garden and in the wild when dispersed by birds.

NATIVE ALTERNATIVE: For similarly dramatic red fall foliage in zones 3-8, plant “Autumn Magic” black chokeberry (Aronia melanocarpa “Autumn Magic”) or the fruit-producing Northern high bush blueberry (Vaccinium sp.). In zones 2-8, fragrant sumac (Rhus aromatica) is a lovely substitute.


INVASIVE: The ornamental Miscanthus grass (Miscanthus sinensis), although still widely sold and planted, has been deemed invasive in more than two dozen states, where it is known to overtake forests, roadsides, fields and other areas.

NATIVE ALTERNATIVES: Plant little bluestem (Schizachyrium scoparium) in full sun or prairie dropseed (Sporobolus heterolepis) in full sun to part shade. Both are suitable for zones 3-9.


Jessica Damiano writes regularly about gardening for The Associated Press. A master gardener and educator, she writes The Weekly Dirt newsletter and creates an annual wall calendar of daily gardening tips. Send her a note at and find her at and on Instagram @JesDamiano.

Hungry, Hungry Microbes in Tree Bark Gobble Up Methane

April 27, 2022 · 8 minute read
Hungry, Hungry Microbes in Tree Bark Gobble Up Methane

Bad news: Trees emit methane, a greenhouse gas. Good news: Some are home to bacteria that can’t get enough of it.

MANY OF TODAY’S geoscientists are carbon voyeurs. Knowing that human disregard for the carbon cycle has screwed the climate, they have kept a close eye on carbon’s hottest variants—carbon dioxide (CO2) and methane. Both gasses trap heat on the planet through the greenhouse effect, and over a span of 100 years, methane is 28 times more potent than CO2. Rigorously accounting for greenhouse gas flow is step one of building models that predict the future climate.

Some line items in the methane budget, such as pipeline leaks and cow farts, are well understood. But others are hazier. “There’s lots of gaps and uncertainties, particularly in wetlands, and inland waters,” says Luke Jeffrey, a biogeochemistry postdoc at Southern Cross University in Australia. By one 2020 tally from the Global Carbon Project, wetlands emit about 20 to 31 percent of Earth’s annual methane release—more than the amount from fossil fuel production.

But in the past decade, researchers have zeroed in on a perhaps counterintuitive source of greenhouse gas emissions: trees. Freshwater wetland trees, in particular. Trees bathing in wet or flooded soil absorb methane and then leak it through their bark. In a 2017 study, ecologist Sunitha Pangala, then at the Open University in the United Kingdom, found that trees in the Amazon were responsible for 200 times more methane than trees in other wetland forests, accounting for 44 to 65 percent of the region’s total emissions.

Does this mean trees are bad for the planet? Of course not. Trees suck carbon dioxide out of the atmosphere. And in a study published April 9 in Nature Communications, Jeffrey and his team report how trees can also be methane sinks, sheltering microbes that convert it to the less damaging CO2. His team discovered methanotrophs, or methane-eating microbes, in a species of trees called paperbarks, which grow in eastern Australian swamps. The microbes gobble up methane, reducing the trees’ potential emissions by about a third. The finding brings more clarity to how trees factor into the elusive methane budget that experts say is vital for climate predictions.

Image may contain Human Person Clothing Apparel and Outdoors

“This is an important contribution and one that’s timely,” says Patrick Megonigal, a biogeochemist with the Smithsonian Environmental Research Center who is not affiliated with the study. Megonigal has researched the release of methane from trees for over a decade, and is an expert in the flows of greenhouse gases throughout wetland and upland forests.

“When I saw this paper, I just said, ‘Holy shit, this is really interesting,’” says Jeffrey White, a professor emeritus at the O’Neill School of Public and Environmental Affairs at Indiana University. White, who was not involved in the study, has studied methane cycling for over 30 years and says it elegantly addressed a hunch that researchers have had—but haven’t been able to nail down—that methanotroph activity occurs in tree bark. He calls the work “profoundly important.”

Methanotrophs are everywhere and have been for as long as atmospheric oxygen has existed on Earth, so White is confident this isn’t an isolated case: He’s noticed similar behavior in Minnesota birch trees.

Wetlands contribute more methane to the atmosphere than any other natural source. But without methanotrophs, they’d release an estimated 50 to 90 percent more. These microbes turn methane into carbon dioxide similar to the way combustion does. The process is, almost literally, a slow burn. But it prevents a majority of wetland methane from reaching the sky, making soil a source and a sink. Far less is known about the methane feasts taking place inside trees.

Jeffrey wanted more clarity. A few years ago, his attention turned to the paperbarks. “It’s such a unique tree with amazing layers of bark,” Jeffrey says. These layers are moist, dark, and known to contain methane. (Jeffrey sometimes refers to it as “treethane.”) “We just thought it could be an ideal spot for methanotrophs,” he continues. So he set out to prove that the gas-eating microbes were hiding there. Jeffrey designed a series of experiments that would cater to their appetites. First, he sliced bark from trees in three wetland sites and sealed those strips inside glass bottles containing methane. Then, he waited. Over a week, he measured as the methane levels in the bottles dropped. In some samples, more than half of it vanished. In control bottles that contained either sterilized bark or nothing at all, methane levels remained paper-flat.

tree bark

Jeffrey’s team also knew that methanotrophs have picky palates. Methane’s one carbon atom can exist as either of two stable isotopes: the classic carbon-12 or the heavier carbon-13 that lugs around an extra neutron. Carbon-13’s bonds are harder to break, so methanotrophs would rather snack on the lighter isotope. Jeffrey’s team found that the relative levels of carbon-13-methane in the bottles increased with time. Something in the bark was alive and selectively eating, like a kid leaving the yellow Starbursts in the bag after picking out the pinks.

Encouraged by these traces of activity, they sent bark across town to the microbiologists at Monash University, who ran a microbial analysis of all of the species that were living in the bark. The verdict: Paperbark samples contained a bustling unique population of bacteria not found in the surrounding soil or swamp, most of which fall into the methane-hungry genus Methylomonas.

But all of those results arose in a lab, and Jeffrey’s team needed to see how real, live trees behave, specifically how fast they leak methane. They waded through a wetland forest in New South Wales, gently attached sealed chambers and spectrometers to the sides of paperbarks, and measured how much the trees emitted per second.

Then Jeffrey injected a gas called difluoromethane into the chamber. Difluoromethane is a sneaky treat for methanotrophs—it temporarily inhibits their appetite. “It actually stops them consuming methane,” Jeffrey says. After letting the gas diffuse in for an hour, Jeffrey flushed it and reexamined the emissions. Because the microbes stopped eating, methane levels jumped. On average, the team calculated, microbes had been removing 36 percent of the methane that would otherwise seep into the atmosphere.

Most of that methane actually originates in the wet soil, Jeffrey says. Microbes digest organic matter in the dirt and release methane. Some burbles out of the soil or water, but some flows up through tree roots like they’re straws, or soaks into the bark then diffuses out through the wood. (Different microbes can also make their own methane within the tree, but Jeffrey has published evidence that isotope signatures of the methane in bark matches that in the soil.) Thanks to the tree-dwelling microbes, less of it gets released into the atmosphere as methane, because they transform it into less harmful CO2. “This methane in soil is possibly going to come up anyway from a wetland. If they’re coming up through trees, they have to get through this gauntlet of bacteria,” says Jeffrey. “So this new discovery—I’m kind of looking at trees now as almost like methane filters.”

“It’s really exciting for me, because this has been a question that I’ve been interested in for a long time,” says Mary Jane Carmichael, a microbial ecologist at Hollins University in Virginia not involved in the study. Carmichael reported in a 2017 study that dead trees emit methane, too. (Similarly, in a previous study, Jeffrey showed that dead trees emitted eight times the methane of living ones.) “I’m never really surprised by what microorganisms are capable of,” Carmichael says. “We probably will see that it’s a pretty widespread phenomenon.”

Understanding how trees add and subtract methane from the environment will help scientists adjust a sort of planet-wide carbon calculus. While satellite data helps track emissions from above, finer details for each source and sink are essential to really make predictions, says Marielle Saunois, an environmental scientist with the University of Versailles Saint Quentin who coordinates the Global Methane Budget. But this study won’t change climate models right away. “The processes are important but very local,” she says. It’s hard to scale up bark microbe effects to a global or even regional perspective. And while this work helps predict how wetland emissions change with climate, global models don’t yet include these feedback effects. “Ideally,” she says, “it should.”

“Vegetation and plant-based pathways in methane emissions are actually a really under-studied component of the global methane budget,” agrees Carmichael.

Earth’s climate behavior is rife with feedback loops: For example, temperature, moisture, and COaffect how tree species are distributed, which affects methane emissions, which affects climate, and so on. Knowing that these microbes exist—and future studies that can pinpoint where else they exist—will improve climate predictions by making methane models more robust.

“This is good news,” says Megonigal. In wetland forests that are rich in methane, the microbes buffer emissions. In drier upland forests that produce less methane, he says, “they might actually be removing methane from the atmosphere on our behalf.”

Jeffrey next plans to examine how the trees’ filtering of the greenhouse gas changes with the seasons. Since he published the study, people have pitched him a variety of ideas for how to harness forest methanotrophs for climate action. Could scientists inoculate other tree species with the microbes to establish methane-gobbling forests? Could we culture them in sawdust and spray them on forest floors? Could we feed them to cows? “I have no idea, to be honest,” Jeffrey says. “And my personal preference is not to tinker with nature too much.”

And, he points out, human help might not even be needed to spread methanotrophs around: “I’m assuming—and hoping—that we’ll probably find these guys living elsewhere, in other trees, too.”

Forest bathing could be the key to feeling better – and you can even do it at work

April 27, 2022 · 4 minute read
Forest bathing could be the key to feeling better – and you can even do it at work

You are walking slowly through a forest with birds gently chirping around you. The wind glides through the trees, and you bend down to scoop up some earth, noticing the aroma.

Relaxed yet?

That sensory experience is an example of a forest bath, a practice that has been shown in about 20 studies to improve mental and physical health, and it has become a prescribed treatment for stress-related conditions in Japan, according to Kirsten McEwan, an associate professor, and research psychologist at the University of Derby in the United Kingdom.

Spending any time in nature is a great way to improve your mental health, and the ideal amount of time is about 120 minutes a week, said health and environmental psychologist Mathew White, a senior scientist at the University of Vienna. That may sound like a lot, but you don’t have to do it all at once.

“Just having those micro-moments of life in nature, whether it is just 5 or 10 minutes a day building up to that 120 minutes, it all has massive benefit,” McEwan said.

Forest bathing can add even more to your well-being – and though it may sound a little inaccessible, experts say everyone can incorporate it into their lives.

How to do it

In fact, forest bathing doesn’t have to take place in a forest.

“Forest bathing is essentially a slow, mindful walk in nature where you pay really close attention to your surroundings, using all of your senses,” McEwan said. “It’s just to kind of switch your brain off and give yourself a little bit of a rest from ruminating about your to-do list.”

All it takes to forest bathe is time in nature and focused attention, experts said.
All it takes to forest bathe is time in nature and focused attention, experts said. Allison Hess/Bloomberg/Getty Images

But you don’t have to walk all that much to reap the benefits if you are appreciating your surroundings. And consider this: Nature isn’t just waiting for you on your next beach or camping trip.

“Nature is oftentimes under our nose if we just take the time to be intentional about connecting with it,” said Chloe Carmichael, a New York therapist. Even those who live in areas surrounded by natural beauty can start to tune it out, so intentional focus is key, she said.

Whether you live in a bustling city or an expansive rural area, Carmichael and McEwan said, everyone can benefit from time in nature – and the best way to build time outdoors into your routine is to incorporate it into what you already do.

On your commute

Walking is great for a forest bath, even if it’s on your way to work or school.

Maybe you leave a little earlier and go more slowly, taking a route with more greenery, McEwan said. Perhaps you pay closer attention to the flowers springing through the cracks in the cement or the trees lining the street, she added.

“It’s like nature reclaiming the city,” McEwan said.

During a meal

If you consider yourself a home chef and regularly cook dinner for yourself and loved ones, maybe it’s time to grow herbs in your kitchen, said Carmichael, who is also author of “Nervous Energy: Harness the Power of Your Anxiety.”

It’s an easy way to bring something natural and fragrant into your routine without requiring too much work, she added.

And once dinner is ready, consider moving the meal outside in mild weather.

If you can put some focus into the environment and observe the world going on around you, having a meal in your yard or on a patio is a great way to get your minutes in nature, McEwan said.

In your office

Getting your forest bath in the office can be good for both you and your work, Carmichael said.

That could mean going on a weekly lunch walk with a work friend, or taking a break to look out the window or even bringing a plant into your office, she added.

If you have meetings in small groups, you could suggest taking the meeting while walking or sitting outside, McEwan said.

“We are more relaxed and creative when we are outside anyway,” she said.

When you can’t get moving

Mobility isn’t always accessible to everyone, and while moving outside is optimal, there are other ways to get the benefits, McEwan said.

Videos online can take you through photos and videos of the natural world, with narration guiding your attention, she said.

An essential oil diffuser can also help if loaded with pine or evergreen scents, since much of the benefit of forest bathing comes from breathing in the organic compounds trees emit, McEwan said.

Above all, be comfortable

However you choose to forest bathe and get your time in nature, the most important thing is to find something that works for you, McEwan said.

Find a guiding audio that makes you feel good and isn’t too prescriptive in how you interact with your natural world, she suggested. And if hugging a tree or smelling the dirt feels unnatural and cringey to you, find a different way.

“To get the maximum benefits of spending time in nature, you have to be comfortable,” she said.

Thinning Out Southern Pine Beetle

April 20, 2022 · 2 minute read
Thinning Out Southern Pine Beetle

By Katlin Dewitt, VDOF Forest Health Specialist

The southern pine beetle (SPB) is the most destructive native insect that threatens pine forests in the Southeast. These tiny insects, about the size of a grain of rice as adults, are especially harmful due to the complex system of pheromones (insect “scents” that are specific to a species) they utilize to find host trees and aggregate. Pheromones allow populations to build up quickly within a pine stand, often leading to classic beetle spots comprised of dead and dying trees.

Aerial view of a classic SPB spot

The VDOF forest health program monitors SPB populations with traps each spring, starting at the time the redbuds bloom. Traps are placed in high-risk locations (areas with a significant volume of pine) and are baited with pheromones. These traps are checked weekly for four weeks and samples are sorted, looking at the number of SPB and their associated predator, a clerid beetle. The relative number of these two insects is used to determine if southern pine beetle populations are increasing or decreasing. This information allows foresters and landowners to be more alert and act quickly should they see SPB.

SPB trap and sample

In addition to monitoring, certain silvicultural practices can reduce the risk of southern pine beetle attack in a pine stand. Pre-commercial thinning is the most effective management strategy to prevent SPB damage. How can forestry practices influence the population of tiny beetles? A lot of it goes back to those tiny clouds of pheromones the beetles rely on to communicate. When stands are overstocked and densely packed, these “scents” can become concentrated and highly aromatic to the beetles, drawing more and more in, thereby creating an SPB spot. A thinned stand allows more air movement, which breaks up the clouds of beetle perfume and makes beetle aggregation more difficult. Thinning also increases the health of the stand, and healthier trees are better able to resist beetle infestation.

Pine stand thinned using Pine Bark Beetle Program cost-share funds

VDOF has a Pine Bark Beetle Prevention Program which is funded by the US Forest Service Southern Pine Beetle Prevention and Restoration Program. VDOF uses this money to operate a cost-share program available to landowners and loggers for specific forest management practices that improve the health of managed pine stands and reduce the risk of SPB infestation. The three cost-share programs offered are:

  • Pre-commercial thinning: Assistance through this program will cover 60% of direct project costs of pre-commercial thinning on parcels greater than 5 acres, with trees no older than 15 years, and tree density before thinning greater than or equal to 800 stems per acre. Cost-share payments cannot exceed $105/acre and $10,000 per federal fiscal year.
  • Longleaf restoration: Longleaf pine is a native pine species that has been historically diminished in Virginia and is somewhat resistant to attack from SPB. To aid in restoring these stands, this program pays 60% of total direct costs associated with site preparation, planting, or post-planting treatments within the first five years of plantation establishment. Cost-share payment cannot exceed $225/acre and $10,000 per federal fiscal year.
  • Logger incentive program: This program reimburses certified SHARP loggers in Virginia who conduct first commercial thinning on smaller stands, 5-25 acres in size, with trees 12-22 years of age. Assistance covers 50% of itemized logging costs, not to exceed $2,000/parcel, and no more than 5 applications (or $10,000) per federal fiscal year.

To learn more about how you can protect your forest from the southern pine beetle, check out the prevention program information, or reach out to your local area forestry staff.


April 20, 2022 · 2 minute read

Virginia’s state forests, State parks, wildlife management areas, and natural area preserves are state lands with distinct purposes. These state-owned and managed lands also differ from federally-owned national forests and national parks. It may be helpful to review these differences before visiting one of these areas.

State Forests

  • Managed by the Virginia Department of Forestry.
  • Managed for multiple resources, including wood products, wildlife, water quality, and passive recreation.
  • Some forests allow hunting and fishing. Regulations for these activities are governed by the Department of Wildlife Resources (DWR) and require the proper licenses.
  • Often have passive or self-guided recreational opportunities (e.g., hiking, mountain biking, horseback riding).
  • Require a State Forest Use Permit for some activities.
  • Typically are not staffed daily and do not have offices and restroom facilities.
  • Do not have camping facilities or allow camping.
  • Do not allow recreational ATV use.
  • May have certain areas designated as natural areas.
  • Not funded by the Commonwealth’s General Fund.

State Parks

  • Managed by the Virginia Department of Conservation and Recreation.
  • Focused primarily on preservation and protection of natural systems, with minimal manipulation or management.
  • Tell the story of Virginia and the broader American experience through unique features, such as geological formations, rare plants, fascinating animals, diverse forest and aquatic communities, archeological sites, Colonial homes, Civil War battlefields, pioneer homesteads, and more.
  • Generally, do not allow hunting and sometimes allow fishing.
  • Offer a wide variety of recreational opportunities, both passive and structured.
  • Some have meeting facilities, festivals, concerts, and other events.
  • Typically staffed daily with an entry area, offices, and restroom facilities.
  • Often have rental cabins or lodges, camping facilities, pools or beaches for swimming, and picnic shelters.
  • Typically require daily access tickets, annual passes, and/or reservations for facility rentals.
  • Are funded by the Commonwealth’s General Fund.

Wildlife Management Areas

  • Managed by the Virginia Department of Wildlife Resources.
  • Solely intended to preserve and improve wildlife habitats with a particular focus on game animals.
  • Provide public space for hunting and fishing activities.
  • Receive some funding from the Pittman-Robertson Federal Aid to Wildlife Restoration Act.
  • Land acquisition and maintenance fees are largely provided by hunters and anglers through license fees and taxes levied on gear.
  • Generally, prohibit swimming, mountain biking, ATV use, and organized sports.
  • Typically are not staffed daily and have limited offices and restroom facilities.
  • Not funded by the Commonwealth’s General Fund.

Natural Area Preserves

  • Managed by the Virginia Department of Conservation and Recreation – Division of Natural Heritage.
  • Focused on protecting threatened or rare plants, animals, and natural communities.
  • Many allow low-impact visitation, such as hiking and birdwatching.
  • Generally, do not allow impactful activities such as camping, hunting, fishing, timber harvesting, vegetation harvesting, and motorized trail vehicles.
  • Typically are not staffed daily and do not have offices and restroom facilities.
  • Some are open to the public only through arrangements made through a land steward.
  • Some are state-owned while others are privately held with a DCR-DNH easement on the property.
  • May be temporarily closed or access restricted to protect sensitive or rare plant and animal species.
  • Receive some General Funds.

National Forests

  • Federal lands managed by the USDA Forest Service.
  • Sustain the health, diversity, and productivity of the nation’s forests and grasslands to meet the needs of present and future generations.

National Parks

Redwood trees have two types of leaves, scientists find – a trait that could help them survive in a changing climate

April 14, 2022 · 6 minute read
Redwood trees have two types of leaves, scientists find – a trait that could help them survive in a changing climate

Coast redwoods are amazing trees that scientists have studied for generations. We know they are the tallest living trees and have survived for millennia, resisting fire and pests. Because redwoods are long-lived, large and decay-resistant, the forests they dominate store more above-ground mass, and thus presumably more carbon, than any other ecosystem on Earth.

Nonetheless, while working on a recently published study, colleagues at the University of CaliforniaDavis, and Cal Poly Humboldt and I learned a secret that had been sitting right under our noses.

Redwoods, it turns out, have two types of leaves that look different and perform very different tasks. This previously unknown feature helps the trees adapt to both wet and dry conditions – an ability that could be key to their survival in a changing climate. Redwoods can live for more than 2,000 years and grow to more than 350 feet tall.

Just enough water

Wherever trees grow, sooner or later their leaves get wet. For trees in wet environments, this can be a problem if films of water cover their stomata. These tiny pores allow carbon dioxide to enter leaves so the tree can combine it with water to make plant tissue through photosynthesis. Many trees that are common to wet forests have leaves with adaptations that prevent these water films from forming.

In contrast, trees growing in dry environments take advantage of brief bouts of leaf wetness to take up valuable water directly across the surfaces of their leaves, through special leaf structures, and even through their stomata. But some trees, including coast redwoods, live in both wet and dry environments with intense seasonal variation.

For broad-leaved trees like the holm oak, which grows in Mediterranean climates with dry summers and rainy winters, this seasonal wetness challenge is relatively easy to overcome. Their stomata are on the sheltered undersides of their leaves, which keeps them clear of water, while the leaves’ top surfaces absorb water. But redwoods are conifers, or cone-bearing trees, with thin, flat needlelike leaves, and they need a different way to balance the competing goals of repelling and absorbing water.

Oval-shaped opening on a wavy green surface.
A single stoma on a tomato leaf, shown via electron microscope. Photohound/Wikipedia

We knew we wanted to explore how redwoods met the paradoxical challenge of leaf wetness, how much water redwoods could absorb and which leaf features caused differences in water uptake capacity. What we learned came as a total surprise.

Big trees with big secrets

Scientists have long known about redwoods’ ability to absorb water through their leaves. But figuring out how much water redwoods can absorb this way, and how the capacity to do so might vary from one type of climate to another, is a real challenge in this species.

First, a big redwood has over 100 million leaves with a massive amount of surface area for water absorption. And these leaves drastically change structure with height, going from long and flat to short and awllike. So we couldn’t get this right by simply picking leaves at ground level.

To complicate matters further, gravity is always pushing down on the giant column of water rising upward through a redwood’s trunk. As a result, leaves at the top of the tree always have less available water than those lower down. The treetop’s inherent dryness should pull water into the leaf more quickly than into water-rich leaves at the bottom, just as a dry sponge picks up water faster than a damp one.

Map showing historic and current distribution of coast redwoods.
Coast redwoods’ range extends from southern Oregon to California’s Big Sur coast. California Department of Parks and Recreation

For an accurate picture of how redwoods absorbed water, we needed leaves from trees in wet and dry environments, and from multiple heights on those trees. To get them to their natural gravity-based water levels for analysis, we put our leaf samples in a fog chamber – in this case, an ice chest hooked up to a room humidifier – and measured weight gain over time to see how much water they could absorb.

A trail of clues

As we took apart clusters of redwood shoots to immerse them in fog, we divided each cluster into pieces. Redwood shoot clusters fan out from a woody core and are segmented into individual shoots of multiple ages, each with its own set of leaves. We separated shoots along the woody central axis from the much more common pliable shoots on the outer edges of each cluster.

It quickly became obvious that shoots from the center axis had leaves that could absorb water three times faster than peripheral leaves. When we looked inside the leaves with a microscope, we understood that they were two completely different types. They don’t look the same on the outside either, but this was so unexpected that we needed to see their internal structure to really convince ourselves.

The axial leaves were packed with water storage cells, but their phloem – tubes in the leaves that export photosynthetic sugars to the tree – appeared to be blocked and useless. If a tree has leaves, the conventional wisdom is that they are there for photosynthesis, but we wondered whether the axial leaves had a different purpose.

Two types of redwood shoots
Redwoods’ broad peripheral leaves, shown at left, make up about 95% of the trees’ leaf area and do all the photosynthesis. Their axial leaves, at right, are adept at absorbing water. Alana Chin, CC BY-ND

With some additional measurements, we found that redwoods’ axial leaves are specialized for absorbing water. Differences between the surfaces of axial and peripheral leaves, especially their wax coverage, cause the differences in their water absorption rates.

Unlike the axial leaves, redwoods’ peripheral leaves have waxy surfaces with lots of stomata. This helped to explain how they photosynthesize year-round regardless of the long wet season in much of their current habitat.

Further analysis showed that the redwoods’ axial leaves account for only about 5% of the trees’ total leaf area, and barely produce enough energy through photosynthesis to maintain themselves. But they contribute up to 30% of the trees’ total water absorption capacity. Together these two types of leaves balance the dueling requirements of photosynthesis and water absorption, allowing redwoods to thrive in both wet and dry habitats.

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Using large-scale tree measurements and equations for estimating redwood leaf area, we estimated that these thirsty giants can absorb as much as 105 pounds (48 kilograms) of water in the first hour of a rainfall wetting their leaves. That’s equivalent to 101 pints of beer.

The significance to redwoods

Understanding what causes the variation in redwood leaves’ uptake capacity can help us gauge differences in water uptake capabilities among trees and environments, now and in the future. In my opinion, this is the most potentially useful part of our study.

