Tree Mortality Caused by Root Pathogen Complex in Deschutes National Forest, Oregon. Gregory M. Filip, Plant Pathologist, USDA Forest Service, Forest Pest Management, Portland, OR 97208. Donald J. Goheen, Plant Pathologist, USDA Forest Service, Forest Pest Management, Portland, OR 97208. Plant Dis. 66:240-243. Accepted for publication 29 April 1981. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1982. DOI: 10.1094/PD-66-240.

Tree mortality caused by root diseases was measured in a severely infected, 1,000-ha forest in central Oregon. Of trees ≥15 cm tall, 98 (11.1%) of 885 trees per hectare (or 21.6% of the merchantable wood volume) had been killed by root diseases during the preceding 20 yr (3.9 m³/ha per year). About 15% of the dead trees, representing over half of the dead volume, had been salvaged. Armillaria mellea occurred on all conifer species, Phellinus weirii on grand fir and Douglas-fir, Ceratocystis wageneri on ponderosa pine and lodgepole pine, and Fomes annosus on grand fir. Two or more root pathogens frequently occurred in close association. This is the first report of C. wageneri on lodgepole pine in Oregon and of extensive infection of ponderosa pine by C. wageneri in the Pacific Northwest.

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