THE ALTITUDE LIMIT OF THE KAYANDER LARCH (Larix cajanderi MAYR) DISTRIBUTION IN THE SPURS OF THE CHUVANSKY RIDGE (BASIN OF RIVER OZERNOYE GORLO, CHUKOTKA)

The Kayander larch ( Larix cajanderi Mayr) is the most important forest forming tree species of Chukotka, located on the northeastern border of its range. In the course of field studies in August 2021, the altitude limits of the larch distribution in the Chuvansky Ridge system, in the basin of the Ozernoe Gorlo River. In the estuary part of the valley of the Ozernoe Gorlo River has a significant array of larch forest. Between the Lednikovoe Lake and the mouth of the Ozernoe Gorlo River, at the height of the riverbed 290-350 m, the parameters of larch communities are significantly reduced. At a height of the riverbed 380 m, larch sparse woodlands are marked only by small fragments on the slopes of the southern exposure, or by single trees, often having branched stems and a widely spreading crown. On the left side of the Lednikovoe Lake basin, with a large gap in distance, at an altitude of 470-480 m, single larches of a significant age category are found among the thickets of dwarf pine ( Pinus pumila (Pall.) Regel). These trees have a height of 4-5 m and a widely spreading crown. South of Lednikovoe Lake, at a distance from the lake approx. 8 km to the south-west, at an altitude of about 660 m, we met larch only once. