Oregon State University Extension Service

What is this fungus and could it indicate internal decay in my Douglas-fir?

A large fungus is growing at the base of a large Douglas-fir tree in my backyard. There are several fungi that can cause root rot in Douglas-fir, so I don't want to lose the tree, and I also don't want it to fall on my house or my neighbor’s house. What information can you provide about this fungus?

It’s Phaeolus schweinitzii, which is called several different things such as "cow pie fungus" or “Schweinitzii root and butt rot.” If your tree is near a house, this is definitely an issue warranting further inspection and possible tree removal. An arborist should be able to detect internal decay in a Douglas-fir.

This fungus could definitely indicate internal decay of the root and butt of a tree – the lower trunk up to 8 feet – but it’s difficult to know how much rot is there just by looking at a photo of the spore-producing structure known as the conk. The conk has more bright colors in the fall and then turns brown and looks like a cow pie. It will be attached to a root below it but can occur on the tree butt also and be shaped more like a bracket.

Source URL: https://extension.oregonstate.edu/ask-extension/featured/what-fungus-could-it-indicate-internal-decay-my-douglas-fir