ES-09. Intersecting fire, insect, and drought disturbance and the fate of western US forests in a changing climate

Abstract
Disturbances in forested ecosystems have dramatic impacts on ecosystem services and stability, and intersecting disturbances in space and time may compound these effects. Interactions between different types of disturbances can be complex and may drive impacts on forest recovery trajectories and outcomes, a system’s ability to avoid a perturbation, or the likelihood of ecosystem-altering state changes. Analysis-ready data characterizing forest disturbances will help to untangle these complexities. Observational datasets representing forest disturbances are often spatially incomplete, have short records, are incompatible or lack integration with data on other disturbance types, or require significant pre-processing. Here we combine LANDFIRE data on wildfire and bark beetle events with an annual hotter-drought metric to create an integrated and accessible dataset of discrete forest disturbances. We show that sequences of temporally- and spatially-overlapping forest disturbances are common in the Western United States, with over half of forests (52.55%; 421,335.6 km2) affected by at least one disturbance event. We found that 68% of forests with multiple disturbances in the period of record experienced them within a short interval (5 or fewer years), likely compounding their impact on forest recovery. Providing open access to a portion of this dataset at a recent working group demonstrated that access to large-scale, analysis-ready data enables creative collaborative data synthesis in the fields of macrosystems ecology and forest resilience.