41 pagesClimate change is expected to increase the frequency and severity of forest fires and drought across the Pacific Northwest (PNW) of the United States. Due to increasingly variable temperature and precipitation patterns, the effects of fire on forest vegetation can be modeled and predicted with great confidence. However, the effect of fire frequency on soils remains poorly understood. Soils in PNW forests have the potential to sequester large quantities of carbon, which can mitigate the effects of climate change. Furthermore, severely burned forests may be “salvage” logged post-fire in which consequences for carbon storage are uncertain. To quantify the effects of fire on soil properties and carbon content, we measured soil organic carbon (SOC), pH, and texture among a fire severity and post-fire management gradient in a region affected by the Biscuit Fire of 2002. Samples were collected at four sites and two depths for percent SOC, pH, and percent clay analyses. Laboratory analyses showed the low severity (8.10 ± 0.5) had higher levels of SOC than high severity sites (7.21 ± 0.9). However, the unburned site contained 4.29 ± 0.4 % SOC, the lowest percentage of the four sites. There were minimal differences in percent SOC between the salvage logged and non-salvage logged sites. Soil from the high severity non-salvage logged site had a significantly higher pH than the other sites, and percent clay remained relatively similar across all sites. The results indicate that low severity fires, potentially in the form of prescribed burns, may be optimal for sequestering SOC and could help mitigate the impact of climate change in montane forests in the PNW region
