Project Title
Mountain Big Sagebrush Post-Fire Recovery (Succession) in the Southern Half of its Distribution
Abstract
Knowledge of past fire regimes associated with mountain big sagebrush-dominated landscapes is inadequate for accurate assessment of current departures from historical conditions and scientifically-based fire planning by land managers. Widely utilized estimates of fire frequency are based upon a few problematic studies using fire-scarred proxy trees located at the forest/shrubland ecotone. These studies, all conducted in the northern half of the species distribution, generally fail to adequately address questions of fire behavior across the fuels threshold at the forest/shrubland ecotone. Alternatively, fire frequencies compatible with big sagebrush have been suggested based upon post-fire succession rates. Specifically, minimum and maximum fire free intervals are estimated based upon the time required for big sagebrush recovery or tree invasion and dominance, respectively. Published studies of mountain big sagebrush post-fire recovery are also limited primarily to higher latitudes, and as a rule are not linked to tree invasion studies. Big sagebrush does not sprout after fire and recovery is dependent upon the availability of seed and post-burn survival of seedlings. Factors that affect seed production, seed bank retention, and post-fire seed survival are not adequately understood. Our objective is to address these deficiencies through the following steps:
- first, using chronologies from fire-scarred trees, develop estimates of fire frequency for at least eight mountain big sagebrush communities in the eastern Great Basin, upper Colorado Plateau and intervening uplands, representing the southern half of the species distribution;
- second, using sites from the same ecoregions with variable time-since fire, develop rate estimates for mountain big sagebrush recovery and tree invasion. As part of this effort, we are investigating the capacity for big-sagebrush seed production as a function of time-since-fire;
- third, model the long-term response of woody species to fire regime, using as model input our proxy fire-scar estimates for fire frequency and empirically-derived estimates of successional rate and pattern. An analysis of model outputs for vegetation cover classes over time will provide a critical test of the appropriateness of shrubland fire frequency estimates based upon fire-scar records obtained from proxy trees.
GSD Principal Investigators
| Kitchen, Stanley | Research Botanist | 801-356-5109 |
Cooperators and Sponsors
Zachary J Nelson, Department of Natural Resources and Environmental Sciences, University of Nevada Reno
Steven L Petersen, Department of Plant and Wildlife Sciences, Brigham Young University
Peter J Weisberg, Department of Natural Resources and Environmental Sciences, University of Nevada Reno
Joint Fire Science Program
