FORCARB2, an updated version of the U.S. FORest CARBon Budget Model (FORCARB), produces estimates of carbon stocks and stock changes for forest ecosystems and forest products at 5-year intervals. FORCARB2 includes a new methodology for carbon in harvested wood products, updated initial inventory data, a revised algorithm for dead wood, and now includes public forest land, reserved forest land, and forest land of low productivity. The model has been used to provide estimates and projections for policyrelated needs, including the Resources Planning Act timber resource assessment and forest-related greenhouse gas inventories of the United States, and has provided the basis for an analysis of forest carbon for Ontario, Canada.