SPRUCE RECRIUTMENT IN SOME SECONDARY FORESTS OF SOUTHERN TAIGA AT DIFFERENT STAGES OF THEIR AGE-RELATED DYNAMIC
The appearance, the survival and the growth of spruce seedlings were studied in some secondary forests of southern taiga. The monitoring was proceeded during 25 years in middle-aged birch forests (from 40 to 80 years after birch appearance), in old-aged birch forests (older 80 years after birch appearance) and in young spruce forests, which have been formed by leaved spruce recruits after felling of birch trees. The quantity of appearing spruce seedlings depends on the quantity of generative spruce trees around and the yield of spruce seeds in present year. The survival of spruce seedlings depends on local conditions. In middle-aged birch forests with dense canopy of young spruces spruce seedlings appeared in few quantity after mast yield years and their surviving was very bad. In old-aged birch forests with second tree layer of spruce the quantity of spruce seedlings was more and their surviving was better, than in middle-aged birch forests. In young spruce forests many spruce seedlings appeared after mast yield years, but their surviving was very bad. The successful recruitment of spruce population by new specimens happens only in microsites when there are the gaps in spruce canopy. This is true and for young spruce forests and for birch forests with dense second tree layer of spruce.