Megan Walsh (Geography)
In the past decades, wildfires have been growing more intense and frequent in the Pacific Northwest (PNW). An example of this was the 2020 wildfire season during which numerous communities were displaced and millions of dollars worth of damage was done. In order to better understand the current pattern of wildfires, we must determine what past wildfire activity was like in various regions of the PNW. The goal of this research was to reconstruct the fire history for the Waterdog Lake watershed. This study site exists in a mid-elevation, mixed conifer forest in western Oregon, which is an under-studied region in the PNW in terms of fire history. We reconstructed the fire history for the post-glacial period (last ~15,000 years) using macroscopic charcoal analysis of a 5 meter-long lake sediment core extracted from the site in 2012. Radiocarbon dates were obtained from the sediment core to create an age-depth model and the charcoal data were plotted to show the trends in fire activity. The primary research question in this study was: “How and why has fire activity changed at Waterdog Lake in the last ~15,000 years?” The results of this research show greater fire activity during the last several thousand years of the record as compared to earlier. Data from this site will help contextualize current rises in fire activity in this area, and can further be used to piece together a greater understanding of the post-glacial fire history of the PNW as a whole.
Keywords: Climate change, Fire history ,Paleoecology