Spatiotemporal Patterns of Post-Fire Vegetation Regrowth in Los Padres National Forest

Large fire scars contain a variety of vegetation communities and environmental conditions, which results in a mosaic of vegetation patches with different post-fire recovery trajectories. Remote sensing is often used to monitor post-fire vegetation regrowth at a landscape scale, however spaceborne sensors are generally unable to classify individual species within vegetation patches. As a result, it is difficult to compare the recovery of individual species using only remotely sensed imagery. In this analysis, we integrate remote sensing imagery with data from vegetation field surveys in order to identify species-level recovery trajectories after the 2007 Zaca wildfire in Southern California. The Zaca fire is notable because it burned more than 240,000 acres that contained a variety of dominant vegetation types. The post-fire recovery was also affected by the extreme drought years of 2011-2016. We use remote sensing imagery to quantify post-fire recovery success and detect vegetation type conversion. We also examine which environmental variables control the rate of post-fire vegetation regrowth and how this varies with plant dominance. Our analysis indicates that the Zaca fire caused significant losses of pine stands, which are now converting to chaparral shrubland. We also observe that oak stands exhibit high resprouting rates, yet still have significantly less biomass than pre-fire conditions. Chaparral species recovered quickly after the fire, however they subsequently declined in health during the 2011-2016 drought.