Sponsor: Forest Stewards Guild
Presenter: Dr. Meg Krawchuk, Oregon State University
Changing wildfire regimes are causing rapid shifts in forests worldwide. In particular, forested landscapes that burn repeatedly in relatively quick succession may be at risk of conversion when pre-fire vegetation cannot recover between fires. Fire refugia (areas that burn less frequently or severely than the surrounding landscape) support post-fire ecosystem recovery and the persistence of vulnerable species in fire-prone landscapes. Observed and projected fire-induced forest losses highlight the need to understand where and why forests persist in refugia through multiple fires. This research need is particularly acute in the Klamath-Siskiyou ecoregion of southwest Oregon and northwest California, USA, where expected increases in fire activity and climate warming may result in the loss of up to one-third of the region's conifer forests, which are the most diverse in western North America. We model the key controls on fire refugia occurrence and persistence through one, two, and three fire events over a 32-year period. Refugia that persisted through three fire events appeared to be partially entrained by landscape features that offered protection from fire, suggesting that topographic variability may be an important stabilizing factor as forests pass through successive fire filters. Results from this study could inform management strategies designed to protect fire-resistant portions of biologically and topographically diverse landscapes.