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Emissions of the principal greenhouse gas (GHG), car-bon dioxide (CO2), are driven primarily by the burn-ing of fossil fuels, but the Earth’s biosphere also plays a major role in the global carbon (C) budget. Forest biomes are an important component of the global C budget, because of the large quantities stored in live biomass, detritus, and soil organic matter, and because forest con-version to other land uses releases C to the atmosphere. Globally, terrestrial ecosystems are currently a major net sink for atmospheric CO2 (about 1 gigaton C per year); this sink mostly represents the difference between C accumulation in forests and CO2 emissions from tropical deforestation (Canadell and Raupach 2008). Particular forest landscapes can be either net C sources or net C sinks, depending on their management and dynamics. Forests can therefore play an important role in regulatin