Trees on farm: analysis of global extent and geographical patterns of Agroforestry ICRAF Working Paper no. 89

Abstract

Agroforestry, the inclusion of woody perennials within farming systems, has been both a traditional landuse approach developed by subsistence farmers throughout the tropics, and a livelihood option promoted by landuse managers and international development efforts. Agroforestry systems range from subsistence livestock and pastoral systems to home gardens, alley intercropping, and biomass plantations with a wide diversity of biophysical conditions and socio-ecological characteristics. The extent of its practice has never been quantified leading to widely varied estimates about its importance. This paper is the first attempt to quantify the extent of agroforestry at the global level. A geospatial analysis of remote sensing derived global datasets investigated the correspondence and relationship of tree cover, population density and climatic conditions within agricultural land at 1 km resolution. Among the key results are that agroforestry is a significant feature of agriculture in all regions, that its extent varies significantly across different regions (e.g. more significant in Central America and less in East Asia), that tree cover is strongly positively related to humidity, and that there are mixed relationships between tree cover and population density depending on the region. This first analysis suggests that patterns of tree cover are influenced by a range of factors we were not able to examine at the global scale and a number of follow up analyses are recommended.