Interacting disturbances: did sudden oak death mortality in Big Sur worsen the impacts of the 2008 basin complex wildfire?

Abstract

In late June 2008, a large, dry lightning storm ignited thousands of fires across California. The largest of these fires became the Basin-Indians Complex Fire in Big Sur, along the State’s central coast. The fire burned over 240,000 acres (USDA Forest Service 2008) and required over a month of intense firefighting operations to contain the perimeter. Media reports and anecdotal accounts from firefighters linked the intensity of the fire and difficulty of firefighting operations to increased fuels from tree deaths caused by an emergent forest disease, sudden oak death (SOD). Coastal California forests have experienced extensive mortality from the pathogen Phytophthora ramorum, causal agent of SOD (Rizzo and others 2005). The forests of Big Sur are among the most impacted by P. ramorum, with 100 percent of tanoaks in some stands infected by the pathogen and hundreds of thousands of dead host trees across the region (Maloney and others 2005). Big Sur is among the earliest sites of P. ramorum infection in California, and the pathogen has spread and become established throughout great portions of the region (Meentemeyer and others 2008). We used an extensive network of forest monitoring plots in Big Sur to examine the potential interactions between these two important disturbance agents, a destructive exotic pathogen and wildfire. We used pre-fire data on tree mortality and pathogen distribution and post-fire surveys of burn severity to ask: i) How did pre-fire fuel loads vary among areas that differ in pathogen presence or impacts? and ii) Was burn severity higher in areas that had previously experienced higher SOD mortality? Ongoing research will track longer-term impacts of the fire on forest structure and recovery.

Parent Publication

• Proceedings of the Sudden Oak Death Fourth Science Symposium

Citation

Metz, Margaret; Frangioso, Kerri; Meentemeyer, Ross; Rizzo, David. 2010. Interacting disturbances: did Sudden Oak Death mortality in Big Sur worsen the impacts of the 2008 basin complex wildfire? In: Frankel, Susan J.; Kliejunas, John T.; Palmieri, Katharine M. 2010. Proceedings of the Sudden Oak Death Fourth Science Symposium. Gen. Tech. Rep. PSW-GTR-229. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. pp. 258-261