What’s That on My Trees?

Beautiful but Dangerous Tree Fungus

Christmas trees aren’t the only trees on our minds here on the East End these days. Even as leaves continue to fall, Fox Tree Service President Bart L. Fuscoa Certified Arborist and Registered Consulting Arborist—shares his expert insights into other things you may have noticed growing on your trees.

The Question: I have a light and dark green growth on the trunks of my trees. Is this bad?

The Answer from Bart L. Fusco of Fox Tree Service: On Long Island we have trees that have both moss and lichen, a type of fungus, growing on the bark of trees.

These growths are not harmful to the trees and other plant material that they colonize. In fact, they are vulnerable to air pollution, and although widespread on the eastern end of Long Island are rarely observed in New York City.

Although these fungi are not parasitic, there are a number of fungi that are harmful—and these are often a sign of rot and decay in the interior of the tree.

Bracket fungi, or shelf fungi, the fruiting bodies also known as conks, can be parasitic and can accelerate the death of the host tree. The fungus continues to feed on the tree even when only a stump remains. Although these photographs show the fungi growth near the base of the tree, the growth can appear anywhere on a tree depending on the location of the rotting material.

With the colonization of the tree by one of these fungi, the tree may appear to be healthy, as the growing organism does not immediately affect the growth of the leaves. However, after the fungus has fed on the interior of the tree, the tree may lose its structural strength.

After the organism has developed it will start to produce fruiting bodies. It is these mushrooms and conks that arborists use to help identify potential tree hazards.

To be a hazard, a tree must have an immediate potential to fail, and a potential target. A tree that has these fungi growing on it does not mean the tree has to be removed—there are a number of arboricultural procedures to reduce risk and even eliminate the hazard.

Have questions about growth on trees in your yard or caring for your trees this fall? You can contact Fox Tree Service in Suffolk at  631-283-6700, and in Nassau at 516-921-7111, or visit online at foxtreeservice.com.

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