Study on SDE Distribution of Forest Vegetation in China Based on Trapezoidal Grid Segmentation

Abstract

The trapezoidal grid segmentation of China was carried out at a scale of 1:10000 to form a grid system covering the Chinese mainland. Based on the standard deviation ellipse (SDE) distribution theory, seven major categories and 53 sub-categories of Chinese forest vegetation were studied respectively. The SDE distribution was obtained and the average area distribution rate of 51.75% major-category vegetation was also obtained. Broad-leaved forests and sparse forests accounted for the largest proportion in China, with a proportion of 68.11%, the deviation rate of the average was 31.61%, and the dispersion was 0.097; the average distribution rate of sub-category vegetation was 9.38%, and the temperate subalpine evergreen coniferous forests accounted for the largest proportion in China, with a distribution rate of 30.23% and a dispersion of 0.032. The spatial distribution pattern of vegetation is mostly "southwest-northeast", but the elliptical center of the major-category vegetation moves more; while in terms of the direction of sub-category vegetation, there were nine categories of vegetation with three long-axis azimuths [<45 degrees], 27 categories of vegetation with long-axis azimuth [>45°∪≤90°], and 27 categories of vegetation with long-axis azimuth [> 90°].