Headwaters are the landscapes where California’s streams and rivers begin. Because California has a Mediterranean climate with dry summers and wet winters, its mountain headwaters play a critical role in supplying the state with water throughout the year. Precipitation stored in snowpack, meadows, and soils is gradually released into streams through the spring and early summer. Headwaters provide more than two-thirds of the water used by Californians each year.
Up until about 150 years ago, most of California’s headwater forests experienced frequent, lower-intensity fires that kept understories open, limited brush, and supported mature, fire-resilient tree species with high, widely spaced canopies—conditions that also helped sustain reliable water supplies. Before 1800, roughly 4.5 to 12 million acres burned annually across California’s forests, woodlands, shrublands, and grasslands; in the second half of the 20th century, only about 250,000–300,000 acres burned annually due to fire suppression and land use change.
Fire suppression has allowed vegetation to build up, increasing the risk of high-severity wildfires. This has major implications for the state’s water supply. When headwater forests burn in severe wildfires, those fires disrupt the processes that regulate water supply—reducing snowpack, degrading water quality downstream, and increasing sediment in reservoirs.
To reduce severe wildfires, California is dramatically shifting how it manages its headwaters
A changing climate is intensifying the conditions that drive severe wildfire. The amount of Sierra–Cascades land burned in severe wildfire annually tripled over the past 30 years.
To address these growing threats to landscapes and communities, California and the federal government, with local partners, redoubled efforts in the early 2020s to reduce wildfire hazard by removing or modifying vegetation to make wildlands less susceptible to severe burns. The state is now engaged in an unprecedented multi-agency effort to reduce the risk of severe wildfire on one million acres of wildlands each year.
The multi-agency task force is treating more acres over time, but it has yet to reach its million-acre goal
Millions of acres treated
NOTES: Agencies report some acres treated on lands they do not own. Estimated acres differ from the dashboard due to the exclusion of tree planting activities. Acres treated are assigned to the agency that reported the largest activity by acreage within each footprint.
The task force is over halfway to meeting its goal, but some improvements could help
The task force treated an average of about 591,000 acres annually between 2021 and 2024 while developing unprecedented partnerships, data sharing, and coordination. A few changes could help target areas where wildfire hazard reduction efforts are most needed, incentivize durable treatments that increase resilience to severe burns for many years, and provide high-quality data to inform future policy decisions:
Clarify and standardize how the task force defines priority areas for treatment. The task force could define priority areas based on a combination of wildfire hazard and community exposure to better assess whether reported treatments align with task force objectives.
Identify persistent gaps in treatment coverage. The extent of treatment varies substantially across landowners and regions, with relatively limited data reported on lands owned by private individuals and in headwater regions outside the Sierra–Cascades. The task force should identify ways to address these gaps.
Refine tracking by treatment longevity. Treatments differ in how long they reduce wildfire hazard, but these differences are not currently accounted for in task force tracking. Where data allow, task force tracking should distinguish between short- and longer-lived treatments and make it easier to track combined treatments, which tend to provide the longest-lasting wildfire hazard reduction benefits.
Require consistent reporting of treatment location. Inconsistent reporting of treatment locations makes it difficult to assess treatment overlap, intensity, and cumulative impact. All treatment reporting should be required to include a standardized spatial footprint to improve tracking progress toward wildfire hazard reduction goals.
Build reporting capacity for small and under-resourced partners. Many small, local organizations, private landowners, and Tribes lack the technical or administrative capacity to report treatment data. As a result, some treatment efforts are underrepresented in task force tracking. The task force could play a coordinating role in identifying these needs and supporting partners in meeting reporting expectations.
Adapted by Sarah Bardeen from Tracking Headwaters Management for Wildfire Resilience in California by Bradley Franklin and Kyle Greenspan.
About the Authors
Bradley Franklin is a research fellow at the PPIC Water Policy Center. He is an agricultural and environmental economist who focuses on ways to inform the design and implementation of public policy in natural resource management. His research covers a range of topics, including the use of market instruments to secure water for environmental use, sustainable groundwater management, irrigated agricultural production, water recycling and urban water markets, urban heat islands, and climate change adaptation in fisheries. He has worked on water resource issues in a number of places, including California, Australia, and India. He holds a PhD in economics from the University of California, Riverside.
Kyle Greenspan is a research associate with the PPIC Water Policy Center, where he focuses on topics ranging from groundwater to carbon sequestration. Previously he worked as a PPIC summer intern for the water center. Prior to joining PPIC, he interned with the United States Forest Service Pacific Northwest and Southwest regional offices and conducted disease ecology research as an undergraduate student researcher. He holds a BA in environment, economics, and politics from Pitzer College.