Redwoods vary their two leaf types to suit their local climates. In wet rainforests in the northern part of their range, above Mendocino County, the trees invest in fewer of the axial leaves that are specialized for absorbing water. These leaves are concentrated in the trees’ lower crowns, leaving the photosynthetically high-performing treetops free to maximize sugar production in the bright sun.

Leaf under a microscope, covered with white dots.
Wax on the surface of a redwood leaf. The white dots are water-resistant plugs in the stomata. Marty Reed, CC BY-ND

In dry forests on the southern margins of redwoods’ range, trees have more axial leaves in their water-stressed tops. This allows them to take better advantage of briefer leaf-wetting events, but it means they photosynthesize less per leaf area than redwoods in wetter areas.

Redwoods’ ability to shift leaf types to match regional climatic differences may help them adjust to climate change in an ever-drier California. That would be good news for conserving these epic trees, and it may be a promising feature to investigate as scientists try to link drought tolerance traits to regional differences among redwood populations.

Discovering the forest wonders of Africa – and the threats they face

April 14, 2022 · 5 minute read
Discovering the forest wonders of Africa – and the threats they face

Africa’s forests are some of the natural wonders of the world. As someone who has spent decades studying the ecology and management of tropical forests, I’m constantly amazed by the unique forest ecosystems on the continent.

Some of them are most likely unknown to the public at large, yet so fascinating and important to face our world’s current biodiversity and climate challenges. Starting in the northwest and ending in the southeast, I’d like to share the ones that are special to me. This is a totally personal choice; others would have chosen other unique African forests, so large is the choice. But for how long?

African forests, like many others, are threatened by over-exploitation, conversion to other land uses, and climate change. Many will likely disappear or be degraded to such an extent as to pass tipping points and become something else, something less.

I hope this trip across Africa will help raise interest and trigger the urge to better conserve and manage these unique ecosystems.

Morocco’s argan trees

Not far from Agadir, on the Moroccan Atlantic coast, grows the argan tree (Argania spinosa). It is the only member of the large Sapotaceae family growing in the northern hemisphere, the only species of its genus and endemic to an area of about 800,000 hectares.

Argan tree. Liubov Mikhailova/Shutterstock

It’s been exploited and managed by humans for more than 3,000 years for argan oil. Argan oil is the most expensive oil in the world, costing up to US$300 a litre in a US$500 million market. Argan oil is perhaps most commonly used as a moisturiser and is often found in products such as lotions, soaps and hair conditioners.

In addition to the oil, argan trees are also a source of wood for fencing, charcoal and fodder for goats. It’s a true multipurpose tree, critical especially for women’s livelihoods.

Unfortunately, despite its status as a UNESCO biosphere reserve, the argan forest is slowly dying from over-grazing, deforestation and climate change. Hopefully the argan oil boom will help to conserve and restore this unique forest ecosystem.

An argan forest. Kokhanchikov

Congo Basin rainforest

Flying south-east, over the Sahara Desert and the Sahelian savannas, we reach the Congo Basin rainforest.

The Congo Basin rainforest is the second largest rainforest in the world (after the Amazon). It’s home to many forest giants, trees like the Sipo or Moabi. These and other giants are the origin of precious timber but also of important resources for local people, such as food and medicines. It’s also home to animals like forest elephants, buffaloes, and lowland gorillas.

Western lowland gorilla in the forest. Photo by: Education Images/Universal Images Group via Getty Images

Deep in the heart of the Congo Basin forests lies the largest peat swamp forest of the world. Only recently “discovered” by science, this place was known by the Aka community who live there as the place where roamed the Mokele Mbembe, a mythical dinosaur-like monster the size of an elephant.

No one has never seen it but now we know that this peatland forest stores more than 30 billion tonnes of carbon. Should these be released, by clearing the forest above, into the atmosphere, we will have unleashed a much worse monster than the Mokele Mbembe.

Logging in Cameroon. Photo by Brent Stirton/Getty Images

Fortunately, because of its remoteness and difficulty of access, the Congo Basin peatland complex has been naturally protected till now, but it could be threatened soon by oil exploration should we not pay attention.

East Africa’s Afromontane forests

At the eastern border of the Congo Basin rise the Ruwenzori mountains. On the mountain slopes are the last Afromontane forests.

These forests are home to the tallest tree in Africa, a whopping 81.5 metres tall Entandrophragma excelsum hidden in a remote valley of Mount Kilimanjaro.

Lena Ha/Shutterstock

These forests harbor a high level of endemism – meaning many of the trees can only be found here – and biodiversity. They also act as water towers, regulating and providing water for the lowlands and their inhabitants.

These Afromontane forests store more carbon per hectare than the Amazon rainforest. Sadly, in the past 20 years, 0.8 million hectares of mountain forests have been lost to agriculture. This is mostly in the Democratic Republic of the Congo, Uganda and Ethiopia. This has resulted in over 450 million tonnes of carbon dioxide being emitted into the atmosphere.

Miombo woodlands

Continuing our journey down south, we soon reach the immense area of Miombo woodlands. They span an estimated total area of around 2.7 million km² from Angola in the west to Tanzania in the east, and down to the northern edge of South Africa.

Over 65 million people rely on these ecosystems for their livelihoods, making use of resources such as fuelwood, timber, charcoal production, fruits, honey, mushrooms, medicinal plants, and fodder for livestock.

One tree species only makes the canopy, Colophospermum mopane.

They are an important ecosystem for large mammal diversity and biomass in southern Africa, including some of the most significant remaining populations of black rhinoceros, elephant, white rhinoceros, hippopotamus, buffalo, giraffe and greater kudu.

The forest is also the only source of a less emblematic but very important animal: the mopane worm. Gonimbrasia belina, by its Latin name, is a very important seasonal source of protein for the populations living near mopane woodlands.

Mopane worm. Shutterstock

Unfortunately, decline in mopane tree density, lower-than-normal precipitation, and higher-than-normal temperatures have significantly affected mopane worm availability and outbreak events, threatening the already precarious livelihoods of local populations.

Madagascar’s Spiny Forest

Crossing the Mozambique channel, we arrive in Madagascar. On the south-west of the “Grande Ile” grows the Spiny Forest. It’s a place like nowhere else on Earth, where endemic oddities like the octopus tree (Didierea madagascariensis) and other strange members of the Didieraceae family grow mixed with swollen baobabs (Adansonia rubrostipa) and other bottle trees (Pachypodium geayi).

The Spiny Forest is inhabited by even weirder animals, ghostly white lemurs impervious to thorns, birds that sing communally and a chameleon that spends most of its life as an egg.

Unfortunately like the other unique forest wonders of Africa, the Spiny Forest is threatened by over-exploitation for charcoal production as local farmers have been put out of business by the more and more unpredictable climate and have few other opportunities in the impoverished and dry Madagascar south-west.

We have reached the end of our trip over Africa. Our choices are subjective and we could have presented other forest wonders but we hope this will be enough to convince you of the importance of these ecosystems and of their threatened status because of us, humans. We should better protect and manage these ecosystems as we depend on them for our survival.

Global team of scientists determine ‘fingerprint’ for how much heat, drought is too much for forests

April 6, 2022 · 4 minute read
Global team of scientists determine ‘fingerprint’ for how much heat, drought is too much for forests

This image, taken in 1993, shows historical forests of Atlas Cedar in Morocco that are most vulnerable to a hotter, drier climate. Photo: Csaba Mátyás, professor emeritus, University of Sopron, Hungary.

By: Kirsten Romaguera

How hot is too hot, and how dry is too dry, for the Earth’s forests? A new study from an international team of researchers found the answers – by looking at decades of dying trees.

Just published in the journal Nature Communications, the study compiles the first global database of precisely georeferenced forest die-off events at 675 locations dating back to 1970. The study, which encompasses all forested continents, then compares that information to existing climate data to determine the heat and drought climatic conditions that caused these documented tree mortality episodes.

“In this study, we’re letting the Earth’s forests do the talking,” said William Hammond, a University of Florida plant ecophysiologist who led the study. “We collected data from previous studies documenting where and when trees died, and then analyzed what the climate was during mortality events, compared to long-term conditions.”

After performing the climate analysis on the observed forest mortality data, Hammond noted, a pattern emerged.

“What we found was that at the global scale, there was this consistently hotter, drier pattern – what we call a ‘hotter-drought fingerprint’ – that can show us how unusually hot or dry it has to get for forests to be at risk of death,” said Hammond, an assistant professor in the UF/IFAS agronomy department.

The fingerprint, he says, shows that forest mortality events consistently occurred when the typically hottest and driest months of the year got even warmer and drier.

“Our hotter-drought fingerprint revealed that global forest mortality is linked to intensified climate extremes,” Hammond said. “Using climate model data, we estimated how frequent these previously lethal climate conditions would become under further warming, compared to pre-industrial era climate – 22% more frequent at plus 2 degrees Celsius (plus 3.6 degrees Fahrenheit), to 140% more frequently at plus 4 degrees Celsius (plus 7.2 degrees Fahrenheit).”

Those higher temperatures would more than double how often forests around the world see tree-killing droughts, he adds.

“Plants do a phenomenal job of capturing and sequestering carbon,” Hammond said. “But death of the plants not only prevents their performing this critical carbon-capturing role, plants also start releasing carbon as they decay.”

Hammond says that relying, in part, upon trees and other plants to capture and sequester carbon, as some proposed climate solutions suggest, makes it is critical to understand how hot is ‘too hot,’ and how dry is ‘too dry’. “Otherwise mortality events, like those included in our database, may wipe out planned carbon gains.”

One of the study’s co-authors, Cuauhtémoc Sáenz-Romero of Universidad Michoacana de San Nicolás de Hidalgo in Mexico, offered an example of how recent climate patterns affected a Mexican temperate forest.

“In recent years, the dry and warm March to May season is even more dry than usual, but also warmer than ever,” he said. “This combination is inducing a lot of stress on the trees before the arrival of the next June-to-October rainy season. For example, in 2021, more than 8,000 mature trees were killed by bark beetles in the Monarch Butterfly Biosphere Reserve in Central Mexico. The effect of the La Niña Pacific Ocean stream resulted in drier, warmer conditions, a deadly combination that favored pest outbreaks.”

Hammond has also developed an interactive application on the website of the International Tree Mortality Network to host the database online and to allow others to submit additional observations of forest mortality to the database.

The organization, founded and coordinated by co-author Henrik Hartmann from the Max Planck Institute in Germany, among others, is a collaborative effort between scientists on every forested continent and aims to coordinate international research efforts on forest die-off events. Hammond is the network’s data management group leader.



Using maps or aerial images, scientists assign to them real-world coordinates.


Information confirmed or validated by direct observation and measurement. In the case of machine learning, it refers to checking results for accuracy.

“We’re hoping that this paper will create a bit of urgency around the need to understand the role of warming on forest mortality,” Hammond said. “Also, we expect that our open-access database will enable additional studies, including other climate fingerprints from local to regional scales. Current climate modeling and remote-sensing research communities need ground-truthed datasets to validate their predictions of important processes like forest mortality. One of the really important elements to this study was bringing all this data together for the first time, so that we can ask a question like this at the planetary scale.”

The paper, “Global field observations of tree die-off reveal hotter-drought fingerprint for Earth’s forests,” can be accessed at In addition to Hammond, Sáenz-Romero and Hartmann, it is also co-authored by A. Park Williams, University of California, Los Angeles; John Abatzoglou, University of California, Merced; Henry D. Adams, Washington State University; Tamir Klein, Weizmann Institute of Science; Rosana López, Universidad Politécnica de Madrid, Spain; David D. Breshears, University of Arizona; and Craig D. Allen, University of New Mexico.

Befriending Trees to Lower a City’s Temperature

April 6, 2022 · 7 minute read
Befriending Trees to Lower a City’s Temperature

As part of its efforts to protect and enhance Melbourne’s tree cover, some 3,000 trees are planted in the city each year. This juvenile Cinnamomum camphor laurel tree was planted on Exhibition Street in Melbourne’s central business district in 2021. Credit…Alana Holmberg for The New York Times

A program in Melbourne, Australia, that tracks every public tree — and even gives each an email address — is seen as a way to manage climate change.

By Peter Wilson

MELBOURNE, Australia — High in the branches of a 122-year-old Dutch Elm, two workers in a bucket crane framed by the city’s skyline used a chain saw to slice large limbs from the top of the tree.

Office workers strolled past, seemingly enjoying the afternoon sunshine of Flagstaff Gardens, the city’s oldest public park, while the workers carried out their “reduction pruning” aimed at controlling the tree’s bulk to help improve its vitality and extend its lifespan.

It is one of the most time-tested forms of tree maintenance, but at ground level, the workers’ supervisor, Jake Shepherd, added a high-tech wrinkle.

Mr. Shepherd, a 27-year-old Englishman, touched a yellow circle on a portable electronic device. The circle was within a map of the park that is part of the city’s elaborate tree database and it instantly turned green to register that this specific elm was back in top shape.

Across town in the Queen Victoria Gardens, another crew recorded the results of its own maintenance work so that it also could be entered into the database, a crucial part of an innovative forest management scheme that has attracted attention around the world because of its successful focus on community engagement.

An arborist performed “reduction pruning” on a mature Eucalyptus Botryoides tree in Queen Victoria Gardens in Melbourne, to help improve its health and extend its life.
An arborist performed “reduction pruning” on a mature Eucalyptus Botryoides tree in Queen Victoria Gardens in Melbourne, to help improve its health and extend its life. Credit…Alana Holmberg for The New York Times

New York, Denver, Shanghai, Ottawa, and Los Angeles have all unveiled Million Tree Initiatives aimed at greatly increasing their urban forests because of the ability of trees to reduce city temperatures, absorb carbon dioxide and soak up excess rainfall.

Central Melbourne, on the other hand, lacks those cities’ financial firepower and is planning to plant a little more than 3,000 trees a year over the next decade. Yet it has gained the interest of other cities by using its extensive data to shore up the community engagement and political commitment required to sustain the decades-long work of building urban forests.

A small municipality covering just 14.5 square miles in the center of the greater Melbourne metropolitan area — which sprawls for 3,860 square miles and houses 5.2 million people in 31 municipalities — the city of Melbourne introduced its online map in 2013.

Called the Urban Forest Visual, the map displayed each of the 80,000 trees in its parks and streets, and showed each tree’s age, species and health. It also gave each tree its own email address so that people could help to monitor them and alert council workers to any specific problems.

That is when the magic happened.

City officials were surprised to see the trees receiving thousands of love letters. They ranged from jaunty greetings — “good luck with the photosynthesis” — to love poems and emotional tributes about how much joy the trees brought to people’s lives.

Members of the public were subsequently recruited to help with forestry programs such as measuring trees and monitoring wildlife, and politicians were left in no doubt about how much Melburnians valued their trees.

City of Melbourne councilors of all political stripes agreed on the ambitious goal of increasing their tree canopy cover to 40 percent of public land by 2040, from 23 percent in 2012.

Their plan is on track after a decade and has been gradually replacing many of the grand European elms and London plane trees that shade the city’s widest boulevards, moving instead to indigenous species such as eucalyptus and other trees better able to cope with climate change.

Abigail Brydon, a 40-year-old project manager for a telecommunications firm, echoed the widespread affection for the city’s greenery as she took a walk past the elm that was being worked on by Mr. Shepherd and his team.

“I have always loved the city’s trees and parks but more than ever during lockdown,” she said, explaining that she was halfway through her twice-daily “sanity check” of a 15-minute walk around the park.

“A lap of the park clears my head, then I can go back inside and get back to work,” she said. “There are even more people now than there used to be sitting under the trees and wandering around, and Covid hasn’t stopped the city from keeping the park fantastically maintained.”

Lemon-scented gum trees were planted in 2016 along Flinders Street, on the edge of Melbourne's central business district. The native trees replaced  mature London plane trees.
Lemon-scented gum trees were planted in 2016 along Flinders Street, on the edge of Melbourne’s central business district. The native trees replaced mature London plane trees. Credit…Alana Holmberg for The New York Times

A walk around the central business district showed a series of recent plantings, including a spindly stand of lemon-scented gums on Flinders Street; new “green” tram tracks on Southbank; and a row of 7-foot camphor laurels near the theaters on Exhibition Street.

Melbourne’s outbreak of talking to trees was noticed far and wide, particularly among urban planners such as Gillian Dick, who helps to plan the forests of Glasgow.

Ms. Dick planned to pay tribute to the Melbourne experience on March 30 when she addresses a global online event on urban ecosystems, the Nature of Cities festival, about ways to encourage city dwellers to appreciate their local trees.

“In Glasgow we have set up a website and a Twitter account to capture community stories about what the city’s trees mean to people, to give us some background information for developing our forest and woodland strategy,” Ms. Dick explained in a telephone interview.

“It’s no good planting millions of trees if you are not going to have the community buy-in to sustain the long-term support you need to make a success of those trees, and if you look around the world at that sort of community engagement with trees, Melbourne’s experience is just amazing.”

“They accidentally discovered the latent desire of people to say how much the trees meant to them.”

Cathy Oke, a former Green Party city councilor who played a pivotal role in Melbourne’s tree policies, said data and evidence-based decisions had been crucial since the city revamped its forest strategy in 2012 after discovering that a 12-year drought had left 40 percent of its trees declining or dying.

Many of its most impressive trees were planted in large batches as far back as 1875, meaning that whole blocks of trees would die at the same time and need to be replaced by immature trees unless they were steadily replaced in advance.

“We learned from what other cities were doing, especially New York with its planting of a million trees,” said Dr. Oke, a researcher in urban sustainability at the University of Melbourne.

A landscape crew planted trees along Sheridan Avenue in the Bronx in 2008 as part of New York City’s million trees project started under the administration  Mayor Michael R. Bloomberg. 
A landscape crew planted trees along Sheridan Avenue in the Bronx in 2008 as part of New York City’s million trees project started under the administration Mayor Michael R. Bloomberg. Credit…Rob Bennett for The New York Times

The program has evolved to focus not only on trees but also on biodiversity including flowers, insects, and native animals. Rohan Leppert, a councilor who now leads the forest program, says the city will soon launch an online “biodiversity visual.”

“In all these things, we are bending over backward to do hyperlocal consultations to find out what trees people want in their own streets because these sort of changes work best when you do them with the community, not to the community,” Mr. Leppert said.

“We are determined to keep at it for the long term because keeping the city cool by planting trees is the single most cost-effective thing we can do to mitigate against climate change,” he said, noting that a healthy tree canopy can reduce a city’s temperature by 4 degrees to 6 degrees Celsius, or 7.2 to 10.8 degrees Fahrenheit.

James Fitzsimons, the director of conservation and science for the Nature Conservancy Australia, said the city of Melbourne’s successful forest strategy had not been matched across the wider metropolitan area, but attempts were underway to get a more united approach to forestry.

“The big challenge is that there is talk about Melbourne doubling its population size by 2050, so housing is becoming much denser and we’re losing native vegetation,” he said.

Gregory Moore, an expert on ecosystems and forests at the University of Melbourne, said another major problem was that planning laws controlled by the state of Victoria did little to protect greenery on private land, allowing development that contributed to the annual loss of 1.5 percent of canopy cover across the greater metropolitan area.

“A good tree cover can save you an enormous amount in health spending alone by reducing deaths in heatwaves and getting people outside and taking more exercise,” he said. “Politicians and bureaucrats seem to think that all of these benefits from planting trees are simply too good to be true, but I think they will eventually get the point when economists keep telling them how much money they will save.”

A version of this article appears in print on March 29, 2022, Section A, Page 10 in The New York Times International Edition.


March 30, 2022 · 8 minute read
Changing the genetic makeup of trees could supercharge their ability to suck up carbon dioxide. But are forests of frankentrees really a good idea?

Of all the potential fixes for the climate crisis, none has captured hearts and minds quite like tree planting. It’s a goal that seemingly everyone can agree on: Scientists, politicians, even billionaires are putting their heft behind efforts to green the land with new forests that will capture carbon and—hopefully—lock it away in trunks and soil for decades.

But no climate fix is ever that simple. Multiple studies have found that tree-planting campaigns don’t always deliver the benefits they promise. If newly planted forests aren’t properly cared for and monitored, the trees can die and any carbon they stored will be released back into the atmosphere. Sometimes there aren’t enough seedlings for these programs in the first place. The mass enthusiasm for tree-planting programs has sparked a partial backlash, with scientists arguing that planting trees is important, sure, but we shouldn’t kid ourselves that it’s a silver bullet for the vast challenges of the climate crisis.

Other scientists point to a different problem with mass tree-planting efforts: the trees themselves. What if existing trees just aren’t good enough at storing carbon? If scientists could find a way to increase trees’ carbon-sucking potential, we’d be unlocking more cost-effective carbon capture with every tree planted. A better tree could be what we’ve been waiting for. We just have to make it.

Maddie Hall, CEO and founder of the climate startup Living Carbon, is looking for the Tesla of trees. “Not just a tree that’s better for the environment, but a tree that grows faster and might be able to survive or perform better in climates than traditional varieties,” she says. “A lot of that comes down to how you could improve the growth rate and also carbon-capture potential of trees.”

The way that plants take carbon dioxide and sunlight and turn them into living material is nothing short of miraculous, a biological alchemy that supports almost all life on Earth. But this process—photosynthesis—is also woefully inefficient. Only a tiny fraction of sunlight that falls on leaves actually gets turned into living material—in the case of most plants around 95 percent of all that energy is wasted. For plant scientists like Amanda Cavanagh at the University of Essex, UK, this waste looks like an opportunity. If she can find a way to get plants to cut out some of this inefficiency, trees might put that energy into growth instead. Like most researchers in this area, Cavanagh’s focus is on faster-growing crops that can feed more people, but the same approach could be a boon for pulling carbon from the atmosphere, too. Photosynthesis-enhanced trees should be quicker at turning atmospheric carbon into trunks, leaves, and roots. That’s the theory, at least.

In 2019, Cavanagh and her colleagues published a paper in Science that strongly suggested they were on to something. By inserting a couple of new genes into tobacco plants, the scientists could get them to recycle a waste product of photosynthesis back into a molecule the plant could use to grow. Once they were planted, Cavanagh’s edited tobacco plants were 40 percent more productive than their non-edited equivalents. (Tobacco plants are the lab rats of the plant science world—the ultimate goal is to repeat this trick with crops like wheat or soy.)

Now a Californian startup has taken the same approach, but this time with poplar trees. In a non-peer-reviewed preprint first posted on February 19, scientists at Living Carbon claimed that by inserting new genes into poplar trees, they can make the plants grow 53 percent more quickly than their non-edited equivalents. Both sets of trees were grown under controlled conditions that differ significantly from the ones the plants would face in the wild, but Hall hopes that the edited trees will supercharge tree-planting plans by drawing down atmospheric carbon more quickly.

“Our belief is that climate change is a problem of relative rates. And also it’s one that we can’t just solve with man-made, intensely managed human processes like direct air capture,” she says. (Direct air capture means building devices that could scrub atmospheric carbon dioxide—or others that might trap methane—but by one recent estimate it could take 10,000 such machines to make a difference in CO2 levels.) Living Carbon’s eventual business model will be to plant its genetically engineered trees on land leased from private landowners, then give those landowners a share of the money earned by selling carbon credits earned against the growth of the trees.

When most plants photosynthesize, they produce a toxic byproduct called phosphoglycolate, which they then have to use energy to break down—a process called photorespiration. Living Carbon’s edited trees have extra genes from algae and pumpkin that help the plant use less energy to break it down, as well as recycling some of the sugars created by this process. This pathway was an obvious target for making plants more efficient, says Yumin Tao, Living Carbon’s VP of biotechnology. “You channel that byproduct into energy and nutrients for plant growth,” says Tao. And more plant growth means more carbon captured.

Tao and his colleagues grew the genetically engineered poplars for 21 weeks in a lab before harvesting and weighing them to see how much biomass they’d accumulated. The best-performing seedling had 53 percent more above-ground biomass than non-edited plants. Tests also showed that the edited plants took up more carbon than their non-edited cousins, an indication that these plants had a higher rate of photosynthesis.

“It’s a really exciting first step,” says Cavanagh, who was not involved in Living Carbon’s research. But she cautions that we don’t know whether these trees will be better at storing carbon in the long run. Living Carbon’s poplars were harvested after only five months, but in the wild, the trees can live for more than 50 years. Only further studies will reveal whether the edited trees will continue to grow quickly as they mature. Their growth rate might slow, or they might become so unhealthy that they fall over and release all that carbon back into the atmosphere when they rot. “Is the effect you see at the seedling phase the same at different stages of maturity, or does the plant fight back?” asks Cavanagh.

Soon this will be put to the test. Living Carbon has already planted 468 of its photosynthesis-enhanced trees in central Oregon, part of a field trial it’s running with Oregon State University. The company will analyze how quickly the trees grow over longer periods of time and also how they perform in different environments. It has also secured agreements to plant poplars created using a slightly different technique on around 3,500 acres of private land in the US, with the first plantings scheduled to start in late 2022, according to Hall.

But releasing genetically engineered trees into the wild is still controversial. Researchers at the State University of New York have engineered a chestnut tree that is resistant to a blight that has ravaged the species in the US, but the tree has still not been approved by the Department of Agriculture. Only two genetically engineered trees have been approved in the US: varieties of virus-resistant papaya and plum trees. The trees that Living Carbon is currently working with don’t produce pollen, which should limit the problem of genetic material from the edited plants mixing with wild trees.

