PAST AND PROSPECTIVE CARBON STORAGE IN UNITED-STATES FORESTS

Global concern about increasing carbon dioxide concentrations in the atmosphere and the possible consequences of future climate changes have generated interest in understanding and quantifying the role of terrestrial ecosystems in the global carbon cycle. Historical changes in carbon storage in US forests have been estimated from periodic, comprehensive national inventories of forest resources. Since 1952, carbon stored on US timberland has increased by 38% or 8.8 X 10(15) g, primarily in the East. This increase is consistent with recently reported trends in Europe and accounts for as much as 21% of a hypothesized carbon sink in Northern temperate forests. Projections of changes in carbon storage over long periods of time were made with a carbon budget model that has been integrated with econometric models of the forest sector. Carbon storage is expected to increase until 2040, but at a slower rate than at present.