Forests can mitigate greenhouse gases by storing carbon (SEQU) and supplying woody biomass for burning in power plants with CCS (WBCCS). The paper uses GTM to understand the global dynamics of forests and WITCH to determine the most cost-effective mitigation methods to limit long-term radiative forcing. The analysis finds that both SEQU and WBCCS are effective but the most effective choice is to use them together. WBCCS + SEQU accounts for 23–28% of all mitigation. SEQU initially dominates while carbon prices are low while WBCCS becomes more important later with especially high carbon prices. Forest mitigation encourages land use to shift towards forests, increasing natural forests and especially managed forests. SEQU leads to larger trees and more natural forestland and WBCCS leads to faster growing trees and more managed stands.