After the Kyoto Protocol, the international consensus toward combatting the global warming, entered into force in 2005, detailed evaluations of forest ecosystem's potential in absorbing carbon dioxide has become an imperative. In Center for Global Environmental Research started Carbon Balance Monitoring in Terrestrial Ecosystems in 1999 under its Global Enviornmental Monitoring Project. Office of Terrestrial Monitoring is striving to provide data of carbon balance over wide area by integrating carbon balance data obtained from site-based forest ecosystem observations and areal parameters obtained from remote sensing.