Carbon Sequestration in Forests (CRS Report for Congress)
Premium Purchase PDF for $24.95 (26 pages)
add to cart or
subscribe for unlimited access
Pro Premium subscribers have free access to our full library of CRS reports.
Subscribe today, or
request a demo to learn more.
| Release Date |
Revised Aug. 6, 2009 |
| Report Number |
RL31432 |
| Report Type |
Report |
| Authors |
Ross W. Gorte, Specialist in Natural Resources Policy |
| Source Agency |
Congressional Research Service |
| Older Revisions |
-
Premium March 29, 2007 (26 pages, $24.95)
add
|
Summary:
Widespread concern about global climate change has led to interest in reducing emissions of carbon dioxide (CO2) and, under certain circumstances, in counting additional carbon absorbed in soils and vegetation as part of the emissions reductions. Congress may consider options to increase the carbon stored (sequestered) in forests as it debates this and related issues.
Forests are a significant part of the global carbon cycle. Plants use sunlight to convert CO2, water, and nutrients into sugars and carbohydrates, which accumulate in leaves, twigs, stems, and roots. Plants also respire, releasing CO2. Plants eventually die, releasing their stored carbon to the atmosphere quickly or to the soil where it decomposes slowly and increases soil carbon levels. However, little information exists on the processes and diverse rates of soil carbon change.
How to account for changes in forest carbon has been contentious. Land use changesâespecially afforestation and deforestationâcan have major impacts on carbon storage. Foresters often cut some vegetation to enhance growth of desired trees. Enhanced growth stores more carbon, but the cut vegetation releases CO2; the net effect depends on many factors, such as prior and subsequent growth rates and the quantity and disposal of cut vegetation. Rising atmospheric CO2 may stimulate tree growth, but limited availability of other nutrients may constrain that growth.
In this context, timber harvesting is an especially controversial forestry practice. Some argue that the carbon released by cutting exceeds the carbon stored in wood products and in tree growth by new forests. Others counter that old-growth forests store little or no additional carbon, and that new forest growth and efficient wood use can increase net carbon storage. The impacts vary widely, and depend on many factors, including soil impacts, treatment of residual forest biomass, proportion of carbon removed from the site, and duration and disposal of the products. To date, the quantitative relationships between these factors and net carbon storage have not been established.
Some observers are concerned that "leakage" will undermine any U.S. efforts to sequester carbon by protecting domestic forests. By leakage, they mean that wood supply might shift to other sites, including other countries, exacerbating global climate change and causing other environmental problems, or that wood products might be replaced by other products that use more energy to manufacture (thus releasing more CO2). Others counter that the "leakage" arguments ignore the enormous disparity in ecological systems and product preferences, and discount possible technological solutions.
Several federal government programs affect forestry practices and thus carbon sequestration. Activities in federal forests affect carbon storage and release; timber harvesting is the most controversial such activity. Federal programs also provide technical and financial help for managing and protecting private forests, and tax provisions affect private forest management. Various federal programs can also affect the extent of forested area, by supporting development (which may cause deforestation) or encouraging tree planting in open areas, such as pastures.
