Laminated root rot damage in a young Douglas-fir stand.

Damage occurring from the disease laminated root rot {Phellinus weirii (Murr.) Gilbertson) on two 10-acre plots in a young (40-year-old) stand of Douglas-fir was studied for 25 years. After 25 years, nearly 5 percent of the basal area was killed by the disease. Stand damage caused by vegetative spread of the fungus was significantly related to previous mortality from the disease and to slower net growth during that period. Nonproductive stand openings caused by the disease occupied over 11 percent of one plot and over 7 percent of the other. Although additional losses can be anticipated before harvest, severe losses are not expected in this stand before commercial maturity.