But some plant scientists think there’s a simpler path to making a better tree: cultivating them the old-fashioned way. Humans have been breeding better crops for thousands of years, says Richard Buggs, an evolutionary biologist who studies plant health at Kew Gardens in London. “I’m totally in agreement with that core premise that we need trees that are more productive and fix carbon faster. I just think there are fantastic opportunities to do that by variation that already exists in nature,” says Buggs. Typically, cultivation means either hybridizing two varieties through cross-pollination—fertilizing the flowers of one tree with the pollen of another—or reinforcing a desirable trait within a species by self-pollinating a plant with that trait.

Rather than meddling with something as fundamental as photosynthesis, Buggs suggests there are other traits that might be useful for making more efficient trees. “There are actually lots of things that are already happening in nature that affect the growth of a tree that we could be working with,” he says, like variation in how quickly trees grow, how straight their trunks are, and when they drop their leaves. All would affect their suitability for carbon capture, Buggs says. “I would prefer that kind of approach. I think it’s more realistic, and you’re much more likely to end up with a tree that will survive and fix carbon in the long term in natural environments.”

Hall doesn’t actually envisage giant public forests of genetically engineered trees. She says that most of the time her trees will eventually be cut down for timber—another reason to find a way to speed up their growth. Other companies are interested in fast-growing trees too: In 2015 the Brazilian government approved a eucalyptus tree engineered by a paper-producing firm to produce 20 percent more wood than conventional trees.

The debate between natural breeding and genetic engineering has been bubbling along in the agricultural world for more than half a century. Now a similar conversation is starting to play out when it comes to forestry. We might be able to cultivate more productive trees, but that approach could take decades. We might not have that kind of time, Cavanagh says. “Thirty years will be the end of my career,” she says. “I would like to know I’ve done everything I can to make sure that there are solutions if things look as bad as the worst-case projections.”

The Great Danger of the Tiny Bark Beetle

March 30, 2022 · 6 minute read
The Great Danger of the Tiny Bark Beetle

As the climate warms, this insect’s population is booming. That’s bad news for the ponderosa pines of the Sierra Nevada.

As he drove through the Sierra Nevada in 2019, Zachary Robbins noticed all the dead trees. Most of them had probably died around 2016 thanks to a combination of California’s drought and its growing population of bark beetles—tiny creatures that kill giant trees. Although workers had tried to salvage whatever they could for commercial timber, Robbins, a researcher in the Dynamic Ecosystems and Landscapes Lab at North Carolina State University, was astounded by how many withered pines still dotted the forest.

Of some 600 species of bark beetles, the western pine beetle is prevalent in this region. They chew away at bark and live within the phloem of ponderosa pines, the living tissue that transports nutrients. The infestation creates bark beetle “galleries” that look like long-legged centipedes living within the tree; these can kill the host by cutting off nutrient flow. Dead trees can present a perilous situation to nearby residents because they create more flammable material for wildfires.

According to the US Forest Service, about 150 million trees died during the state’s five-year drought, which ran from 2012 to 2016, and in its aftermath. Drought itself kills trees, but the lack of water also weakens them, making them easier for the beetles to attack. These infestations can be fatal for pines—a 2019 study found that among ponderosa pines attacked by bark beetles following the drought, an estimated 90 percent of them died.

Talking it over later with his colleagues, Robbins thought the pine die-off might be attributable to climate change: A warmer climate would mean more beetles, and more beetles would mean more dead trees. “We realized that this landscape will be fundamentally different in the next century,” Robbins says.

To test the theory, Robbins and his team used a computer model to show how both drought and warming temperatures could affect the Sierra Nevada. The data for their model was gleaned from other studies based on either satellite imaging or academic field researchers who counted the number of trees that have already died from beetle infestations. In a paper published in October in Global Change Biology, the team wrote that their model calculated that for each 1 degree Celsius that temperature rises, the number of dead trees will increase by about 20 percent, thanks to the increased success of the beetle population. During a drought, their model showed, this figure can worsen, climbing to 35 to 40 percent.

Beetles have more success in a drier, warmer climate because trees are more stressed. When an insect starts to chew through bark, a tree has a chance to defend itself by releasing waxy resin and chemicals to push the critter out. But under the stress of droughts, trees close the pores in their leaves and needles, reducing their ability to photosynthesize and create the carbon the tree needs to live. The tree then devotes its resources to tissue maintenance, making less of these defense chemicals and resins. All of this creates an opportunity for bark beetles to invade.

At the same time, the life cycle of the beetle speeds up. These creatures are ectotherms, which means their function depends on the external temperature. If temperatures rise, they reach reproductive age sooner and produce more and more offspring.

“Warming temperatures allow bark beetles to go through stages of maturation more quickly, allowing populations to grow to larger, more explosive sizes,” says Chris Williams, director of environmental sciences at Clark University in Massachusetts, who studies droughts, bark beetles, and wildfires. Their larvae live within the tree, and when they are old enough, they turn into beetles, which fly out to find other trees to destroy. Once they start an invasion, they release pheromones, which signal to other beetles that there is room for more. (Beetles are also less likely to die during a warmer winter, but Robbins says this was not a main factor in his California study.)

The 2012 to 2016 drought was particularly harmful because of just how long it lasted. But 2018, 2020, and 2021 have also been extreme drought years. Tom Smith, a California Department of Forestry and Fire Protection senior plant pathologist, has witnessed the droughts’ effects firsthand. “We are seeing this right now with increased bark beetle activity of the western pine bark beetle and other species around California while we enter yet another year of drought,” Smith says. “My major concern is that with the vast number of dead trees on the landscape there is a huge amount of dry fuel just waiting to burn.” These tree graveyards act as catalysts for the landscape-scale wildfires that have been plaguing California.

Mass deaths of 100-year-old ponderosa pines can increase the risk of wildfire for another reason: The pines are a fire-resistant species due to their thick bark. Yet after a beetle outbreak, the old trees are replaced by much younger pines and also incense cedars, which are less resistant. The combination of younger trees that can ignite more easily with dead trees that provide fuel is a recipe for high-intensity forest fires.

Robbins and his team of researchers were floored that a small environmental change, like 1 degree Celsius of warming, could have such long-lasting effects. “This is one of those instances of climate change where there’s no putting the genie back in the bottle,” Robbins says. “Those trees, many were hundreds of years old, and they’re now dead—and they won’t be back for another 100 years.”

“Climate change is not a future event. We are living through the results of the altered climate now,” Robbins continues. “Our ecology is already behaving in ways we could not have predicted, and we will have to manage forests and natural resources with this assumption.”

But what might some of those management decisions be? Robbins thinks that increasing forest diversity will be a protective factor against bark beetle attacks. “And not just tree species, but tree ages,” Robbins says. “We often have trees that are the same age, and they’re all susceptible to bark beetle attacks at similar times.” Without reforestation efforts, Robbins thinks that forests may convert to chaparral shrublands.

Controlled burns to get rid of dead material should be part of the answer, Robbins says, but the sheer scale necessary is enormous. Smith wants to see this happen, too, but he agrees that there are some roadblocks: The right weather conditions don’t occur regularly, the terrain is often difficult to work with, and there are limited numbers of trained fire personnel. “The best option would have been to harvest the trees quickly to remove the dry fuel,” Smith says, but the cost of transportation is prohibitive and there are only so many mills ready to process the timber.

Biogeneration plants, which convert forest residue to heat for power generation, would be another option, Smith says, but not enough of them exist. He also thinks it’s important to educate people about fire prevention, as the National Park Service estimates that 85 percent of fires are human-caused.

It’s harder to imagine a solution directed just at the beetles. Their natural predators are white-headed woodpeckers and black-bellied clerid beetles, but Robbins doesn’t think it would be wise to increase the number of these predators. This is because during non-outbreak years, when beetle populations are low, the predator population would quickly collapse, undoing all the work. Another idea might be to use another kind of pheromone the beetles produce, one that lets their compatriots know when space has run out. But, Robbins adds, that’s not realistic given the size of the forest. 

Now, Robbins is looking ahead to how his team’s model can be applied to other ecosystems that might host the same kind of beetle. “We think about the ponderosa pines throughout Oregon and Washington,” he says. “They may also be impacted by these things—just not yet.”

The World’s Biggest Tree House Resort Is Opening Near This U.S. National Park

March 24, 2022 · 3 minute read
The World’s Biggest Tree House Resort Is Opening Near This U.S. National Park

The finished resort will have 130 treehouses on 40 acres in East Tennessee.

By Rachel Chang March 22, 2022

When Amanda Jensen’s four kids were younger, her husband Brian built them a treehouse, complete with bunk beds, a trap door, a swing, and a zip line. “After the kids decided they were on to more important things than playing in it, we joked about renting it out because treehouses were becoming ‘a thing,'” she told Travel + Leisure.

But after staying at an impressive treehouse in South Carolina themselves, they’ve turned that thought about their kids’ playhouse into even bigger ambitions. They’ve set out to build what they hope will become the world’s biggest treehouse resort, called Sanctuary Treehouse Resort, in the Smoky Mountains of Tennessee. When it’s completed, it will be the largest in the world with 130 treehouses spread out across 40 acres. Most of the treehouses will be in rows, but a few will be in circular pod formation.

Building a treehouse at The Sanctuary Treehouse Resort

The couple is working with Mountain Modern Architectural firm MossCreek to bring their vision to life. The resort will feature three types of accommodations. The Tree Fort can accommodate two to six guests and will have a king-size bed with a queen-size trundle bed that rolls out underneath and a bunk bed, along with a LED fireplace, kitchenette, whiskey barrel bathroom sink, and shower, plus a deck with Adirondack chairs, a grill, and wood-burning fireplace. But the real design fun comes with the tree house’s spiral slide, climbing rope, bucket pulley, net swing, secret ladder, trapdoor, telescope, and even a custom drink shoot for bottles and cans from the kitchen to the lower porch. For group accommodations, there will also be a Tree Fort Double, which is two of the treehouses connected with a movable drawbridge. Finally, the Luxe accommodation steps everything up a notch with a king-size gel cooling bed, copper clawfoot bathtub, bamboo jet shower, heated bidet toilet system, and outdoor tub.

Side view of a Treefort atThe Sanctuary Treehouse Resort

“It will not be just a place to stay with astounding views, you will be able to interact and play in your treehouse, just as you would a ‘real’ treehouse,” Jensen said of the playful features.

About six to 10 of the treehouses will be available for stays starting this summer, with the rest of the first phase rolling out through the rest of the year. By the end of 2023, there will be about 30 units, as well as a check-in area. The plan is to keep building another 20 to 25 units each year until the resort is complete.

A map of The Sanctuary Treehouse Resort

The Jensens, who also run the Gaitlinburg SkyCenter at the top of the Gatlinburg SkyLift, originally had planned just to build a handful of treehouses to rent out on their own property, but once they heard that the 40-acre site was available, they knew they had to expand their plans, especially since other potential buyers were looking to raze the area for apartments and other buildings. “We want to preserve the property as it is and build around the trees and into the existing landscape to respect its beauty and the nature that lives there,” she said of the property they just started construction on this year.

The resort will eventually also have walking trails, a community area, a central hot tub, and a lit enchanted forest for events and gatherings. Also part of the draw is its East Tennessee location, near two 18-hole golf courses and Great Smoky National Park.

Front view of a Treefort atThe Sanctuary Treehouse Resort

“We are cultivating a unique resort like no other anywhere for guests to stay, play, and retreat for a one-of-a-kind experience,” the couple said. “We hope to provide our guests with lasting memories, breathtaking views, and customizable options to leave them with a desire to come back and stay with us year after year.”

Learn more about Sanctuary Treehouse Resort and follow the property’s progress here.

The three reasons you should chop down your Bradford Pear trees

March 24, 2022 · 3 minute read
The three reasons you should chop down your Bradford Pear trees
A blight on our native ecosystem, these trees look gorgeous but bring a huge cost.

By Andrew Freiden Published: Mar. 23, 2022 at 4:33 PM EDT

RICHMOND, Va. (WWBT) – They are a staple of early spring and easy to spot: those puffy white Bradford pear trees. But once you get to know them, they are easy to hate.

Some central Virginia garden centers, like the Great Big Greenhouse and Cross Creek Nursery, don’t even carry them anymore. But they carry on in our landscape.

1. The first thing that’s wrong with a Bradford pear is its structure.

They have huge heavy limbs that all radiate out from one point. That makes the tree exceptionally weak and prone to breakage once it matures. When high winds hit – or snow or ice – these trees come apart easily. That’s a lot of weight coming down on a person, car, roof, or even a power line.

Photo taken by Chris of a fallen bradford pear tree outside his home near Maize, Kan.
Photo taken by Chris of a fallen Bradford pear tree outside his home near Maize, Kan.(KWCH viewer named Chris near Maize)
Bradford Pear split in Dalzell (Source: Deborah Shade)
Bradford Pear split in Dalzell (Source: Deborah Shade)

2. The second (and biggest) problem? They are invasive and spreading.

Once you see the puffy white trees in early spring, you’ll see them everywhere. Originally from China, they don’t have any threats here.

“They’ve been liberated from their predators in pathogens in their native range and brought to a place where they don’t have these predators or diseases so their energy is freed up to grow and reproduce,” said Kevin Heffernan, a Stewardship Biologist at Virginia Department of Conservation and Recreation.

And they are really good at reproducing.

Originally thought to be sterile, when Bradford pear blossoms get cross-pollinated by bees, fruit production begins. It doesn’t look like a pear you get at the grocery store, but native birds love the small, sugary fruit. Sadly, it’s basically junk food and hurts our songbird’s ability to migrate.

Heffernan says eating the pear fruits, “tend to debilitate species ability to get all the way to their destinations. They should be filling up with more fatty fruits from other species.”

Plus, the birds spread the trees far and wide. If you look alongside highways and in unmaintained areas, you’ll see the white trees easily. They are one of the first trees to bloom in our early spring landscape.

And once they start running wild, they revert to their rootstock: a Callery pear. And that tree is nasty. It forms a thicket, crowding out native trees and it has huge, sharp thorns.

That makes it very hard to remove once it takes over an area. Just ask Laura Greenleaf, she spends her days removing invasive species and teaching others about them, and she says this piece of land, like many others across the state, just isn’t right.

“Ideally, this would be a naturalized area of the native Flora. native trees shrubs and a herbaceous layer,” she said.

Here’s more on Laura’s efforts to remove Bradford Pears from Richmond’s Forest Hill Park.

And it’s not just us! Many other states are realizing the error of our planting ways. In South Carolina, there’s even a bounty! If you send a picture of a Bradford pear you cut down, they’ll give you a free native tree!

That hasn’t happened in Virginia, yet.

3. The third thing: they smell horrible.

Pretty much everyone agrees on that.

So cut them down if you have them in your yard. Spring is a great time because you can easily spot them.

Laura Greenleaf and Kevin Heffernan gave me a great list of links that might be helpful if you are interested in learning more about invasive species and how changes you make at your house can help our native species.

VA Department of Conservation & Recreation:

Virginia Native Plant Society (includes a list of native plant nurseries & sales)

Blue Ridge PRISM (Partnership for Regional Invasive Species Management). While PRISM is based in a different region, many of the invasives are statewide or common to central piedmont as well.

Homegrown National Park – Tallamy’s Hub

There are also some upcoming events to attend if you’d like to learn more:

Copyright 2022 WWBT. All rights reserved.

Tree Planting Is Booming. Here’s How That Could Help, or Harm, the Planet.

March 16, 2022 · 8 minute read
Tree Planting Is Booming. Here’s How That Could Help, or Harm, the Planet.

Reforestation can fight climate change, uplift communities, and restore biodiversity. When done badly, though, it can speed extinctions and make nature less resilient.

A tree planted for every T-shirt purchased. For every bottle of wine. For every swipe of a credit card. Trees planted by countries to meet global pledges and by companies to bolster their sustainability records.

As the climate crisis deepens, businesses and consumers are joining nonprofit groups and governments in a global tree planting boom. Last year saw billions of trees planted in scores of countries around the world. These efforts can be a triple win, providing livelihoods, absorbing and locking away planet-warming carbon dioxide, and improving the health of ecosystems.

But when done poorly, the projects can worsen the very problems they were meant to solve. Planting the wrong trees in the wrong place can actually reduce biodiversity, speeding extinctions and making ecosystems far less resilient.

Addressing biodiversity loss, already a global crisis akin to climate change, is becoming more and more urgent. Extinction rates are surging. An estimated million species are at risk of disappearing, many within decades. And ecosystem collapse doesn’t just threaten animals and plants; it imperils the food and water supplies that humans rely on.

Amid that worsening crisis, companies and countries are increasingly investing in tree planting that carpets large areas with commercial, nonnative species in the name of fighting climate change. These trees sock away carbon but provide little support to the webs of life that once thrived in those areas.

“You’re creating basically a sterile landscape,” said Paul Smith, who runs Botanic Gardens Conservation International, an umbrella group that works to prevent plant extinctions. “If people want to plant trees, let’s also make it a positive for biodiversity.”

There’s a rule of thumb in the tree planting world: One should plant “the right tree in the right place.” Some add, “for the right reason.”

But, according to interviews with a range of players — scientists, policy experts, forestry companies and tree planting organizations — people often disagree on what “right” means. For some, it’s big tree farms for carbon storage and timber. For others, it’s providing fruit trees to small-scale farmers. For others still, it’s allowing native species to regenerate.

The best efforts try to address a range of needs, according to restoration experts, but it can be hard to reconcile competing interests.

“It’s kind of the Wild West,” said Forrest Fleischman, a professor of environmental policy at the University of Minnesota.

The Batéké Plateau covers some six million hectares and spans three countries: The Democratic Republic of Congo, the Republic of Congo and Gabon. 
The Batéké Plateau covers some six million hectares and spans three countries: The Democratic Republic of Congo, the Republic of Congo and Gabon. Credit…Robert Ross/Gallo Images, via Alamy

There is not enough land on Earth to tackle climate change with trees alone, but if paired with drastic cuts in fossil fuels, trees can be an important natural solution. They absorb carbon dioxide through pores in their leaves and stash it away in their branches and trunks (though trees also release carbon when they burn or rot). That ability to collect CO2 is why forests are often called carbon sinks.

In Central Africa, TotalEnergies, the French oil and gas giant, has announced plans to plant trees on 40,000-hectares in the Republic of Congo. The project — on the Batéké Plateau, a rolling mosaic of grasses and wooded savanna with patches of denser forests — would sequester more than 10 million tons of carbon dioxide over 20 years, according to the company.

“Total is committing to the development of natural carbon sinks in Africa,” said Nicolas Terraz, who was then Total’s senior vice president for Africa, exploration and production, in a company news release on the project in 2021. “These activities build on the priority initiatives taken by the group to avoid and reduce emissions, in line with its ambition to get to net-zero by 2050.”

To achieve net-zero, companies must remove at least as much carbon from the air as they release. Many, like TotalEnergies, are turning to trees for help with that. On the Batéké Plateau, an acacia species from Australia, intended for selective logging, will cover a large area.

The project, part of a Congolese government program to expand forest cover and increase carbon storage, would create jobs, the company said, and ultimately broaden the ecosystem’s biodiversity as local species are allowed to grow in over decades.

But scientists warn that the plan may be an example of one of the worst kinds of forestation efforts: planting trees where they would not naturally occur. These projects can devastate biodiversity, threaten water supplies and even increase temperatures because, in some cases, trees absorb heat that grasslands — or, in other parts of the world, snow — would have reflected.

“We don’t want to cause harm in the name of doing good,” said Bethanie Walder, executive director of the Society for Ecological Restoration, a global nonprofit.

The Batéké Plateau is one of the least-studied ecosystems in Africa, according to Paula Nieto Quintano, an environmental scientist who has focused on the region. “Its importance for local livelihoods, its ecology and ecosystem functions are poorly understood,” Dr. Nieto said.

Those who study forest restoration emphasize that trees are not a cure-all.

“I fear that many corporations and governments are seeing this as an easy way out,” said Robin Chazdon, a professor of tropical forest restoration at the University of the Sunshine Coast in Australia. “They don’t necessarily have to work as hard to reduce their emissions because they can just say, ‘Oh, we’re offsetting that by planting trees’.”

A forest of Eucalyptus trees at the Pulpit Rock lookout in the Blue Mountain World Heritage Site, Australia.
A forest of Eucalyptus trees at the Pulpit Rock lookout in the Blue Mountain World Heritage Site, Australia.Credit…Ashley Gilbertson for The New York Times

All trees store carbon, but their other benefits vary widely depending on the species and where it’s planted.

Eucalyptus, for instance, grows fast and straight, making it a lucrative lumber product. Native to Australia and a few islands to the north, its leaves feed koalas, which evolved to tolerate a potent poison they contain. But in Africa and South America — where the trees are widely grown for timber, fuel and, increasingly, carbon storage — they provide far less value to wildlife. They are also blamed for depleting water and worsening wildfires.

Experts acknowledge that forest restoration and carbon sequestration are complex, and that commercial species have a role to play. People need timber, a renewable product with a lower carbon footprint than concrete or steel. They need paper and fuel for cooking.

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Planting fast-growing species for harvest can sometimes help preserve surrounding native forests. And, by strategically adding native species, tree farms can help biodiversity by creating wildlife corridors to link disconnected habitat areas.

“This restoration movement can’t happen without the private sector,” said Michael Becker, head of communications at, a group created by the World Economic Forum to push for the conservation and growth of one trillion trees with help from private investment. “Historically, there have been bad actors, but we need to bring them into the fold and doing the right thing.”

A challenge is that helping biodiversity doesn’t offer the financial return of carbon storage or timber markets.

Many governments have set standards for reforestation efforts, but they often provide broad leeway.

In Wales, one of the most deforested countries in Europe, the government is offering incentives for tree planting. But growers need only include 25 percent native species to qualify for government subsidies. In Kenya and Brazil, rows of eucalyptus grow on land that was once ecologically rich forest and savanna. In Peru, a company called Reforesta Perú is planting trees on degraded Amazonian land, but it’s increasingly using cloned eucalyptus and teak, intended for export.

Investors prefer them because they bring better prices, said Enrique Toledo, general manager of Reforesta Perú. “They are well-known species internationally and there is an unsatisfied demand for wood.”

When researchers from University College London and the University of Edinburgh evaluated national commitments toward reforestation and restoration, they found that 45 percent involved “planting vast monocultures of trees as profitable enterprises.”

Seedlings for a planting project in Doddington, England. 
Seedlings for a planting project in Doddington, England. Credit…Dan Kitwood/Getty Images

When businesses promise to plant a tree for every purchase of a given product, they typically do so via nonprofit groups that work with communities around the world. The support may reforest after wildfires or provide fruit and nut trees to farmers. But even these projects can compromise biodiversity.

The planet is home to nearly 60,000 tree species, and about a third are threatened with extinction — mainly from agriculture, grazing and exploitation — a recent report found. But globally, only a tiny fraction of species are widely planted, according to tree planting groups and scientists.

“They’re planting the same species all over the world,” said Meredith Martin, an assistant professor of forestry at North Carolina State University who found that nonprofit tree planting efforts in the tropics tend to prioritize the livelihood needs of people over biodiversity or carbon storage. Over time, she said, these efforts risk-reducing biodiversity in forests.

Nonprofit tree planting groups often say they plant nonnative species because local communities ask for them. But deeper engagement can yield a different story, said Susan Chomba, who oversees forest restoration and conservation in Africa for the World Resources Institute, a global research nonprofit group. When given the chance to consider what they want to accomplish on their land, farmers will recall, for instance, that when they had more trees, they also had streams, she said. They want the water back.

“Then you say, ‘In your traditional, local knowledge, what kind of tree species are suitable for returning water into the ecosystem?’” Dr. Chomba continued. “They will give you a whole range of indigenous tree species.”

A major hurdle is the lack of supply at local seed banks, which tend to be dominated by popular commercial species. Some groups overcome this problem by paying people to collect seeds from nearby forests.

Another solution, experts say, is to let forests come back on their own. If the area is only lightly degraded or sits near an existing forest, a method called natural regeneration can be cheaper and more effective. Simply fencing off certain areas from grazing will often allow trees to return, with both carbon sequestration and biodiversity built-in.

“Nature knows much more than we do,” Dr. Chazdon said.

The (Very Slow) Race to Move Forests in Time to Save Them

March 16, 2022 · 26 minute read
The (Very Slow) Race to Move Forests in Time to Save Them

Trees have always migrated to survive. But now they need help to avoid climate catastrophe.

I drove to Oregon because I wanted to see the future. Our rapidly changing climate vexes me, keeps me up at night—perhaps you’ve felt this, too—and recently I’d become particularly preoccupied with trees. In California, where I live, climate change helped kill nearly 62 million trees in 2016 alone, and last year, 4.2 million acres of our state burned. I wanted to know what was in store for our forests and, because we humans rely on them for so much—for clean air, for carbon sequestration, for biodiversity, for habitat, for lumber and money, for joy—what was in store for us.

I’d read about a group of scientists who were not only studying the calamities befalling our forests but also working to help the trees migrate in advance of coming doom. So in May, I headed to a 3-and-a-half-acre stand of roughly 1,000 Douglas firs at a US Forest Service nursery outside of Medford. The grove was situated in a wide valley in the southwestern corner of the state, nestled between the Cascades to the east and the Coast Range to the west. Brad St. Clair, a Forest Service scientist who has studied the genetic adaptation of trees for more than two decades, met me by the road. He’s short and rugged as if built for adventuring and tending to the lives of trees, and he arrived in a souped-up Sprinter van loaded with an armory of outdoor gear. In 2009, he and his team planted this and eight other stands of firs after they’d gathered seeds from 60 tree populations all over Washington, Oregon, and California and grown them into seedlings in a greenhouse. The seeds were sourced from as high as 5,400 feet in the Sierras and as low as the coast, from Mendocino County, California, all the way north to Central Washington, and were planted in intermixed clusters at each of the nine sites to see how they would fare in a hotter, drier climate than the ones they’d come from. In other words, to see if they’d make it in the future.

