Phellinus weirii is a plant pathogen causing laminated root rot

Laminated root rot

Laminated root rot also known as yellowing ring rot is caused by a fungal pathogen Phellinus weirii . Laminated root rot is one of the most damaging root disease amongst conifers in northwestern America and affects mostly fir trees and cedars.. Douglas fir, mountain hemlock, Western Hemlock grand...

 in certain conifers, typically Douglas-fir

Douglas-fir

Douglas-fir is one of the English common names for evergreen coniferous trees of the genus Pseudotsuga in the family Pinaceae. Other common names include Douglas tree, and Oregon pine. There are five species, two in western North America, one in Mexico, and two in eastern Asia...

 and western redcedar. It is widespread in the Douglas Fir Growing regions of British Columbia

British Columbia

British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...

, Washington and Oregon

Oregon

Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

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It is easily recognized when timber is cut because a brown stain will appear on the butt cut. In early stages it will be just a spot in the heart wood, but as the disease advances it will extend most of the way around the heart wood, and in extreme cases may result in a hollow stump.