A practical demonstration of a method for
rating forest stands as to their probability of
defoliation by the Douglas-fir tussock moth
using aerial photographs and available cruise
data was done in the Palouse Ranger District,
Clearwater National Forest, Idaho.
A nonlinear computer program, RISK, was used to
identify significant independent...
The current western spruce budworm, Choristoneura occidentalis Freeman, outbreak on the Clearwater National Forest was first detected in 1966. Since then, the infestation has increased to epidemic proportions with over 500,000 acres of State, Federal, and private forest land visibly defoliated. In addition, incipient budworm populations are present throughout much...
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...
Epidemic levels of the pine butterfly, Neophasia menapia (Felder and
Felder) have been evident in ponderosa pine stands in the Bitter Root
Valley since 1969. Evaluations of this infestation were initiated in
1970 to assess overwintering egg populations at 20 locations within
the infestation (Ciesla et al. 1971). Defoliation was...