Carbon Trends in U.S. Forestlands: A Context for the Role of Soils in Forest Carbon Sequestration

This chapter discusses forest carbon budgets of US forests and provides the context in which to compare the soil carbon component of forests with other components of the forest ecosystem, such as trees. It presents historical and estimates of forest carbon and carbon in harvested wood, summarized by attributes such as region, forest type, and owner. The chapter also discusses uncertainties and needs for future research for national-level estimates. The flux is the exchange of carbon between forests and the atmosphere over a specified period of time, usually one year. A positive flux means net carbon is being sequestered from the atmosphere into forests; a negative means net carbon is being emitted from forests. Although forest carbon pools are often thought of as uncertain, permanent continuous inventory plots such as those measured in the United States provide estimates that are reliable and that feature the desired precision built in the sampling design.