Douglas fir, a tall, narrow-trunked evergreen often dragged indoors for Christmas, is a favorite of foresters and logging companies because of its combination of strength, fast growth, and pliability. It can also withstand a change in climate of about 4 degrees Fahrenheit without much trouble. But global average temperatures have already risen by almost 3 degrees since the 1900s, and all models predict average temperatures to blow through the 4-degree threshold in the next several decades, perhaps rising above 7 degrees by the end of the century.

Brad St. Clair Justin Maxon

In the wide, flat expanse of the nursery, the firs were rimmed by fallow land on all sides. St. Clair instructed me to put on safety glasses, and then ducked down, pushed aside the outermost branches, and slipped into the trees. I followed him. Within two steps, there we were in a veritable, dense forest as if an enchanted wardrobe had been pulled open to reveal a world transformed. On the periphery, it had been hot, but here, as we moved through the dapple, it was cool and fragrant with pine.

A sign mounted on a PVC pipe marked the provenance of the cluster of trees we stood beneath. They came, St. Clair explained, from the Oregon Siskiyou, a dry zone at only slightly higher elevation than where we were today. This is why they were doing so well: Their native climate wasn’t so different from Medford’s. As we moved on, the trees, while still lush and full, grew shorter. Because this next batch was from up in the Cascades, he pointed out, at an elevation far higher than where we stood, the trees were somewhat stunted in this new habitat and couldn’t grow as tall. We kept walking, and after a while the trees grew taller again, looming three times my height before breaking into the sky. These trees also came from climates that were dry like Medford, and so found here a happy home—at least for now.

We ducked and trudged through the lower thickets of the healthy trees until we suddenly emerged from the woods onto what I can only describe as an arboreal apocalypse—an open tangle of dead branches, brown and brittle, like an upright graveyard. These ill-fated trees, St. Clair said, had come from the Oregon coast, where it is far wetter. While they’d done okay in the first three years of the study, they just couldn’t make it in the long term. “As the climate warms,” St. Clair said, looking around and pointing up to a dead fir with his walking stick, “you’re going to see more of this.”

The future of forests is a grim one—too grim for some of us to bear. By 2030, 75 percent of redwoods will disappear from some of their coastal California habitats. In some climate scenarios, almost none of the namesake species in Joshua Tree National Park will exist. Sea level change is creating ghost forests all along the Eastern Seaboard—­already, less than a third of New Jersey’s Atlantic white cedar habitat remains.

Like humans, forests have always migrated for their survival, with new trees growing in more hospitable directions and older trees dying where they are no longer best suited to live. The problem now is that they simply can’t move fast enough. The average forest migrates at a rate of roughly 1,640 feet each year, but to outrun climate change, it must move approximately 9,800 to 16,000 feet—up to 10 times as fast. And in most habitats, the impact of highways, suburban sprawl, and megafarms prevent forests from expanding much at all. Forests simply cannot escape climate change by themselves.

Back in 1992, forest geneticists F. Thomas Ledig and J.H. Kitzmiller coined the term “assisted species migration” in a seminal study in the journal Forest Ecology and Management. Since then, hundreds of biologists and geneticists like St. Clair have been studying how best to move forests in advance of their looming destruction. To do so requires a complex set of mapping and experiments—understanding, for instance, what climate trees are best suited to grow in, what region will most closely resemble that same climate in, say, 50 years, and what adaptations best ensure that a tree will take root and flourish, build symbiosis with the soil fungi, and not end up a mere matchstick awaiting the next mega fire.

St. Clair is something of an assisted migration evangelist, a firm believer that we need to move tree populations, and fast if we want to keep apace. But due to bureaucratic logjams and a fervent commitment to planting native species, there’s very little assisted migration in the United States— unlike in Canada, where the practice has been adopted with more urgency in recent years. St. Clair and other Forest Service scientists are working to transform assisted migration from a mere research subject to a standard management strategy in our vast, imperiled public lands.

We finished our walk through St. Clair’s baby forest, making our way back to the cars along its outer edges. “The future is terrifying,” I told him. He understood what I meant, he said.

During the talks he gives about his research, he likes to show an image from Lewis Carroll’s Through the Looking-Glass, in which the Red Queen charges forward with her crown and sturdy scepter, pulling frenzied Alice along in her wake. He had the slide printed out and handed it to me as we walked. “Now, here, you see,” the Red Queen says to Alice, “it takes all the running you can do, to keep in the same place.”

“So that’s what we gotta do,” he told me, pointing to the Red Queen. “We gotta run.”

While assisted migration is a relatively new concept, the movement of forests is as old as trees themselves. Since they first evolved, trees have been shifting north and south, east and west, up and down in elevation as the climate has changed. Forests outran the frost as an ice age set in, and as the ice began melting, they darted back the other way, traversing mountain ranges and unfurling themselves across continents—moving, sentiently, toward climatic conditions that suited their ability to grow and produce the trees of the future.

Of course, while forests move, individual trees can’t. “They are stuck where they are,” explained Jessica Wright, a senior Forest Service scientist based in Davis, California, who studies conservation genetics. Trees must try to survive in whatever environment they land in. And yet, Peter Wohlleben writes in The Hidden Life of Trees, while every tree has to stay put, “it can reproduce, and in that brief moment when the tree embryos are still packed into seeds, they are free.” The seed sets forth, as Zach St. George chronicles in The Journeys of Trees, carried by the wind or in the belly of a blue jay or stuffed in the cheek of a squirrel, toward its destiny. If it is among the luckiest, it will find a hospitable home and carry the forest forward. Because seeds will only take root in areas suited to their growth, forests tend to move in the direction of their future survival.

Trees from across the West Coast thrive and die at a Forest Service nursery in Oregon. Justin Maxon

Unlike humans, most trees are long-life species, ranging from the yellow birch, which lives roughly 150 years, to the bristlecone pine, the oldest known of which is nearly 5,000 years old. Forests are the trees’ complex civilization, functioning not unlike human cities: a community of beings that talk to one another and organize and defend themselves and create offspring and bid farewell to their dead. In this way and many others, recent research has revealed, trees are spellbinding, rife for anthropomorphism. They tend to live in interdependent networks, like families, where, with the help of symbiotic fungi, scientists like Suzanne Simard have discovered, they care for their sick, feed one another, and, like a mutual aid society, share resources with those in need. Trees of the same species—and sometimes even those across species—tend to respect one another’s personal space, shifting their growth patterns so that everyone gets enough sunlight. Trees are also adept community organizers who know how to band together to crowd out competitor trees and guard against other threats. When a pest comes, trees can issue chemical warnings to one another so they can launch their defenses. Trees can also register pain. Scientists have found that their root networks, which work with the underworld organisms of fungal mycelia, seem to hold intergenerational knowledge, like a collective brain. Read enough about the mesmerizing science of trees and one begins to feel certain that, if humans behaved like a healthy forest, we’d be far better off—and that we wouldn’t be in our current climate mess in the first place.

Left to their own devices, forests migrate on a near-geologic scale. But people have been moving trees for our own purposes for thousands of years. We’ve done this in small doses, such as planting trees in city gardens or backyards for shade and aesthetic delight, or planting a wall of cypress along a tract of farmland to block the wind. We’ve also moved trees on a far more substantial scale, to a range of outcomes. While apple trees originated in Central Asia, early settlers brought seeds to the Americas and infamously scattered them throughout what is now the United States, where apple pie is now both a signature dessert and a cultural symbol.

Such interventions haven’t always panned out so well: In 1895, the emperor of Ethiopia ordered the planting of fast-growing eucalyptus trees imported from Australia so people would have abundant firewood. But the thirsty eucalyptus crowded out existing trees, and parched once-fertile farmlands. (Eucalyptus trees are also invasive transplants in California, though they have also become critical nesting habitat for the threatened monarch butterfly—the web of interconnectivity is a tangled one.) And in 1904, US foresters began planting Japanese chestnuts to cultivate for wood, which brought chestnut blight to their North American cousins ill-equipped to fight the fungus; by 1940, most adult chestnuts were gone. The movement of trees, scientists caution, must be done with extreme care—and based on history, many are hesitant to do it for fear of throwing off the delicate balance of an existing landscape.Three Ways Humans Move Forests»»

Assisted Population Migration Trees or their seeds are moved from one place where they traditionally grow to a new place that’s also within the historical range of their species. Not only is this considered the least risky type of assisted migration; it’s also the one that scientists in the United States and Canada have tested out the most.

Assisted Range Expansion Think of this as sylvan sprawl: To increase the area currently inhabited by a given species, scientists plant it beyond its traditional boundaries—farther than where it would have otherwise naturally lived. Because range expansion introduces new trees to places they’ve never lived, there is some risk of disturbing the balance of the new habitat.

Assisted Species Migration Species are transported from their native habitat to regions where they’ve never lived—or haven’t for millennia. The risk here is substantial: These invasive species could weaken or wipe out native ones, but it might be the only chance for trees in critical need of a lifeboat.

Illustrations by Brown Bird Design

Proponents of assisted migration claim that this balance has already been upended by climate change. They also stress that assisted migration is an umbrella term for a range of activities, some way more far-reaching than others. The most drastic intervention is known as assisted species migration, which transplants species of trees from places where they naturally occur to faraway places where they do not. Then there’s assisted range expansion, which plants trees slightly outside their naturally occurring territory. The strategy involving the least human intervention is known as assisted population migration, which, like St. Clair’s studies of Douglas fir, plants trees of a single species with certain adaptations to a new location where other members of that same species already live. Most scientists advocate the latter two strategies and consider the first one too extreme.

So how to safely move a population to a new habitat—and to know how far to do it, and how fast? “If I knew the answer to that,” Forest Service scientist Kas Dumroese told me, “I’d have the Nobel Prize.” To find out which plants are best suited to which environments, scientists tend to use something called the Common Garden Study, which, like the artificial forest I visited in Oregon, plants flora from a wide range of locations—and thus adapted to a range of conditions—on a single plot to study their response and growth patterns. What scientists have found in most assisted migration garden studies is that the trees that do best are those whose parents and ancestors thrived in similar terrain.

If you move a population of trees adapted to a particular climate too slowly, it’s bound to succumb to the hotter, drier conditions brought on by climate change. But move it too fast to a colder, wetter climate, and the trees might fall victim to too much frost, or to root rot in damp conditions that make them vulnerable to pests. Shifting trees that can handle midcentury climate projections—so new forests are adapted to the temperatures of roughly 2040 to 2070—seems to be the Goldilocks balance that will ensure a population’s survival.

But there are other important considerations, including the symbiotic relationship between soil fungi and trees. Simard, the author of the recent bestselling book Finding the Mother Tree, explains that, while trees will likely find some symbiotic mycelium as long as they are moved within their species’ existing range, that mycelium might not be the best adapted for their needs. Trees can’t be seen as growing in isolation, but need to be considered in terms of the overall health and relationships of a larger ecosystem. “There’s a lot we don’t know,” she told me. Assisted migration “is risky, but, you know, we also have no choice. We have to start experimenting with this. We have to start moving things around and watching and seeing how they do.”

The Forest Service scientists who study assisted migration couldn’t agree more, and they hope that the agency’s forest managers will start using this strategy in actual forests. Despite decades of research, the Forest Service has rarely put assisted migration into practice, in part due to some foresters’ and scientists’ resistance to moving trees outside their agreed-upon range. In the 1930s, the Forest Service created the idea of seed zones—mapping the landscape into areas “within which plant materials can be transferred with little risk of being poorly adapted to their new location,” as the agency states on its website. Ever since, forest managers have stayed loyal to these zones when selecting seeds for planting.

Seedlings planted in widely spaced clusters in a portion of the Eldorado National Forest that was burned by the 2014 King Fire near Georgetown, California. As the threat of wildfire intensifies, a debate has emerged in about the best way to plant trees. Max Whittaker/Bloomberg/Getty

While assisted migration isn’t strictly prohibited by the Forest Service Manual and its accompanying handbooks—the official policy documents that, as Forest Service land manager Andy Bower explains, guide “every aspect” of how the agency operates—it isn’t encouraged, either. Last fall, Bower, St. Clair, and five other forest geneticists in the Forest Service proposed changes to the manual that include assisted population migration and, in some cases, slight range expansion, as forestry strategies. If their recommendations are accepted, it could drastically accelerate the use of assisted migration nationwide.

The Forest Service doesn’t have to look far for an example of a country taking a more aggressive tack: Canada is substantially ahead of the United States in research and implementation of assisted migration. This is, in part, a result of urgency. In the early aughts, aided by worsening climate change, lodgepole pine forests were devastated by invasive bark beetles and massive wildfires. This was also true in the United States, but when it happened in Canada, the country acted far more aggressively. “It was huge,” Greg O’Neill, a scientist working for the Canadian Forest Service, told me, “like they got hit by a sledgehammer. It really woke up the forestry community.” The Forest Service of British Columbia launched the Assisted Migration Adaptation Trial, or AMAT, in 2009, planting roughly 153,000 trees to see how each would fare in different climates. With more than a decade of results, they have begun to use this data to reforest areas that have been logged or burned.

This is not to say that the method should become the land management strategy in all or even most scenarios. Moving species across a landscape in response to climate change, Dumroese says, should be undertaken according to the Hippocratic Oath. “We’re talking about making some decisions that have some implications that we may not understand or even be recognized for 100 years,” he said, “or even longer.”

One of the troubles with assisted migration is that it’s difficult to know what future climate to plan for. Human choices are hard to predict. The adoption of a Green New Deal, for instance, would significantly affect climate modeling, as would the reelection of Donald Trump in 2024 or the continued reign of Amazon-destroying Jair Bolsonaro in Brazil.

But even in the most optimistic of climate scenarios, the forests need to get moving, from south to north, from lowlands to highlands, so that our landscapes remain populated with trees.

“It’s almost like we have this temporal-­centric view of nature,” O’Neill said. “A lot of people view climate change as something that’s going to happen, not something that has already happened.” And though all trees can generally survive a change of 4 degrees Fahrenheit in either direction, O’Neill reminds me that 2.7 degrees—the amount that the climate has already warmed in the past century—is a cataclysmic change of circumstances from a tree’s perspective. Seen this way, he said, “these trees are already a long way from home.” If all we do is help them get back to the kinds of habitats they’d lived in before the climate began to change so rapidly, he added, “I think we’ll be doing a great service.”

In May, a few weeks before driving to Oregon, I accompanied Forest Service scientist Jessica Wright from her research station in the Sierra Nevada foothills up Route 50 and into the mountains of the Eldorado National Forest, one of the most ecologically diverse tracts of land in California, spanning nearly 1 million acres. The road wound us upward into the rolling expanse of the Sierras, where towering green pines spread in all directions. Such sights always reminded me of the state’s largesse, and I used to find them transcendental: the sanctity of open space, the vastness of the landscape a mirror for the vastness of the human spirit. But now, this feeling is accompanied by a twin coil of fear. Fire. Those trees are exquisite fuel, and it all feels doomed to burn.

We turned onto a dirt road and knocked our way through the forest. After a few minutes, the trees thinned; the lowest branches of ponderosa pines and Douglas firs were charred, and the blackened sticks of former trees pointed skyward like bayonets. The road took us to an open clearing, bare and treeless like a wound. This was the site of the King Fire, which destroyed roughly 250 square miles of the central Sierra foothills in 2014, and it was only now, seven years later, looking green again.

A few years back, Wright started talking to a Forest Service program manager named Dana Walsh about the prospect of an assisted migration research trial on a tract of land that Walsh oversaw—and they decided to plant along this 12-acre patch that had burned. In the winter of 2019, they sowed their 1,200 trees sourced from 24 origin populations. Their hope is to convince other forest managers that assisted migration can be used to replant burned forests in the future—instead of reforesting strictly with local seeds. And several Forest Service scientists, including Wright and St. Clair, are building new seed selection databases that map climate predictions with seed source adaptations, should assisted migration finally be put into practice in the States.

Wright, who has hip-length hair and seems equally at home sporting a hard hat and presenting at a conference, is particularly optimistic about the prospects of planting in burn zones. If a forest will be replanted anyway, why plant what was already there and burned, when we can reforest these burn sites—which have grown all the more common, and so much bigger—with trees that will be better suited to that future in 30 to 50 years? A stressed forest brings diseases and pests, which kill trees, offering more kindling to burn. The healthier a forest, the less likely it is to catch fire.

Justin Maxon

Assisted migration “is risky, but, you know, we also have no choice.

We have to start experimenting with this.

We have to start moving things around and watching and seeing how they do.”

Burn zones, like this one seen from a drone in California’s Shasta-Trinity National Forest, offer a unique opportunity to create the forests of the future. As assisted migration has gained more traction, researchers believe burn zones are prime spots to plant trees that will be adapted for the warmer climates of the middle of the century—and beyond.

Along 12 acres of the King Fire site, Wright and her team had planted two kinds of pine: ponderosa—which grow up to 200 feet tall with thick, striated bark—and a type of sugar pine resistant to white pine blister rust, a fungus decimating western sugar pines. To mimic nature, the trees had been planted somewhat willy-nilly along the hillside, as they would grow in the wild. We walked along the planting site, where I tried to spot the trees; at only two years old, the saplings were not much higher than my ankle. Some hadn’t made it at all, and some were still slight wisps of life, while others were growing strong and burly.

I asked Wright what she made of the differences in growth. She laughed.

“It’s too early to say,” Wright told me.

But weren’t they impatient, I wanted to know? I was. Why was this tree, on the lower slope, doing so beautifully, its tiny trunk much thicker than the rest, its needles skewering outward like porcupine quills, its yellow-green buds promising new growth?

Wright countered that it’s not until about 10 years into a study that the data starts to be meaningful. “That’s when I start to believe it,” she said. So many things could happen between now and then, and early growth might not end up meaning much. After all, those dead Douglas firs that had so rattled me in Oregon had done great the first few years of the study.

We found some shade under the trees that had survived the 2014 fire, and sat down for lunch. To consider the future of forests is to slip into a timeline so abstract that it’s hard to conceive, but scientists like Wright are in it for the long haul, imagining a lifespan far beyond their own.

“I won’t see this big tall forest we’re planting now,” she said. Her kid might see it, or perhaps her grandkid. Tending to any kind of future is a gesture of optimism, she concedes, particularly such a distant one. “But I’m good with that.”

As a member of the living, it can be difficult to understand how unlikely it is, statistically speaking, to become alive. A healthy beech tree, explains Wohlleben in The Hidden Life of Trees, will produce roughly 1.8 million beechnuts in its lifetime. “From these, exactly one will develop into a full-grown tree,” he writes, “and in forest terms, that is a high rate of success, similar to winning the lottery.”

For Joshua trees, the odds of successful reproduction are even longer. For a Joshua tree to be born—a tree that lives in far starker conditions than the beech—its mother has to flower and seed when it reaches sexual maturity. The seed, which resembles a flat puck of black putty smaller than a dime, has to find a home conducive to its germination and bloom. That’s hard enough in the dry expanse of the desert, and harder still as the landscape warms. Its best-case scenario is to find its way to a spot beneath a nurse shrub or blackbrush, where it can germinate protected from the chomp of roving jackrabbits. It would particularly benefit from finding a spot atop a symbiotic soil fungus that lurks beneath the sandy loam and can help the baby Joshua tree grow. If the tree makes it past the perils of early life, it needs another 30 to 60 years before it’s ready to reproduce. Then it would rely on the yucca moth to pollinate it; otherwise, it won’t bear fruit. Then and only then, after this confounding and unlikely gauntlet has been run, will a Joshua tree be able to set seed, the whole tenuous cycle repeating itself.

Scientists have mapped Joshua tree survival against the most dire climatic conditions—i.e., if humans continue at our current rate of consumption and emission—and found that by the year 2100, essentially zero Joshua tree habitat will remain in California’s Joshua Tree National Park, even for trees that are already among the most drought-tolerant.

Lynn Sweet, a plant ecologist who studies Joshua trees at the University of California, Riverside, told me that her team calculated that, under more mitigated scenarios in which carbon emissions were reduced, “we could preserve up to 20 percent or so of habitat in the park and the surroundings,” assuming the moth and mycelium make it in this scenario, too.

When it comes to conservation efforts, humans most often think of the forests most dear to them—the places they grew up visiting, the places where they got married or take their beloved weekend hikes, the national parks known for their iconic trees. These places—Sequoia National Park, Olympic, Muir Woods, the Everglades—loom large in our collective consciousness. “I often joke with reporters,” Sweet told me, “that no one is coming out to do a climate change article on the blackbrush bush,” an equally imperiled species in the desert.

Joshua Tree National Park is central on my personal map of sacred places. It was the first place I went backpacking as a kid, the first place I slept under the stars, and a place I’ve returned to again and again to reattune with the world. The Joshua tree’s silhouette is imprinted on many significant memories throughout my life—these are trees I really, really, really want to survive.

A Joshua tree against a smoky sunset as the Bobcat Fire burns in Southern California’s Angeles National Forest. Robert Gauthier/ Los Angeles Times/Getty

After getting vaccinated last spring, I headed down for a few days in search of desert light and those fabled trees. I drove from the south end of Joshua Tree to the north, moving through a low, flat valley where Joshua trees and cholla clustered in mighty, baffling stands. The Joshua trees here in the valley looked healthy enough, but botanists know better: Look closely, they told me, and you’ll see there are no young sprouting among the noble elders. This was a forest of childless parents, living their final days as the last of their kind to call that spot their home.

Sweet had directed me to visit Black Rock Canyon, where the healthiest of Joshua trees were now finding space to grow. Here we were at a higher elevation than the park’s sweeping flatlands, meaning it was cooler and slightly wetter. “They’re essentially running uphill,” she told me, on an intergenerational march toward higher ground. I took a long solo hike through these highlands where hundreds of Joshuas stood. The trees were lovely to behold from all angles, like benevolent apparitions from some absurdist underworld. But the best view was from above: beholding all those Joshua trees across the valley floor that were thriving, surrounded by their young, with room still to move upward. The problem with up is there’s only so far to go before it’s just sky.

The living will do whatever they need to survive. In the apocalyptic grove near Medford, I had seen one desiccated former tree whose branches were covered in hundreds of cones still affixed to it like Christmas ornaments. St. Clair explained that this behavior was normal enough for a tree in distress. Sensing it will die, the tree bursts forth into cones in a frantic final act of hope: not so much for itself, but for its species.

I left the desert like I’d left Oregon, having seen what I’d come to see: the future. There wasn’t a single version of it, but many. Another quote St. Clair likes to share is by the late forester and politician Gifford Pinchot: “The vast possibilities of our great future will become realities only if we make ourselves responsible for that future.” If we look into the crystal ball, we see ourselves peering back at us in search of answers to the same questions.

Contrary to Common Belief, Some Older Trees Make Fewer Seeds

March 9, 2022 · 1 minute read
Contrary to Common Belief, Some Older Trees Make Fewer Seeds

The paper
T. Qiu et al., “Is there tree senescence? The fecundity evidence,” PNASdoi:10.1073/pnas.2106130118, 2021.

According to Duke University ecologist James Clark, many researchers think that, given the right conditions, trees can generally continue to grow for a very long time, producing more seeds all the while. But the common agricultural practice of replacing fruit and nut trees every few decades to avoid declining yields belies this dogma, he points out. “Nobody who’s trying to produce seeds or nuts for a profession would rip out their trees and plant new ones if they didn’t have to.”

To get to the root of this apparent contradiction, Clark and a team of more than 60 researchers from 12 countries embarked on a massive undertaking: analyzing a long-term plant monitoring database to analyze the relationship between tree size (which they used as a proxy for age) and seed production in more than half a million trees representing nearly 600 species.

The researchers found that although seed output, or fecundity, initially increased dramatically with tree size across all species, there was a point where fecundity started to decline in 63 percent of the species they studied, while in another 17 percent, the rate of fecundity instead plateaued at a certain size. In the remaining 20 percent, there appeared to be no negative effect of tree size on fecundity, although the authors note this could have been due to the difficulty in finding larger members of those species. 

Because the team didn’t have access to data on tree age, it’s impossible to know whether the observed decrease in fecundity was due to aging or to some other aspect of their large size, says plant physiologist Sergi Munné-Bosch at the University of Barcelona, who was not involved with the study. Nevertheless, “it’s amazing to collect such huge amounts of data,” he says, adding that “having almost 600 species is a treasure.” 

New Environmental Education Center Partners for Outside Experiential and Place-Based Learning in Henrico County

March 3, 2022 · 5 minute read
New Environmental Education Center Partners for Outside Experiential and Place-Based Learning in Henrico County

In the fall of 2022, Henrico County Public School (HCPS) students will make nature their classroom – on land protected by Capital Region Land Conservancy (CRLC).

MARCH 2, 2022 PRESS RELEASE from Capital Region Land Conservancy

RICHMOND, VA – In the fall of 2022, Henrico County Public School (HCPS) students will make nature their classroom – on land protected by Capital Region Land Conservancy (CRLC). The School District announced the establishment of a new Center for Environmental Science and Sustainability anchored at Varina High School at a School Board meeting in August and entered into a memorandum of understanding with CRLC. Applications for the new program were accepted until January 10th.

