Simulating Historic Landscape Patterns of Fire in the Southern Appalachian Mountains: Implications for Fire History and Management



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Fire suppression policies implemented in the early 20th century led to a decrease in fire-associated species and ecosystems in the southern Appalachian Mountains. As managers work towards restoration, a greater understanding of the pre-suppression fire regime is needed. Fire frequency and seasonality can be determined from physical fire records, such as fire scars, but fire size, fire cycle, ignition density, and ignition source are more difficult to ascertain. Using FARSITE, a spatially explicit fire model, I predicted past fire spread in the western Great Smoky Mountains National Park (GSMNP). Results showed a mean pre-suppression fire size of over an order of magnitude larger than fires on current landscape conditions (567 ha vs. 45 ha). Large fire sizes would have encouraged fire-associated vegetation and continuous flammable fuelbeds. In addition, the current lightning ignition rate within the study area resulted in a 120-135 year pre-suppression lightning fire cycle, which indicates that natural fires were influential on the landscape. This fire cycle is shorter than the lightning fire cycle experienced today (approx. 25-30,000 years). Using the mean fire return interval from previous research, I determined the potential contribution of lightning and anthropogenic ignitions to the fire cycle. This contributes to the debate on the importance of lightning versus anthropogenic ignitions to the pre-suppression fire regime. Most importantly, the estimation of mean fire size, fire cycle, and ignition density for lightning and anthropogenically ignited fires may aid federal resource managers as they use lightning ignitions and prescribed burns to restore fire-associated ecosystems in the GSMNP and other areas of the southern Appalachians.