This paper documents the impact of the trial application of a knowledge based systems approach to interdisciplinary research on tree fodder at a front line agricultural research centre in Nepal. The study reveals the depth and consistency of indigenous ecological knowledge about agroforestry on one hillside in Nepal and its complementarity with existing scientific knowledge. Farmers already combined sophisticated knowledge of fodder production by trees, their impact on associated soil and crops, and the feeding value of fodder for livestock in arriving at complex trade-offs between these elements.