Estimating Extent of Mortality Associated with the Douglas-Fir Beetle in the Central and Northern Rockies

Data collected from Douglas-fir stands infected by the Douglas-fir beetle in Wyoming, Montana, Idaho, and Utah, were used to develop models to estimate amount of mortality in terms of basal area killed. Models were built using stepwise linear regression and regression tree approaches. Linear regression models using initial Douglas-fir basal area were built for all study sites but produce low precision estimates. Regression tree models using initial Douglas-fir basal area of stand density index or both were also build for all sites. Regression tree models provide a more realistic approach to estimate potential mortality by creating more homogenous mortality classes with reduced variance. The models developed provide land managers with a basis for determining the potential mortality should a Douglas-fir beetle outbreak develop

First Nebraska State Collection Record of the Mountian Pine Beetle, \u3ci\u3eDendroctonus Ponderosae\u3c/i\u3e Hopkins (Coleoptera: Curculionidae: Scolytinae)

The mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae: Scolytinae), is the most destructive bark beetle in western North America (Furniss and Carolin 1977). Extensive outbreaks are currently in progress across the region. In 2009 alone, approximately 0.41 and 0.49 million hectares (1.0 and 1.2 million acres) were affected in Colorado and Wyoming, respectively, and since 1996, an estimated 160,000 hectares (396,000 acres) in the Black Hills of Wyoming and South Dakota have been impacted (USDA Forest Service 2010). The mountain pine beetle attacks many pine species including Rocky Mountain ponderosa pine, Pinus ponderosa var. scopulorum (Engelm.) E. Murray, and limber pine, Pinus flexilis James (Pinaceae), both native to Nebraska, as well as exotics such as Scotch pine, Pinus sylvestris L., which is widely planted in Nebraska. The mountain pine beetle occurs in British Columbia and Alberta, throughout the western United States, and into northern Mexico (Wood 1982), yet to our knowledge recorded confirmation from Nebraska is lacking both in published literature and in collections. Here we present documentation that the mountain pine beetle is currently widespread at low densities across western Nebraska