Fire in North American Wetland Ecosystems and Fire-Wildlife Relations: An Annotated Bibliography

40. Christensen, N. L. 1981. Fire regimes in southeastern ecosystems. Pages 112-136 
         in H. A. Mooney, T. M. Bonnicksen, N. L. Christensen, J. E. Lotan, and 
         W. A. Reiners, tech. coords. Proceedings of the conference: fire regimes 
         and ecosystem properties. 11-15 December 1978, Honolulu, HI. U.S. For. 
         Serv. Gen. Tech Rep. W0-26.

Fire has significantly influenced the evolution of ecosystems throughout the Southeast, particularly in the Coastal Plain. In areas where fire occurrence is stochastic and fires are intense, vegetation response is similar to classical successional schemes. In areas of chronic, low intensity fires, fire may play an integral role in ecosystem stability. Frequent low intensity fires maintain savannas. Moist savannas protected from fire are invaded by shrubs typical of adjacent evergreen shrub bogs. The location and abruptness of the boundary between shrub bog and savanna is a function of fire. Grass-sedge bogs may form after intensive cutting of moist savannas and subsequent frequent fire. Intense fires during drought burn a depression in the peat which then remains perennially moist. Herbs grow rapidly in these depressions, and their combustible litter burns comparatively frequently. These sedge bogs may be maintained by this change in fire frequency. Shrub bogs (pocosins) are subject to intense fires, but vegetation quickly recovers and shrub composition after low intensity fires remains unchanged. After high intensity fires, some shrub succession occurs. Atlantic white-cedar forests are the product of low frequency, relatively high intensity fire regimes related probably to their marginally moist soil conditions. Too frequent fire converts such areas to shrub bogs; infrequent fires result in succession to hardwoods. Infrequent low intensity fires may increase cypress dominance in swamp forests with substantial deciduous species. In nutrient-poor areas, evergreen species will increase with fire. The vegetational outcome following fire in a swamp forest is dependent upon fire intensity and the level of the water table. A shallow burn would be revegetated by shrub bog which in the absence of further fire would succeed to white-cedar swamp. A deep burn in an area of high water table may initiate a sedge bog which will be maintained indefinitely by frequent fire. Fires that remove substantial peat may lead to deciduous swamp forests. [K-L-S]

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