United States Forest Service.

Pacific Southwest Region
1323 Club Drive
Vallejo, CA 94592
707.562.8737
TTY: 707.562.9240
FAX: 707.562.9130

Carbon Inventory Assessment

Background

A team of Forest Service experts and scientists from the Pacific Southwest Region and Research Station completed a rapid assessment that evaluates how different management activities on national forest lands in California might affect forest growth and disturbance and determine the changes in carbon storage and loss over the next 100 years. This assessment was done to evaluate the potential in assisting California in meeting greenhouse gas reduction goals established under the Global Warming Solutions Act of 2006.

The following chart depicts four management scenarios that were analyzed and the projected changes in carbon inventories associated with each scenario.

Projected Changes in Carbon Inventories

Includes above ground live biomass, wood products and biofuels substitution

This figure has four trend lines that show the projected changes in carbon inventories, including wood products and biofuel substitution, using various management scenarios in national forests in California from 2000 to 2120. The highest trend line shows that in the long run Maximum Forest Resiliency scenario will sequester the most carbon and the Current Management Activities scenario will sequester the least carbon in the long run

Scenarios

Current Management: Based on current levels of forest management activities. Projections indicate that national forests will eventually become net emitters of carbon due to inventory losses from wildfire, disease and other disturbances.

Current Management plus Reforestation: Based on current management activities with the addition of an aggressive post-fire reforestation program. Projections indicate that this will produce long term carbon benefits but overall, disturbance will exceed growth and forests will become net emitters of carbon.

Forest Land Management Plans: Based on full implementation of the Forest Land Management Plans for each national forest as currently written and amended. Projections indicate that carbon will be stored in trees longer than in current management scenario but forests will become net emitters of carbon.

Maximum Forest Resiliency: Based on forest management activities that shift carbon inventory to larger trees, reduces ground and ladder fuels and introduces prescribed fire. Projections indicate that forests will be more resistance to disturbance but may not be compatible with the maintenance of other multiple resource values.

Key Findings

  • The national forests in California will become net emitters of carbon by the end of the century. For the next 4-6 decades, under a “Current Management” trajectory, the national forests will accumulate carbon at a higher rate than carbon will be lost through disturbances such as wildfire, pest mortality and inter-tree competition. However, at some point in the mid-21st century, losses from wildfire, disease and other disturbances will exceed growth. National forest carbon sinks will become unstable and unsustainable, under the Current Management scenario.
  • Substantial levels of investment in management will be required for systemic, long-term carbon returns. This includes significant investments in post-fire reforestation and pre-fire thinning operations. Given the history of national forest management in the United States, nearly all future management strategies will be increasingly costly, whether driven by fire suppression, vegetation management or intensive protection of high-value resources on the landscape.
  • Achieving high levels of carbon sequestration may be incompatible with other resource objectives. For example, the Maximum Forest Resiliency scenario would reduce canopy cover below current forest plan requirement for some forest types, and may not be compatible with the maintenance of other multiple resource values.

The results from this peer-reviewed preliminary assessment raise significant questions regarding the sustainability of national forest ecosystems under current management practices and program levels. It also poses important challenges to the Forest Service and its partners as all interests consider the long-term implications of federal management choices. The intent is for this assessment to provide a cornerstone for building and extending the kinds of analyses that will meet the national scope of the challenges ahead. It provides the foundation for more rigorous and comprehensive work in evaluating the potential role of national forest lands in supporting California's climate change mitigation efforts.