AB 1504

Assembly Bill 1504 California Forest Ecosystem and Harvested Wood Product Carbon Inventory Annual Reports

  1. AB 1504 California Forest Ecosystem and Harvested Wood Product Carbon Inventory: 2006 – 2015
  2. AB 1504 California Forest Ecosystem and Harvested Wood Product Carbon Inventory: 2006 – 2015 ERRATUM/ SHEET
  3. AB 1504 California Forest Ecosystem and Harvested Wood Product Carbon Inventory: 2007-2016 DATA UPDATE
  4. AB 1504 California Forest Ecosystem and Harvested Wood Product Carbon Inventory: 2017 Reporting period
  5. AB 1504 California Forest Ecosystem and Harvested Wood Product Carbon Inventory: 2018 Reporting Period DATA UPDATE
  6. AB 1504 California Forest Ecosystem and Harvested Wood Product Carbon Inventory: 2019 Reporting Period DATA UPDATE
  7. California Harvested Wood Product End-Use Ratios

Methods in 2019 were revised and are described in the 2019 Reporting Period Data Update. Because of these changes, it is difficult to compare 2019 estimates to previous reporting periods.

NEW PUBLICLY AVAILABLE HWP C ESTIMATION TOOL! - HWP C vR

This is the tool used to generate carbon storage and losses associated with harvested wood products, described further below. Data templates and documentation of data sources are provided. Any landowner can enter their own harvest volumes to understand these carbon dynamics from harvest on their own lands.

Assembly Bill 1504 California Forest Ecosystem and Harvested Wood Product Carbon Accounting

Background

The Global Warming Solutions Act (Assembly Bill 32, Chapter 488, Statutes of 2006) and subsequent legislation, require the state to reduce emissions to 40% below 1990 levels by 2030 and achieve net zero emissions by 2045.. The initial AB 32 Scoping Plan established by the California Air Resources Board (CARB) in 2008 included a forest sector target with a goal of maintaining the forest carbon sink with a net annual sequestration rate of 5 million metric tons of carbon dioxide equivalent (MMT CO2e). The  2022 update projects that natural and working lands, including forest land, will be a carbon source in the future. However, conducting restoration actions on 2.3 million acres per year (including shrublands and grasslands) can reduce these carbon losses. Building in part on CARB’s work, Assembly Bill 1757 (C. Garcia, Chapter 341, Statutes of 2022) required the Natural Resources Agency to develop an ambitious range of targets for natural carbon sequestration and for nature-based climate solutions that reduce greenhouse gas (GHG) emissions for natural and working lands. These targets include 2.5 million acres per year of wildfire resilience and restoration work by 2045 on forests, shrublands, and grasslands.

The responsibility for setting forest carbon policy to ensure the AB 32 forest sector goals are met lies with the California Board of Forestry and Fire Protection (i.e., the Board), as formalized in Assembly Bill 1504 (AB 1504, Chapter 534, Statutes of 2010). AB 1504 emphasizes the critical and unique role California’s forests play in the state’s carbon balance by sequestering carbon dioxide from the atmosphere and storing it long-term as carbon. It also emphasizes the goal of maximum sustained production of high-quality timber products in serving the public while also providing other benefits and ecosystem services such sequestration of carbon dioxide, recreation, watershed, wildlife, range and forage, fisheries, regional economic vitality, employment, and aesthetic enjoyment. The bill requires the Board to ensure the rules and regulations governing the harvest of commercial tree species consider the capacity of forests to sequester 5 Million Metric Tons (MMT) of CO2e annually by 2020.

The annual inventory

The California Department of Forestry and Fire Protection (CAL FIRE) Fire and Resource Assessment Program (FRAP) develops an annual Forest Ecosystem and Harvested Wood Product Carbon inventory (Forest Carbon Inventory) through collaboration with the U.S. Department of Agriculture (USDA) Forest Service (FS) Forest Inventory and Analysis Program (FIA), USDA FS Pacific Northwest Research Station (PNW) and the University of Montana Bureau of Business and Economic Research (BBER).

This annual Inventory assists the Board of Forestry and Fire Protection in assessing whether forest sector carbon targets established by Assembly Bill 32 and related legislation are being met. This inventory also serves to verify portions of CARB’s Natural and Working Lands carbon inventory. 

California Forest Ecosystem Carbon

These forest ecosystem carbon estimates for California are based on the current USDA FS Forest Inventory and Analysis (FIA) program data. The FIA program is a ground-based, permanent plot re-measurement system of the same trees over time, which captures and quantifies growth, removals and mortality well. It is repeatable, provides low errors, and is consistent with forest carbon inventory data and reporting nationally.

The FIA program switched from a periodic to an annual inventory of forest land in California in 2001 by installing a complete sample of the state each year using 10% of the full set of plots. This equates to a complete sample of all inventory in California every 10 years, with completion of the first full annualized inventory of California forests in 2010. In 2011, FIA began re-measuring the same plot locations as established in 2001. Full re-measurement expected in 2020 was delayed by the covid-19 pandemic and extensive wildfires that year. Data from full re-measurement is expected to be available in the Summer of 2023. Beginning in 2021, California moved to a 5-year re-measurement cycle. Covid-19 and wildfire impacts also delayed the full initiation of the intensified re-measurement cycle in 2021. Despite this delay, the integrity of the data in the core FIA program is maintained while the state will continue to achieve intensification goals. Reducing the FIA measurement cycle provides more frequent estimates of forest conditions, change and drivers of change, allowing forest managers to assess and respond to the effects of disturbance and management more rapidly under a changing climate.

