THE CHANGING OF THE HERB LAYERS OF TWO SOUTHERN TAIGA BIRCH FORESTS AFTER THE CUTTING OF THE DENSITIVE LAYER OF SPRUCE YOUNG GROWTH
The degradation of the herb layer has been ceased after full cutting of the densitive layer of spruce young growth in two southern taiga birch forests. The monitoring was continued during 13 years after the spruce cutting on nine sample areas 3×3 meters in each forest.In an younger birch forest the crowns of spruce recruits had united recently, the height of spruce layer was only 4 meters. The herb cover was slightly less than it was in sites without spruces. 24 species of plants were found in the herb layer. After the full spruce cutting the cover of the herb layer has increased, quantity of plant species of the herb layer on some sample areas has been increased too.In an older birch forest the crowns of spruce recruits had united long ago, the height of spruce layer was more 10 meters. The herb cover was little, mosses formed main part of the ground cover. 17 species of plants were found in the herb layer. On some sample areas there were especially little species - only 2-6. After the full spruce cutting the covering and the species diversity of the herb layer on the sample areas have been increased. Many species of herb layer have appeared in the locations, where they had been absent until the cutting of spruce. But percent of new species from the appeared species was very small. Much part of them already have existed on the cut squares in some locations. The positive reaction has been demonstrated by species of different ecology: shade-tolerant forest species, sun forest species, boreal and same Nemoral do.