Comparison of Burn Severities of Consecutive Large-Scale Fires in Florida Sand Pine Scrub Using Satellite Imagery Analysis

Remotely sensed imagery has been used extensively in the western US to evaluate patterns of burn severity and vegetation recovery following wildland fires. Its application in southern US ecosystems, however, has been limited. Challenges in southern areas include very high rates of vegetation recovery following fire, frequent cloud cover, and the presence of standing water. Use of remote sensing in southern forests should therefore be coupled with concurrent ground-based assessments, at least until the methods are tested for different ecosystems. Here, we assessed burn severity using remote sensing in a sand pine scrub ecosystem, which occurs on the central ridge of the Florida peninsula and is characterized by infrequent (>40 years on average) high severity fire. Two overlapping fires that burned in 2006 and 2009 provided a unique opportunity to explore compounded fire severity patterns. Landsat-based imagery analysis matched ground-based severity measures roughly half of the time. In general, higher severity fire led to lower severity or unburned conditions, while low severity fire had a less pronounced impact on either preventing or reducing fire severity in the subsequent fire. The unusually frequent fires both occurred during drought conditions. As the region’s climate is predicted to be drier and hotter in the future, this work has implications for potential climate change effects on sand pine scrub fire regimes and, hence, ecosystem perpetuity.