Potentials and limitations of agroforestry for changing land-use in the tropics: Experiences from Central America

With increasing population pressure, the agricultural frontier in tropical countries is being expanded into previously untouched or little changed areas, frequently resulting in environmental degradation. At the same time, the use of agricultural lands is undergoing rapid changes in response to increasing environmental concerns and external market forces. In large areas of Central America, for example, the production systems for coffee have lost much of their biological diversity in the last couple of decades. Observations of apparently higher yields in high-input and low-diversity systems resulted in recommendations to eliminate trees. In recent years, however, as a result of low coffee prices and environmental concerns, calls to reverse this trend have been made in many countries and research and implementation initiatives are being developed to, once again, increase the diversity of the systems by incorporating trees. The necessary changes in the objectives and management of land-use systems must be gradual to assure high acceptability of the new practices, Under such conditions, which are typical for most traditional land-use systems, the development of practices which integrate trees into the agricultural land-use systems assumes special importance. Agroforestry practices can help to improve land-use systems towards higher sustainability and/or provide a stepping stone towards other, often tree-based, land-use systems of higher viability. Using examples from the research and extension experiences at CATIE, some silvopastoral and agrisilvicultural systems are discussed with their potentials and limitations. To help evaluate improved systems, promising methodologies for appropriate research and extension are outlined. New research has shifted the focus to on-farm experimentation, and economic and extension aspects of agroforestry.