A fire history of a subalpine forest in south-eastern Wyoming, USA

Fire history was determined for part of the Routt-Medicine Bow National Forest in south-eastern Wyoming using fire-scar and age-class analysis. A composite chronology of fire events was used to determine mean fire intervals (MFI) for pre-EuroAmerican settlement, EuroAmerican settlement (before 1868 AD), EuroAmerican settlement and modern (after 1912) periods, for all fires and stand-replacing fires. Point-scale MFI was also determined using grand means from individual trees. Stand-replacing fires were reconstructed to determine fire rotation. MFI for the entire time period is 5.5-8.4 years. MFI decreased from 9.3 to 15.7-1.9-2.9 years from the preto post-EuroAmerican settlement periods, and increased during the modern period. Point-scale MFIs are longer than MFI of the study area. Fire rotation is 182 years for the total period of record, but increased from 127 years during the pre-EuroAmerican settlement period to 170 years during the EuroAmerican settlement period. Fire rotation during the modern period dramatically increased to 27,035 years. Results suggest fire suppression may have influenced the fire regime. Comparison of regional fire events with fire events from this study indicate regional weather has an important influence on Rocky Mountain fire regimes.