The goal of this paper is to introduce FABLE (Forest, Agriculture, and Biofuels in a Land use model with Environmental services), a dynamic global model, aimed at analyzing the optimal profile for global land use in the context of growing commercial demands for food and forest products, increasing non-market demands for ecosystem services, and more stringent greenhouse gas mitigation targets. The model seeks to determine the optimal allocation of scarce land across competing uses across time. FABLE integrates distinct strands of agronomic, economic and biophysical literatures into a single, intertemporally consistent, analytical framework, at global scale. It is based on a dynamic long-run, forward-looking partial equilibrium framework, in which the societal objective function places value on food production, liquid fuels (including first- and second- generation biofuels), timber production, forest carbon and biodiversity. The forestry sector is characterized by multiple forest vintages, which add considerable computational complexity in the context of this dynamic forward-looking analysis. Our baseline accurately reflects developments in global land use over the years that have already transpired, and determines the optimal path of global land use over the course of next century based on projections of population, income and demand growth from a variety of recognized sources.