Polypores are a group of fungi that form fruiting bodies with pores or tubes on the underside (see Delimitation for exceptions). They are a morphological group of basidiomycetes like gilled mushrooms and hydnoid fungi, and not all polypores are closely related to each other. Polypores are also called bracket fungi, and their woody fruiting bodies are called conks.
Most polypores inhabit tree trunks or branches consuming the wood, but some soil-inhabiting species form mycorrhiza with trees. Polypores and their relatives corticioid fungi are the most important agents of wood decay. Thus, they play a very significant role in nutrient cycling and carbon dioxide production of forest ecosystems.
Over one thousand polypore species have been described to science, but a large part of the diversity is still unknown even in relatively well-studied temperate areas. Polypores are much more diverse in old natural forests with abundant dead wood than in younger managed forests or plantations. Consequently, a number of species have declined drastically and are under threat of extinction due to logging and deforestation.
Polypores are used in traditional medicine, and they are actively studied for their medicinal value and various industrial applications. Several polypore species are serious pathogens of plantation trees and are major causes of timber spoilage.