陕北黄土高原植被区划及与林草建设的关系

在陕北黄土高原，根据植被的地理分布、植物区系背景、环境条件的地理变化及造林种草实践，从南至北可划分为落叶阔叶林区、森林草原区和干草原、沙化草原区。以延安一线为界，南部为森林地区，北部为草原地区；再以长城沿线为界，南部为森林草原区，北部为干草原、沙化草原区。延安一线和长城沿线为两条重要的生态分界线，就是这两条生态线把陕北黄土高原划分为森林、森林草原及干草原、沙化草原三个植被区。植被区划是造林种草的理论依据之一，陕北黄土高原的种树种草应遵循这两条生态线，使其与植被分区相符合。

A Study on Correlation Between Vegetation Division and Construction of Forest and Grasslands in Loess Plateau of Northern Shannxi

According to the geographical distribution of vegetation, background of plant district, geographical change of the environmental condition, and the practice of afforesting and planting grass, the vegetation can been divided into broad leaf forest zone, fores grass and dry grassland zone, desert grassland zone from south to north.On Loess Plateau of northern Shaanxi, there are two important ecological lines:one is nearly in Yan’an city, where the south is forest area, the north is grassland area.Another line is nearly in Great Wall zone, where the south is forest grass zone, the north is dry and desert prairie.The vegetation division is an important theory basis for afforesting and planting grass, the author suggest that the two ecological lines must be paid a great attention to so as to make practice of planting tree and grass correspond with the rule of vegetation division.