Montane mainland SE Asia refers to the areas with an altitude of > 300m in Xishuangbanna (Southern Yunnan province, China), Laos, Myanmar, Thailand and Vietman. Garrity (1993) gives an estimate of approximately 180 million hectares, for the area of swidden agriculture in montane mainland SE Asia. Can anyone help me with a more recent estimate?
(Garrity, Dennis P. "Sustainable land-use systems for sloping uplands in Southeast Asia." Technologies for sustainable agriculture in the tropics technologiesfor (1993): 41-66.)