Agrarian transition and lowland-upland interactions in mountain areas in northern Vietnam: application of a multi-agent simulation model

The agrarian transition that accompanied the decollectivisation of agriculture in the northern Vietnam uplands challenges traditional approaches to land use analysis. In the 1980s, a series of reforms progressively returned means of production to individual farmers. Over the same period the mountains in the study area lost 50% of their forest cover. This paper provides an overview of the impact of changes in government policies on farmers' practices, on land use, and on environmental dynamics. It applies a multi-agent simulation model to validate the hypotheses derived from household survey and remote sensing data about the mechanisms linking the allocation of paddyland to farm households with shifting cultivation on the hillsides, and deforestation. The model explains the diversity of the current land use systems by analysing the interactions between land tenure policies in the lower part of the toposequence and the dynamics of land use in the upper part. The findings are based on an extensive diagnostic survey of a number of representative sites, on generation of primary data from an intensive survey of 50 randomly selected households, and on insights gained by the authors during their long association with an action research project using a participatory observation method. The authors also explore whether the modelling approach can capture the main features of complex human-environment interactions of a site and can help apply the findings to the broader agroecosystem the site represents.