Development of Mountain Forest and its Environmental Impact in the Upper Reaches of Heihe River Basin of Ming and Qing Period

摘要

After the latter half of the 15th century, the deforestation of mountain became active in the northern frontier of Ming dynasty. Therefore, around the 16th century, Ming government prohibited the deforestation around Great Wall chiefly by military reasons. However, a lot of virgin forests have still extended at the northern foot of Qilian mountains in the upper reaches of Heihe river basin until about the 17th century. Tibetan and Mongolian people lived in this region from ancient times by nomadism, stock raising, hunting or farming. It was chiefly Han people who promoted the development and the use of timber resources. They came from Ganzhou in summer, cut down and carried away the forest woods in order to sell them. After the 18th century, under the rule of Qing dynasty, the full-scale deforestation of the Qilian mountains has begun in the upper reaches of Heihe river basin. Because the area of the forest reduced rapidly and the water-holding capacity of mountain forest decreased, the amount of water necessary for the irrigation agriculture came to be insufficient and the flood came to happen many times in the middle reaches. To deal with such a situation, the officials of Qing government understood the function of the mountain forest enough based on the field survey. They decided to make regulations concerning to the usage and the management of the mountain forest and severely punished the offender, but the effect was not so satisfactory.