Re-introduction of fire for longleaf pine (Pinus palustris) forest restoration at Horseshoe Bend National Military Park

Horseshoe Bend National Military Park (HOBE) is in initial stages of longleaf forest restoration.  This requires re-introduction of fire after 50+ years of fire exclusion.  Lack of burning plus past logging altered forest composition, structure and fuel.  Longleaf forests are naturally open-canopied and support a grassy groundcover with little mid-story and few hardwood trees.  Frequent fires top-kill non-longleaf stems and consumes most available litter resulting in little duff formation.

Due to lack of burning, HOBE currently supports excessive hardwoods; litter depths reach 10 cm and duff sometimes exceeds 6 cm.  Bases of residual adult longleaf are surrounded by large mounds of fuel.  At other sites with prolonged fire exclusion, burning often results in smoldering duff and eventually dead longleaf.  HOBE hopes to avoid that result by careful use, and at times even micro-management, of prescribed fire.

Re-introduction of fire began in 2006.  Pre-burn, bases of many longleaf were soaked with approximately 200L of water.  Prescriptions targeted litter but not duff consumption, using low-severity fire with short residence time.  Initial results appear successful and burns removed much of the litter but little duff around treated trees.  Scattered untreated trees were damaged by smoldering.  Although effective for protecting trees, soaking was expensive and so other treatment will be considered.  Current thought is that duff at the base of many adult trees may need to remain for the near future and that areas within seed dispersal distance and suitable for longleaf regeneration may be the most important sites to target for duff consumption.