PNNL

Abstract

Background: Modern land management faces unprecedented uncertainty regarding future climates, novel disturbance regimes, and unanticipated ecological feedbacks. Mitigating this uncertainty requires a cohesive landscape management approach that utilizes multiple methods to optimize benefits, while hedging risks amidst uncertain futures. We designed a process-based landscape simulation model (LANDIS-II) to forecast forest growth, climate effects, and future wildfire dynamics, and we distilled results using a decision support tool allowing us to examine tradeoffs between alternative management strategies. We developed plausible future management scenarios based on factorial combinations restoration-oriented thinning prescriptions, prescribed fire, and managed wildfire. Results were assessed continuously for a 100-yr simulation period, which provided a unique assessment of tradeoffs and benefits among seven primary topics representing social, ecological, and economic aspects of resilience. Results: Projected climatic changes had a substantial impact on modeled wildfire activity. In the baseline scenario (no treatments), we observed an inflection point in area burned around mid-century (2060) that had detrimental impacts on landscape carbon storage. While mechanical treatments reduced the incidence of high-severity fire, it did not eliminate this inflection completely. Scenarios involving managed wildfire resulted in greater reductions in high-severity fire and a more linear trend in cumulative area burned. Mechanical treatments were beneficial for subtopics under the economic topic given their positive financial return on investment, while managed wildfire scenarios were better for ecological subtopics, primarily due to its greater ability to mitigate high severity fire. Benefits among the social subtopics were mixed, reflecting the inevitability in landscapes that we rely on for diverse and countervailing ecosystem services. Conclusions: Our results provide evidence that the best future scenario will involve a mix of management strategies, allowing spatially varied management strategies to coexist within and among ownerships classes, and making space for both active and passive management actions that work to build more robust and resilient future landscapes.