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陕北次生林是指我省桥山、梁山两山系次生林而言的。据“四五”森林资源清查,其面积为1256.1万亩,分布在宜川、黄龙、甘泉县全部,志丹、安塞、延安、富县、黄陵、宜君、铜川、澄城、韩城、白水、耀县、旬邑等县(市)的大部或一部。陕北次生林,大体上位于我省面积约为11万平方公里的黄土高原的腹部,数量虽然不多,但对我省甚至黄河下游各省的生态环境的作用则是重大的。现仅举其防止水土流失的数据即可见其一斑。据资料:桥山黄龙山次生林属轻度流失区,山地梢林区年侵蚀模数为500～1000吨/平方公里,林区侵蚀模数为100～500吨/平方公里。与其毗邻的渭
The secondary forest in northern Shaanxi refers to the secondary forest in Qiaoshan and Liangshan Mountains in our province. According to the “April 5” Forest Inventory, the area is 12,561,000 mu, distributed in Yichuan, Huanglong, Ganquan, Zhidan, Ansai, Yan’an, Fuxian, Huangling, Yijun, Tongchuan, Chengcheng, South Korea City, white water, Yao County, Xunyi county (city) most or one. The secondary forest in northern Shaanxi is generally located on the belly of the Loess Plateau with an area of about 110,000 square kilometers in our province. Although its number is small, the role of the secondary forests in our province and the ecological environment of the lower reaches of the Yellow River is significant. Now just to show its data to prevent soil erosion can be seen. According to the data, the secondary forest of Qiaoshan Huanglongshan is a light loss area. The annual erosion modulus of mountain forest area is 500-1000 tons / km 2, and the erosion modulus of forest area is 100-500 tons / km 2. Wei adjacent to it