Bark Falling Off Oak Tree

Q: Can you tell what caused a big patch of bark to fall off the bottom of my oak tree? No marks or tunnels at all; the bark looks like it just fell off suddenly.

A: My bet would be armillaria root rot. The disease is common on oak trees, particularly if they have wounded or stressed roots. Soil piled up around the base of the tree or excavation that wounded the roots are common sources of the damage. The fungus grows up underneath the bark and the bark sloughs off. Probably more bark will come off in the future. There’s nothing you can do about armillaria root rot. If a tree is hazardous to property or people, you need to hire a certified arborist to come and take a look. The Georgia Arborist Association, georgiaarborist.org, maintains a list of certified arborists who can come and inspect the tree.