Fungus & Tree Rot

Fungus on a living tree stands as a fatal sign of destruction already underway at the tree's heart. Depending on the tree's location it may not have to be removed. Safety issues remain the best guideline for tree care.

Shelf Fungi

Fungus and Salamanders

According to the State University of Utah, shelf fungi can't be killed once they infect a tree. A tree rotted by these may snap at the trunk and fall even though the tree still has green growth. These fungi create major wood rot damage in trees, attacking the top of trees, base of trees and heartwood. Shelf fungi stand out from the tree in ripples and shelf-like growths. (See Ref 1, paragraph 5)

Benign Growths

Moss

Trees attract many growths, including moss and lichens. Not all are harmful to the tree or signs of disease.

Conk

A conk is a large, hoof-shaped fungus. It indicates heart rot.

Heart Rot Fungi

Thriving Fungus

The University of Minnesota reports that heart rot fungi take advantage of injuries to trees to enter a tree, and states that all types of fungi growing on a tree indicate rot. These tree-rotting fungi can't attack intact bark, though some can infect the roots. Fungi create a number of chemicals, including enzymes, to break down and digest the wood. (See Ref 2: Paragraph 4)

Hazardous Trees

Broken Tree

The National Forest Service warns that conks, mushrooms and other fungi on living trees are signs of significant decay. The weakened tree becomes susceptible to breaking. Prevent risk of injury or property damage by having the tree assessed by an arborist.

References

• Utah State University: Herbarium: Shelf Fungi
• University of Minnesota:Fungi Sprouting on Trees Have a Scary Story to Tell
• USDA Forest Service: How to Recognize Hardous Defects in Trees