清代西南地区森林空间格局网格化重建

Spatially explicit reconstruction of forest cover of Southwest China in the Qing Dynasty

基于遥感土地利用数据和全球潜在植被数据,确定了中国西南地区土地垦殖前森林植被可能的分布范围,并通过量化地形(海拔、坡度)和气候生产潜力(光照、温度、水分)与农林地分布间的关系,构建了土地宜垦性评估模型和历史森林面积网格化分配模型,重建了清代西南地区5个时点、分辨率为10 km×10 km的森林空间格局。结果表明:①本文设计的森林空间格局网格化重建方法具有一定的可行性,其结果能较好地反映森林变迁历史过程的基本特征;②西南地区森林覆被率从雍正二年(1724年)的54.7%下降至宣统三年(1911年)的27.8%,其减少地区主要分布在四川盆地、云南中南部以及贵州大部;③从网格占比的变化趋势看,1724-1911年,西南地区森林覆被率小于10%的网格占比上升了约31个百分点,而覆被率大于80%的网格占比则下降了约13个百分点。

We determined the possible extent of forest distribution before reclamation on the basis of satellite-based land use data and global potential vegetation data. Then, topography （including altitude and slope）, production potential of climate （including light, temperature and water） were selected and their relationships with cropland spatial distribution were quantified to create land suitability for cultivation model and historical forest spatially explicit reconstruction model. And the models were used to reconstruct forest cover in Southwest China of five time points between 1724 and 1911 in the Qing Dynasty. The results show that： （1） The model we designed is reasonable on the whole and the forest cover can be recreated well by the model; （2） The RFT （i.e., the ratio of forest area to total land area of each administrative unit, hereafter RFT in short） of Southwest China decreased from 54.7% in 1724 to 27.8% in 1911. And the changes were mainly found in the Sichuan Basin, the central-eastern part of Yunnan and most parts of Guizhou. （3） In terms of the change tendency of the percent of grids in each interval, the percentages of grids whose RFT is less than 10% increased by 31% while the percentages of grids whose RFT is more than 80% decreased by 13%.