Heavily managed, frequently burned forests of the southeastern US have been experiencing longer, hotter summers and more precipitation variability. These landscapes often have an intermingled patchwork of frequently burned pinelands immediately bordering wetlands, which are traditionally ‘hands off’ when applying management. During periodic drought, when wetlands can ignite, the results can be catastrophic to the wetland overstory. As climate changes and wetland flammability increases, adjacent pine forest management may need to adapt as well. The consequences of more frequent and severe wildfire regimes on carbon pools in managed pine and especially in wetland ecosystems are poorly understood. However, they will likely shift the historically recalcitrant carbon stocks stored in the low flammability wetland forests to a more labile and frequently volatilized carbon pool. Our goal was to investigate how the landscape patchwork of managed pine and wetland ecosystems would respond to a fire regime governed by more frequent and more prolonged high temperature events, and to determine a management solution to these changing fire and fuels interactions at the landscape scale. We combined empirical data and simulations driven by ensembles of projected climate to compare contemporary management to treatments that were spatially optimized to mitigate high-severity fire.
Results/Conclusions
Our initial results suggest projected fire weather increased the frequency and severity of fire occurring in wetlands, which conferred an increase in area burned (25% relative to contemporary) and mean severity across the landscape (30% relative to contemporary). These projected changes to area burned and mean fire severity increased cumulative wildfire carbon efflux by approximately 20% when compared to contemporary fire weather. We developed and tested a management approach based on minimizing the contribution of wetland initiated fire spread, by prioritizing the treatment of forest at the ecotone between wetlands and managed pine. Our study suggests that by informing treatment placement using the proximity of the pine stands to wetland ecosystems, we can increase carbon stability of the landscape in the face of increasing wildfire frequency and severity.