5: Maintenance of forest contribution to global carbon cycles

Forests are renewable and one of the largest terrestrial reservoirs of biomass and soil carbon. They have an important role in global carbon cycles as sinks and sources of carbon. Carbon stocks in forests include above ground biomass, below ground biomass, dead and decaying organic matter and soil carbon. Carbon is also stored in wood products. Global climate change could have significant impacts on the structure, distribution, productivity, and health of temperate and boreal forests as well as impacts on forest carbon stocks and fluxes, and the prevalence of forest fires, disease and insect outbreaks, and storm damages.

Forest management practices also affect the carbon cycle and fluxes. Deforestation has a negative impact, but management activities that maintain and enhance the carbon stored in forests and forest products over the medium to long term can make a positive contribution to mitigating atmospheric carbon dioxide levels. In addition, biomass from forests can be used as a substitute for fossil fuels thereby reducing greenhouse gas emissions.

Associated Indicators

Acres of California Forestland Being Managed as Carbon Offset Projects

Measure the impact of carbon offset projects on management of California forestlands. There are two types of offset projects. First, under the California Cap-and-Trade Program, the Air Resources Board has the authority to approve forestry compliance offset projects. Project types include reforestation, improved forest management, and avoided conversion. Second, there are voluntary forestry offset projects that have been approved by voluntary agencies such as the Climate Action Reserve (Reserve), the American Carbon Registry (ACR), and the Verified Carbon Standard (VCS). The acreage in California being managed for carbon offset projects provides a measure of the impact of these programs on actual forest management in California, in terms of land managed to maintain or improve carbon storage, and to provide additional environmental benefits such as improved water quality and habitat.

Annual Average Precipitation – Departure from long term average by ecosystem units

Evaluate departure in average annual precipitation as a measure of climate change. Trends in precipitation patterns and amounts can have a large influence on forest health, productivity, and species distribution. Use climate data from downscaled Global Climate Models (GCM) to assess precipitation trends among ecosystem units. Indicator will evaluate both historic conditions and project future conditions.

Annual Average Temperature – Departure from long term average by ecosystem units.

Evaluate departure in air temperature by ecosystem units as a measure of climate warming. This will allow comparison of differing degrees of climate warming across forest ecosystems. Air Temperature is a direct indicator of climate change and can have impacts on forest and ecosystem health. Use climate data from downscaled Global Climate Models (GCM) to assess warming trends among ecosystem units. Indicator will evaluate both historic conditions and project future conditions.

Carbon sequestration rate

Carbon is sequestered/stored in plants and soil, removing it at least temporarily from the atmosphere. The rate of carbon sequestered can be estimated using satellite/remote sensing methods, or more directly measured at the plot scale in forests. When carbon emission rates exceed carbon sequestration rates, then net accumulation of carbon-containing gases in the atmosphere can result in global warming and climate change.

Carbon stocks on forestlands and in forest products

For a given time period, this indicator will spatially map changes in carbon stocks on forestlands where forests, forestland losses. forestland gains, and forest products are acting as: a) net sources of carbon dioxide through releases of carbon to the atmosphere, b) net sinks for carbon storage through the removal of carbon dioxide from the atmosphere, or c) neither sources or sinks. Through the use of this indicator, forest managers, policy makers and the public will be able to see the changes in the carbon sink capacity on the state’s forestlands from the interaction over a given period of time of disturbance, land use change, forest management, and forest product manufacture efficiency and utilization. By comparing indicator results over successive time periods,

Conservation and Maintenance of Soil and Water Resources: Soil carbon

Global carbon cycling includes storage and release of organic and inorganic carbon from soil, which is the largest reservoir of carbon. Carbon is added to soil primarily through decomposition of dead plant material. Carbon is lost from soil through runoff and oxidation of soil carbon by chemical and biological processes. Because of its size, the soil carbon pool is one of the most important considerations in modeling carbon cycling as a cause of and in response to climate change.

Contribution of Forest Biomass to California Electricity Generation

Measure contribution of forest biomass towards attainment of policy goals for use of renewable energy sources. California's Renewables Portfolio Standard (RPS) requires investor-owned utilities, electric service providers, and community choice aggregators to increase procurement from eligible renewable energy resources to 33% of total procurement by 2020 (CPUC). Forest biomass is one of many eligible sources.

Contribution of Forest-based Biomass to Production of Low-carbon Biofuels

Measures the contribution of forest-based biomass towards attainment of policy goals set by the California Low-Carbon Fuel Standard. California’s Low-Carbon Fuel Standard, established by AB32 (2006) and Executive Order S-01-07 (2007), sets a goal of a 10% reduction in carbon intensity of transportation fuels by 2020. Biofuels produced from wood biomass are one potential source to achieve the target.

Contribution of Renewable Energy Sources to California Electricity Generation

Measure progress towards attainment of policy goals for use of renewable energy sources. California's Renewables Portfolio Standard (RPS) requires investor-owned utilities, electric service providers, and community choice aggregators to increase procurement from eligible renewable energy resources to 33% of total procurement by 2020 (CPUC). Eligible sources relevant to forest and rangelands include biomass, geothermal, solar, wind, and small hydroelectric.