We present a modeling framework for simulating afforestation, deforestation and sustainable forest management that is composed of an interlinked economic model and a spatially explicit forestry model. The linkage of models allows addressing a number of important issues relevant to REDD+, in particular, estimation of cross-country comparable CO2 mitigation potential for individual countries and selected activities, "carbon-leakage" problem, estimation of marginal abatement cost curves for the mitigation activities etc. We demonstrate the application of the model framework for development of marginal abatement cost curves and discuss the results.