The Approach of Pawpaw Season

August 19, 2020 · 1 minute read
The Approach of Pawpaw Season

When it comes to edible fruit in Virginia, most people think of apple orchards and blackberries. However, Virginia is home to a unique fruit that is naturally abundant here in Richmond and often hidden in plain sight. What is this mysterious fruit and tree of the same name? The pawpaw. Pawpaws line the James River and are usually ready to harvest around late August into September.

The pawpaw tree (Asimina triloba) is an understory tree that grows in well-drained, fertile soil. In Richmond, they’re usually found close to water. Native American tribes were known to cultivate the pawpaw, and colonial settlers were such big fans of the fruit that they often grew it on farms and made it into various desserts. Most say the fruit tastes like a hybrid of a banana and a mango, but the flavor can vary widely.

The author looking for pawpaws with his grandmother.

I recently purchased a copy of “Pawpaw: In Search of America’s Forgotten Fruit” by Andrew Moore for my grandmother while she enjoyed an extended stay with my family in Virginia. As a native of California, she’s always been fascinated with our state’s native flora and fauna. A few weeks ago, we explored Richmond’s urban forest to track down pawpaw groves that might prove bountiful once the fruit ripens. It was truly a special experience getting to walk a rugged trail with my 90-year-old grandmother, watching her discover this tree and its fruit she had just read so much about. Luckily we found quite a few fruit-bearing trees and will be sure to check on them in the coming weeks!

As with any type of foraging, make sure you know what you’re looking for. Never eat something you’re unsure of, and never overharvest a location. Leave some for other foragers, both human and animal!

Here are some pawpaw resources, if you’re interested in learning more:

National Park Service on pawpaws

NPR story on pawpaws

All the pawpaw details from wildflower.org

‘Slime Flux’: Great Name But a Problem for Trees

July 13, 2020 · 2 minute read
‘Slime Flux’: Great Name But a Problem for Trees

Truetimber’s tree care advisors often get called out to look at a plethora of phenomena related to homeowners’ trees. This spring and summer, it seems like one issue has been the most common: bacterial wetwood

Bacterial wetwood, also known as “slime flux” (great band name!) is a very common occurrence. In the Richmond area, it’s usually seen in elms, oaks, and maples, although it can make an appearance in other trees. Wetwood is usually brought on by bacteria entering a tree through some sort of wound. Wounds can be anything from a pruning cut to an impact from a vehicle, but, according to the Morton Arboretum, since the “bacteria associated with wetwood are common in soil, root wounds are probably a major point of entry. Infection is usually confined to the inner sapwood and heartwood.”

As the bacteria ferments, it pushes liquid out of the tree, resulting in a wet stain. The build-up of gases fluctuates during the year, with the highest pressure usually found in summer when the bacteria are most active. Often this liquid will have a sour, alcoholic aroma, which attracts different insects to feed. I recently saw a swarm of bald-faced hornets on one patch of wetwood!

So is bacterial wetwood anything to worry about? Yes and no. While the infection can definitely affect a tree’s vigor and overall health, it’s not considered to be a fatal condition. Currently, there are no known methods to completely cure a tree from infection. The best steps to take to prevent and/or manage bacterial wetwood are as follows:

  1. Prune correctly, and during the right time of year. Any time you prune a tree, you are creating a wound. It is best to limit any pruning on susceptible trees (i.e. elms, oaks and maples) during the summer months, as this is when bacterial wetwood is the most active.
  2. Boost the soil health around your tree. Adding nutrients to the soil will help boosts a tree’s vigor, allowing it a better chance at fighting off a potential infection, or better dealing with a current one.

In the past, some arborists would drill a small hole into an infection site and insert a metal tube. This was believed to help release pressure and direct the flow of fluid out of the tree. Today this is not considered a sound practice, potentially causing more harm than anything.

The Ins and Outs of Air Spading

June 16, 2020 · 3 minute read
The Ins and Outs of Air Spading

One of the first things I do when assessing a tree’s health is look down. So much of what we as arborists as problems in a tree’s canopy originate from issues underground. Soil compaction, buried root flares, lack of soil nutrients, and improperly planted trees are some of the most common tree health concerns I see on a daily basis.

So what can be done to remedy these problems? Well, prepare to meet what might be my favorite tool in our industry: the Air Spade. As opposed to manual digging tools, an Air Spade allows us to control highly compressed air to move soil from a tree’s root system with very minimal, if any, damage. It should be noted that any disruption to the soil around a tree inevitably damages the soil’s microbiome. It is up to a trained arborist to determine if and when using the air spade is the right call. We use this tool for numerous tasks, some of which we’ll go over in this article.

Examples of Air Spading techniques

Root Collar Excavation

You may remember an earlier article entitled “Root Flare: Where Trees Meet the Earth”. In that article, we discussed the importance of a tree’s root flair. It’s extremely common in an urban environment for a tree to be planted too deep or for mulch to be built up to an excessive level, burying a tree’s root flare. Over time, this can lead to stem-girdling roots that can encircle a tree’s stem—or trunk—and prevent the uptake of nutrients. 

It can also lead to root decay, which can eventually lead to tree failure. Using an Air Spade to expose a tree’s root flare is perhaps the most common application for the tool. An arborist is then able to prune any roots that may be growing in a way that is detrimental to the tree’s health.

Truetimber at work with the Air Spade

Vertical Mulching and Radial Trenching

When a tree is looking less than great, another common cause is soil compaction. Over time, constant foot or vehicle traffic, as well as construction, can compress the soil around a tree preventing the uptake of oxygen, water, and nutrients by the tree’s roots. We use the Air Spade to decompact the soil in two ways. 

Vertical Mulching is much like aerating your grass. We drive the tool straight down into the soil, creating a vertical tube. This is repeated in a grid pattern around the prescribed root zone. Finally, we backfill these holes with compost to boost the nutrients in the soil. The second method is called radial trenching. In this procedure, the air spade is used to create long trenches that fan out from the root flare of the tree, and are then backfilled with compost. Both methods are designed to cover as much surface area as possible while still retaining the soil’s preexisting microbiome. Our arborists are able to make an informed decision as to which method should be used.

Transplanting

Occasionally, trees end up in the wrong location. Whether it be due to construction, the size of the tree, or simply to make way for something else. As an alternative to removing a tree entirely, an Air Spade can be used to help us move a tree from one spot to another. By exposing a tree’s root’s we are able to make safe pruning cuts to extract the tree and replant in a different location. While this can be a risky procedure, it can be worth the effort!

Some Air Spade projects are massive

Construction Management

Oftentimes when we see trees that are in decline, they are suspiciously close to some form of new development. This may be a new driveway, an addition to a house, etc. While the issue may be just compaction from the constant presence of construction machinery, compiled on construction backfill devoid of nutrients, many times there is root damage present as well. An air spade allows us to expose and preventively prune roots back from a construction project so that they aren’t destroyed by machinery.

Truetimber wants to see Richmond’s trees thrive. If you have a tree that looks like it could use some love, have us take a look. We might be able to discover the ‘root’ of the problem.