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...
A multistage sampling survey to measure annual and cumulative mortality of lodgepole
pine by mountain pine beetle was conducted
on the Beaverhead and Gallatin National
Forests, 1978-79. The survey area, 270,000
acres, was stratified into three intensity classes
from aerial sketchmapping. This was followed
by large scale (1:6,000) aerial photography,...
A 3-year evaluation of Douglas-fir cones in Montana and Yellowstone National Park, Wyoming, showed the western spruce budworm, Choristoneura occidentalis Freeman, and midges were the most common and injurious insects found each year. Injury was so severe at some plots that no sound seeds could be found.
An active infestation of ash borer, Podosesia syringae (Harris) was detected in green ash, Fraxinus pennsylvanica Marsh, surrounding the Bowman-Haley Reservoir in 1973. A survey in 1974 showed that 40.4 percent of 690 trees examined contained active ash borer attacks. Forty-three out of 140 windbreaks were sampled and each one...
A survey to determine distribution and intensity of cankers and associated damage in North Dakota windbreak plantings of Russian-olive and Siberian elm was conducted in 1972. Four hundred and thirty-five (76 percent) of 574 Russian-olive examined had cankers, and 552 (72 percent) of 769 Siberian elm examined had cankers. Cankers...
"Holes" with dead, dying, and downed trees in the forest canopy could be reliably identified on 9- by 9-inch Kodak Ektachrome Infrared Aero film 2443 as root disease centers. Film scales larger than 1:4000 were best for detection of these "holes."
Most commonly occurring causal organisms in root diseased trees...