STABILITY OF THE BETULA FORESTS IN THE TAIBA MOUNTAIN OF QINLING MOUNTAIN RANGE

The present paper deals with stability of the birch forest. The birch forests are considered as the forests of zone at geological period and modern times. They are climatic climax in cool-warm moist climate, and distribute in the cool-warm moist zone between the temperate deciduous broadleaf forest region and the cold-temperate needleleaf forest region Therefore the flora elements of the birch forests are mixed elements of the temperate deciduous broadleaf forest and cold-temperate needleleaf forest at geologica period and modern times.