The Center will provide students with a unique opportunity to expand their understanding of environmental stewardship through student-centered learning, community partnerships, and foundational academic knowledge. The goals of the new Center are to utilize the broader community as a context for learning, encourage interdisciplinary instruction, incorporate experiential learning that fosters collaborative, creative, and critical thinking skills, implement environmental service-learning projects, and to allow students to earn college credits and credentials. As one of several sites where students will have outdoor access, CRLC’s recently acquired 353 acres near Deep Bottom and Four Mile Creek will provide an environmentally and historically rich location with abundant opportunities for experiential and place-based learning.

“The innovative learning opportunities created by this partnership are boundless. CRLC’s property offers a rich landscape for hands-on learning about sustainability, environmental science, and stewardship,” said Amy Cashwell, Superintendent of Henrico County Public Schools. “We are fortunate to have a visionary school board, board of supervisors, and community partners who understand and embrace the immense possibilities when learning extends beyond the traditional classroom.”


CRLC Land Holdings LLC, a single-member, wholly-owned subsidiary of Capital Region Land Conservancy, received the Deep Bottom property in May 2021 as the result of a generous donation from the prior landowner, Randy Welch. The conservation easements protecting the property, recorded in 2017 and 2018, will remain enforced. The property boasts over 400 feet of frontage along the James River, 1.3 miles along Four Mile Creek, 3,700 feet along Roundabout Creek, and contains more than 75 acres of wetlands and riparian buffer within a resource protection zone. The land contains 173 acres of prime farmland and 57 acres of soils of statewide significance. Deep Bottom’s historical significance is equally impressive. There are documented historic resources associated with the Battles of First Deep Bottom, Second Deep Bottom, and New Market Heights in which the U.S. Colored Troops fought. With all these values protected, CRLC’s land makes for a perfect campus to explore many of the great natural and historic resources of eastern Henrico County.

“While the property was already protected by conservation easements, taking ownership of it affords us a greater opportunity to enhance connections to the land through meaningful, site-specific immersive learning for our youth and the general public,” said Parker C. Agelasto, CRLC’s Executive Director.

Since August, CRLC has convened HCPS representatives along with representatives of Henrico Education Foundation, Henricopolis Soil & Water Conservation District, James River Association, National Park Service, Virginia Commonwealth University, Richmond Audubon Society, Virginia Department of Conservation and Recreation, Virginia Department of Forestry to begin envisioning the possible educational uses of the property. Funding provided through the Upper and Middle James Riparian Consortium ($10,000) as well as the James River Buffer Program of the Virginia Department of Forestry ($22,000) has allowed CRLC to initiate the restoration of 9 acres of important forest buffer which will enhance water quality and habitat. Students could study these improvements in water quality, forest succession, native grass propagation, migratory bird breeding and stopover habitat, and more. These educational opportunities support the center’s goal for an integrated interdisciplinary approach to science, technology, and history.

“It feels good knowing that our work will enhance the riparian forest around the streams and river on the Deep Bottom property and will contribute to CRLC’s goals for nature-based education, especially around the role of trees in water quality protection,” said Deya Ramsden, Middle James River Forest Watershed Project Coordinator for the Virginia Department of Forestry.

In addition to the work of the Advisory Group to support the educational initiatives of the new Center for Environmental Science and Sustainability anchored at Varina High School, CRLC is working on a land management plan for the property. Funding for the plan is provided in part by a $23,000 grant from the Chesapeake Bay Restoration Fund, a fund generated from the sale of Chesapeake Bay license plates at the Virginia Department of Motor Vehicles. The plan for the property will include the interpretation of the property’s historic resources, maintaining and/or improving the ecological health of the plant communities found there, and providing for quality recreational opportunities for the public that also educates them regarding the history and ecology of the site. The plan will promote healthy ecosystems and clean water mitigating threats to the various sensitive features of the property. For example, the entire 353 acres fall within the National Audubon Society’s Lower James River Important Bird Area and with the right management, goals can support many migratory species. Future public access for outdoor recreation may include camping, hiking, bird watching, orienteering, geocaching, and other potential uses which are compatible with ecological goals.


About Capital Region Land Conservancy (CRLC): Incorporated in March 2005 as a non-profit 501(c)(3) organization, CRLC seeks to conserve and protect the natural and historic land and water resources of Virginia’s Capital Region for the benefit of current and future generations. CRLC is the only non-profit organization devoted specifically to the conservation of land within the capital region serving the City of Richmond and the Counties of Charles City, Chesterfield, Goochland, Hanover, Henrico, New Kent, and Powhatan. CRLC educates landowners about voluntary land protection tools, facilitates the process of donating conservation easements, and holds or co-holds conservation easements. CRLC is accredited by the Land Trust Accreditation Commission, an independent program of the Land Trust Alliance. CRLC has helped protect more than 13,000 acres that includes fee simple ownership of 460 acres as well as easements on more than 2,300 acres.

For more information: Contact Parker C. Agelasto, Executive Director

The mystery of Mexico’s vanishing stream oaks

March 3, 2022 · 12 minute read
The mystery of Mexico’s vanishing stream oaks

By Alejandra Martins 22nd February 2022

Mexico has more species of oak trees than any other country. In recent years, the saplings of one of its most vulnerable and well-loved oak species have disappeared.

By the banks of a seasonal riverbed in north-western Mexico, a collection of towering, gnarled oak trees stand guard. These trees descend from ancestors that lived more than 50 million years ago and their species has faced, and survived, any number of challenges.

Today fewer than 5,000 of them are still standing, and they are found only in the Sierra La Laguna mountains, in the state of Baja California Sur. These trees, at the tip of the Baja California peninsula, are the last living populations of Quercus brandegeei, a species of oak known locally as “encino arroyero” (stream oak) due to its restricted habitat along the banks of streams.

“They are survivors, those trees are heroes,” says Silvia Álvarez Clare, a Costa Rican ecologist who is the director of the Global Tree Program of the Morton Arboretum, a botanical garden and conservation center in Illinois.

Mexico is home to more species of oak than any country in the world, though many of them are threatened. In the case of the arroyo oak, as it is known, the species now faces a particularly troubling problem. Though plenty of trees aged more than 100 years can be found, locals noticed that in recent years there had been no seedlings that have sprouted from their acorns in sight. For some reason, the trees had simply stopped reproducing.

The arroyo oak likely had a much wider range in the past, but is now restricted to a small pocket of Mexico (Credit: The Morton Arboretum)

The arroyo oak likely had a much wider range in the past but is now restricted to a small pocket of Mexico (Credit: The Morton Arboretum)

Álvarez Clare describes the trees as “a community of arroyo oak pensioners, because we haven’t been able to find juveniles. And in a healthy population of trees there are a lot of young individuals”.

Mexican and US scientists, alongside local communities, are now seeking not only to solve this mystery of the missing stream oak saplings but to save this iconic species from extinction.

Global but vulnerable

“It is estimated that there are between 400 and 600 species of oaks in the world,” explains Maricela Rodríguez, a Mexican botanist specializing in oaks and the coordinator for Mexico and Central America of the Global Consortium for the Conservation of Oaks (GCCO).

Some scientists conservatively estimate there to be “a figure of 435 species, of which 168 are found in Mexico”, says Rodríguez. “In other words, 38% of the total are found in this part of the world. Other regions with high oak species richness are South East Asia, which is home to 140 species, and the United States with 91 species.”

The Red List of Oaks 2020, a study published by the Morton Arboretum and the Botanic Gardens Conservation International (BGCI), indicates that at least one-third of oak species are endangered. And for about another 105 species, there is not enough information to tell how the population is doing.

Arroyo oaks provide rare shade in hot weather, but this can lead to its own problems for the trees' acorns (Credit: The Morton Arboretum)

Arroyo oaks provide rare shade in hot weather, but this can lead to its own problems for the trees’ acorns (Credit: The Morton Arboretum)

“I find it incredible. They are such rare, new [to science] or unknown species that we don’t even know if they are threatened or not,” says Álvarez Clare.

In the case of Mexico, the Red List estimates that 32 of the country’s oak species are in danger of extinction. And among the most threatened is the arroyo oak.

A haven in Mexico

Part of the puzzle lies in the species’ limited range, far from its evolutionary relatives. The most closely related species to the stream oak is Quercus fusiformis, which is found in Texas, Oklahoma and north-east Mexico says botanist Allen Coombes, who curates scientific collections at the Botanic Garden of the University of Puebla in Mexico.

So how did the stream oak come to survive only at the tip of the Baja California peninsula?

“Since its appearance about 55 million years ago, in the late Paleocene, the genus Quercus has survived many biological and physical changes,” says Rodríguez. “Since then, climatic changes have caused population movements, expansions, and decreases in their distribution, both latitudinally and altitudinally.”

The arroyo oak probably had a wider distribution in the past, and found a haven in the Sierra La Laguna, says Mexican ecologist Aurora Breceda from the Centre for Biological Research of the Northwest (Cibnor). “Everything indicates that it is a relict species,” she says, referring to species that survive only in small populations, serving as remnants of the past.

“There is only that relic of the historical distribution of the arroyo oak that we calculate must have a total of less than 5,000 individuals, very restricted to only the banks of the streams,” says Álvarez Clare.

Local people have helped revive the arroyo by planting, caring for and "adopting" seedlings (Credit: The Morton Arboretum)

Local people have helped revive the arroyo by planting, caring for, and “adopting” seedlings (Credit: The Morton Arboretum)

Scientists believe that the species failed to adapt to changes that, over millions of years, created a near-desert climate in this region. Today, the habitat is so dry that many streams are only filled with water by winter rains or hurricanes that create powerful but ephemeral currents.

It is only in the humidity of sandy soil on the banks of the streams of the Sierra La Laguna, that the arroyo oak found its refuge.

An oasis and a resource

Quercus brandegeei is considered a key species for the ecosystem and is highly valued by the local population.

The arroyo oaks “are beautiful”, says Breceda. “Here in Baja California Sur, an area with scarce vegetation cover, you have these huge trees.

“An arroyo oak can measure 20m [66ft] in height and have crowns of 30sq m [320sq ft]. They are like a peaceful oasis.”

Most of these scattered oak populations are found within a range of 3,000sq km (1,200sq miles), most inside the perimeter of the Sierra La Laguna Biosphere Reserve. Biosphere reserves are natural spaces identified by Unesco – the United Nations Educational, Scientific, and Cultural Organization – where biological conservation coexists with the cultural and economic development of local people. The arroyo oak survives here alongside humans and their cattle, which are allowed to roam the area freely.

Many locals report having lived with this species for generations. “I remember my grandmother who used the acorns to make oil, tortillas,” says Rogelio Rosas López, owner of a local tour agency, Rancho Ecológico El Refugio. His grandmother, he recalls, also cooked with the seeds “atole”, a typical Mexican pudding. “And she used to take us and pinch us because we had to gather sacks of acorns to give to the pigs.”

Livestock such as pigs have shared the landscape with the arroyo oak for generations (Credit: The Morton Arboretum)

Livestock such as pigs have shared the landscape with the arroyo oak for generations (Credit: The Morton Arboretum)

The acorns of the stream oak are food for pigs and goats, as well as wild animals. Occasionally, if there is a fallen tree, the wood is used.

“A lot would be lost for the ecosystem if the oaks weren’t there, mainly the shade. We wouldn’t enjoy such a beautiful landscape,” says Juan Refugio Manríquez Rosas, another member of the community. “People would lose the best acorns, and everything from birds to raccoons and squirrels would be affected.” The honey from this oak, too, is highly valued and has become a source of local income, he adds.

The missing saplings

No one knows exactly how old the arroyo oaks of the Sierra La Laguna are. “It really is a great mystery. We think they are definitely over a hundred years old. But it could be that they are hundreds of years old,” said Álvarez Clare. In 2022, a team of experts in dendrochronology, the science of dating trees, is expected to find a conclusive answer to the question.

But the biggest puzzle is the absence of juveniles, something that has long drawn the attention of local inhabitants.

“My grandfather used to say that there were many more trees,” said José Abelino Cota, owner of a plot of land in the Sierra La Laguna. “It is very rare to see a new tree. I don’t know what is the reason for it.”

Explaining this lack of regeneration is vital. Although oaks can sometimes reproduce asexually, producing underground stems with shoots that give rise to new individuals, this form of reproduction does not protect the future of the species. It only creates clones of the same tree, without the genetic variability necessary to respond to drastic environmental changes or new diseases.

Only sexual reproduction, with small trees born from acorns, is likely to maintain the arroyo oak in the long run.

Looking for answers

Scientists explored various hypotheses to explain the lack of regeneration. The first was the impact of climate change, which, according to Álvarez Clare, has caused “the dry season to be drier and hotter, and the rains to be more unpredictable in this area of ​​Baja California Sur”.

The second hypothesis was the lack of viability of the acorns – but a study at Cibnor showed the opposite. “We collected seeds from several locations. At Cibnor we measured them, did a morphological study, and put them to germinate. And they have a very high germination rate – more than 90% germinate,” says Breceda.

The acorns of the arroyo oak had no trouble in germinating, researchers found – the limitations to the oak's regeneration must lie elsewhere (Credit: The Morton Arboretum)

The acorns of the arroyo oak had no trouble in germinating, researchers found – the limitations to the oak’s regeneration must lie elsewhere (Credit: The Morton Arboretum)

The third hypothesis, according to the Morton Arboretum’s Álvarez Clare, was the conflict with the ranchers’ cattle. “We think the cows are definitely a problem for the oak because they love to be in the shade and they crush the seedlings,” she says. “And besides, the pigs eat the acorns.”

For Álvarez Clare, the mystery of the stream oak’s lack of regeneration continues and “has only been partially solved”. Scientists agree on the impact of livestock crushing and eating acorns, but the consequences of climate change raise further questions. “Climate change is indeed a problem, but how much and to what magnitude is something we are still not sure about,” she says.

For Breceda, the big problem could be the changes in the temporary patterns of both rainfall and temperatures. “We really don’t know if the effects of climate change could be causing variations in these seasonal patterns, which could be affecting the species. We don’t know, a separate study is required.”

‘Let’s Save the Arroyo Oak’

Although the precise impact of climate change on the germination of acorns is unknown, there is one thing that the project’s experts are certain about: the way to save these oaks lies in the hands of the community members themselves.

“The ranchers have a double function: they are part of the problem, but they are our only solution if we want to save the arroyo oak,” says Álvarez Clare.

The scientists’ response has been to establish a tree care and adoption program with ranchers and other residents called Salvemos al Encino Arroyero, or “Let’s save the Arroyo Oak”. The project is part of the Global Trees Campaign, an initiative to save the world’s threatened trees coordinated by the BGCI.

The idea is that local people plant, care for, and “adopt” seedlings, becoming guardians of the species, says Mexican biologist and researcher Daniel Wblesther Pérez Morales, who leads the work with the communities, explains. The residents will in turn benefit from the acorns and the many other services that these trees provide.

“We established a community nursery and propagated seedlings to plant new arroyo oak trees in the region,” says Pérez Morales. It’s important that collected acorns are planted, as the seeds of the stream oak do not tolerate being dehydrated. So far, close to 500 new trees have been planted with the help of the inhabitants of the communities.

Researchers like Silvia Alvarez Clare have worked to collect arroyo acorns, before they are devoured by pigs (Credit: The Morton Arboretum)

Researchers like Silvia Alvarez Clare have worked to collect arroyo acorns before they are devoured by pigs (Credit: The Morton Arboretum)

“We plan to plant about 1,200 new oaks in the region. We will plant within the fences of the ranches to ensure that each oak is growing protected and well cared for,” says Pérez Morales.

“We will also plant outside the ranches in areas where there is less pressure from predators. And with the help of the municipal authorities, we will plant in public spaces, where each planted tree has protection, care, and its growth can be monitored.”

The Morton Arboretum and the GCCO are also working with botanic gardens in Mexico to establish the oak elsewhere beyond its current range, to improve the chances for conservation of the species. Currently, 15 trees are growing in the botanic garden of the University of Puebla in central Mexico.

An exchange of knowledge

Scientists, local authorities, ranchers, and other members of the community in the town of San Dionisio in Baja California Sur came together to discuss the oak’s future at a workshop on the initiative in late 2021. “It was a workshop where we co-constructed knowledge,” says Breceda. “Because it’s not like ‘wise’ scientists are going to tell local people what to do with something that has been theirs for hundreds of years. They grew up with these trees.”

Local people know better than anyone the best places to plant, says Pérez Morales. And they know that without their help, in an increasingly dry and unpredictable climate, it will be very difficult for the oak to survive.

“It is important that we ranchers give ourselves the task of taking care of these spaces, of watering the trees until they are at least two years old,” says Rogelio Rosas López.

More workshops are planned in 2022, as well as the first “Festival of the Arroyo Oak” in San Dionisio. The idea is also to promote other activities that are a source of income, including ecotourism and artisan products such as mango jelly or a drink from damiana, a local plant.

Clinging to life

The stream oak project shows how complex, and case-by-case, the task of saving endangered species is.

“The work has not been easy since the results of these efforts are not immediate and it must be understood that they will be seen over longer periods. However, we are on the right track,” says Pérez Morales.

Noelia Álvarez de Román, director of conservation for Latin America and the Caribbean of the BGCI, has praised the outcomes so far. “The Quercus brandegeei conservation project has resulted in important advances in knowledge of the species and its threats, in the dissemination of the importance of its conservation, and in the increase of capacities of local collaborators,” she says.

“If this species disappears, it disappears from the face of the known universe,” says Cibnor’s Aurora Breceda. “And on the other hand, we lose the possibility of sustainable resources for the rural populations of Baja California Sur, for which I have enormous respect and admiration.”

The Morton Arboretum’s Álvarez Clare never ceases to be amazed that “currents, storms, hurricanes, droughts happen to these oaks and they are still clinging there, producing their acorns, providing shade, cleaning the air, giving life”.

“Actually, when I’m next to one of those trees, I just touch the trunk and say, ‘thank you!’.

“The arroyo oaks have been there much longer than we have,” says Álvarez Clare. “And we want to ensure that they are there for our children and our grandchildren, that they can have the shade of that wonderful tree that our grandparents had.”

Alejandra Martins is a broadcast journalist at BBC Mundo. This article was originally published in Spanish on BBC Mundo – you can read it here.

300-year-old tree rings confirm recent uptick in hurricane-driven rainfall

February 23, 2022 · 4 minute read
300-year-old tree rings confirm recent uptick in hurricane-driven rainfall

There’s been nothing like these cyclone seasons for at least several centuries.


Tropical cyclones like Hurricane Ida can cause severe flooding, producing disruptions, damage, and loss of life. Like many other types of weather, tropical cyclones and hurricanes on the US East Coast have become more extreme over the past several decades. Although there is some controversy over the extent of the increase in intensity, there is evidence that such storms are moving more slowly than in the past. This slower movement causes storms to last longer and produce more rain. However, because conventional weather records only go as far back as 1948, it’s unclear how unusual these slow-moving cyclones are compared to earlier weather patterns. 

recent study addresses this question by using tree rings to reconstruct hundreds of years of seasonal cyclone precipitation levels. The studied trees, some over 300 years old, show that precipitation extremes have been increasing by 2 to 4 mm per decade, resulting in a cumulative increase in rainfall of as much as 128 mm (five inches) compared to the early 1700s. The greatest increases have occurred in the last 60 years, and recent extremes are unmatched by any prior events. 

Beyond establishing these reconstructed historical records, researchers are working with these data sets to improve forecasts of what this region might expect in the future. 

Good for growth—at least for trees

In earlier work, Dr. Justin Maxwell and his collaborators found that longleaf pine trees on the East Coast of the US could act as indicators of tropical cyclone precipitation, as measured by the trees’ late season (June to October) growth bands. These smaller, more local studies indicated that recent precipitation levels were far greater than anything the trees had experienced earlier in their lifetimes. 

That’s an unexpected finding since tree-ring records generally show evidence of extreme weather scattered throughout their history, although the frequency may vary. The discovery prompted a new study, which checked whether this pattern held over a wider area.

“Often, tree-ring reconstructions show us that the extreme climate we have recorded with instruments (weather stations) over the last 120 years was surpassed back in time,” Dr. Justin Maxwell told Ars Technica. “Our past research showed that recent extremes were unmatched in the past—all the highest values are mostly since the 1990s, which was a big surprise, and that encouraged us to sample a broader area to see if this increase was local or present over a larger region.”Advertisement

Combining existing data sets with two new locations, the researchers included trees from a total of seven sites across North and South Carolina. Within North America, this region receives the most rain from tropical cyclones, and it also has the world’s most complete record of this type of precipitation. 

The new data sets included a selection of samples from 13–36 old-growth trees per site (taken in a way that caused minimal damage to the trees), as well as stumps. The researchers’ next step was to calibrate their model by comparing tree ring patterns to known rainfall measurements from 1948 to the present. 

Reconstructing the past to predict the future

As might be expected, tree rings are more representative of seasonal rainfall than of the frequency or extremity of individual storms. But the growth patterns clearly suggested less cyclone season precipitation in centuries gone by. 

A year with a lot of rain doesn’t necessarily mean a giant storm passed through. “[It] could represent rainfall from one hurricane, or it could’ve been multiple hurricanes,” wrote Maxwell. “What we found in this paper is that this area is receiving more tropical cyclone precipitation for the entire season.” While researchers in the field are still debating the cause, many have suggested that it’s related to the trend of storms moving over the area more slowly. 

Worldwide, cyclones’ translational speeds have decreased by as much as 10 percent in the last 70 years due to weakening global wind currents. “This [increased precipitation] is because hurricanes are hanging around one area longer than they used to,” Maxwell explained.

The team is expanding its historical reconstruction by including samples from across the southeastern US. The study’s co-author, Dr. Joshua Bregy, is also collaborating with other experts to explore whether these reconstructions can be used to help project what we might expect from future cyclone seasons. 

“Based on our current knowledge of the global climate system, in a warmer world, global winds will be weaker, and we are seeing this happen already,” said Maxwell. “If warming continues, as is predicted, these global winds will continue to be weak. Global winds are what steer tropical cyclones, so having weaker winds leads to more meandering storm tracks and stalled storms in one location, producing more rainfall. Therefore, these large seasonal totals of tropical cyclones are likely to continue into the future.” 

PNAS, 2021. DOI: 10.1073/pnas.2105636118

K.E.D. Coan is a freelance journalist covering climate and environment stories at Ars Technica. She has a Ph.D. in chemistry and chemical biology.

Genome Spotlight: Lychee (Litchi chinensis)

February 23, 2022 · 4 minute read
Genome Spotlight: Lychee (Litchi chinensis)

By: Christie Wilcox

Whole-genome sequences reveal multiple domestications of this agriculturally important tree and may hold the secrets to producing the sweet fruit year-round.

If you happen to be in the Fujian province of China and know the right people, you could have the opportunity to see the oldest living lychee tree—a Songxiang variety that most likely first sprouted more than 1,250 years ago during the Tang dynasty. That was around the time Emperor Xuanzong created a relay of sprinting horses to race the quick-spoiling fruit 700 kilometers from where it was grown to the capital in a week to ensure his beloved consort Yang Guifei had her fill of fresh lychee throughout its short fruiting season.

If it also happens to be June or July and you’re really lucky, you might even taste the ancient tree’s fruit, because even after a millennium, the plant continues to bear the sweet lychee that made its species a major agricultural crop in the region.

Chinese artist Ding Fuzhi’s 1941 painting of lychees with a poem about Emperor Xuanzong’s imperial lychee delivery service inscribed on the left© RAWPIXEL.COMCC BY 4.0

While the first records of lychee cultivation date back around 3,000 years, the source of domesticated varieties has remained unclear. That may be because the tree’s agricultural history is complex: comparative analyses of wild and cultivar genomes suggest there wasn’t a single moment in history when lychee trees were tamed. Instead, whole-genome sequencing analyses published January 3 in Nature Genetics indicate that people domesticated the plant twice to obtain trees that bloom at different times.

A team composed of scientists from the US and Chinese universities set out to generate a high-quality genome sequence for Feizixiao, a popular lychee hybrid bred by crossing an early-flowering variety with a late-blooming one. Using PacBio long reads corrected with Illumina short reads, the team assembled the cultivar’s 470-megabase genome, which they estimate is 96.2 percent complete. They then annotated it using RNAseq data and used it as a reference for whole-genome resequencing of 72 previously sequenced individuals, including 38 wild ones, representing various types of lychee.  

Phylogenetic analyses of these genomes suggested that the species originated in the southwestern province of Yunnan and then spread eastward and southward, including all the way to Hainan Island off China’s southeastern coast by an estimated 18,000 years ago. Millennia later, people began to cultivate trees from both places: ones from Yunnan that flowered early in the summer, and ones from Hainan that flowered later. These were then interbred to create Feizixiao and other intermediately flowering cultivars.

In addition to publishing the high-quality reference genome, the researchers dug into the differences between early- and late-flowering varieties in the hopes of discovering the genetic basis for bloom timing. Among their findings is a 3.7-kilobase deletion correlated with early flowering. The earliest-flowering varieties lack the region on both of their chromosomes, while late-flowering ones have two copies of the sequence. The hybrid Feizixiao is heterozygous for it.

“This is very useful for breeders. Because the lychee is perishable, flowering times have been important to extending the season for which the lychee is available in markets,” says Victor Albert, a University at Buffalo evolutionary biologist and a senior author of the study, in a press release. South China Agricultural University professor Rui Xia, also a senior author on the paper, adds that the deletion can serve as a biomarker for flowering time.

The authors also note that new genome sequence could facilitate a deeper understanding of other agriculturally useful traits and aid breeding programs in developing novel varieties—including, perhaps, trees that flower at dramatically different times, Albert tells Popular Science. And if so, then fresh lychee might become available year-round—something that could have only been a dream to Yang Guifei (and a nightmare to Emperor Xuanzong’s horses).

