High severity fire in forests of the southwest: Conservation implications. Progress Report August 2005

Abstract

The occurrence of large, severe fires in southwestern ponderosa pine (Pinus ponderosa) forests has resulted in concern that these forests may not persist under such an extreme disturbance regime. In our research, we are examining the outcomes of high-severity fire in ponderosa pine forests and their neighboring communities across an elevational gradient. One goal of our work is to contribute to understanding the resiliency of these systems, but we also want to investigate the conservation values intrinsic to the diverse communities that represent alternative successional trajectories after severe fire. One assumption of our research is that the spatial pattern of a disturbance becomes increasingly important when the disturbance is large and biological legacies are few and sparse. We ask, therefore, what spectrum of plant communities results from high severity fire, and what is their relationship to spatial patterns of severity mapped in early post fire timeframes? Also, do spatial patterns of older burns (1950–80) differ from recent burns (1998–present) in ways that make us expect successional changes years from now to differ from those we observed at our older burn field sites? Here, we describe the first stages of our work in mapping burn severity at old and new burns as well as the work we have recently completed at our two field sites. The report is organized under our two main objectives with the purpose of summarizing the steps we have taken in working toward these objectives, as well as changes we have made in methodologies since the original study plan. We present some general observations and plans for the next steps in data analysis and product generation. This report, the study plan, a photograph gallery, slide presentations, and our contact information are available on the project Web site http://www.umass.edu/landeco/research/swfire/swfire.html .