It is a plant pathogen that causes laminated root rot in certain conifers, typically Douglas-fir and western redcedar.

[2] It is widespread in the Douglas-fir growing regions of British Columbia, Washington and Oregon.

[3] 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.

[4] Particular attention is invited to the growth ring patterns visible in the images below.