Fuel Consumption Models for Pine Flatwoods Fuel Types in the Southeastern United States

Modeling fire effects, including terrestrial and atmospheric carbon fluxes and pollutant emissions during wildland fires, requires accurate predictions of fuel consumption. Empirical models were developed for predicting fuel consumption from fuel and environmental measurements on a series of operational prescribed fires in pine flatwoods ecosystems in the southeastern United States. Total prefire fuel loading ranged from 4.6 to 23.7 Mg.ha(-1) (2.1 to 10.6 tons.acre(-1)); between 12 and 69% of the total loading was composed of shrub species, including saw palmetto (Serenoa repens), gallberry (Ilex glabra), and other common associates. Fuel consumption ranged from 1.3 to 15.7 Mg.ha(-1) (0.6 to 7.0 tons.acre(-1)). On average, 76% of the prefire fuel loading was consumed, although fuel consumption as a percentage of prefire loading was somewhat variable (range: 28-93%). Model predictors include pref ire shrub loading and season of burn for shrub fuels (R-2 = 0.90); pref ire dead and down woody fuel loading and 10-hour fuel moisture for dead and down woody fuels (R-2 = 0.68); pref ire litter loading and pine litter fuel moisture for pine litter fuels (R-2 = 0.92); and prefire aboveground fuel loading and litter fuel moisture for all aboveground fuels (R-2 = 0.89). Models specific to season of burning predicted independent consumption measurements within 4.5% (dormant season) and 12.4% (growing season) for flatwoods fires. The models reported here predicted fuel consumption more accurately than the decision support tools First Order Fire Effects Model (FOFEM) and Consume and will allow fire and fuels managers in the region to better estimate fuel consumption and air quality impacts from prescribed burning.