東部ヒマラヤにおける土地開発史

Abstract

Mountain environmental changes caused by human impacts in the Himalayas have caught the attention of conservationist, scientists, and administrators within the last 30 years. Particularly in eastern Nepal (Solu-Khumbu area), it has often been stated that deforestation (forest destruction by human impact with fire) has accelerated during the latter half of 20th century because of population growth. In this study, dated charcoal and buried humic soil layers (including humus materials), both of which are evidence of forest fires indicate past deforestation and agricultural land development by tribal migration around Eastern Himalayas (Eastern Bhutan to Arunachal Pradesh, north-eastern India). Around the eastern Bhutan to Arunachal Pradesh area, human impacts such as population growth by tribal migration may have accelerated environmental and agricultural changes after ca. 2 ka BP, mainly. Relatively intense agricultural land formation that occurred since ca. 1 ka BP (mainly after ca. 0.5 ka BP) was due to tribal migration.