Vegetation Response and Regrowth after Fire on Cumberland Island National Seashore, Georgia

Vegetation response after natural fire was investigated in the Georgia Sea Islands. Nearly all above-ground stems were killed in the scrub and marsh communities. Within two years burned marshes strongly resembled unburned marshes in vegetation cover and species diversity. In the first year after burning, diversity increased in freshwater cordgrass (Spartina bakeri) marsh, but then fell again as water levels rose. By the second year, vegetation cover had returned to pre-burn levels. Sawgrass (Cladium jamaicense) marsh was lower in diversity and slower to return to potential pre-burn cover. Burned scrub regenerated into extremely dense vegetation and exceeded 2 m in height two years after the fire. Regrowth was almost exclusively woody. Mature hardwoods suffered high mortality only where the trees bordered the more flammable scrub or dense pine. Mature individuals of Pinus palustris, P. serotina, and P. taeda survived all but the most severe burns. With the exception of pine species, the proportion of different species in post-fire regrowth was generally similar to pre-fire stand composition. With a potential fire rotation of 23 years or less, both oak and pine scrub communities on Cumberland Island are probably pyric dis-climaxes.