Fire Regime of the Okefenokee Swamp and Its Relation to Hydrological and Climatic Conditions

Abstract

A fire record of the Okefenokee Swamp National Wildlife Refuge during the period 1938-1989 was examined in this study. Frequency analysis indicated that fires with burnt area 50% or more of the swamp area have return periods longer than 100 years, much longer than the previously assumed 20-25 year return period. Results of statistical analysis showed that fire activity is significantly related to die water level of the Okefenokee Swamp. Based on this relationship, a potential fire size can be estimated for a given water level. It seemed difficult to prove the link between the fire activity in the Okefenokee Swamp and the El Nino/Southern Oscillation (ENSO) events. However, further analysis revealed that the hydrological condition of the swamp is significantly related to the ENSO events. During the warm events, the Okefenokee Swamp area is wetter than normal; during the cold events, the area is drier than normal, and major fires tend to occur. The investigation of the fire regime may help achieve a better understanding of the effect of fires on the dynamics of this large complex ecosystem. The results are also useful for the refuge managers, especially in the mid- to long-term planning of fire management practices.