Thursday, 20 November 2003: 8:00 AM
Anthropogenic fuel alteration and changes in spatial fire behavior in a southeastern pyrogenic ecosystem
Southeastern pyrogenic ecosystems have evolved and adapted along with natural fire regimes. Humans have disrupted natural fire regimes by fragmenting fuels, introducing exotic species, and suppressing fires. Information is needed quantifying how these alterations specifically affect spatial fire extent and pattern. To address this need, we applied historic (1920 and 1943) and current (1990) GIS fuels maps and the FARSITE fire spread model to quantify the differences between historic and current fire spread distributions. We held all fire modeling variables (wind speed and direction, cloud cover, precipitation, humidity, air temperature, fuel moistures, ignition source and location) constant with exception of the fuel models representing different time periods. Model simulations suggest that modern fires are much smaller than historic ones and that anthropogenic features play a major role reducing landscape flammability. Fire extent declined linearly with patch density, and there was a quadratic relationship between fire extent and percent landscape covered by urban features. As little as10 percent urban landcover caused a 50 percent decline in fire extents.