COS 238-2 - Climate change mitigation and carbon dynamics from forest management activities in California's statewide program

Abstract: Forests have long been recognized for their important role in the carbon cycle, including sequestration, storage, and emissions. With informed and effective forest management, substantial additional carbon storage is achievable while also creating more fire-resilient forests. The California Climate Investments (CCI) program reinvests proceeds from the Cap-and-Trade program to reduce greenhouse gas (GHG) emissions and improve public health and the environment. California's Department of Forestry and Fire Protection’s Forest Health (FH) program, the primary CCI forest management program, supports activities to reduce GHG emissions and mitigate wildfire risk, a challenge exacerbated by climate change.

Using a reproducible methodology outlined in the California Air Resources Board's Quantitative Methodology for Forest Restoration and Management, we assessed a diverse set of forest management activities sponsored through the Forest Health program (pest management, fuels reduction activities, conservation easements, biomass utilization, and reforestation) and quantified the GHG impacts on a project and statewide level. This methodology models forest carbon with the Forest Vegetation Simulator, a growth and yield model used by the US Forest Service, as well as the Interagency Fuels Treatment Decision Support System, an application that supports fuels treatment planning and fire modeling. We present comparable GHG benefits per hectare values from diverse activities and case studies to demonstrate that the GHG impacts of a large-scale (e.g., statewide) forest management program can be quantified and evaluated using a practical and reproducible method. We analyzed 91 funded projects that spanned from 2017-2021 and resulted in net carbon sequestration of over 14.8 million metric tons of CO2e through the life of the projects.

While some forest management practices such as fuels reduction activities might initially result in a loss of carbon stored in the forest (820,520 metric tons of CO2e lost across 69 FR projects), the decrease in competition from the removal of small-diameter trees enables the larger trees to sequester more net carbon when tracked over several decades after treatment implementation. Reforestation activities sequester the most amount of carbon through the life of the project (over 12.4 million metric tons of CO2e across 46 reforestation projects). Pest management activities, which include the removal of diseased trees and thinning the forest to decrease the disease and pest risk will sequester about 897,320 metric tons of CO2e across 13 projects. Additional GHG benefits are accrued through biomass utilization, either through the development of wood products and/or the generation of energy via combustion and gasification.