THE PRICIPAL TYPES OF VEGETATION AND ITS RATIONAL UTILIZATION IN THE NORTHWEST OF SHANXI

The northwest of Shanxi, including nine counties, is on Loess Plateau. There are hill lands, meso mountains and low mountains, basins and valley plains in topography. The characteristic features of the climate is continental—cool and rainy in summer, very cold and dry in winter. The principal soil are gray-cinnamonic soil, mountain gray-cinnamonic soil, brown forest soil and subalpine meadow soil.There are seven vegetation types: the cold-temperate coniferous, the deciduous broad-leaved forest, the deciduous broad-leaved bush-wood, the bush-grass land, the steppe and the meadow. They include 26 formations, each of which is described in composition, structure and distribution.Because of the destruction of vegetation for a long time on Loess Plateau, the ecological equilibrium was broken, the water and soil were lost in large quantities. Natural vegetation, as we know, plays an important role in harnessing the Loess Plateau. So we must take strong measures to protect and develope vegetation, including not only forest but also bush-wood and herbosa.