Description:
An impact survey to determine extent and distribution of root disease centers was completed for the Nezperce National Forest, Idaho, in 1980. Lowlevel
color infrared photography was used to delineate root disease centers
within National Forest inventory subcompartments. Suspected root disease
centers were ground checked to determine associated fungi and insects and
verify accuracy of photointerpretation. More than 3,800 hectares (about 1.0
percent) of commercial forest land were occupied by large root disease
centers. Most root disease occurred in well-stocked, pole to small
sawtimber stands and medium-stocked, two-storied stands. The major root
pathogen associated with disease centers was Armillaria mellea. Phellinus
weirii and Phaeolus schweinitzii were found less frequently. Major bark
1 beetle associates included Dendroctonus ponderosae on lodgepole pine, D.
pseudotsugae on Douglas-fir, Dryocoetes confusus on subalpine fir, and Scolytus ventralis on grand fir.