Pioneer shifting agriculture villages, largely belonging to ethnic groups of Hmong, Lahu, Yao, Lisu, and Akha, appeared to perceive the need to adapt to cope with the mounting pressure on the land even 30 years ago. Rotational shifting agriculture villages were already sedentary. Figure 5 presents the process in a schematic form and figure 6 shows the transect of land use in Ban Tuan of Mae Chaem district in Chiang Mai province. In the past, population increases had been managed by a group of households splitting off to form new villages. The government's forests and watershed conservation policy has further aggravated this increasing pressure on the land.
People become economically poorer, their land and nearby forest become degraded.
Cash cropping is adopted, sometimes with economic success, sometimes with economic failure. The resource base becomes degraded and there may also be a negative impact on the forests and watershed. Adoption of sustainable land-use alternatives that are economically viable, and also have positive impacts on the forests and watersheds. The remaining part of this paper will focus on this third strategy, examining the mechanisms by which highland land use might adapt to various external and internal pressures. Our preliminary studies have indicated that biological diversity plays a primary role in the development of sustainable landuse alternatives in the highlands.