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一、解放前雁北地区的自然概况雁北地区西北面多为黄土丘陵区,东南面多为半石山区和石山区。全区总土地面积为三千四百五十万亩,其中山区为二千五百八十万亩,占总土地面积的68.8%;平原区为一千一百七十万亩,占31.2%。山区中黄土丘陵地带占55%,半石山区和石山区占45%。这些山区,特別是黄土丘陵区,由于树木稀少,复盖极差,因而水土流失与洪害极为惊人。根据調查,朔县上石碣峪村每年表土流失一至二市寸,渾源塘峪每年表土流失六分至一寸,初
First, before the liberation of the natural conditions of Yanbei area Northwest of Yanbei area mostly loess hilly area, southeast of mostly semi-rocky and stone mountain area. The region’s total land area of 34.5 million mu, of which 25.8 million mu of mountainous areas, accounting for 68.8% of the total land area; plain area of 17.7 million mu, accounting for 31.2% . Loess hills in the mountains accounted for 55%, Rocky Mountain and Stone Mountain 45%. These mountainous areas, especially the loess hilly areas, are extremely alarming because of sparsely populated trees and extremely poor coverage. According to the survey, the Shuo County Shek Kip Yu village annual top-soil loss of one to two inches, Hunyuan Tongyu annual topsoil six points to an inch early