UC Berkeley researchers published a study suggesting a revision of California’s forest carbon policy in order to maintain projected greenhouse gas reduction goals.

The study, published last Friday in Environmental Research Letters, looked at historical forest characteristics and projected how restoration of these characteristics will manifest under a future climate. According to a press release for the study, California lost 1.1 million metric tons of stored carbon to drought, wildfires and invasive pests between 2018 and 2019, so researchers worry that existing forest management policy in California will cause a further decline.

“The Sierra Nevada and southern Cascade mountains have been essential to California’s carbon policy proposals for decades,” the press release states. “They currently store close to half of California’s captured carbon and will likely play an outsize role in reducing emissions to 40% below 1990 levels by 2030.”

Prior to European colonization, California’s conifer forests were made up of fewer trees and therefore stored less carbon, noted professor of forest ecology and study co-author John Battles. According to Battles, the Sierra Nevada Forests stored 25% of the carbon in the 1900s that they store today.

California is currently a leader in climate policy. However, current climate projections will require a significant reduction in density and stored carbon for our forests to be considered “resilient” to intense environmental conditions such as droughts and wildfires, as stated in the study.

Battles emphasized these “fundamental trade-offs” that come with forest management policy, noting the decisions that must be made between the state’s climate goals.

“California has ambitious goals about reducing fire hazard, using forests to store carbon, maintaining water supplies, and protecting biodiversity,” Battles said in an email. “Given the fundamental function of forests, these objectives cannot all be simultaneously maximized.”

The researching team used tree heath and forest diversity statistics from the 1900s to determine historic forest density, according to Battles. This data combined with future projections led them to suggest a new model of forest “resiliency” more similar to how forests were historically composed.

Another recent study by UC Berkeley researchers on land management and forest structure found results in the Klamath Mountains similar to Battles’ and his co-author’s findings in the Sierra Nevadas: Forests in the future will likely be unable to act as major carbon sinks.

“It would take more stewardship, more prescribed burning, more proactive mechanical restoration treatments, and more managed wildfire in remote areas to keep fuel hazards down and maintain the ability of those forests to survive wildfire and other processes,” said Scott Stephens, professor of fire science, in the press release. “But without intervention and maintenance, we will continue to experience terrible wildfires and their impacts.”