Windthrow occurred during late April on the Glacier View, Hungry Horse, Spotted Bear, and Swan Lake Ranger Districts, Flathead National Forest. An evaluation to determine potential for development of spruce beetle and Douglas-fir beetle outbreaks was made during late June and early July. All areas examined were classed as having...
Baseline data for the first year of a two-year study to assess
the current status of ponderosa pine stands in southeastern
Montana relative to coal-fired electric power development are
presented. Sixteen permanent plots in pine stands were established
in eastern Montana, South Dakota, and Wyoming. Several characteristics
believed to be...
Dipel (R) was applied by helicopter to three blocks of Douglas fir and Engelmann spruce infested with Choristoneura occidentalis Free., in southwestern Montana. Dosage was 1 pound (7.2 Bill) in 2 gallons of water/acre (453 g in 7.5 t/0.4 ha). A commercial surfactant, Bio-film (R) was added at the rate...
Aerial surveys of six Montana National Forests in 1975 found a 22.1% increase in the area of visible defoliation caused by the western spruce budworm. It is estimated that 2,278,804 acres of Douglas-fir forests are now suffering at least 25% defoliation. This is an increase of 503,706 acres over the...
The pine needle cast fungus, Lophodermella concolor, caused severe discoloration and subsequent defoliation of lodgepole pine on over 4,000 acres and light defoliation on over 4,500 acres of lodgepole pine in the lower Clark Fork River drainage in 1975. Some trees had lost the last 3 years' growth of needles,...
Mortality from various causes was recorded in a Douglas-fir tussock moth, Orgyia pseudotsugata McD., outbreak southeast of Coeur d'Alene, Idaho, in 1974. Observations began June 27 when about 50 percent of the larvae were second instars and continued until pupation. Within a 35-day period, there was a 93 percent average...
Emerged beetles were first collected July 17 and peak emergence occurred between August 10 and 26, 1975. Density of attacks averaged four per 0.5 ft. 2 (0.05 m2). Parent to brood ratio was 1:4.6. Thirteen associate insects, representing six families of Coleoptera and one of Diptera, were recovered. Associates included...
Mountain pine beetle reached epidemic levels in the Lap, Cool, Lang, and Caribou Creek drainages in 1974. From 1973 to 1975, approximately 56,282 trees with an estimated volume of 4,365,660 board feet were killed in these areas. An additional 61,721 trees are predicted to be killed in 1976. Currently infested...