Contrasting effects of future wildfire and forest management scenarios on a fire excluded western US landscape

Context Restoring wide areas of fire excluded western US landscapes to fuel limited, fire resilient systems where fires self-regulate and burn with low or mixed severity will require expanded use of both prescribed and natural fire, coupled with strategic mechanical fuels management. However, optimal admixtures of fire and fuel management to set landscapes on trajectories to improve fire resilience and conserve carbon are not well understood. Objectives To understand the effect of accelerating restoration and fuel management in response to potential future fire regimes on a large fire excluded mixed-owner forest landscape. Methods We simulated 50-year wildfire and active forest management scenarios on a multi-owner landscape in southcentral Oregon, crossed in a factorial design with a range of wildfire and forest management intensities. Results Wildfire was more efficient at reducing potential high-severity fire, whereas restoration treatments created patches of fire resilient old forest, especially on federally managed land. With some exceptions, both disturbances reduced aboveground carbon over time, although the magnitude varied among the combinations of fire and active management intensities. We observed interactive effects from specific combinations of fire and management in landscape response metrics compared to stand-alone disturbances. Conclusions Fire and active management have similar landscape outcomes for some but not all restoration objectives, and active management will be required under future predicted fire regimes to conserve and create fire resilient old forest. Achieving widespread fire resilient forest structure will be limited by divergent landowner management behaviors on mixed-owner landscapes.

Automated summary

This study simulated future wildfire and active forest management scenarios and found that wildfire was more effective than restoration treatments in reducing high-severity fire. However, restoration treatments were able to create fire resilient old forest on federally managed land. Both disturbances reduced aboveground carbon, but the extent varied depending on the combination of fire and active management intensities. The study also observed interactive effects from specific combinations of fire and management in landscape response metrics compared to stand-alone disturbances.