Coniferiporia weirii

Coniferiporia weirii is a species of fungus. It is a plant pathogen that causes laminated root rot in certain conifers, typically Douglas-fir and western redcedar. It is widespread in the Douglas-fir growing regions of British Columbia, Washington and Oregon.

Description
Coniferiporia weirii root rot is recognized first by the symptoms it induces in its hosts. Reduced terminal growth is usually the first symptom to appear, followed by yellowing (chlorosis) and thinning of crowns. Reduced growth rate is an attribute of tree infection. Particular attention is invited to the growth ring patterns visible in the images below.

Commercial losses
Losses due to the fungus are estimated at 4.4 million m3 (157 million ft3) of timber in the Northwestern United States and in British Columbia.