Terrestrial Carbon Storage

Terrestrial carbon sequestration involves changing the management of forests, rangelands, agricultural lands, and wetlands to either remove more CO₂ from the air and/or to reduce CO₂ emissions from these ecosystems. To be effective in curbing the rise in atmospheric CO₂ concentrations, these changes must persist for decades or longer.

Terrestrial sequestration can be illustrated by looking at three types of measures:

First, land management practices can be altered to decrease the decomposition of organic matter (which releases CO₂) and to sustainably increase the rate of plant photosynthesis. Examples include reforesting cleared or mined lands, switching crops to those that require little or no tillage, and conservation of large tree stands.

Second, harvested trees can be used to produce long-lasting products, such as high-quality building materials and furniture, that can keep captured CO₂ from re-entering the atmosphere (via decomposition or fire) for many years.

Third, forests that are choked with brush, invasive plants, or an unhealthy number of small trees can be managed to reduce “fire fuels” by removing this material for renewable biomass power production. This approach helps control the severity of fires and the associated ecological damage and massive CO₂ emissions. Electricity from biomass power plants also displaces fossil fuel use for power generation and associated CO₂ emissions.

Measuring the amount of carbon stored through terrestrial sequestration is a multi-step process. Establishing “baselines” of current carbon stocks and changes that would normally take place over time are vital first steps. WESTCARB's terrestrial sequestration field tests address both the effectiveness of proposed land management practices and the accuracy and repeatability of carbon measurement methods.

One of the attractions of terrestrial sequestration is its lower initial cost relative to other approaches to CO₂ storage and the potential for significant environmental, economic, and aesthetic co-benefits. The latter may include:

• Improved forest health
• New wildlife habitat
• Reduced soil erosion and stream sedimentation
• Stronger local economies
• Reclamation of poorly managed soils
• Improved recreational opportunities

Terrestrial sequestration also offers the opportunity for broad participation in climate change solutions. Economics can be favorable at project sizes much smaller than those required for geologic sequestration, allowing owners of even modest forest tracts to adopt carbon storage measures. Many current carbon offset programs rely on forest-based terrestrial sequestration projects.