Swidden farmers are rapidly transitioning to other types of land use. This study was conducted in 2 villages (T village and P village) in southern Chin State, Myanmar. The number of swidden-cultivating households decreased by 50% in T village over 2003–2013, and varied over 2004–2013 in P village; 21% and 13% of the total population in T and P villages, respectively, have out-migrated for employment. In addition, the introduction of terrace farming, development of animal husbandry, marketing of non-timber forest products, and other activities that generate cash income have reduced dependency on swidden agriculture. Remittances from out-migrated family members also contribute significantly to household incomes. As a result, the area devoted to swidden agriculture has decreased. By establishing site-specific allometries and applying best-fit allometry coefficients, total aboveground biomass was estimated for both villages. Generally, the aboveground biomass increased with the age of the fallow. Out-migration, insufficient crop productivity, and the development of alternative income sources resulted in the decrease in swidden agriculture in the areas studied. Further biomass regrowth can be expected in both villages in the future.