The terrestrial carbon sink has been large in recent decades, but its size and location remain uncertain. Using forest inventory data and long-term ecosystem carbon studies, we estimate a total forest sink of 2.4 T 0.4 petagrams of carbon per year (Pg C year^-1) globally for 1990 to 2007. We also estimate a source of 1.3 T 0.7 Pg C year^-1 from tropical land-use change, consisting of a gross tropical deforestation emission of 2.9 T 0.5 Pg C year^-1 partially compensated by a carbon sink in tropical forest regrowth of 1.6 T 0.5 Pg C year^-1. Together, the fluxes comprise a net global forest sink of 1.1 T 0.8 Pg C year^-1, with tropical estimates having the largest uncertainties. Our total forest sink estimate is equivalent in magnitude to the terrestrial sink deduced from fossil fuel emissions and land-use change sources minus ocean and atmospheric sinks.