Don’t forget to look down!

June 23, 2022 · 4 minute read
Don’t forget to look down!

Last week my colleague, James, suggested you take a bit more time to “look up” in your day-to-day activities to appreciate your surroundings and sometimes see a truly remarkable tree that you might otherwise overlook. I felt that it was only fitting to piggyback on James’ advice and hopefully urge you to look down a little more often as well when it comes to trees. Humans love trees for many reasons and almost all of those reasons are for the above-ground benefits trees provide for us. Be it shade, wind-blocking, beauty, or useful resources, most of the time we look from the ground up and don’t acknowledge how much of the tree we can’t actually see. From the interior of the tree to the roots spreading out from the tree, there is a significant portion of each tree that is very important to the health and stability of the tree that we can’t even see. So let’s look down for a moment!

I do sometimes wish I was Superman and had all of the superpowers that our heartland superhero has, but when it comes to my job, the most valuable power would be that of x-ray vision. The ability to see underground and inside of a tree would be a game-changer, allowing for unbelievably thorough structural evaluations that could catch big problems before they can become even bigger problems. Root and stem decay would be immediately identifiable and preventing tree failures would be a simple task. Alas, I am no superhero and I surely do not possess the skills needed to identify every tree hazard, but I do have one tool that goes a long way in determining potential issues and that is looking for and identifying mushrooms growing on and around the base of trees.

A common talking point when I am meeting with new clients is to keep an eye out for mushrooms growing on and/or around mature trees in their landscapes. Mushrooms can be an indicator of a much larger issue that is invisible to those without x-ray vision because the mushroom itself is only a small portion of the larger fungus body. The fungal body that we call a mushroom is actually just the fruiting body of the much larger organism that produces spores to help the fungus spread throughout its environment. This fruiting body can be ephemeral, popping up sometimes for no more than a week or two, which then withers and decays while the fungus itself is still happily feeding on the wood of the tree. By looking down a little more often, it is possible to catch these mushrooms before they disappear, allowing us to briefly glimpse inside of a tree.

Typically, if a mushroom is growing on the tree itself, it is an indicator that the tree is being parasitized by a fungus which is likely weakening the tree’s structure. If mushrooms appear to be clustered around the base of a tree or radiating outward from the tree linearly, it is likely the fungus is feeding on the roots or very base of the tree. All of these signs are often overlooked indicators that the tree may have structural deficiencies that could lead to the failure of the tree.  Keeping an eye out for mushrooms gives a homeowner and an arborist the opportunity to catch unseen problems before they lead to a possible failure. As with everything in life, this is not always a hard and fast rule so identifying the mushroom species is especially important.

When mushrooms pop up around a tree, the best thing to do is take several photos of the mushroom or mushrooms to show their size and proximity to the tree. Singular small mushrooms of one species may be completely innocuous while the same from another species may be signs of a large issue. Once photos of the mushroom are obtained, the next best course of action is to reach out to an arborist to look at the mushroom on site. This allows for a detailed assessment of the fungus itself and the tree. When this can’t be accomplished in a timely manner, the next best option is to then remove the mushroom and photograph the underside of the fruiting body as the spore structures can be a very important tool for identifying the species of fungus. This should be done as a last resort as it usually requires removing the mushroom from the tree and breakdown begins almost immediately after it is severed from the rest of the fungal body. Also, note that removing the mushroom itself does little to help the tree as much of the fungus is still within the tree where it can continue to do damage.

The best time to “look down” is in the late spring and early summer after heavy rains and later summer to early fall when fall rains begin as the conditions at these times foster mushroom growth. Don’t panic when mushrooms do begin popping up but do take the time to acknowledge them and identify them as best as possible. By paying attention to these signs, it can be possible to catch otherwise invisible issues that could lead to the failure of a tree. Sadly, in most cases, it is not possible to treat wood decay fungi so identification is only useful in determining what should be done with the tree if decay has progressed too far. Keep an eye out this year and years to come as it could possibly save you and your property from damage.