Following Intergovernmental Panel on Climate Change (IPCC) Tier 3 methods, stock and stock-change estimates for standing live and dead trees (including foliage and roots), understory vegetation (including roots), down dead trees, forest floor litter, and soil organic carbon are provided in the report. Changes from forest land-use conversions and non-CO2 emissions are also included.

California Harvested Wood Product Carbon

Harvested wood product (HWP) carbon estimates for California are based on an  estimation tool initially originally created by the USDA FS for National Forest System regional HWP carbon inventories (Stockmann et al. 2014) and modified specifically for use in the California state-level inventory (Loeffler et al. 2018). A new tool, HWP C vR, was then created through a partnership between CAL FIRE, the Oregon Department of Forestry (ODF), Oregon State University's Institute for Natural Resources, and Groom Analytics, LLC. This tool expands upon the tool originally created by the USDA FS.

The HWP C model follows annual harvest volumes through their timber product class allocation (i.e., softwood sawlogs, softwood pulpwood, etc.) and primary product allocation (i.e, softwood lumber, softwood plywood, etc.). The model uses a complex series of calculations based on a variety of parameters such as product half-lives and discarded product disposition ratios to determine how much carbon remains stored in harvested wood products in use and at solid waste disposal sites.

Estimates follow the IPCC Tier 3 Production approach and therefore include all California-origin timber, but exclude imported wood. Estimates also include carbon stored in HWP from historic harvests dating back to 1952. Harvested wood product carbon emissions associated with and without energy production are also provided for informational purposes, but are not included in the IPCC forest sector carbon accounting.

Carbon modeling

CAL FIRE and American Forests have completed a modeling study examining future climate change impacts and alternative forest management and wood utilization scenarios on carbon sequestration and storage in California’s tree-dominated forested lands. The study incorporates substitution, leakage, and an economic analysis. Similar to the CARB 2022 Scoping Plan update, this study finds that California’s forests will be a carbon source in the future, with approximately 50% loss of forest carbon and 48% loss of forest area by 2071. At the peak of initial treatments, active management on approximately 1.3-1.4 million acres per year improves forest resilience and reduces climate-driven carbon losses when paired with innovative wood utilization. This study provides one example of how treatments on the forested landscape can contribute to overarching goals for California’s natural and working lands.

The effects of forest management and wood utilization on forest carbon storage and sequestration in California Report

California sawmill energy-use and emissions study

This report analysis focuses on energy use and associated emissions by the sawmill industry in California in 2016. The study was completed for the Board of Forestry by the Forest Industry Research Program, Bureau of Business and Economic Research at the University of Montana. The report provides information on the energy used on-site at the respondent sawmills, the industry’s contribution to renewable energy production through the use of woody biomass used on-site, and the industry’s use of renewable and non-renewable energy from electricity purchased from utilities. 

For more information please contact:

Nadia Tase

Climate Change and Forest Inventory Specialist

Fire and Resource Assessment Program

California Department of Forestry and Fire Protection

(530) 573-2320

nadia.tase@fire.ca.gov

Sources:

Loeffler, D., Anderson, N., Stockmann, K., Morgan, T.A., Tase, N.A. 2019. Harvested wood product carbon chapters 5 & 6 in Christensen, G.A.; Gray, A.N.; Kuegler, O.; Tase, N.A.; Rosenberg. M; Loeffler, D.; Anderson, N.; Stockmann, K.; Morgan, T.A. AB 1504 California Forest Ecosystem and Harvested Wood Product Carbon Inventory: 2017 Reporting Period. Final Report. U.S. Forest Service agreement no. 18-CO-11052021-214, 17-CO-11261979-086, California Department of Forestry and Fire Protection agreement no. 8CA04056 and 8CA03714 and the University of Montana. Sacramento, CA: California Department of Forestry and Fire Protection and California Board of Forestry and Fire Protection. 539 p.

Ryan, M.G.; Harmon, M.E.; Birdsey, R.A.; Giardina, C.P.; Heath, L.S.; Houghton, R.A.; Jackson, R.B.; McKinley, D.C.; Morrison, J.F.; Murray, B.C.; Pataki, D.E.; Skog, K.E. 2010. A synthesis of the science on forests and carbon for U.S. forests. Issues in Ecology 13: 17.  https://www.fs.fed.us/rm/pubs_other/rmrs_2010_ryan_m002.pdf (accessed: November 2, 2017).

Stockmann, Keith; Anderson, Nathaniel; Young, Jesse; Skog, Ken; Healey, Sean; Loeffler, Dan; Butler, Edward; Jones, J. Greg; Morrison, James. 2014. Estimates of carbon stored in harvested wood products from United States Forest Service Intermountain Region, 1911-2012. Unpublished report. Missoula, MT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Forestry Sciences Laboratory. 28 p.