PAST AND CURRENT WILDFIRE TRENDS IN THE OKANOGAN-WENATCHEE NATIONAL FOREST: AN ANALYSIS USING GIS AND PALEOECOLOGICAL METHODS

Environmental change and human activity have been the driving forces of fire activity in Pacific Northwest forests throughout the Holocene. Fire exclusion policy following the fires of 1910 was intended to remove fire from federally-managed forest ecosystems. To evaluate the effectiveness of fire suppression over the last century, we examined area burned by wildfires in the Okanogan-Wenatchee National Forest in decadal intervals using GIS. Analyses of these data indicate that for the better part of the 20th century, fire exclusion efforts were very successful. However, despite technological advancements in wildfire suppression the data demonstrate that area burned in recent decades has greatly increased. It is understood that the removal of fire from eastern Cascade forests has increased their susceptibility to high-severity wildfires. In order to more effectively manage these forests it is important to understand how fire regimes have varied in longer timescales. To address this, we retrieved Holocene-length sediment cores from Blue Lake and Doheney Lake in the Sinlahekin Wildlife Area, Okanogan County, WA. Through the use of macroscopic charcoal and pollen analysis we will reconstruct the vegetation and fire history for the Sinlahekin study sites. Preliminary results indicate major shifts in fire activity prior to and after Euro- American settlement. Further analysis of these records will establish a Holocene fire record and determine its linkages with vegetation change, climate variability, and human activities. The results of this research will aid in management decisions regarding the use of fire in eastern Cascade forests