“Birch Polypore” Brown rotter associated with hardwoods, mainly birch. An annual bracket fungus that grows primarily on birch. Cap surface is smooth and gray-brown. The pores are white to cream. Saprotrophic after the tree has died and possibly slowly parasitic on wounded living trees. The cap surface has been used to sharpen razor edges. Often populated by many species of insects for breeding and for a source of nutrition. It may have medicinal properties.