Runners Up

California wild radish (Raphanus sativus x raphanistrum

Despite the name, the California wild radish isn’t native to the US state—instead, it’s a hybrid of two species that were separately introduced to the region more than a century ago. First detected in the 1920s, this botanical mash-up has taken over, out-competing both parental species to become a widespread invasive weed. Its ecological success is likely due to its “unique combination of parental traits” write the authors of a December 16 Journal of Heredity study detailing the first whole-genome assembly for the hybrid. The sequence will shed light on the genetics of those traits, as well as generally “facilitate basic and applied research on this fascinating and problematic species,” they write in the paper’s conclusion.

A PHA-producing bacteria (Tepidimonas taiwanensis)

Reducing humanity’s reliance on oil requires finding substitutes for petroleum-based plastics. Among potential alternatives are biologically produced polyhydroxyalkanoates (PHAs), which accumulate naturally in bacteria such as Tepidimonas taiwanensis, a rod-shaped, motile species isolated from a hot spring in Taiwan. T. taiwanensis has also attracted interest from biotech companies because it exhibits potent alkaline protease activity, which is useful in sundry industries. The first whole-genome sequence for the species, published December 15 in Genome Biology and Evolution, should provide insight into the molecular basis of both of these useful features, the authors write.

Untouched old-growth forest holds ‘Underground Railroad Tree’ from the 1700s

February 17, 2022 · 6 minute read
Untouched old-growth forest holds ‘Underground Railroad Tree’ from the 1700s

By Heather Leah, WRAL multiplatform producer

GREENSBORO, N.C. — Tucked away in Guilford County, a patch of old-growth woods undeveloped since the 1800s still holds traces of the Underground Railroad’s hidden history.

Pieces of written and oral history tell stories of men and women escaping slavery, who hid in these woods, protected by the surrounding community of Quakers and free Black families.

At least one tree, far broader and taller than those around it, has been dated at more than 250 years old. Known as the ‘Underground Railroad Tree,’ it has stood as a silent witness to the countless men and women who hid here while escaping to freedom.

Local families were known to bring food, water, and supplies to freedom seekers hiding in the woods – which, at the time, were known as the New Garden Woods. Today, the woods are located on the campus of Guilford College, which was established first as a boarding school primarily for the Quaker community in 1837. Students and teachers were known for helping people hiding in those nearby woods, as well as providing education for African-Americans who were free from slavery.

Underground Railroad Tree: Old-growth forest by Guilford College in Greensboro hosts ancient trees where Freedom Seekers once sheltered in a Quaker community.

‘My home Deep River:’ Signal songs created a virtual map to the Underground Railroad

Because the penalties for attempting to escape, or for helping someone else escape, were so severe, the Underground Railroad was often spoken about in code.

Signal songs were one way of communicating to freedom seekers hiding nearby, without directly alerting anyone to their hidden presence.

In this area of North Carolina, each ‘stop’ could often be found 20 to 30 miles apart. A ‘triangle’ of Quaker communities surrounded much of the Triad area – New Garden, Snow Camp, and Deep River – each of which provided their own ‘stop’ on the Underground Railroad. Each of these communities can still be found today.

A helper on the Underground Railroad might walk past the woods, knowing someone was hiding within, singing loudly to themselves, “My home, Deep River. My home is over Jordan. Deep River. I want to cross over into Camp Ground.”

These lyrics would let a person hidden nearby know that they could continue to Snow Camp or Deep River to find more helpers.

“Many of the enslaved people had some indication of where they could find help,” said Dr. Adrienne Israel, a retired professor of history at Guilford College. “They would find out here in New Garden where they could find other Friends.”

Members of the Quaker community, even today, often refer to themselves as ‘Friends.’ Back during the antebellum period, Israel says a common code phrase was: “Find a friend of a Friend.”

‘A friend of a Friend’ referred to anyone friendly with the Friends, who were known for helping with the Underground Railroad. Even advertisements in newspapers seeking men or women who had escaped slavery would often warn, “They might be hiding among the Quakers or free Black community.”

Underground Railroad Tree: Old-growth forest by Guilford College in Greensboro hosts ancient trees where Freedom Seekers once sheltered in a Quaker community.

Friends bringing food, supplies to those hiding in the woods

People would often hide in the woods until they could safely move on to their next stop.

“They would hide there until they could find someone who was going north, who would hide them in their traveling group,” said Israel. “A group would pretend they were a free Black man or woman or hide them in a false-bottom wagon.”

They may even have falsified documents saying they had been freed, just in case they were caught or stopped.

This is very different than how the Underground Railroad functioned in Halifax County near the Roanoke River or along the coast like Elizabeth City or Washington. Depending on what geographical and cultural features you had to work with, the network to freedom worked very differently.

Quaker and abolitionist Levi Coffin, who lived in New Garden, walked into those very woods as a child, carrying armfuls of food, water, and supplies to the Freedom Seekers hiding there.

Underground Railroad Tree: Old-growth forest by Guilford College in Greensboro hosts ancient trees where Freedom Seekers once sheltered in a Quaker community.

He wrote about his first formative experience seeing the injustices and cruelty of slavery in his book Reminiscences Of Levi Coffin.

“At a young age, Coffin saw a big cart full of enslaved people chained together walking along the road, and it included a child who was 8 years old, about the same age as he was,” said Israel. “The child was being abused – with whips and chains and all that, to force them along.”

Israel said Coffin broke down crying and asked his father: Why?

“He’d later say that was his awakening. It made him resolve to try and do something about it,” said Israel.

The New Garden Quaker community was not the only helpers in the area. The land along Horse Pen Creek Road was owned largely by Black families who were free from slavery. Many of them, Israel said, were also collaborators with helping along the Underground Railroad.

A Freedom Seeker could disguise themselves, carrying false papers, and travel with other free African-American families. However, the risk for helping was extremely severe – it could include being killed, or even losing your own freedom.

“White people could lose their property,” said Israel. “Free Black people caught helping someone escape could be enslaved.”

However, there were cases of both white and Black members of the Underground Railroad being killed for helping someone escape.

Likewise, anyone attempting to escape slavery was legally allowed to be killed.

“Any white person who stopped you could ask you to surrender yourself, and they could kill you,” said Israel.

Aside from Quakers and members of the free Black community, there were also people enslaved locally who participated in helping others to freedom. Gwen Erickson, Quaker Archivist & Special Collections Librarian, said, “In Coffin’s book, he mentions enslaved people who were crucial to this network.”

Underground Railroad Tree: Old-growth forest by Guilford College in Greensboro hosts ancient trees where Freedom Seekers once sheltered in a Quaker community.

Visiting the Underground Railroad Tree

While the woods themselves are historic, the Underground Railroad Tree is one of only a handful of NC sites designated on the Underground Railroad Network to Freedom.

The tree isn’t hard to miss – towering over typical North Carolina trees, with an extremely thick trunk and antique bark. Historic signage has been put up nearby, as well as a wooden platform with benches, where visitors can sit in the shelter and contemplate the history that once happened beneath these very branches.

Guilford College’s archives have preserved some of the written and tangible history of the Underground Railroad’s activity on their campus and in the surrounding community.

Their collection includes antique copies of a local anti-slavery newspaper called The Liberator, old maps that show the historic layout of the area, and an original copy of Levi Coffin’s book.

The old maps give a clue as to why the New Garden Woods was an ideal hiding spot.

“If you look at the locations of New Garden, and Horse Pen Creek, and triangulate that with the local plantation — the woods are right in the center,” said Erickson.

Essentially, the woods were a private hiding place surrounded by helpful Quakers, free Black families, and even helpers who were enslaved locally.

The archives also have the ledger book of the New Garden Boarding school, which shows accounting of employees and teachers who worked there during its earliest years – some of whom continued to teach skills like reading and writing to members of the Black community, even as that became a riskier practice.

Today, the Underground Railroad tree is still standing in Guilford College Woods and is open for self-guided tours.

“It was there as a silent witness to all that took place,” said Erickson. “This root system and structure were here documenting all that unfolded.”

Many, Erickson said, feel this land is sacred. They visit to sit beneath the tree – a silent reminder of the men and women who risked everything for freedom – and those who helped them.

Underground Railroad Tree: Old-growth forest by Guilford College in Greensboro hosts ancient trees where Freedom Seekers once sheltered in a Quaker community.

Study shows how climate change can worsen impact of invasive plants

February 17, 2022 · 2 minute read
Study shows how climate change can worsen impact of invasive plants

by University of Florida

Synergy isn’t always a good thing—take climate change and invasive plants.

Scientists have long hypothesized that climate change, by intensifying stressors like drought or wildfires, would make an ecosystem more vulnerable to invasive plants. Those invasive plants may in turn alter the environment in ways that amplify the impacts of climate change, explained Luke Flory, a professor of ecology in the UF/IFAS agronomy department. 

A new long-term field study conducted by Flory’s lab offers the first experimental evidence to support this hypothesis.

The study, published in the journal Ecology Letters, exposed small plots of long-leaf pine to three scenarios: drought conditions, colonization by the invasive plant cogongrass, and a combination of these two factors.

To test how the different scenarios influenced the trees’ survival, the scientists added another stressor: fire. But before lighting the first fire, the team waited almost six years for the trees to grow under each scenario.

When the smoke cleared, the researchers found that trees that experienced both drought and cogongrass invasion were least likely to survive after a fire.

“Less water meant the trees didn’t grow as tall. At the same time, the cogongrass, which is drought-tolerant, provided extra fuel to the fire, making it burn hotter and increasing the height of flames,” Flory said.

Shorter trees plus taller, hotter flames meant those longleaf pines didn’t stand much of a chance, he explained. In plots where the pines were able to grow taller or weren’t surrounded by fire-fueling cogongrass, the trees fared much better and nearly all trees survived.

Experiments that show the interplay of climate change and invasive plants provide important information for land managers in fire-prone areas or areas where prescribed fire is used, Flory said.

“In addition, these findings are one more reason why managing invasive plants is so important to conserving native ecosystems,” Flory said.

The experiment took place at UF’s Bivens Arm Research Site in Gainesville, Florida. To simulate drought, Flory’s team installed shelters over the growing trees that partially blocked rain.

Cogongrass and longleaf pines are no strangers to each other. Longleaf pine, the tree species used in the experiment, once covered much of the southeastern U.S., though it now covers only a small percentage of its historic range. This is also a region where cogongrass, which is native to southeast Asia, has established. Fast-growing and highly adaptable, cogongrass is known for taking over pasture and forest areas.

The Flory lab’s experiment is part of a larger global scientific effort called Drought-Net, which collects data from sites around the world to understand how different ecosystems respond to extreme drought. 

More information: S. Luke Flory et al, Interacting global change drivers suppress a foundation tree species, Ecology Letters (2022). DOI: 10.1111/ele.13974

Journal information: Ecology LettersProvided by University of Florida

Fungi: the missing link in tree planting schemes

February 9, 2022 · 3 minute read
Fungi: the missing link in tree planting schemes

By Aileen Baird & Francis Pope

To slow climate change and restore dwindling wildlife populations, the UK government aims to plant enough trees to expand the country’s woodland cover from 13% to 20% by 2050. Creating healthy woodlands on this scale is an enormous challenge, but forestry experts have developed guidance that, if followed, ought to give these new habitats the greatest chance of success.

It is really important that the right trees are planted in the right places. Choosing trees that are well suited to the habitat means they will grow better, be less prone to disease, and provide plentiful food and habitats for other organisms, such as lichens and insects.

It’s equally important to avoid planting trees in the wrong places. Preventing tree planting on grasslands and wetlands protects the unique species in them, and helps them hold onto the huge stores of carbon in their soils.

Despite containing detailed plans for the creation of healthy woodlands for plants and animals, there is a glaring omission in much of the new tree planting policy. For example, in the UK government’s Tree Action Plan – arguably the most important document relating to the country’s new reforestation agenda – there is no mention of fungi at all.

Fungi belong to an entirely separate kingdom of life from plants and animals and are found in every habitat on Earth. Beneficial mycorrhizal fungi form close relationships with trees, growing around or within their roots. These fungi harvest nutrients such as nitrogen and phosphorus from the soil and deliver them to the tree in exchange for carbon-rich sugars generated via photosynthesis.

The trees use their nutrients to make essential compounds such as chlorophyll, and the fungi convert their sugars into long-term stores in the soil which can hold up to 20% of the carbon taken up by trees. Fungi also control most decomposition in forests, breaking down compounds in leaves and dead wood that no other organisms can digest. Without fungi, forest systems simply would not function.

The fungus among us

Fungal friends in forests should not be ignored. To help guide people involved in creating new woodland, our new paper offers a number of ways that fungi can be considered to make these forests, and the people in them, as healthy as possible.

We need to maximize the benefits of beneficial fungi by protecting fungal diversity. Ancient woodlands and veteran trees are important habitats for lots of vital and rare fungi. Their rich fungal communities can disperse and populate new woodlands, helping to develop friendly mycorrhizal and decomposer networks in new forests.

Researchers don’t know enough about what happens to fungi in the soil when we plant trees. We don’t know which species are present before trees are planted and whether they change afterward. This means we don’t yet know how to maximize the benefits of fungi for tree health.

To build up our understanding, we suggest assessing the fungal populations in proposed and existing forest sites. As well as helping to keep trees healthy and storing carbon, this will also develop the list of fungi threatened with extinction and allow their legal protection.

This is important, as the study of fungi is hampered by the lack of legal protections for species. Without a policy to require surveys and studies of fungi, we never find out which species could help us store more carbon in forests, which can cause tree diseases, and whether these fungi are likely to become extinct soon. Only four fungal species are legally protected in the UK, but the country has lots of other important species, including globally rare grassland fungi. Similar to other groups of organisms, we think a Red List of fungal species at risk of extinction should be produced and made into law.

As well as the beneficial fungi, there are also fungi that can cause problems. Fungal diseases like ash dieback affect not only the tree populations themselves but the hundreds of other organisms which rely on trees to survive.

To minimize the risks of tree diseases, it’s important to monitor their emergence and spread in existing woodlands, as well as in tree seeds and saplings. To minimize the risks of woodland fungal spores to humans, which can exacerbate respiratory ailments, adding fungal spores to weather and pollen forecasts can help vulnerable people living near new woodlands prepare.

Remembering fungi in this new era of woodland creation will enable our forests, and the people in them, to be as healthy and resilient as possible.

Ancient trees form bloodlines that bolster forests for thousands of years

February 9, 2022 · 4 minute read
Ancient trees form bloodlines that bolster forests for thousands of years

By Stephanie Pappas 

The oldest trees in the forest carry outsized importance.

Ancient trees, the venerable sentinels of forests, may preserve genetic diversity that helps woodlands thrive for thousands of years, a new study suggests. 

In a typical deciduous forest, the oldest of the old trees — many of which were standing during the First Crusade — can act almost like time-travelers, representing the forest as it stood centuries before most of the trees around it were saplings. These ancient trees may have taken root in very different environmental circumstances as most other trees in the forest, meaning their offspring may have advantages should the environment change again. 

Some species of trees are famous for living to mind-bogglingly ripe old ages: The White Mountains of California are home to unique populations of extremely long-lived bristlecone pines (Pinus longaeva), which can survive more than 5,000 years. California’s Giant Sequoia (Sequoiadendron giganteum) has been recorded living longer than 3,000 years, as has the alerce (Fitzroya cupressoides) of Chile and Argentina. 

But even typical trees can have extraordinarily long lives, stretching for centuries. These ancients are now rare in North America thanks to logging and forest clearing, except in a handful of places in the Pacific Northwest and in some parts of Appalachia, said Charles Cannon, the director of the Center for Tree Science at the Morton Arboretum in Lisle, Illinois. Surviving ancients are now mostly found in the tropics, in places like Borneo and the Amazon, Cannon told Live Science – and those forests are shrinking every day. 

“I am getting more and more convinced that they are quite important and do play a crucial role,” Cannon said. “And once we lose them, they are gone. They are this property that emerges out of old-growth forests, out of centuries, and once we cut them down we’re not getting them back.” 

Forest elders 

In his new study, Cannon used computer models to estimate the prevalence of ancient trees as forests grow and mature. Because trees’ life spans are so much longer than humans’, computer modeling is one of the best ways to understand how forests change over long time periods, Cannon said. 

Unlike animals, trees aren’t programmed to die after a certain life span. Instead, their deaths come as a result of external forces, like a gale that turns their canopies into matchsticks or an insect infestation that saps them of nutrients. Once trees reach maturity and establish themselves, their death rates fall off dramatically, and death comes almost randomly. Studies of tree mortality in established forests peg the rate of mature tree death at around 1.5% to 2% of trees each year. 

With no internal clock ticking them closer to death, some trees win the life-span lottery, dodging drought, disease, and weather and surviving two to three times longer than the average tree in the forest. These oldest-old trees in an old-growth forest can reach ages of nearly 1,000 years. The age of the oldest trees in a forest depends heavily on the overall mortality rate of mature trees, Cannon and his colleagues reported on Jan. 31 in the journal Nature Plants. At 1% mortality, for example, the oldest trees can easily approach 1,000 years, and there can be hundreds of these ancients. At 3% mortality, the oldest trees are no more than 200 or 300 years old. This is troubling, Cannon said, because researchers have recorded increasing tree mortality around the world. This is due to climate impacts like drought and insect infestation, according to the Government of Canada website.  

The importance of age

A tree that rooted and flourished nearly a millennium ago may have done so in very different conditions than the younger trees around it. That’s important, Cannon said, because the ancient trees in the forest may have a different genetic profile compared with their younger neighbors. These oldest trees may provide something like a genetic insurance policy, producing seeds and pollen that can withstand unusual environmental conditions. 

Alternatively, Cannon said, the trees might sometimes be a drag on the forest. If their seedlings are adapted for nonexistent circumstances, their genetic contribution might actually weaken the forest as a whole. Either way, the large size of most ancients means that they produce large amounts of seeds and pollen, he said. And trees don’t stop reproducing with age, as animals do. Together, the trees’ size and age mean they can have an outsized impact on forest diversity and reproduction. 

It’s not easy to study ancient trees, Cannon said. They’re large, but may not be the largest in the forest, and dating trees isn’t always straightforward. Tropical trees, for example, don’t have the clearly delineated rings that trees in temperate regions with clear seasons do. Even in areas where trees are well-studied, scientists may not have a good catalog of tree ages.

“If you could go out and sample the age of many trees in one forest, we could see how the natural process is different from the statistical process [in the computer model],” Cannon said. “And that might give us some insight into the biology of what’s going on.”

Originally published on Live Science. 

Earth Has More Tree Species Than We Thought

February 2, 2022 · 1 minute read
Earth Has More Tree Species Than We Thought

By Helen Briggs

There are 14% more tree species than previously thought, according to what researchers are calling the first “scientifically credible” estimate.

Of the 73,300 estimated species, the researchers predict there are 9,200 that are yet to be discovered. But most rare species are in tropical forests, fast disappearing because of climate change and deforestation. The study is based on a database of tens of millions of trees in more than 100,000 forest plots around the world. The researchers used statistical techniques to predict the likely number of tree species, correcting for gaps in existing data. The findings suggest more must be done to protect the incredible life forms needed for food, timber, and medicine and to fight climate change by sucking carbon dioxide from the air.

Lead researcher Dr. Peter Reich, of the University of Minnesota in St Paul, said the findings highlighted the vulnerability of global forest biodiversity. “Our data will help us assess where biodiversity is the most threatened,” he told BBC News. “This is in the tropics and subtropics of South America, Africa, Asia, and Oceania and those are places where we discovered hotspots of known and unknown rare species. “Knowing about these hotspots, hopefully, can help prioritize future conservation efforts.”

South America – the continent with the most “missing” species – has about 43% of the total number, followed by:

  • Eurasia (22%)
  • Africa (16%)
  • North America (15%)
  • Oceania (11%)

Diverse natural forests are the most healthy and productive, important to the global economy and to nature. The vast majority are in tropical countries where deforestation is largely driven by:

  • growing the ingredients of food eaten in the West, such as beef, palm oil and soy (the last two of these are also used for cattle feed)
  • climate change
  • fires

More than 140 international researchers worked on the study, in the Proceedings of the National Academy of Sciences journal. Dr. Yadvinder Malhi, of the University of Oxford, said tropical forests were the “global treasure chests of biodiversity” and significant absorbers of carbon dioxide emissions, slowing global warming. “This study shows that tropical forests are even more diverse in their trees than we had previously imagined,” he said.

We Almost Forgot About the Moon Trees

February 2, 2022 · 6 minute read
We Almost Forgot About the Moon Trees

A collection of tree seeds that went round and round the moon was scattered far and wide back home.

By Marina Koren

The American moon missions, more than 50 years later, are each memorable in their own way. Apollo 11, of course, is known for being the very first time human beings set foot on the moon. Apollo 12, for being a little rowdier. Apollo 13, for nearly ending in disaster. Apollo 14—the third of six moon landings—is known, as I recently discovered, for its “moon trees.”

Stuart Roosa, one of the Apollo 14 astronauts, took a small canvas bag of tree seeds with him on the journey. While his fellow astronauts walked on the lunar surface, Roosa and the seeds flew round and round the moon until the crew was ready to come back. A few years after the astronauts returned home, some of the seeds—sycamores, redwoods, pines, firs, and sweetgums—were planted across the United States, to see how they would grow, or simply to keep a piece of moon history close by.

I learned about the existence of moon trees earlier this month while thinking about the anniversary of Apollo 14, which launched on this day in 1971. (My tired pandemic brain had thought this year was the mission’s 50th anniversary but turns out we’re living in 2022!) I read online that one moon tree, a loblolly pine, had been planted by the White House, within walking distance of my apartment in Washington, D.C. What a great pandemic-appropriate outing for a space reporter, I thought. Then I noticed an asterisk next to the tree’s name, and scrolled down to discover: “An asterisk denotes a tree that is no longer alive.”

Oh. Nevermind.

That I could find a database of these trees, and go through the experience of identifying and losing the moon tree nearest me in five seconds, is because of Dave Williams, a planetary scientist at NASA’s Goddard Space Flight Center, who 25 years ago took it upon himself to locate as many of them as he could. NASA didn’t keep any records on where the seeds from Apollo 14 ended up, nor did the agency keep up with the trees they became. But Williams does, even though it’s not part of his job description. He is not a tree expert, but he has become, through his efforts, the world’s foremost—and perhaps only—expert on moon trees.

Williams was once just as surprised as I was about the existence of these trees. He discovered them in 1996, through a third-grade teacher in Indiana. Joan Goble and her class had been working on a project about trees near their school, and a student came in one day saying she’d heard that something called a moon tree grew at a nearby Girl Scout camp. When the class went out there, they found an entirely normal-looking sycamore, with a little sign next to it that described the sycamore as a moon tree. Goble’s class wanted to write a thorough report, so the teacher emailed NASA for more information.

No one in Williams’s office in Maryland, not even the folks who had worked at NASA during the Apollo program, had heard of a moon tree. Williams checked with the agency’s history office, which uncovered some newspaper clippings revealing the existence of at least six such trees. From the outside, the moon trees were no different than their Earth-bound brethren. “There’s nothing strange about the moon trees at all,” Williams said. He emailed Goble back with what he’d learned, and then continued to dig.

Williams discovered that the head of the U.S. Forest Service had pitched Roosa, a former smoke jumper who fought forest fires, on the idea. The astronaut took about 500 seeds stuffed in sealed bags inside a metal canister, packed in the small canvas bag that every Apollo astronaut was allowed to fill with whatever they wanted. When the astronauts came back, the sealed bags went through a vacuum chamber—part of the standard decontamination protocol at the time—and accidentally burst, scattering the seeds. Stan Krugman, a geneticist at the forest service, sorted them by hand, then passed them on to a scientist who used some to experiment with germination at NASA’s Johnson Space Center, in Houston. The rest were sent to forestry-science facilities, which doled them out to communities across the country, grateful for a free piece of the Apollo era to spice up their municipal grounds.

The trees, planted mostly in 1976, took root just fine on Earth. Some of the moon seeds were planted next to seeds that had never traveled to space, to see whether they’d develop any differently. The most surprising result, Williams told me, occurred when the two seeds grew into two completely different species—a result of a gardening mixup, of course, not the weird effects of microgravity. NASA didn’t undertake any serious study of the moon trees. The effort was more a PR move, Williams said, than a science experiment.

After Williams wrote back to Goble, he posted an appeal online, asking anyone who came across a moon tree to contact him at NASA. Their story had been forgotten once, and if he didn’t keep track of these trees, who would?

And then people started reaching out, telling Williams that they’d spotted a tree paired with an intriguing plaque on their hike around town, sharing pictures. Over the years, Williams has waited for the moon trees to reveal themselves in this way, through an emailed proof of life. “It really can go for quite a while with getting nothing,” he said. “And then I’ll get a bunch.” As of today, Williams has located about 100 trees. Of those, 30 have died or been cut down. The sycamore that Goble discovered is still there; a storm twisted its top off some years back, but the tree has managed to recover, she told me.

Williams thinks that more undiscovered moon trees are out there. He just heard from a student at Delta State University, in Mississippi, who said they’ve heard rumors about a moon tree somewhere on campus and will try to find it, promising Williams that they’ll report back. Williams has visited quite a few over the years, and even hosted Goble and some of her students in Maryland to show them the sycamore growing near the Goddard center. What’s it like, I asked, seeing a moon tree? Isn’t it kind of anticlimactic, because it doesn’t look any different? Not to them. “I’m just in awe that this seed, the seed it grew from, went to space,” Goble said. “It went to orbit the moon.”

