Southwest CASC Research Assesses Ecological and Cultural Dimensions of Western Fire Regimes

The western United States has experienced record-breaking fire seasons in recent years, with just a small number of severe fires accounting for the majority of damages to infrastructure, landscapes, and human health. To help address this growing challenge and support proactive fire management, Southwest CASC-funded researchers are assessing the impacts of changing fire regimes on both ecosystems and communities.  

Faster fires, slower recovery: extreme wildfires threaten long-term forest health 

As wildfires become more extreme, forests may be less likely to recover. In a recent study, researchers funded in part by the Southwest CASC measured daily fire growth rate from 3,499 fires occurring between 2012 and 2023 in conifer forests across Canada and the western U.S. to understand the relationship between fast-moving wildfire behavior and postfire ecological outcomes. Canada and the western U.S. to understand the relationship between fast-moving wildfire behavior and postfire ecological outcomes.  

Their results showed that as fires burn more area, they tend to burn more severely. Under strong winds and low fuel moisture, fast-moving fires can consume tree canopies and expand the distance to nearby surviving tree groves. Because many western tree species depend on seed dispersal from mature tree seed sources, recovery rates after a fire are especially constrained. In the short-term, this can lead to habitat loss, reduced carbon storage, and altered streamflow. Over time, fire-impacted landscapes could see gradual shifts from forest to shrublands or grasslands, with implications for species and ecosystem functions. Managing postfire landscapes to sustain forest health will be increasingly important as wildfires become faster, larger, and more severe. 

The full publication titled “Faster, bigger, more severe: Extreme wildfire spread sets the stage for forest ecosystem change in western and boreal North America” was published in the journal Science Advances. 

Beneficial burns: returning fire to California Indian allotments  

In California, where explosive wildland fires are generating substantial economic and ecological costs, the effects of fire on California Indian communities are largely overlooked. Prior to colonization, cultural burning (the application of controlled, low-intensity fires) was used by Indigenous peoples to promote species diversity, improve water quality, and prevent soil erosion. After decades of prohibiting cultural fire as a land management tool, progress has been made towards returning beneficial, intentional fire to the landscape.  

However, for California Indian public domain allottees (who reside on small land parcels managed by the federal government and held in trust for the descendants of original allottees), fire-management activities are still limited. In a paper developed by Southwest CASC-funded researchers, the authors analyze the policy context behind the return of intentional fire to public domain allotments and identify pathways to support future restoration and resilience planning.  

The full publication titled “Restoring fire sovereignty on California Indian allotment lands” was published in the journal Fire Ecology.