Abstract. The rapid appraisal and farmer selection procedures, preceding the establishment of
over fifty agroforestry research trials on farms in Talamanca, Costa Rica are described. The
highest probability of success and impact of these long-term collaborative trials is obtained by
selecting innovative, experienced, motivated and locally respected farmers. The methodological
lessons learned from implementing three types of researcher managed trials (shade-cacao;
black pepper on living support posts; timber production in boundary lines) are discussed. The
importance of fitting farmer selection criteria to project objectives, experimental designs to onfarm
limitations, and project goals to farmers' goals, are emphasized.