Sample of the Week: Canker Rot on Oak

Fruiting body of Inonotus hispidus on the
trunk of an oak in Craven Co., NC. December
2011. Photos courtesy Tom Glasgow, NC
Cooperative Extension Service.

This sample actually came in last month, but we made the definitive identification this week. You might be seeing more conks (a type of fungal fruiting body) now that our deciduous trees have dropped their leaves.

Inonotus hispidus is one of many fungi capable of causing a white rot of the heartwood of trees. It is, however, one of only a few such fungi that can kill living tissues of the tree. The common name of "canker rot" is a reflection of this fact. It  is widely distributed in North Carolina and the United States, and occurs on hardwood trees, especially oaks. For a technical description of this organism, see its page among the Fungus Profiles on the web site of the Larry F. Grand Mycological Herbarium.

Fruiting bodies of Inonotus hispidus can occur much farther up the trunk than what is pictured here. Also please note that the presence of these fruiting bodies indicates decay within the tree, but wood decay can be present without any externally visible signs or symptoms in a given year.