Using Prescribed Fire in Oak-pine Forests

Due to the hazards of using fire in steep topography and the susceptibility of these soils to erosion, prescribed fire has is far less common in the Southern Appalachians than in the Coastal Plain and Piedmont. Consequently, little information is available on the appropriate frequency, intensity and season fires should be prescribed for ecological restoration. However, some information is starting to accumulate as federal land managers reintroduce prescribed fire on public lands. 

Low intensity stand restoration burns have been used in recent years to restore oak-pine forests or pine-dominated stands in the southern Appalachians.  Sometimes there are additional objectives of stand restoration burns, such as stimulating forage production and oak regeneration. There is evidence suggesting that these low-intensity stand restoration burns can be used without significantly altering ecosystem pools and cycling rates of carbon and nitrogen in xeric oak–pitch pine communities (Knoepp and Swank, 1993; Vose et al., 1999) and shortleaf, oak–pine community types (Hubbard et al. 2004).  Also, low-intensity prescribed burns are unlikely to cause soil erosion if conducted under the correct conditions.  

In 2003, the Great Smoky Mountains National Park executed the largest prescribed burn (1,000 acres) in the park’s history to restore pitch pine, short-leaf pine, and Virginia pine along ridges and slopes.  The low-intensity backing fire was designed to reduce competition and enhance germination for the pines by burning the underbrush and reducing the ground litter.  Another objective of these restoration burns is to benefit wildlife and herbaceous species adapted to frequent fires, such as the Red-cockaded Woodpecker, purple fringeless orchid, mountain catchfly, whiteleaf sunflower, dwarf larkspur, goldenseal, and Indian grass.  Research and monitoring of sites such as this will be invaluable sources of knowledge for land managers hoping to restore oak-pine communities in the Southern Appalachians.

More intense stand-replacement burns have also been used with successful results in oak-pine forests of the Southern Appalachians.   Vose et al. (1999) evaluated the effects of a stand replacement burn used to restore a pine-hardwood forest in the Wine Spring Creek, North Carolina. Nitrogen losses during the stand replacement burn were confined to where fire temperatures were highest on a ridge, but were small enough (i.e. 78 kg N/ha) to be rapidly replenished by atmospheric inputs and N fixation. Moreover, soils and streams showed no response to the burn, and the authors concluded that the effects of the stand replacement burn were limited to the forest floor. Ironically, restoration burns can actually affect soil more when fire intensity is low. For example, Clinton et al. (1998) found that an understory burn in a mixed pine-hardwood stand in Northern Carolina consumed about 40% more humus mass than would have occurred during a stand-replacement burn due to longer residence time of the fire.