Spatial variability of historical fires across a red pine–oak landscape, Pennsylvania,USA

Abstract

AbstractLong‐term, ecosystem‐specific fire regime information improves natural community restoration and management by providing a basis for scientifically reasoned fire management prescriptions. Historical fire regimes can be reconstructed to sub‐annual resolution using fire‐scarred trees, and while such reconstructions have become increasingly prevalent across the easternUSA, little information regarding how they vary at landscape scale is available. Most studies report fire regime characteristics (i.e., frequency, seasonality) at site‐composite levels, commonly at ≤1 km2spatial resolution. In this study, we analyzed the historical spatial variation of fire regime characteristics over the past four centuries (1620CEto present) in a red pine/oak landscape (30.75 km2) in north‐central Pennsylvania,USA. Fire event data were reconstructed based on fire scars and locations of 192 living and dead red pines. The spatial and temporal distributions of fire scars revealed a historical fire regime dominated by frequent, dormant season fires most often detected at relatively small spatial extents and by relatively few trees. There was, however, evidence of less frequent, relatively large fires that scarred high percentages of trees. These fire regime characteristics likely resulted in a spatially and temporally transient patchwork of varying vegetation age and structures resulting in a heterogeneous landscape. At the landscape scale, fire frequency changed with human cultures, while fire spatial extent and scarring patterns appeared to be modulated by drought conditions. Results from this study show historical precedence for landscape‐scale burning across a broad range of drought conditions and spatial extents, which should be considered when designing fire‐management and ecosystem restoration objectives.