Aerial surveys of the Nezperce National Forest in Idaho revealed 138,692 acres of aerially visible top kill and tree mortality due to repeated defoliation by western spruce budworm, Choristoneura occidentalis Freeman.
A small ground sample indicates that up to 47 percent of the grand fir volume was affected by top...
An attempt was made in January 1971 to relate the numbers of hibernating western spruce budworm larvae on a square foot of bark surface with subsequent shoot damage on Douglas-fir and grand fir in northern Idaho.
Twenty-six plots sampled in January were also sampled in April to determine
if larval...
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...
Annosus root disease (Heterobasidion annosum (Fr.) Bref.) is causing notable conifer
mortality in grand fir habitat types in central Idaho. The most significant mortality is occurring in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco.) trees of all age classes. This project was designed to study some aspects of the general biology of...
Two concentrations of dimethoate were applied with a hydraulic ground sprayer to cone-bearing Douglas-fir and grand fir trees. Single application (mid-June) and a double application (mid-June and mid-July) were compared. Three of the four treatments applied to Douglas-fir resulted in a significantly higher number of sound seeds produced per cone...
