Managed wildfire, drought, and overstory survival: a case study in the Ouachita Mountains of Arkansas
Fire managers are increasingly using natural ignitions to restore and maintain fire-adapted ecosystems. Managing natural ignitions after decades of suppression, however, holds inherent ecological, economic, and personal risks. During the severe drought of 2011, fire management staff on the Ouachita National Forest used a range of strategies to manage the lightning-ignited High Peak Wildfire because full suppression was infeasible and there were potential resource benefits (e.g., restoration of desired forest structure and composition). Because of concerns that the combined effect of drought and fire could adversely affect overstory tree health and timber value, we established plots in burned and unburned areas in dry and dry-mesic pine-oak forests and loblolly pine (Pinus taeda) plantations immediately after the fire, and remeasured them 2 and 5 y post-burn. Between inferred pre-burn condition and 2 y post-burn, overstory trees across community types were resistant to fire (94% survival) while midstory trees were less resistant (35% survival). Survival between 2 and 5 y post-burn was near 100% for both overstory and midstory. Both the density and diversity of the midstory were reduced by 2 y post-burn, which had the desired effect of moving forest structure and composition toward an open woodland condition. This study provides evidence that wildfire, even in a drought, can be used in restoration efforts and that overstory trees in dry and dry-mesic pine-oak forests and pine plantations of the Ouachita Mountains can survive with little effect on resource values, provided that weather and fuel conditions are conducive to low- and moderate-severity burning.