That’s why people see the moon trees as special: They know where those seeds went. Reaching the moon doesn’t take long—Apollo astronauts took just three days to get there—but it’s the moon. People haven’t stepped foot on the lunar surface since 1972, and it’s unclear when the next crew will go. All the trinkets and tchotchkes that the Apollo astronauts took with them in their personal canvas bags are cool for this reason, bestowed with a magical sheen the second they were returned to Earth—space souvenirs. But the seeds that Roosa, who died in 1994, carried feel different from other mementos. They weren’t put in museums or auctioned off. They were buried in the soil of the Earth, the only soil like it in the solar system—in the entire universe, as far as we know. Some might have disappeared, felled by storms or saws, before someone could find them and feel curious enough to ask NASA about them. But the ones that remain are living monuments to the time humankind escaped this world’s gravity and felt that of another.

This Vast Wildfire Lab Is Helping Foresters Prepare for a Hotter Planet

January 26, 2022 · 0 minute read
This Vast Wildfire Lab Is Helping Foresters Prepare for a Hotter Planet

SILVER LAKE, Ore. — When a monster of a wildfire whipped into the Sycan Marsh Preserve here in south-central Oregon in July, Katie Sauerbrey feared the worst.

Ms. Sauerbrey, a fire manager for The Nature Conservancy, the conservation group that owns the 30,000-acre preserve, was in charge of a crew helping to fight the blaze — the Bootleg fire, one of the largest in a summer of extreme heat and dryness in the West — and protect a research station on the property.

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2021: A Game-Changing Year for Trees

January 26, 2022 · 0 minute read
2021: A Game-Changing Year for Trees

It’s not every year that firefighters wrap the world’s largest living tree in an oversized aluminum blanket. But there they were this fall, in California’s Sequoia National Park, covering the 36-foot-wide base of the tree known as General Sherman to protect it from the state’s devastating fires.

Images of the wrapped giant seem to symbolize the world’s race to protect forests in the face of everything from extreme heat to a booming beef industry. Many trees burned this year across the West Coast and Canada, and others were deliberately cut down.

Deforestation in the Amazon rainforest reached its highest level in more than 15 years. And the consequence of losing all of those trees became clearer than ever: A study published in July found that parts of the Amazon now emit more carbon dioxide than they absorb, contributing to rapid global warming.

But there was plenty of hope, too. General Sherman survived, for one. And scientists discovered a handful of new forest-dwelling species, including what’s likely the world’s smallest reptile.

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In Search of Nímbulos, Guardians of Costa Rica’s Cloud Forests

January 20, 2022 · 1 minute read
In Search of Nímbulos, Guardians of Costa Rica’s Cloud Forests

It was around midnight when biologist Paola Muñoz awoke to the sounds of children laughing as pots and pans clattered to the kitchen floor. She listened from her room to an adult voice scolding the mischief-makers. It was followed by the whack of a broom and the barking of Alaska, the resident dog of the field station where she was staying, high in the Talamanca Mountains of Costa Rica. In the morning, she asked the station’s caretaker about the midnight ruckus. “He said, ‘It was those stupid nímbulos, they think it’s funny!’” she recalls. More than a decade after the incident, she regrets staying in her room. “I had the opportunity to see them,” she says. “I was just too afraid.”

Muñoz’s apparent near-encounter with the nímbulos is not unusual in this corner of the Talamancas. These child-like spirits are said to live in the forests around Cerro de la Muerte, the Mountain of Death. Rooted in Indigenous folklore, stories of the nímbulos have evolved in the telling. Spanish incursions in the 16th century tinged them with elements of Catholicism; more recently, concerns about climate change and deforestation have infused the tales with eco-activism. As the landscapes change, the stories change with them, reflecting and influencing the experiences of local people. Now, stories told of the nímbulos echo the plight of the region’s endangered and threatened species, such as the resplendent quetzal and Baird’s tapir: They must be actively protected or face extinction.

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US Plans $50B Wildfire Fight Where Forests Meet Civilization

January 20, 2022 · 0 minute read
US Plans $50B Wildfire Fight Where Forests Meet Civilization

BILLINGS, Mont. — The Biden administration said earlier this week that it will significantly expand efforts to stave off catastrophic wildfires that have torched areas of the U.S. West by more aggressively thinning forests around “hot spots” where nature and neighborhoods collide.

As climate change heats up and dries out the West, administration officials said they have crafted a $50 billion plan to more than double the use of controlled fires and logging to reduce trees and other vegetation that serves as tinder in the most at-risk areas. Only some of the work has funding so far.

Projects will begin this year, and the plan will focus on regions where out-of-control blazes have wiped out neighborhoods and sometimes entire communities — including California’s Sierra Nevada mountains, the east side of the Rocky Mountains in Colorado, and portions of Arizona, Oregon and Washington state. Homes keep getting built in fire-prone areas, even as conditions that stoke blazes get worse.

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Scientists Name New Tree After Leonardo DiCaprio

January 12, 2022 · 0 minute read
Scientists Name New Tree After Leonardo DiCaprio

A tree that is new to science has been named after Leonardo DiCaprio. Scientists at Great Britain’s Royal Botanic Gardens, Kew, said they wanted to honor the star for his help in saving a rainforest from logging.

The tree, which has been given the official name, Uvariopsis dicaprio, grows only in the Cameroon forest known for its incredible biodiversity.

“We think he was crucial in helping to stop the logging of the Ebo Forest,” said Dr Martin Cheek of Kew.

Scientists and conservationists were horrified when they heard of plans to allow vast swathes of the Ebo Forest to be opened up for logging.

One of the largest relatively untouched rainforests in Central Africa, it is home to the Banen people and an array of unique flora and fauna, including threatened gorillas, chimps and forest elephants. International experts wrote a letter to the government documenting the precious animal and plant species at risk of extinction. The issue was picked up by DiCaprio, whose social media posts to his millions of followers added momentum to the campaign.

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The Old Man and the Tree

January 12, 2022 · 1 minute read
The Old Man and the Tree

I meet Bob Leverett in a small gravel parking lot at the end of a quiet residential road in Stockbridge, Massachusetts. We are at the Ice Glen trailhead, half a mile from a Mobil station, and Leverett, along with his wife, Monica Jakuc Leverett, is going to show me one of New England’s rare pockets of old-growth forest. 

For most of the 20th century, it was a matter of settled wisdom that the ancient forests of New England had long ago fallen to the ax and saw. How, after all, could such old trees have survived the settlers’ endless need for fuel to burn, fields to farm and timber to build with? Indeed, ramping up at the end of the 17th century, the colonial frontier subsisted on its logging operations stretching from Maine to the Carolinas. But the loggers and settlers missed a few spots over 300 years, which is why we’re at Ice Glen on this hot, humid August day. 

To enter a forest with Bob Leverett is to submit to a convivial narration of the natural world, defined as much by its tangents as its destinations—by its opportunities for noticing. At 80, Leverett remains nimble, powered by a seemingly endless enthusiasm for sharing his experience of the woods with newcomers like me. Born and raised in mountain towns in the Southern Appalachians, in a house straddling the state line between Georgia and Tennessee, Leverett served for 12 years as an Air Force engineer, with stints in the Dakotas, Taiwan and the Pentagon, but he hasn’t lost any of his amiable Appalachian twang. And though he’s lived the majority of his life in New England, where he worked as an engineering head of a management consulting firm and software developer until he retired in 2007, he comes across like something between an old Southern senator and an itinerant preacher, ready to filibuster or sermonize at a moment’s notice. Invariably, the topic of these sermons is the importance of old-growth forest, not only for its serene effect on the human soul or for its biodiversity, but for its vital role in mitigating climate change.

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This Tree Has Lived 500 Years. Will It Be Sold for $17,500?

January 5, 2022 · 0 minute read
This Tree Has Lived 500 Years. Will It Be Sold for $17,500?

TONGASS NATIONAL FOREST, Alaska — The Sitka spruce soaring more than 180 feet skyward has stood on this spot on Prince of Wales Island for centuries. While fierce winds have contorted the towering trunks of its neighbors, the spruce’s trunk is ramrod straight. Standing apart from the rest of the canopy, it ascends to the height of a 17-story building.

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White Oak Decline Rocks Kentucky Bourbon Industry

January 5, 2022 · 0 minute read
White Oak Decline Rocks Kentucky Bourbon Industry

White oak trees that play a key role in the ecosystem and economy of Kentucky will see a significant decline soon without action to help the species regenerate.

That’s the takeaway from a recent report from an organization called the White Oak Initiative, which is aimed at bringing attention to the challenges facing the tree and recommending ways to counter the looming decline.

White oaks are a cornerstone species in forests of the eastern U.S., providing habitat and food for birds and animals and wood for a wide range of products such as flooring and cabinets. In Kentucky, that includes barrels for the signature bourbon industry. Bourbon has to be aged in new charred oak containers, which give it color and flavor.

All told white oaks play a role in billions of dollars of economic activity in Kentucky annually. The problem is that they are not regenerating at a sustainable level, according to the report.

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Mapping the Rainforests of Britain

December 29, 2021 · 0 minute read
Mapping the Rainforests of Britain

GUY SHRUBSOLE IS ON A mission to map one of the world’s most endangered rainforests—a moss- and mist-shrouded stretch of ancient oak, pine, birch, and ash along the western shores of Britain. Fed by fierce gales, intense rainfall, and high levels of humidity, Britain’s Atlantic coast was once home to vast swathes of woodland known as “temperate rainforests,” and is now the unlikely location for Shrubsole’s ambitious conservation project.

Woodland conservationists consider the few fragments of ancient temperate rainforests that survive in Britain to be in more danger than their tropical counterparts, says Shrubsole, who describes himself as a “very amateur, but very enthusiastic naturalist.” “Knowing where the rainforests are is a crucial part of knowing how to save them,” he says. So Shrubsole, using crowdsourced information collected through his Lost Rainforests of Britain website, has begun plotting Britain’s first comprehensive rainforest map.

Atlas Obscura spoke to Shrubsole about his rainforest wanderings, rare moss and curious ferns, and how a crowdsourced mapping project can help save Britain’s ancient woodlands from destruction.

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To Regrow Forests, U.S. Needs Billions of Seeds — and Many More ‘Seed Hunters’

December 22, 2021 · 0 minute read
To Regrow Forests, U.S. Needs Billions of Seeds — and Many More ‘Seed Hunters’

SISTERS, OREGON — Brittle pine needles and twigs snap under Don Grandorff’s boots as he crunches his way through Deschutes National Forest, the August air scented with sap and wildfire smoke. Without hesitating, he veers off the path and wades through the brush, on the hunt for Ponderosa pine seeds.

Grandorff has been a seed forager for 45 years, and he spots the signs of a squirrel’s hidden cache immediately: clusters of green pine needles fanned out on the forest floor; a newly nibbled cone; and a long, shallow dirt trail that disappears under a log.

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China’s Xi Axes Officials for Destroying Thousands of Banyan Trees

December 16, 2021 · 1 minute read
China’s Xi Axes Officials for Destroying Thousands of Banyan Trees

China punished and demoted 10 officials in the southern city of Guangzhou after thousands of banyan trees were cut down or uprooted by the local government, prompting a rare personal intervention by President Xi Jinping. 

Li Xi, the party chief of Guangdong province, told local cadres that a spate of tree destruction in the provincial capital since late 2020 had “severely damaged natural ecology” and “hurt people’s fond memories” of the city, leading to “irreversible losses.” He spoke at a meeting held on Sunday, according to a report by the official Southern Daily. 

Li indicated that the president had directly expressed displeasure with the situation. While ordering officials to rectify the tree issue, Li urged them to closely study Xi’s instructions and “deeply comprehend” his special care for the city and province.

With China’s environment under immense pressure after decades of historic growth, Xi has sought to cast himself as a champion of green causes, expressed in his edict that “green mountains are gold mountains and silver mountains.” He says he wants China to become an “eco-civilization,” where humans live in harmony with nature. That Xi commented directly on a relatively minor city-level issue indicates the close attention he’s paying to environmental matters.

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Across the Mid-Atlantic, Giant Oak Trees are Dying

December 15, 2021 · 0 minute read
Across the Mid-Atlantic, Giant Oak Trees are Dying

Jason and Aga Jones loved the magnificent oak tree that was once the centerpiece of their backyard. In 2013 — a year after they bought their home in Takoma Park, Md. — they restored a circular stone retaining wall around the base of the tree. In 2019, they added an extension to the back of the home with enormous windows from which they could admire the majestic branches and watch squirrels build nests and collect acorns.

Then late last summer, when they hired a company to lop off branches encroaching on the neighbor’s yard, the company’s workerspointed out ominous symptoms: browning leaves, dead branches. Within a year, the tree was dead.

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Winter Trees as a Portal to Aliveness

December 8, 2021 · 0 minute read
Winter Trees as a Portal to Aliveness

By Maria Popova, The Marginalian

There is something about the skeletal splendor of winter trees — so vascular, so axonal, so pulmonary — that fills the lung of life with a special atmosphere of aliveness. Something beyond the knowledge that wintering is the root of trees’ resilience, beyond the revelation of their fractal nature and how it salves the soul with its geometry of grief. Something that humbles you to the barest, most beautiful face of the elemental.

I know of no one who has captured that singular enchantment better than the artist, naturalist, philosopher, entomologist, and educator Anna Botsford Comstock (September 1, 1854–August 24, 1930).

In 1902, nine years before she laid the cultural groundwork for what we now call youth climate action in her exquisite field guide to wonder, Comstock wrote an article for the magazine Country Life that became, fourteen years later, her slender, tender book Trees at Leisure (public library | public domain) — a love letter to the science, splendor, and spiritual rewards of our barked, branched, rooted chaperones of being.

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The World’s Largest Organism Is Being Devoured

December 8, 2021 · 1 minute read
The World’s Largest Organism Is Being Devoured

IN THE WASATCH MOUNTAINS OF the western United States, on the slopes above a spring-fed lake, there dwells a single giant organism that provides an entire ecosystem on which plants and animals have relied for thousands of years. Found in my home state of Utah, “Pando” is a 106-acre stand of quaking aspen clones.

Although it looks like a woodland of individual trees with striking white bark and small leaves that flutter in the slightest breeze, Pando (Latin for “I spread”) is actually 47,000 genetically identical stems that arise from an interconnected root network. This single genetic individual weighs around 6,000 metric tons. By mass, it is the largest single organism on Earth.

Aspen trees do tend to form clonal stands elsewhere, but what makes Pando interesting is its enormous size. Most clonal aspen stands in North America are much smaller, with those in the western U.S. averaging just 3 acres. Pando has been around for thousands of years, potentially up to 14,000 years, despite most stems only living for about 130 years. Its longevity and remoteness mean a whole ecosystem of 68 plant species and many animals have evolved and been supported under its shade. This entire ecosystem relies on the aspen remaining healthy and upright. But, although Pando is protected by the U.S. Forest Service and is not in danger of being cut down, it is in danger of disappearing due to several other factors.

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How Old Is Zimbabwe’s Famed ‘Big Tree’?

December 1, 2021 · 1 minute read
How Old Is Zimbabwe’s Famed ‘Big Tree’?

ADRIAN PATRUT AND HIS TEAM flew in from three different continents to study the “Big Tree” at Victoria Falls in Zimbabwe, and for good reason. The Big Tree is a colossal structure, soaring over 80 feet in the air, around 75 feet in circumference, with bulky branches, many stems that make up its trunk, and a wide, gaping hole at its core. The Big Tree is thought to be one of the largest and oldest African baobab trees in the world.

Once the team of three arrived at Victoria Falls, they immediately rented a car to see the Big Tree in person. Its proximity to the falls, a major tourist destination, means that millions of visitors see it in a normal year, making it a sensation in its own right. The sight did not disappoint, Patrut says. “It was as if we had entered straight into a museum, into a well-known painting of a master, but we operated as scientists,” according to the nuclear chemist at Babes-Bolyai University in Romania. “I circled the baobab and admired it from all possible angles.”

Patrut, who has been studying ancient trees for decades, and his team made the pilgrimage to study the growth, age, and architecture of the tree. Dating ancient trees often involves counting “growth rings” that appear seasonally, a tried and true method that unfortunately doesn’t work well for baobabs. These often massive trees have only very faint growth rings, and many have large cavities in their trunk and stems that confound attempts to date them. Until recently, most evaluations of African baobab trees have been “guesstimates,” he says.

But over the past decade, Patrut has been refining a more precise method for estimating the age of baobab trees: radiocarbon dating. Patrut has used it on trees across the continent: South AfricaMozambiqueNamibia. For the Big Tree, his team found that its multiple stems have different ages, with its oldest one dating back to about 870, around the time that Vikings first settled in Iceland.

Click here to keep reading the Atlas Obscura article by Jonathan Moens…

Struggling with Blight, American Chestnut Faces New Disease

December 1, 2021 · 1 minute read
Struggling with Blight, American Chestnut Faces New Disease

Erie, Pa. has a Chestnut Street.

So do the Erie County municipalities of Cranesville and Corry, Girard and Lake City, Edinboro, Waterford and North East.

There’s a reason you find so many stretches of road that carry that name here and elsewhere in the eastern United States. American chestnut trees once numbered into the billions, stretching from Maine to Mississippi.

“The American chestnut was a very plentiful tree, especially in Pennsylvania,” said Sara Fitzsimmons, director of restoration at The American Chestnut Foundation at Penn State University.

The American chestnut was known as a cradle-to-coffin tree because its rot-resistant wood served people’s needs from birth to death. It also produced healthy and tasty nuts eaten by humans and their animals as well as by wildlife.

Then a blight, first officially identified in 1904 in the Bronx Zoo, struck American chestnut trees. They never recovered and are now considered to be “functionally extinct.” New trees sprout, but most don’t live that long. A few old “survivors,” often scarred by the blight, are known to be out there, including in Erie County. And now the American chestnut is facing another challenge, identified by a Penn State Behrend student at a research site in North East Township.

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New England’s Forests Are Sick. They Need More Tree Doctors.

November 24, 2021 · 0 minute read
New England’s Forests Are Sick. They Need More Tree Doctors.

Bear and Melissa LeVangie spent much of their childhood aloft, in a then-forested area of Massachusetts. “Our mother would say, I don’t want to see you until it is dark,” said Bear LeVangie. “We would climb an 80-foot — it seemed like a 100-foot then — white pine and hang out and not think twice about it.”

The twins still spend much of their time in and around trees: Both are arborists, which is akin to being tree doctors. Both are seeing a surge in demand for arborists because the region’s trees are faring so poorly.

“I would never have anticipated how fast things are declining,” said Melissa LeVangie, who works for Shelter Tree, a tree care supply company, and is tree warden, or caretaker, for the town of Petersham in central Massachusetts.

As climate change accelerates, the trees in the Eastern forests of the United States are increasingly vulnerable. For many arborists, the challenges facing trees are reshaping and expanding the nature of their work. Many said they are spending more time on tree removal than ever before — taking down dead or unhealthy trees, or trees damaged or felled by storms.

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Research Reveals How Wildfire Accelerates Forest Changes

November 17, 2021 · 1 minute read
Research Reveals How Wildfire Accelerates Forest Changes

Refugees are on the move in forests across the western U.S. As climate conditions change, the ranges of tree species are shifting, especially toward cooler or wetter sites. A new Stanford analysis provides some of the first empirical evidence that wildfire is accelerating this process, likely by reducing competition from established species. The study, published Nov. 15 in Nature Communications, raises questions about how to manage land in an era of shifting ecosystems – a key issue as President Biden prepares to sign into law an infrastructure bill that allocates more than $5 billion for forest restoration and wildfire risk reduction.

“Complex, interdependent forces are shaping the future of our forests,” said study lead author Avery Hill, a graduate student in biology at Stanford’s School of Humanities & Sciences. “We leveraged an immense amount of ecological data in the hopes of contributing to a growing body of work aimed at managing these ecosystem transitions.”

As the climate changes, animal and plant species are shifting their ranges toward conditions suitable for their growth and reproduction. Past research has shown that plant ranges are shifting to higher, cooler elevations at an average rate of almost five feet per year. In many studies, these range shifts lag behind the rate of climate change, suggesting that some species may become stranded in unsuitable habitats. The factors that impact plant species’ ability to keep up with climate change are key to maintaining healthy populations of the dominant trees in western forests, yet have remained largely mysterious.

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Blue Bananas, Why Leaves Change Color, and the Ongoing Mystery of Chlorophyll

November 10, 2021 · 0 minute read
Blue Bananas, Why Leaves Change Color, and the Ongoing Mystery of Chlorophyll

From The Marginalian by Maria Popova…

Autumn is the season of ambivalence and reconciliation, soft-carpeted training ground for the dissolution that awaits us all, low-lit chamber for hearing more intimately the syncopation of grief and gladness that scores our improbable and finite lives — each yellow burst in the canopy a reminder that everything beautiful is perishable, each falling leaf at once a requiem for our own mortality and a rhapsody for the unbidden gift of having lived at all. That dual awareness, after all, betokens the luckiness of death.

But autumn is also the season of revelation, for the seeming loss unveils a larger reality: Chlorophyll is a life-force but it is also a cloak, and when trees shed it from their leaves, nature’s true colors are revealed.

Photosynthesis is nature’s way of making life from light. Chlorophyll allows a tree to capture photons, extracting a portion of their energy to make the sugars that make it a tree — the raw material for leaves and bark and roots and branches — then releasing the photons at lower wavelengths back into the atmosphere. A tree is a light-catcher that grows life from air.

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Don’t Even Breathe Around America’s Deadliest Tree

November 3, 2021 · 0 minute read
Don’t Even Breathe Around America’s Deadliest Tree

THROUGHOUT THE COASTS OF THE Caribbean, Central America, the northern edges of South America, and even in south Florida, there can be found a pleasant-looking, beachy sort of tree, often laden with small greenish-yellow fruits that look not unlike apples.

You might be tempted to eat the fruit. Do not eat the fruit. You might want to rest your hand on the trunk or touch a branch. Do not touch the tree trunk or any branches. Do not stand under or even near the tree for any length of time whatsoever. Do not touch your eyes while near the tree. Do not pick up any of the ominously shiny, tropic-green leaves. If you want to slowly but firmly back away from this tree, you would not find any argument from any botanist who has studied it.

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Florida is Ditching Palm Trees to Fight the Climate Crisis

October 28, 2021 · 1 minute read
Florida is Ditching Palm Trees to Fight the Climate Crisis

When you think of Florida, beaches and palm trees come to mind. But what if those palm trees were slowly replaced with other trees? That could happen over time because of climate change, and communities in South Florida are trying to save the world from the climate crisis, one tree at a time.

“Palm trees do not sequester carbon at the same rate as our native canopy trees and do not provide shade, cool down streets and sidewalks to help counter the urban heat island effect that canopy trees do,” said Penni Redford, the Resilience and Climate Change Manager for West Palm Beach.

With atmosphericcarbon dioxide levels today higher than at any point in at least the past 800,000 years, according to the National Oceanic and Atmospheric Administration (NOAA), the Earth needs to remove it or humans have to stop adding it. In fact, the last time carbon dioxide concentration was this high was more than 3 million years ago.

Scientists are working on solutions to capture and safely contain atmospheric carbon. One approach is called “terrestrial sequestration” — which is essentially planting trees. A tree absorbs carbon during photosynthesis and stores it for the life of the tree.

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Plant Trees or Let Forests Regrow? New Studies Probe Two Ways to Fight Climate Change

October 20, 2021 · 1 minute read
Plant Trees or Let Forests Regrow? New Studies Probe Two Ways to Fight Climate Change

Forests are having their moment. Because trees can vacuum carbon from the atmosphere and lock it away in wood and soil, governments and businesses are embracing efforts to fight climate change using trees.

Nations have pledged to plant or restore forests over a combined area larger than India. One corporate-backed initiative has secured pledges to conserve or restore 855 million trees by 2030. Even President Donald Trump, an ardent climate change skeptic, endorsed a trillion-tree planting initiative at the World Economic Forum in January; a companion bill was introduced in the U.S. House of Representatives in February.

Scientists agree that new trees and forests can, in theory, cool the planet. But many have warned that the enthusiasm and money flowing to forest-based climate solutions threaten to outpace the science.

Two papers published this week seek to put such efforts on a firmer footing. One study quantifies how much carbon might be absorbed globally by allowing forests cleared for farming or other purposes to regrow. The other calculates how much carbon could be sequestered by forests in the United States if they were fully “stocked” with newly planted trees. Each strategy has promise, the studies suggest, but also faces perils.

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To Save Forests, Researchers are Hooking Trees Up to Twitter

October 13, 2021 · 0 minute read
To Save Forests, Researchers are Hooking Trees Up to Twitter

In July 2018, a century-old red oak went live on Twitter. The account @awitnesstree, tweeting from the Harvard Forest in Petersham, Massachusetts, introduces itself in its bio:

“Witnessing life as a tree in a changing environment for more than a century. Views are my own – sort of (data translated by scientists and communicators at HF).”

Every few days, the tree updates its 9,118 followers. On February 24 2020 it posted: “The last 2 days were extremely hot for February. When is this heatwave going to end?”

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The Author of ‘The Overstory’ on What We Can Learn from Trees

October 13, 2021 · 0 minute read
The Author of ‘The Overstory’ on What We Can Learn from Trees

From the transcript of Ezra Klein’s podcast, “The Ezra Klein Show.”

