Rebuilding Healthy Headwater Forests

July 6, 2020

Headwater forests are critical to California’s water supply, a fact made plain by recent state funding decisions.

  • The Sierra Nevada Conservancy awarded more than $8 million in grants for forest health projects funded by Proposition 1 and Proposition 68. Other Conservancy funding went to projects focused on climate change, community resilience, and land conservation that also will benefit forest health.

  • The Department of Fish and Wildlife awarded $24 million in Proposition 1-funded watershed restoration grants to 19 projects statewide.

  • The Department of Water Resources announced forest and water supply projects were among the beneficiaries of more than $90 million in Proposition 1 first-round funding for integrated regional water management projects. This funding will help water infrastructure systems adapt to climate change, foster regional collaboration in setting priorities and managing water resources, and improve regional water self-reliance. The remainder of the first-round awards will be announced in upcoming months. The proposition allocates $510 million in total toward these goals, and requires a minimum of 10 percent to be spent in disadvantaged, underrepresented, or economically distressed communities.

Restoring and maintaining resilient headwater forests was a primary concern for the Little Hoover Commission in its 2018 report, Fire on the Mountain: Rethinking Forest Management in the Sierra Nevada. These headwaters are the lifeblood of California. More than 60 percent of California’s developed water supply originates in the forest headwaters of the Sierra Nevada. Seventy-five percent of the fresh water coursing through the San Joaquin-Sacramento Delta originates from the Sierra Nevada. More than 25 million Californians and three million acres of agricultural land rely on this water. But California’s headwaters are imperiled by the state’s overgrown and unhealthy forests.

Healthy forests are critical to the state’s water supply for several reasons. California’s water storage is concentrated in the alpine snowpack that accumulates during the wet season and releases water during the dry months. That snowpack is in jeopardy: “Historically, Sierra forests and meadows yielded more water, of a higher quality, and later in the summer than they do today,” writes the Sierra Nevada Conservancy. Research by the UCLA Center for Climate Science predicts that by the year 2100, the Sierra Nevada snowpack will have nearly halved from 1981-2000 levels. Overgrown forests exacerbate the problem by blocking snow from reaching the ground and amassing into a deeper snowpack. Further, in warmer climes, the heat from tightly packed trees melts snow faster than the sun would in open areas.

Forest meadows are also essential, because they absorb water during the wet season and release it later on, providing relief in California’s parched dry months. However, overgrown forests increasingly are encroaching into and overtaking meadowland. Trees in overgrown forests compete with each other for water, depleting the supply for users downstream. During the 2011-19 drought, researchers found that water supply in a Yosemite watershed managed for resiliency either remained unchanged or increased during the drought. Three unmanaged watersheds all produced less water during that time. A recent Public Policy Institute of California publication reported that managing forests for resiliency can increase average annual streamflow in some areas by up to an estimated 14 percent.

Forest health, water, and wildfire are interconnected. While resilient, healthy forests benefit from low-intensity wildfire, overgrown forests contribute to and are annihilated by catastrophic wildfire, resulting in massive soil erosion. Deputy Administrator for the County of Tulare and Commission witness Eric Coyne described the aftermath of such a fire to Commission staff:

The Rough Fire hit Fresno and parts of Tulare hard. You’ve got the standing vertical load that creates a wall of fire. It burns so hot, so long, that instead of seeing scorched earth, you see moonscape. Nothing is able to grow there for well over a decade. It’s sterile. It can’t support life.  So, you’ve had your first hit, which is to air quality. Then it starts raining.  You’ve lost all of the binders and this hill is just going to come down because there’s no root system or anything to hold it. It washes into the watershed, and then is carried down to the valley floor in the water system and you get all the contaminants in there.
Catastrophic wildfire can also leave the ground unable to capture water and recharge aquifers: Soil in some areas subjected to multiple firestorms has scorched into hardpan.

Realizing the extent to which Californians rely on healthy forests for their water, the Commission, in Fire on the Mountain, made several recommendations to encourage headwater forest restoration, including:

  • Abandoning a jurisdictional or parcel approach to forest management and approaching it from a landscape, or watershed, level. This collaborative approach would allow stakeholders to leverage combined resources and take a holistic look at desired outcomes and how to get there. The Commission highlighted a successful collaboration that included an unlikely combination of stakeholders ranging from conservationists to sawmill owners.

  • Spreading the costs of creating and maintaining forest resiliency fairly among the beneficiaries.

  • Enlisting the participation of lawmakers and other representatives from coastal and inland areas in designing solutions to enhance forest resilience. This will underscore the relevance of forest headwaters to regions that use the water.

  • Creating a robust educational campaign to teach Californians about the sources of their water and build the public support that is needed to fund and prioritize investments in forest resiliency.

The Commission urges policymakers to consider these recommendations as they continue working to restore California’s headwater forests.

Sign up to receive email updates on specific study topics here or stay up-to-date with our efforts by following us on our social channels: