The larch casebearer Coleophora laricella (Hbn.) is now established throughout all western larch stands in Region 1. Population levels have begun to fluctuate in some of the older infested stands; however, it is still on the increase in more recently invaded territory. During the past 2 years work was begun...
Numerous stands of western larch, Larix occidentalis, on the St. Joe, Coeur d'Alene, and Kaniksu National Forests, Idaho, show signs of gradual deterioration following repeated defoliation by larch casebearer, Coleophora Zaricella Hbn. (Tunnock et al. 1969). Stand deterioration can occur after 4 years of continued heavy defoliation. The main symptom...
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...
The Douglas-fir tussock moth, Orgyia pseudotsugata McD., periodically
defoliates Douglas-fir, true firs, and other host trees in forests of
the western United States. In the Northern Region, these infestations
occur about once every decade.
This history covers the earliest recorded outbreak in northeastern
Washington from 1928 to 1930 and includes...
Dwarf mistletoes exert an impact on forest productivity, but this impact can be reduced through management practices. Even infested stands can yield considerable volumes if proper control methods are used. Projections of future yield increases due to control efforts are made. Cost of treatment in fiscal year 1973 was $51...
Shade tree insect and disease activity within the city limits of Bozeman, Montana, were evaluated. Other than a few minor insects, the park, cemetery, and street trees are in remarkably good condition. Both the Park Department and private homeowners appreciate the value of trees in the urban environment. Recommendations on...
Epidemic populations of the western spruce budworm persist in the Northern Region. Aerial surveys made in August 1976 showed a decline in the acreage of aerially visible defoliation. In northern Idaho, the defoliated area dropped from 831,487 acres in 1975 to 655,711 acres in 1976, down 21 percent. Surveys in...
Preliminary analysis of data from this study in the mountains southwest of the Anaconda Copper Smelter, an industrial source of SO2 and heavy metal particulate, reflects a complex pattern of pollutant impact. The differential effect of smelter emissions on plant life in the study area is best explained by the...