vegetation that covers the slopes of mountains. It is characterized by rapid vertical change in dominant forms of plant cover, with slight changes in elevation. This change is determined by the nature of the change in climatic conditions between the base of the mountains and their peaks; the distribution of products of weathering and erosion, which occur in greater volume with descending altitude; and the history of the formation of the mountain mass and its vegetation. Overall mountain vegetation occurs in belts: the vegetation of the lower mountain belt is usually close to the zonal vegetation of the adjacent plain, while the vegetation in higher belts resembles that of plains situated to the north (in the northern hemisphere) or south (in the southern hemisphere) of the foot of the mountains.
There is no complete correspondence, however, between the vertical zonality and the plain zonality because not all elements of climate change identically in the horizontal and vertical directions. Light conditions, in particular, vary in different ways. The elevation boundaries of particular belts of mountain vegetation depend on the geographic latitude, exposure of the slopes, and other conditions. Each belt of mountain vegetation includes several different plant communities because of the variety of local conditions related to the dissection of relief, degree of weathering of surface rocks, and variation in the physical and chemical composition of surface rocks.
V. S. GOVORUKHIN