The paper analyzes the agro-ecological transformations caused by changes in prevailing socio-economic conditions in an Akha village of Chiang Rai province, now also targeted by a new reforestation scheme. A farming systems survey led to a diagrammatic synthesis of the diversity and functioning of whole family-based systems. They were classifed into a farmer typology and plotted along evolution trajectories displaying their respective patterns of changes. A complementary field-level on-farm survey was carried out to rank the main cropping systems, accross different landform situations, for their respective susecptibility to soil erosion. The most critical types of farming systems, comprising important susbsistence upland rice and/or ginger each crops sub-systems, were then targeted for future soil conservation measures. The integration of the farm and field levels information into GIS maps visualized the spatial distribution of the erosion risk at watershed lever. This output was designed to facilitate a dialogue on reforestation between stakeholders. If guided by relevant policies, the current agricultural diversification process provides options for significant progress in both resource base conservation and improvement of farmers' living conditions