Carbon sequestration by forests of the United States. Current status and projections to the year 2040

National-level forest carbon budgets are of interest in relation to understanding the globalcarbon cycle. comparing anthropogenic and biogenic sources of carbon. and developing possiblestrategies for conserving and sequestering carbon. In this study, forest carbon pools and flux fortimberlands in the conterminous United States were projected over the corning 50 years bycoupling a forest economics model, a forest inventory model and a forest carbon model. In thebase case scenario. US forests sequestered carbon in the 1990s at a rate of 80 Tg yr- but cameclose to carbon equilibrium by the 2020s. The dominant factors driving this change were anincreasing forest harvest, a decreasing forest land base. and a reduction in average stand age.Scenarios in which alternative forest policy options were implemented related to increased paperrecycling and increased afforestation (5 x 106 ha) produced long-term increases in carbonsequestration on the forest land base of up to 15 Tg yr" I. The carbon sink on the forest land basecurrently offsets 6 °A of US fossil carbon emissions but that proportion is likely to decrease overthe coming decades.