Dwarf mistletoes reduce tree height and diameter, and thereby cause a reduction in volume production. We estimate that volume reduction in Montana is about 33.2 MM cubic feet per year. Mistletoe effects are problems in some areas because of the demands we have placed on the Forests for goods and...
A permanent study was established in 1970 and 1971 to measure the impact, spread, and intensification of dwarf mistletoe on precommercially thinned Douglas-fir and lodgepole pine in Montana. Mean diameter growth on all plots was reduced 21 percent in Douglas-fir, but the reduction is only significant at the 0.15 level....
Cooperative Forestry and Pest Management conducted a pilot control project in central Montana to determine the effectiveness of two commercial formulations of BaaiUus th,uringiensis Berliner applied at 8 billiori international units (BIU) per acre (19.8 BIU per hectare) when used under operational conditions against the western spruce budworm, Choristoneu:roa ocaidentalis...
Western spruce budworm defoliated area in the Northern Region has differed significantly across three discrete geographic zones during the past decade. Aerially visible defoliation in northern Idaho increased from 1.7 million acres in 1969 to a high of 2.2 million acres in 1974, and declined to none in 1979. Defoliated...