Historic range of variability for upland vegetation in the Bighorn National Forest, Wyoming

Abstract

An approach for synthesizing the results of ecological research pertinent to land management is the analysis of the historic range of variability (HRV) for key ecosystem variables that are affected by management activities. This report provides an HRV analysis for the upland vegetation of the Bighorn National Forest in northcentral Wyoming. The variables include live tree density, dead tree (snag) density, canopy cover, abundance of coarse woody debris, species diversity, fire return intervals, the abundance of various diseases, the proportion of the landscape in different land cover types, and the degree of patchiness in the landscape. The variables were examined at the stand and landscape scales, using information available in the literature and USFS databases. High-elevation landscapes were considered separately from low-elevation landscapes. Much of the report pertains to forests dominated by lodgepole pine, subalpine fir, and Engelmann spruce at high elevations, and by ponderosa pine, aspen, and Douglas-fir at lower elevations. We defined the HRV reference period for the BNF as approximately 1600 to 1890.

Subalpine forest development following a blowdown in the Mount Zirkel Wilderness, Colorado

“…Based on our findings and previous studies (e.g. Dillon & Knight 2000;Eisenhart & Veblen 2000;Mayer & Knight 2001), we suggest that there may be regional variations in forest susceptibility to beetle outbreak and blowdown -beetle interactions. Such regional variation in the susceptibility of Picea-Abies forests to D. rufipennis outbreaks needs to be considered along with stand level habitat variation (Schmid & Frye 1977;Bebi et al 2003) in assessing the risk of outbreaks following blowdowns.…”

The use of historical range and variability (HRV) in landscape management

“…Wong et al (2003) compiled an extensive reference of historical disturbance regimes for the entire province of British Columbia, Canada. Dillon et al (2005) and Meyer et al (2005) detail the historical variations in upland vegetation for two national forests in Wyoming. These efforts are excellent qualitative references for understanding and interpreting historical conditions, however, they do not provide the quantitative detail needed to implement the described reference conditions directly into management applications (see Fig.…”

Common Birds of the Brinton Museum and Bighorn Mountains Foothills

“…The plant communities of the Bighorns are similar to those in other parts of the Rocky Mountains. The Brinton lies on the eastern slope of the mountains, where the drier lower-elevation grasslands grade both to foothills and into higher-elevation forests and finally terminate in the cold-adapted alpine vegetation (Meyer et al, 2005).…”