See:
Cedar, Western Red (Thuja plicata) - Pencil Rot (Brown Pocket Rot)
Fir, Douglas and True - Stem Decays (Heart Rots)
Note Although not common, several heart rots have been reported including: Brown Crumby Rot - Fomitopsis pinicola; Brown Cubical Rot - Laetiporus sulphurascens (the sufur fungus); Ganoderma Trunk Rot - Ganoderma applanatum; Pencil Rot (Brown Pocket Rot) - Postia sericiomollis; and Red Ring Rot (sometimes called white speck) - Porodaedalea pini (formerly Phellinus pini). Pencil Rot is the most common decay encountered. Stem decay in living trees is caused by various fungi that enter trees through wounds or small branches. Decay fungi usually do not kill trees but trees, which are affected, are structurally weakened and more likely to break during storms or harvest. Decayed trees can be a serious hazard when near roads, buildings or developed recreation areas.
Reference Goheen, E.M., and Willhite, E.A. 2006. Field guide to the common diseases and insect pests of Oregon and Washington conifers. R6-NR-FID-PR-01-06. Portland, OR. USDA Forest Service, PNW Region.