Relationship between initial vegetation structure and alternative management scenarios in southwestern woodlands and forests

The structure and composition of southwestern vegetation communities are transforming as a result of past and current land uses including livestock grazing, large-scale timber harvesting, human development, and invasions of non-native plants. Contemporary changes in climate and fire regime are exacerbating this situation. To mitigate the risk of extensive, high-intensity fires and ecological degradation, resource managers are interested in implementing fuel-reduction and restoration treatments (e.g., prescribed fire) over large areas. Accordingly, there is a need to predict the effects of treatments on ecosystem processes and components, such as fire and wildlife, and locate these efforts strategically. For woodlands and forests in the Southwest, we are developing tools and maps of current vegetation conditions to assess the cumulative impacts of alternative restoration and fuel-reduction treatments at landscape and regional scales. We are using empirically-derived, spatially-explicit models of initial stand conditions to predict post-treatment fire behavior, avifaunal composition, and wood supply. For example, stakeholder-defined management scenarios can be used to parameterize reductions in basal area, stem density, and canopy cover that mimic outcomes and guide placement of treatments. Because large-scale treatments are complex and expensive, information on treatment-induced changes to vegetation may be limited. Pre-treatment structural attributes can be central in developing predictive models to understand the likely outcomes of restoration and fuel-reduction treatments on vegetation structure. Results can be overlaid and integrated with taxonomic distributions, inhabited areas, and other spatial data.