Farmers in montane mainland Southeast Asia (MMSEA) have long practiced shifting cultivation with plots of land cultivated temporarily and then allowed to revert to secondary forest for a fallow period. In recent years, shifting cultivation has given way to more intensified forms of mono-cropped agriculture, including cultivated crops, orchards and, of increasing importance, rubber tree plantations. Today, more than one million hectares have been converted to rubber plantations. By 2050, the area under rubber trees in MMSEA is predicted to increase fourfold (Fox et al. 2012). This massive conversion of primary or secondary forests to rubber mono-cropping could threaten the resilience of both ecosystems and livelihoods. Despite environmental concerns and market fluctuations, both local farmers and outside entrepreneurs are likely to continue expanding rubber plantations because of their high economic returns. We argue that more diversified agroforestry systems that provide an optimal balance between economic returns and environmental sustainability are needed to improve the long-term outlook for the region in the face of climate change.