Increasingly, fire managers are using natural ignitions in conjunction with prescribed burns to restore and maintain fire-adapted ecosystems. Accumulation fuels due to fire suppression and increasing drought indices associated with climate change, however, may cause natural ignitions to burn with greater intensity and severity. Managers must weigh risk factors versus benefits before allowing a lightning ignition to burn under these conditions. During the severe drought of 2011, managers on the Ouachita National Forest decided to allow a wildfire to burn within a designated containment area (~700 ha).
Results/Conclusions
Given the drought conditions, there was concern that significant overstory mortality would occur. We installed 29 randomly placed 10-m-radius circular plots directly after the fire to measure stem mortality of trees over 2.5 inches dbh. Overstory (>15.0 cm dbh) and midstory (≤15.0 cm dbh) stem densities were reduced significantly 1 year postburn by 5 and 64 percent respectively, but not significantly between one year postburn and two or five years postburn. We also evaluated the applicability of recently created post-burn stem mortality equations developed using prescribed fire data to stem mortality on this wildfire. This study demonstrates the ability of wildfires to aid in restoration and maintenance of forest structure and composition.