<i>PINUS SIBIRICA</i> (<i>PINACEAE</i>) LIVING FORM AT FOREST-TUNDRA MOUNTAIN ECOTONE IN SEVERO-CHUISKY RANGE (THE ALTAI MOUNTAINS)
Seven Pinus sibirica living form (single-stemmed, few-stemmed and multi-stemmed straight-stemmed trunk trees, supra nival skirted, shrub-like form, elfin tree, and living windfallen tree) as well as one relatively autonomous morphological structure (elfin wood form in the tree butt of the straight-stemmed trunk mother tree) are identified and described at forest-tundra mountain ecotone in the Aktru mountain glacial basin (Severo-Chuisky Range, the Altai Mountains). Ways of their formation are considered. The main reason of the formation of the living forms excluding the one-stemmed straight-stemmed trunk trees with symmetric crown is death of tree fragments because of weather factors or geomorphological events. During XX century the climatic conditions at the forest-tundra mountain ecotone in the basin were favourable for growth of the living forms of P. sibirica straight-stemmed trunk trees.