Tracking Forest and Hydrological Resilience to Compound Stressors in Burned Forests Under a Changing Climate

In the Northern Rockies, the annual area burned by wildfires has risen sharply in recent decades and is expected to continue growing. As a result, burned forests increasingly comprise a significant portion of the land base. However, burned areas represent a difficult paradox for land managers, especially in the context of other climate-linked disturbances (e.g., droughts, bark beetle outbreaks) that are also on the rise and may compound initial fire-induced stressors. While, burned areas have experienced major recent changes that may decrease their resilience to subsequent, compounding stressors, fire-induced changes can also lead to longer-term increases in resilience. The evolving landscape conditions triggered by fires and interacting climate-related disturbances require dynamic information and decision-making. In the face of this uncertainty, managers need effective post-fire monitoring tools and practical information about the factors that influence post-fire resilience.  

This project will focus on two ecological subregions within the northern Rockies, the Canadian Rockies in western Montana and the Idaho Batholith of central Idaho. These subregions encompass lands that have experienced widespread fire and feature similar tree species and cover types, including ponderosa pine, dry mixed-conifer, moist mixed-conifer and subalpine forests. The project team will combine a suite of field data, remote sensing, simulation models, and statistical models to assess post-fire forest and hydrological resilience to compounding drought and beetle outbreaks by (1) determining the rates of forest survival, recovery, and conversion to non-forest in burned areas over intermediate time scales (1-15 years post-fire), (2) characterizing soil moisture regimes in burned and unburned forests and quantifying their relative sensitivity to post-fire drought, and (3) building predictive statistical models to map and mechanistically link forest and hydrological resilience to post-fire drought and beetle outbreaks. 

The resulting datasets and information will inform government and tribal managers in fire management planning, prescribed fire use, and planning of post-fire responses, rehabilitation, and monitoring.