Duff Removal as a Pre-Fire Treatment in the Restoration of Long Unburned Longleaf Pine Woodlands in Central Alabama

Abstract

Fire dependent longleaf pine (Pinus palustris) ecosystems are among the most biodiverse and imperiled ecosystems in North America and occur across a wide range of settings across the southeastern United States, from savannas to mesic woodlands to xeric sandhills. Long-term fire suppression has greatly reduced the extent of these historically dominant ecosystems and fundamentally altered their structure and composition, resulting in accumulated litter and duff, the layer of decomposing organic material between leaf litter and mineral soil, and the decline of diverse herbaceous understory communities. Restoring these conditions requires reintroducing prescribed fire, but heavy duff accumulation around the base of large longleaf pines increases the risk of post-fire mortality through fine root and cambium injury via extended smoldering of basal duff. To limit mortality, land managers currently restrict burns to periods following heavy rainfall when duff moisture is high enough to prevent smoldering, narrowing the burn window. This study addresses two components of longleaf pine restoration in a long unburned woodland in the sandhills of central Alabama: first, the potential for duff removal treatments to prevent duff smoldering and expand the current window for utilizing prescribed fire, and second, evaluating early understory response to prescribed fire reintroduction in the sandhills region of the longleaf pine range.