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Across the western United States aspen stands are valued as areas of relatively high forage production, excellent native ungulate habitat, and sources of aesthetic value. Aspen decline is a major concern to many ranchers and land managers in Colorado. We partnered with landowners and land managers in western Colorado to develop state-and-transition models specific to aspen stands occurring within the areas in which these individuals live and work. The process of working with land owners and land managers to develop locally-relevant STMs for these systems led us to ask the following research questions: 1) What aspen stand functional types are present in the study areas? 2) Do aspen stands in the study areas occur on one ecological site or across multiple ecological sites? 3) Is the severity of aspen die-off correlated with abiotic site characteristics that distinguish specific ecological sites? 4) Are levels of herbivory, root density, or suckering positively or negatively correlated with foliar cover and the proportion of live/dead trees in a stand? We surveyed soils and vegetation on 21 plots in aspen stands and 21 plots in adjacent non-aspen vegetation communities. These paired aspen and non-aspen plots are located within the same soil map units (as identified by the National Conservation Service's Web Soil Survey) and within similar slope ranges. We conducted community classification and ordination using nonmetric multidimensional scaling, multi-response permutation procedures, and indicator species analysis. We describe how the results of these analyses are applied to create more locally-relevant STMs for aspen-dominated ecological sites.