The main focus of efforts to mitigate climate change is on the avoidance of fossil fuel emissions. However, the Kyoto rules permit the use of forestry activities that create carbon offset credits. These could obviate the need for lifestyle-changing reductions in fossil fuel use. It is necessary for policy purposes, therefore, to determine the cost effectiveness of creating forest sink carbon credits. In this study, meta-regression analyses with 1047 observations from 68 studies are used to determine factors that affect carbon sequestration costs. Results indicate that soil carbon is not very important, but that forest plantations and use of biomass for energy make forestry activities more attractive. It also turns out that forestry activities are competitive with emissions reduction in tropical regions and, perhaps, boreal regions, but certainly not in Europe. Finally, the regression estimates are used to project the potential costs of carbon uptake for various forest management scenarios.