Douglas-Fir Defects caused by the Douglas-Fir Beetle

Abstract The Douglas-fir beetle is shown to cause pitch streaks in Douglas-fir. These insects are attracted to dead or dying trees but also attack nearby healthy, standing trees. Usually only a small percentage of the attacked trees are killed. The rest sustain some kind of beetle-caused defect in the form of pitch pockets or streaks. Most Douglas-fir incur attacks before being removed from the stand. Silvicultural practices based on an understanding of this relationship can result in a reduction in wood defects.