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 Medicine Bow National Forest in southeastern 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 and aspen at lower elevations. We defined the HRV reference period for the MBNF as approximately 1600 to 1860.Keywords: aspen, bark beetles, canopy gaps, coarse woody debris, comandra blister rust, dwarf mistletoe, Engelmann spruce, fire effects, disease in Rocky Mountain forests, forest fragmentation, insects in forests, interior forest, landscape ecology, lodgepole pine, mistletoe, mountain pine beetle, ponderosa pine, roads, Rocky Mountain forests, snags, spruce beetle, subalpine fir, subalpine forests, timber harvesting effects, white pine blister rust, wind in forests
Executive SummaryThe challenges of sustainable land management have led to an increased emphasis on incorporating the results of science in the decision making process. One approach for accomplishing this objective is through the analysis of the historic range of variability (HRV) for key ecosystem variables that are affected by management activities. The rationale for HRV analyses is that the chances of sustainable forest management are greater if the variation in managed ecosystems includes the range of conditions that are expected at various scales in ecosystems relatively uninfluenced by humans. This report provides an HRV analysis for the upland vegetation of the Medicine Bow National Forest (MBNF).By definition, HRV analyses require the identification of specific variables and an estimation of how those variables fluctuated, at more than one scale, prior to the advent of resource extraction and management by EuropeanAmericans. A complete list of the variables that we examined is found in table 7. Examples 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. We examined variables at two scales-the stand and the landscape-and we separated high-elevation landscapes from low-elevation landscapes. Much of the repo...