Decay fungi of oaks and associated hardwoods for western arborists

Examination of trees for the presence and extent of decay should be part of any hazard tree assessment. Identification of the fungi responsible for the decay improves prediction of tree performance and the quality of management decisions, including tree pruning or removal. Scouting for Sudden Oak Death (SOD) in the West has drawn attention to hardwood tree species, particularly in the urban forest where native or introduced hardwoods may predominate. Consequently, the tree risk assessment specialist needs a working knowledge of the fungi associated with hardwood decay. We present here some of the common fungi responsible for decay of hardwoods, particularly of oak (Quercus spp.), tanoak (Lithocarpus densiflorus), and chinquapin (Castanopsis spp.) in Western North America.