CURRENT STATE OF UPPER FOREST LINE IN HIGH ELEVATIONS OF THE KATUNSKY RANGE (THE ALTAI MOUNTAINS)

elevations of the Katunsky Range of the Russian Altai Mountains (the upper reaches of the Akkem river as an example). The upper forest line is a strip between the upper line of closed forests and the upper line of the single trees. This line is the most important biogeographic boundary and an internationally recognized indicator of climate change. The following upper lines are defined on the slopes of the Akkem river valley: closed forest lines (2300 m a.s.l. on the eastern slope and 2200 m a.s.l. on the western slope); tree group lines (2330 and 2265 m a.s.l., respectively); single tree lines and seedling lines (2440 and 2290 m a.s.l., respectively). Closed forests are grass-reed-green mossy and grass-cowberry-green mossy Siberian stone pine ( Pinus sibirica ) and Siberian larch ( Larix sibirica )-Siberian pine forests with 2-3 generations., The age of pine and larch trees of the first generation is 270–400 years, of the second generations is up to 180 years on the eastern slope and the age of the trees of the first generation is 530–590 years, of the second generation is 250–440 years, and of the third generation is up to 140 years on the western slope. On the eastern slope of the Akkem river valley, Siberian stone pine is mainly formed the tree group lines and single tree lines and Siberian larch do on the western slope. The seedlings is absolutely dominated by stone pine, larch seedlings older than 18 years is rare and the younger seedlings are absent. All lines are very tortuous. The altitude of the lines is significantly (up to 80 m) reduced on the western slope as compared with the eastern one due to the active landslide processes. The reproductive line of the Siberian stone pine is 2370 m a.s.l.