In recognition of the importance of forests in removing carbon dioxide (CO2) from the atmosphere, various mechanisms have been introduced to track changes in forest carbon stocks and to provide incentives for increasing carbon stocks or sequestration rates on public and private lands. At the national scale, annual estimates of carbon stocks in forests and wood products are included in the U.S. greenhouse gas inventory submitted by the Environmental Protection Agency to the United Nations Framework Convention on Climate Change. Some states and regions have established greenhouse gas markets or registries to facilitate greenhouse gas reductions that include forestry activities on private lands, and there is an active voluntary market where payments may be made to increase carbon stocks or sequestration rates.