This fire history study is conducted within the Douglas-fir forest of the Little River watershed (LRW) in southwestern Oregon. In the LRW, fire has historically been one of the most prevalent disturbance elements in upland forests. The primary goal was to characterize the temporal and spatial variability of the historic fire regime within the LRW. For temporal variability, the main objective was to determine if and when the fire regime as shown by fire frequency had changed over the length of the record. There were several objectives to elucidate the spatial patterns of fire occurrence, 1) determine if fires were clustered near each other or randomly dispersed throughout the study area in the past, 2) characterize the spatial pattern of site-level fire frequencies, 3) determine through regression methods if historical fire frequencies were correlated with topographic variables for the length of the record and for each time period, and 4) extrapolate the predicted relationship between fire frequency and topography from the site-level over the study area.
The secondary goal was to describe the frequency, extent, and severity of the historical fire regime as much as possible within the limitations of the study design. The objective regarding fire frequency was to compare how the study area fire frequency compared to those of nearby studies in the western Cascade Range of Oregon. For fire extent, the objective was to identify relatively large fires and compare their numbers to that of smaller fires. The objective regarding fire severity was to characterize general site-level and study area fire severities based on the relationship between fire severity and frequency.
Frederick J. Swanson, Kelli J. Van Norman, Steven L. Garman