The importance of carbon
Rising CO2 in the atmosphere from human-caused sources such as burning fossil fuels and deforestation is now accepted as effecting climate change. Projections indicate that under a business as usual scenario, by 2030 sea level may rise by 4-12 inches, temperatures increase by 1.8-2.7 degrees F, and precipitation may change -1 to 8% at a global-level. Forests reduce CO2 in the atmosphere through the process of photosynthesize by taking in CO2, storing carbon in wood, and releasing the oxygen.
Forests in the United States are vast, covering a total of 751 million acres. They currently sequester about 700 million metric tons per year of carbon dioxide on an inventoried 635 million acres according to estimates based on FIA data. This offsets 10% of the gross emissions from sources in the US.
All aspects of forests contain or affect carbon. Live trees (both aboveground and roots), standing dead trees (including roots), down dead wood, forest floor carbon, and soil contain carbon. FIA currently samples all these pools. Harvesting releases carbon, and, also transfers carbon in wood to products, landfills. Wood burned for energy in place of fossil fuels helps mitigate carbon in the atmosphere because it provides energy and then the trees regrow and take up the released carbon again. Timber products output and utilization studies contribute information about these activities. Fires release carbon, and may also convert wood to charcoal, which keeps carbon captured for a long time. Scientists use remote sensing and FIA field data to provide estimates of greenhouse gas emissions.
In the last several decades, forest carbon estimates based on FIA data have been recognized as the standard by which all other estimates are judged (for example, Pacala et al 2001). They were the basis for: the official forest greenhouse gas statistics of the US (EPA 2007), carbon estimates in the National Report on Sustainable Forests 2003, Heinz Center reports, carbon accumulation (growth and yield) 1605b Voluntary Reporting Program curves (DOE or Smith et al) and other carbon tools, and a number of state Climate Action Plans or other needs such as for California (Fried and Zhou 2008). One reason to use as consistent estimates as possible is because radically different estimates without good reason would probably be difficult to explain to policymakers or negotiators with other countries.
Last Modified: 06/16/2008