Mortality and growth reduction of white fir following defoliation by the Douglas-fir tussock moth

Abstract

In 5 years after a 1954-56 outbreak of Hemerocampa pseudotsugata in Calaveras and Tuolumne Counties, California, 20 percent of the merchantable white fir, or 11,071 board feet per acre, died in heavily defoliated stands. Another 1,113 board feet per acre was lost owing to radial growth reductions in partly defoliated trees; 12 percent of these trees were top-killed. Defoliation alone, and the combined effects of defoliation and attacks of cambium-mining beetles were the main causes of mortality.

Citation

Wickman, Boyd E. 1963. Mortality and growth reduction of white fir following defoliation by the Douglas-fir tussock moth. Res. Paper PSW-RP-7. Berkeley, CA: Pacific Southwest Forest & Range Experiment Station, Forest Service, U.S. Department of Agriculture; 15 p