Siberian stone pine regeneration on the high altitudinal Seminsky range (the Central Altai Mountains).

On the Seminsky Range we revealed that the undergrowth quantity varies widely: from complete absence to 7000 species per hectare, depending on a degree of human impact and a type of phytocoenosis, while regeneration is represented only by one tree, Siberian stone pine. One of the main limiting factors for the regeneration in the research area is considerable height and density of grassy and shrub stories that promotes high competitiveness between species and blocks the nutcracker's seed spread. The formation of such vegetation cover is caused by moderate moistening and high trophness of study sites (62,1-64,9 and 9,2-10,1 degrees by I.A. Tsatsenkin.s scales, respectively).In stone pine forests we observed different ontogenetic structure of Siberian stone pine subcoenopopulations - sometimes with dominance of individuals in the juvenile stage (in the open Siberian stone pine forest with various herbs, green mosses, and Betula rotundifolia), sometimes - with dominance of immature ones (in the herbaceous stone pine forest). Constant anthropogenic pressure reduces tree generation succession speed and causes the alteration of the stone pine population ontogenetic structure on the upper forest limit. At the same time, the vitality of the stone pine undergrowth on the juvenile stage in all study coenosises is high (up to 100%), while there are considerable variations of it (from 0 to 90%) on the immature stage. Thus, in the open Siberian stone pine forest with various herbs, green mosses, and Betula rotundifolia there are no individuals with low vitality on the juvenile stage. While in the herbaceous stone pine forest their percentage is 40% of juvenile plants, which is mainly caused by humus soil destruction, its impoverishment with biophilic elements, soil consolidation and water and air soil regimen deterioration because of being close to a cattle pasture.The increase in individuals with a low vitality is typical of the immature stage, for these ones are more often grazed by the cattle. Differences in a degree of human impact (pasturing) cause considerable disparity in the part of plants with low vitality in the subcoenopopulations. On the sample area with a low impact about one third of individuals is damaged, and by intensive pasturing practically every plant had reapexation (often repeated), tops grazing and significant death of young individuals.Thereby, in mountain conditions of the upper forest belt the death of Siberian stone pine undergrowth or its low vitality caused by strong human impact can result in shifting of the upper forest limit down to 100-200 m of altitude. Only poor pasturing inconsiderably influences for the better the appearing of regeneration followed by decreasing herbage height and, correspondingly, creating more favorable conditions for spreading seeds by a nutcracker and small gnawers. On the whole, the regeneration on the north-east slopes of the Seminsky Range with the best moistening conditions for a Siberian stone pine is generally insufficient because of complete absence of virginal trees.

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