Historic Fire Regimes

Fire in the Appalachians. 

Ecological and meteorological evidence suggests that lightning‑caused fires were a major environmental force shaping the vegetation of the southern Appalachians for millions of years (Van Lear and Waldrop 1989).  Lightning served as a mutagenic agent and as a factor in natural selection that forced species to adapt or perish.  The frequency of fires increased dramatically upon the arrival of Native Americans in the southern Appalachians about 10,000 years ago.  These early Native Americans were hunters and gatherers, using fire to improve food abundance.  They began land clearing for agriculture around 800 to 1000 A.D., when corn and beans were first cultivated in the southeastern United States.  Regular burning created large open meadows with widely spaced trees and abundant wildlife.

Table Mountain pine communities were once maintained by frequent low intensity fires ignited by both lightning and anthropogenic sources.  These fires burned on average every 10 to 12 years from the 1850’s until the late 1930s (Harmon 1982).  Sutherland et al. (1995) used dendrochronology techniques to develop the fire history of three Table Mountain pine stands in southwestern Virginia.  They found that fires occurred periodically during the 1800’s and the first half of the 20th century with a mean fire return interval of 9 to 11 years.  Age distribution of the pines was bimodal.  The vast majority of the trees were established in the mid-1850’s and again in late-1930’s, suggesting an intense fire in the early 1850’s and early 1930’s.

With frequent burning, Table Mountain pine stands were probably open with little understory development, which allowed pine regeneration.  Since that time, fire suppression prevented pine regeneration and has allowed succession to oaks and other hardwoods.  As the pines continue to die, fuel loading is increasing to levels of concern.  Also, decomposition rates are slow allowing fuels on the forest floor to become as much as 6 to 8 inches deep (Robichaud and Waldrop 1994).

Prescribed burning was rarely used in the southern Appalachian Mountains until the mid 1980’s.  At that time, site preparation burns were being tested (Phillips and Abercrombie 1987).  Other renewed interests have dealt with restoration of habitat for endangered species and declining communities.  In the 1990’s, s limited amount of prescribed burning was attempted to restore habitat for smooth coneflower (Echinacea laevigata) (Emanuel et al. 1995), Table Mountain pine (Pinus pungens) (Waldrop and Brose 1999, Welch et al. 2000), pitch pine (P. rigida) (Elliott et al. 1999) and grassy balds (Barden 1978).  Prescribed fires have also been tested to improve oak regeneration on mesic Appalachian sites (Loftis et al. 1993, Brose and Van Lear 1998).