Sometimes I finish these conversations, and I feel I’ve been given a gift. And this is one of them. This is really one of them. Richard Powers is the author of 13 novels, including, famously, “The Overstory,” which won the Pulitzer Prize in 2019. I loved “The Overstory.” I loved it. I’ve never walked through a forest the same way again. And a lot of people loved it. When I interviewed him earlier this year and asked for his three books, former President Barack Obama recommended “The Overstory.” And he said, quote, “it changed how I thought about the Earth and our place in it.” Hell of an endorsement.

Powers has a new book out, “Bewilderment.” And I think “Overstory” and “Bewilderment” should be understood as a couplet. “The Overstory” is about the world beyond us — the slow, powerful life of the trees and the forests and the way all of that shapes us. You can also call it the outer story. And “Bewilderment,” by contrast, is the inner story.

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In Nashville, Trees are ‘Civic Infrastructure’

October 6, 2021 · 0 minute read
In Nashville, Trees are ‘Civic Infrastructure’

Two good things happened here recently that I didn’t see coming. First, our Metro Council passed a bill, which Mayor John Cooper signed, that increases protections for trees on city land. Second, the proposal for an outrageously terrible subdivision in Whites Creek, one of the few remaining rural tracts of Davidson County, was rejected by the Metro Planning Commission.

Positive as the recent environmental news here may be, small-scale victories like these don’t normally rise to the level of national attention. But as a measure of what is possible, they have given me more hope for the future than I’ve had in a long time.

That’s because these particular environmental wins were not the result of lawsuits or transfers of political power. They were the result of widespread and nonpartisan public outcry. And they tell us of what can happen in any city, anywhere, when people start recognizing trees as a kind of civic infrastructure and the natural world as a public good.

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Oregon Is Burning Trees in Order to Save Them

September 29, 2021 · 0 minute read
Oregon Is Burning Trees in Order to Save Them

Ebba Patterson was driving home from work along Highway 101 in Oregon this April when something caught her eye—a flash of red along the side of the road. Peterson, a plant epidemiologist, recognized it as the foliage of sick trees and pulled over.

After bushwhacking to reach the site, Peterson was dismayed by what she saw: two trees, seemingly in the throes of a disease called sudden oak death. They had flaring brown-red canopies and blackening twigs. “I’m looking out the window, I see these dead crowns, I think: ‘Shit!” Peterson recalls.

She clipped some samples and took them back to her lab for analysis. “The second time I cursed was when I looked at those petri plates,” she remembers. The culture tested positive: It was sudden oak death.

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The Lost Generation of Ancient Trees

September 22, 2021 · 1 minute read
The Lost Generation of Ancient Trees

At around 1,100 years old, and almost 11m (36ft) in girth, the Big Belly Oak is the oldest tree in Savernake Forest in southwest England. A tiny sapling at the Battle of Hastings in 1066, Big Belly Oak has lived through the War of the Roses, the Black Death, the English Civil War, the Industrial Revolution, and two world wars. Now gnarled and knobbly, Big Belly Oak’s trunk is strapped up with a metal girdle to keep it from falling apart.

While an ancient tree like this is impressive at a distance, take a look inside and you will see something even more intriguing.

Oak polypore fungi and stag beetle larvae feast on the dead heartwood, adult stag beetles sup the sugary liquid from the “sap runs”, the living layers of wood that transport water and minerals throughout the tree. Hoverflies lay eggs in water-filled rot holes, rat-tailed maggots devour leaf litter and violet click beetles eat up wood mold that is rich with feces and other remains, accumulating over a century. Knothole moss and pox lichen cling to the bark in rainwater channels. Barbastelle bats hibernate in crevices and under loose bark. Woodpeckers and nuthatch enlarge holes for nesting, while owls, kestrels, marsh tit, and tree-creeper move into ready-made cavities.

These rich pockets of life are a secret world, a diverse habitat teeming with insects, fungi, lichen, birds and bats. The ancients of our forests provide essential food and shelter for more than 2,000 of the UK’s invertebrates speciesIn Savernake Forest alone, these trees are home to nearly 120 species of lichen, more than 500 species of fungi, and other important wildlife such as the elusive white-letter hairstreak butterflies.

We face losing these micro-worlds as, one by one, the ancient trees of today are dying and there are not enough ready to replace them.

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4,000-Year-Old Tree Trunk Coffin Discovered in Golf Course Pond

September 14, 2021 · 0 minute read
4,000-Year-Old Tree Trunk Coffin Discovered in Golf Course Pond

In July 2019, construction workers renovating a pond at a golf course in Tetney, England, stumbled onto a 4,000-year-old wooden coffin. Now, reports BBC News, the Bronze Age relic is set to go on display at the Collection Museum in Lincoln after undergoing extensive preservation work.

Per a statement from the University of Sheffield, the half-ton sarcophagus contained human remains, an ax and plants used as a bed for the deceased. Made from the hollowed-out trunk of an oak tree, it was buried beneath a gravel mound—a practice typically reserved for elite members of Bronze Age society. The coffin measures around ten feet long and three feet wide.

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The Grassroots Effort to ‘Regreen’ Puerto Rico

September 8, 2021 · 1 minute read
The Grassroots Effort to ‘Regreen’ Puerto Rico

WHEN THE FURY OF HURRICANE Maria subsided long enough to allow Amira Odeh to leave her grandmother’s home in Bayamón, Puerto Rico, she stepped into a terrifying scene. “It was like waking up in a sci-fi, alien-invasion kind of movie,” she says. “All of this destruction.”

The storm that swept through the Caribbean in the fall of 2017 devastated Puerto Rico, where Odeh was born and raised. High winds, floods, and landslides killed people across the island, destroyed the power grid, and wrecked innumerable homes. Next came months of hardship, as shuttered ports and a carelessly executed aid effort from the mainland United States meant few supplies for weeks on end. “We didn’t have anything to eat,” says Odeh. While the semi-official death toll from the storm is 4,645, the lack of food, clean water, electricity, and shelter led to many more preventable deaths.

But in the immediate aftermath of the storm, the memory that most stands out for Odeh was that first glimpse of the post-Maria landscape. “There wasn’t green anymore,” she says. “A tropical landscape always has green. And the only thing green was the grass. There were no trees.”

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Study: Almost Half of World’s Wild Tree Species Could Be At Risk of Extinction

September 1, 2021 · 0 minute read
Study: Almost Half of World’s Wild Tree Species Could Be At Risk of Extinction

Between a third and half of the world’s wild tree species are threatened with extinction, posing a risk of wider ecosystem collapse, the most comprehensive global stocktake to date warns.

Forest clearance for farming is by far the biggest cause of the die-off, according to the State of the World’s Trees report, which was released on Wednesday along with a call for urgent action to reverse the decline. The five-year, international study found 17,510 species of trees are threatened, which is twice the number of threatened mammals, birds, amphibians and reptiles combined.

This was 29.9% of the 58,497 known species of trees in the world. But the proportion at risk is likely to be higher as a further 7.1% were deemed “possibly threatened” and 21.6% were insufficiently evaluated. Only 41.5% were confirmed as safe.

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Where Are the Last of Maine’s Historic King Pines?

August 20, 2021 · 1 minute read
Where Are the Last of Maine’s Historic King Pines?

ON A BRIGHT, BUGGY JUNE day, I set off across a Maine river into a preserve called The Hermitage. I was in search of a pine tree claimed by the king of England centuries ago. Snow, mud, and raging water make the preserve impassable at different times of the year, but in early summer the river reached just above my ankle. Ahead of me, on the river’s north bank, sloped a stand of tangled beech, sugar maple, and hemlock—and then, rising above the understory, the straight mud-brown trunks of eastern white pines, crowned by ragged branches at their peaks. These were big trees, ancient trees, more than 120 feet tall, the kind you don’t expect to see on the logging-decimated East Coast.

It was Jeff McCarthy, a roofer who grew up here in north-central Maine, who first told me that I should come here to look for the last king pines, trees that were marked by surveyors for the king centuries ago. McCarthy grew up playing in sporting camps—rustic resorts that are a treasured Maine tradition—near The Hermitage. In the 1990s, he and his friends would try to wrap their arms around the preserve’s larger trees. Sometimes, even three of them together couldn’t complete the circle. When wind felled the trees around the camps, they would count the rings on the stumps: Once, he said, they counted 275, making the tree older than the United States.

Click here to read the rest of the article in Atlas Obscura.

12 Forests with Hidden Secrets

August 18, 2021 · 0 minute read
12 Forests with Hidden Secrets

Forests can be enchanting places — the sunlight filtering through the trees, wildlife scampering in the underbrush, trunks reaching to the sky. They can also be bastions of solitude and quiet, the only break in the stillness from the snap of a branch,  a breeze rustling the leaves, or, perhaps, the faint whispers of a secret. Some forests hold ruins, sculptures, artifacts, even entire museums waiting to captivate the next intrepid explorer.

On the outskirts of the Forest of Fontainebleau in Noisy-sur-École, France, is a sandy but waterless beach surrounded by pine and birch, perhaps a relic of an ancient ocean. In the woods of Härjedalen, Sweden, a statue of one of Hollywood’s greatest actors is hidden in the dense foliage, fitting for a starlet with a reputation as a recluse. And in New Jersey, forest is taking over the remains of a grand mansion. From a stained-glass window that illuminates the forest floor to strange stone carvings, here are a dozen of our favorite woodland secrets.

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Pitching in for the Next Generation of Trees at the Augusta Forestry Center

August 18, 2021 · 2 minute read
Pitching in for the Next Generation of Trees at the Augusta Forestry Center

The James River Association, the Virginia Department of Forestry, and the Chesapeake Bay Foundation are working with landowners across the middle and upper James watershed to restore or create forest buffers that improve the quality of local waterways through their James River Buffer Program.

The James River Buffer Program will require hundreds of thousands of tree seedlings to meet established goals for improving water quality and soil health. However, Virginia’s current capacity to supply hardwood seedlings does not match the growing demand.

The Augusta Forestry Center, a Virginia Department of Forestry nursery in Crimora, supplies most of Virginia’s seedlings. The self-supported nursery has served the tree planting needs of the Commonwealth for over a century, but it is currently short-staffed, an issue that has worsened since the Covid-19 pandemic. To meet the increased demand for hardwoods like oaks, maples, and hickories, they need more support (especially in the form of hands-on labor).

The Chesapeake Bay Foundation hosted two volunteer events this summer. CBF staff, partners, and volunteers worked alongside nursery staff to assist with the simple—yet critical—task of weeding in the seedling beds. While weeding isn’t quite as glamorous as tree planting, it’s equally important. If seedlings aren’t healthy when they’re planted, they won’t have a great chance at success in a riparian buffer or elsewhere, which can be disheartening for landowners and conservation professionals alike.

Among basic inputs like water, light, and nutrients/fertilizers, young trees must be free of unnecessary competition from other plants to thrive. And while there are certain situations for which herbicides can be used, the majority of weed removal must be completed by hand to prevent damage to seedlings. Though it can be tough work to remove weeds manually, there’s no better way to start the day than by working in the shadow of the magnificent Blue Ridge Mountains with our hands in the soil.

“I just want people to know that we exist, we are here, and we have high-quality product,” says Nursery Manager Joshua McLaughlin. Starting October 1, 2021, you can place an order with the Augusta Forestry Center for the next planting season by visiting McLaughlin also asks for help collecting acorns and nuts this fall. Locally sourced seeds have better chances of long-term survival, since they are adapted to local environmental conditions. In September, VDOF will announce the details for this year’s acorn/nut drive at

Meeting Virginia’s goal of 70,000 acres of new riparian buffer within the James River watershed by 2025 requires the collaboration of several partners. The James River Association (JRA) convenes the Upper & Middle James Riparian Consortium that supports this wide network of partners that acquire and provide funding and technical assistance for landowners such as the Natural Resources Conservation Service, local Soil and Water conservation Districts, and non-profits such as JRA and CBF, as well as contractors who prepare sites for tree planting and install and maintain buffers. Those who source the plant material, our nurseries, are also crucial to this collaboration. Thus, our partnership with the Virginia Department of Forestry and their Augusta Forestry Center is critical for the health of the James and Chesapeake Bay watersheds.

If interested in learning more about the Augusta Forestry Center, volunteer opportunities, or other ways you can get involved, email Joshua McLaughlin at

Conservation Groups Announce Acquisition of Richmond Riverfront Property

August 11, 2021 · 0 minute read
Conservation Groups Announce Acquisition of Richmond Riverfront Property

Yesterday morning, JRA’s CEO Bill Street joined leaders from The Conservation Fund, Capital Region Land Conservancy, Virginia Department of Conservation & Recreation, The Salvation Army Boys & Girls Club, and Richmond Public Schools to announce the purchase of 5.2 acres on Richmond’s riverfront and plans for a future river education center.

The JRA is under contract to purchase just under one acre of land from The Conservation Fund with the intention of building a river center for environmental education programs. The James River Center will focus on connecting Richmond youth with immersive river-based, hands-on learning experiences while inspiring confidence, ecological understanding, nature appreciation, and conservation action.

“I applaud The Conservation Fund, Capital Region Land Conservancy, and James River Association for working together to expand the James River Park System with the purchase of 5.2 acres of riverfront property. This significant acquisition, and plans for the James River Center, will benefit Richmonders for generations to come.” -Levar Stoney, City of Richmond Mayor

Click here to learn more about the land acquisition and the future James River Center.

What We Can Learn from Paris’ Oldest Tree

July 21, 2021 · 2 minute read
What We Can Learn from Paris’ Oldest Tree

From the window of the apartment I’m staying in I can see the top of a not very tall but very remarkable tree, one that has occasionally been distracting me from the story I came to Paris for. I know the tree (pictured above) is remarkable because a plaque identifies it as the city’s oldest, planted in 1601. It’s a black locust, Robinia pseudoacacia, and it came originally from the Appalachians, in the United States.

Now, for various reasons that 1601 date is doubtful. But it appears likely that the tree was indeed planted sometime in the early 17th century by one Jean Robin, gardener to a succession of French kings. It has survived wars and revolutions and this summer has sprouted a nice full head of greenery. A wounded old soldier itself—its scarred trunk is kept upright by concrete braces—it turns out to have been the spearhead of an invading army: Since the 17th century, American black locusts have advanced across Europe and indeed the world.

In Central Europe, especially, foresters soon fell in love with them. Black locusts grew quickly on land that had been denuded for firewood, protecting it from erosion. More recently, on the Loess Plateau in northwestern China, 25 million acres have been planted with black locusts over the last few decades to combat some of the worst soil erosion on Earth. Black locust wood is valuable too, and not just for burning; it’s hard and durable. Four centuries after Robin first planted the American import in his garden, Robinia is advertised here as the only “European” wood that can be used for garden furniture without pesticide treatment—a sustainable alternative to imported tropical teak.

The trouble is, black locust doesn’t stay where it’s planted. It’s incredibly invasive, spreading by underground runners. In that it’s like another hardy pioneer, Ailanthus altissima, aka the tree of heaven, which in the 18th century traveled the world in the other direction, from China to America, with Paris botanists again offering a crucial assist. American gardeners fell in love with the pretty tree, which grows just about anywhere, even through cracks in pavement—it’s the central character in A Tree Grows in Brooklyn. But as Troy Farrahreported recently for Nat Geo, scientists are now desperately looking for a way to kill the biodiversity-wrecking “tree of hell,” pinning their hopes on a newly discovered fungus.

The world is a mess, our mess. Czech scientists, reviewing the spread of black locusts in southern Europe recently, concluded: “Our results confirm that it is difficult to answer an important question, whether Robinia should be cultivated and promoted, widely tolerated, or eradicated as a dangerous invasive alien.” The answer has to be local, case-by-case, they said.

About 500 feet north of the oldest tree lies the wreck I came here for: the cathedral of Notre Dame. It’s a portal into the 12th and 13th centuries, but also the 19th, when it was extensively rebuilt. The team now rebuilding the church again, after the catastrophic 2019 fire that sent its steeple crashing through its soaring vaults, are trying to recapture both those layers of history. The scruffy black locust that’s rarely noticed in the little park across the Seine is a reminder that in the natural world too, we can only rarely unwind the complicated history we’ve created. We can just try to manage it better.

Redwood ‘Ghosts’ May Hold Clues to Ecosystem Health

July 14, 2021 · 1 minute read
Redwood ‘Ghosts’ May Hold Clues to Ecosystem Health

Thirty miles north of San Francisco, Tom Stapleton sets out on a trail that takes him deep into the forest, weaving around the massive trunks of redwoods. The trees have special significance for him. “Being in a redwood forest is actually like being in a cathedral,” he says. “There’s something that’s very spiritual, very humbling and moving there. It makes you seem so insignificant because you’re this human being that’s a tiny speck compared to these towering trees.” He veers off the trail, consulting a secret map that will lead him to the “ghosts of the forest.”

For decades, Stapleton has searched for and logged rare albino redwoods, their silver-white branches a stark contrast to the dark wood of the surrounding forest, and even less common wild chimera redwoods, which sport patchworks of green and white needle leaves. Collaborating with albino redwood researchers and enthusiasts, he has found more than 500 albino redwoods and 116 wild chimeras. Their locations are kept secret to protect them from souvenir hunters or other vandals. Although curiosity and wonder drove his initial interest, Stapleton is now working with researchers to understand why these unusual trees exist, and what their presence may mean for the health of surrounding trees and even entire ecosystems.

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Chicago Man Ticketed in Dog Park for Tree Treatment

July 7, 2021 · 0 minute read
Chicago Man Ticketed in Dog Park for Tree Treatment

NAPERVILLE, Ill. — A man who said he sprayed trees in a suburban Chicago park to protect them after an anxious dog chewed off the bark has been ticketed by authorities.

Asher Thomas is accused of “altering flora” in a Naperville dog park. The ticket from the Will County Forest Preserve carries a $225 fine, the Aurora Beacon-News reported.

“Just as you can’t go around doing things to other people’s property, even if intentions are good, you can’t allow your dogs to do damage or spray a foreign substance on trees,” said Forest Preserve Deputy Police Chief Dave Barrios.

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‘Tree Farts’ Raise Ghost Forests’ Carbon Emissions

June 30, 2021 · 0 minute read
‘Tree Farts’ Raise Ghost Forests’ Carbon Emissions

Along the Atlantic coast of the United States, climate-driven sea-level rise is sending salt water increasingly farther inland. The encroaching brine is killing off coastal woodlands in places like North Carolina, leaving behind “ghost forests” of lifeless trees.

Now, a new study suggests these expanding, ghoulish ecosystems are also contributing to climate change via a much less spooky-sounding phenomenon: “tree farts,” reports Valerie Yurk for E&E News.

When these dead trees—or snags as researchers call them—break wind, they release greenhouse gases, including carbon dioxide, methane and nitrous oxide, according to the paper published last week in the journal Biogeochemistry. While tree farts still pale in comparison to emissions from soil, they increased the total emissions of the ecosystem by around 25 percent, according to a statement.

The researchers say quantifying the carbon emissions of these ghost forests will become even more important in the future as sea-level rise drowns more trees.

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Fire Destroyed Over 10% of World’s Giant Sequoias Last Year

June 23, 2021 · 0 minute read
Fire Destroyed Over 10% of World’s Giant Sequoias Last Year

Last year, California’s Castle fire may have killed off ten to 14 percent of the world’s giant sequoias, reports Joshua Yeager of the Visalia Times-Delta.

The tally of dead trees comes from a new draft report that used satellite imagery, forest modeling, and surveys to revise initial estimates of how many titanic trees were lost when flames ripped through parts of Kings Canyon and Sequoia National Parks. That initial estimate was around 1,000 dead sequoias, but now scientists with the National Park Service and U.S. Geological Survey (USGS) suspect between 7,500 and 10,600 mature trees may have died, reports Kurtis Alexander for the San Francisco Chronicle.

Per the Chronicle, among the fallen is the planet’s ninth-largest giant sequoia, nicknamed the King Arthur tree. Sequoias can live for thousands of years and grow to more than 250 feet tall and measure 30 feet in diameter, per the Chronicle.

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UN: World Needs Massive Rewilding

June 9, 2021 · 1 minute read
UN: World Needs Massive Rewilding

The world must rewild and restore an area the size of China to meet commitments on nature and the climate, says the UN, and the revival of ecosystems must be met with all the ambition of the space race.

Existing conservation efforts are insufficient to prevent widespread biodiversity loss and ecosystem collapse, the global body has warned at the launch of the decade on ecosystem restoration, an urgent call for the large-scale revival of nature in farmlands, forests and other ecosystems.

Governments must deliver on a commitment to restore at least 1bn hectares (2.47bn acres) of land by 2030 and make a similar pledge for the oceans, according to the report by the UN Environment Programme (Unep) and the Food and Agriculture Organisation (FAO) to launch the decade.Advertisement

Humans are using about 1.6 times the resources that nature can sustainably renew every year and the UN said short-term economic gains are being prioritised over the health of the planet. The rallying cry calls on all parts of society to take action, including governments, businesses and citizens, to restore and rewild urban areas, grasslands, savannahs and marine areas.

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The Scientist Who Shoots Trees to Study How They Migrate

June 2, 2021 · 0 minute read
The Scientist Who Shoots Trees to Study How They Migrate

In Black Rock Forest, just north of New York City, Angie Patterson aims a shotgun at a northern red oak tree. Patterson is a plant ecophysiologist, and the leaves that she’s shooting out of the canopy will give her data to understand how and why trees migrate.

Trees have been on the move since at least the last ice age. As their native habitats become inhospitable, tree ranges shift, slowly, to areas they can thrive. But climate change is disrupting the process, scientists say. As of 2019, the IUCN Red List categorized more than 20,000 tree species as threatened, and upward of 1,400 as critically endangered.

As scientists scramble to learn more about what drives tree migration, others are planning for the future. To preserve biodiversity, both citizens and researchers are employing interventionist tactics once steeped in controversy like “assisted migration” — taking tree seedlings and planting them in new locations. Rising global temperatures may force wildlife agencies and forest managers to decide what to save and what to leave behind.

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‘Zombie Fires’: Blazes That Refuse to Die

May 26, 2021 · 0 minute read
‘Zombie Fires’: Blazes That Refuse to Die

Zombie forest fires are on the rise.

According to a study published Wednesday in the journal Nature, fires in far northern forests that smolder throughout the wet, cold winters and pop up again in the spring could become more common because of climate change. That presents challenges — but also opportunities — for fire management, and for minimizing the release of greenhouse gases, the researchers say.

Most of us think of forest fires as being contained within a single year. And for the most part, they are. But in the Arctic-boreal forests of Alaska, Siberia, Canada’s Northwest Territories and similar landscapes, fires can burn deep into the carbon-rich soil where they linger and lurk, often undetected.

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Why You Should Plant Oak Trees

May 19, 2021 · 0 minute read
Why You Should Plant Oak Trees

These large, long-lived trees support more life forms than any other trees in North America. And they’re magnificent.

When I arrived years ago at the piece of land I now garden, I saw it as a blank canvas and set about madly planting things, imagining my efforts would bring every square foot to life. I did not understand then that the heavy lifting had already been done — and probably by some blue jay, or maybe a squirrel.

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One of the World’s Longest-Running Experiments Sends Up Sprouts

May 12, 2021 · 0 minute read
One of the World’s Longest-Running Experiments Sends Up Sprouts

David Lowry was impatient for the very old seeds to wake up. For days, Dr. Lowry, an associate professor of botany at Michigan State University, had entered a basement room at the school, peeked into the growth chamber and seen only dirt.

But on April 23, he checked again and there it was: A tiny plant, its two leaves reaching upward. “It was kind of an amazing moment,” he said.

This was no average springtime sprout. Back in 1879, the botanist William James Beal plucked that seed and thousands of others from different weedy plants in and around East Lansing, Mich. He then stashed them in bottles and buried them in a secret spot on the Michigan State campus, with the goal of learning whether they’d still grow after years, decades or even centuries of dormancy. In mid-April, Dr. Lowry and four colleagues sneaked out under cover of night to dig one of the bottles up and plant its contents, thus continuing one of the longest-running experiments in the world.

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The Farmer Trying to Save Italy’s Ancient Olive Trees

May 5, 2021 · 1 minute read
The Farmer Trying to Save Italy’s Ancient Olive Trees

In early 2016, Giovanni Melcarne, an agronomist and the owner of an extra virgin olive oil farm in Gagliano del Capo, walked through the southern Italian countryside of Puglia. He was with a fellow olive oil farmer who had called and told him there was something he had to see.

The two approached a centuries-old olive tree growing at the edge of the street along a traditional stone wall. All around, the old olive trees that covered the red clay were either dead or in an advanced state of decay, filling the landscape with an unnatural greyness. Melcarne was not surprised: At least 2 million olive trees in Puglia looked this way, including many of his own.

The cause of the blight was Xylella fastidiosa, a bacteria that researchers believe arrived around 2010 from Latin America, possibly from Costa Rica on an imported ornamental plant. Today, Xylella has infected at least one-third of the 60 million olive trees in Puglia, which produces 12 percent of the world’s olive oil. The bacteria leaves no chance of survival: Once a plant is infected, it’s doomed to die in a handful of years. Today, Xylella is spreading fast across Puglia, crossing into other Italian regions and Mediterranean countries, and upending the production of olives and olive oil, the symbols of the Mediterranean.

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The Ultra-Wealthy’s Newest Must-Have: Trophy Trees

April 27, 2021 · 0 minute read
The Ultra-Wealthy’s Newest Must-Have: Trophy Trees

For decades, Walter Acree operated a modest landscaping business in Deerfield Beach, Fla. A self-described rebel, he mowed lawns in his bare feet, his then-long hair falling around his shoulders. Then, a few years ago, he stumbled into a lucrative niche business: helping South Florida’s superrich find trophy trees—the latest in status symbols for the most well-off