Science in agroforestry -- Agroforestry policy issues and research directions in the US and less developed countries: insights and challenges from recent experience -- Economic evaluation of financial and non-financial costs and benefits in agroforestry development and the value of sustainability -- Farmer costs and benefits from agroforestry and farm forestry projects in Central America and the Caribbean: implications for policy -- Contribution of agroforestry trees to nutrient requirements of intercropped plants -- Tree root characteristics as criteria for species selection and systems design in agroforestry -- Soil amelioration and root symbioses of Parkia biglobosa (Jacq.) Benth. in West Africa -- Root architecture in relation to tree-soil-crop interactions and shoot pruning in agroforestry -- A model simulating above- and below-ground tree architecture with agroforestry applications -- The tree-crop interface: representation by coupling of forest and crop process-models -- A framework for a modular modelling approach for agroforestry -- Incorporation of indigenous knowledge and perspectives in agroforestry development. Part 1: Review of methods and their application -- Incorporation of indigenous knowledge and perspectives in agroforestry development. Part 2: Case-study on the impact of explicit representation of farmers' knowledge -- The use and value of multiple methods to capture the diversity of endogenous agroforestry knowledge: an example from Rwanda -- Historical development of agroforestry in China.

Agroforestry research is central to developing methods for the sustainable use of natural renewable resources, evolving to address the needs of the coming century. It is now necessary to consolidate the scientific gains now being made in process-oriented research and to develop a policy framework to encourage the adoption of sustainable land use practices. Agroforestry plays an important role in conserving forest resources, reducing the need for deforestation. Further, if `forest' is broadly defined as tree cover, agroforestry will also increase the proportion of woody biomass in farming landscapes. The papers selected for inclusion in Agroforestry: Science, Policy, and Practice establish agroforestry as an interdisciplinary science focused on the practical imperative of assisting farmers, forest dwellers and landscape-level planners to achieve sustainable food, fuel and timber production into the 21st century.