Both Grifola frondosa and Meripilus sumsteinei grow at the base of trees and cause a white rot.  Likely weakly parasitic as well as sabropic. The types of wood destroying fungi encountered by pest management professionals and homeowners fall into two basic categories: brown rot and white rot. White rot attacks the cellulose and lignin in the wood giving the wood an off-white appearance. In the later stages the wood becomes spongy to the touch. White rot typically attacks hardwoods and lacks the cubical checking appearance of brown-rotted wood.
Brown rot commonly attacks softwoods turning the wood dark brown. In advanced stages of decay, wood attacked by brown rot becomes friable and splits appear across the grain giving the wood a "checkerboard" appearance. Infested wood may be structurally weakened in a relatively short period of time. Once brown rot has extracted all of the nutrients from the wood the wood may become dry and powdery. This leaves the impression that dry wood has rotted (dry rot) but in reality it is an old infestation of brown rot. G. frondosa, they can appear year after year in the same location.  This polypore, however, has larger lobed caps and smaller pores than Grifola frondosa.  It stains black on handling. Though often confused with Grifola frondosa, both are choice edibles. Meripilus giganteus is a European species. 054-001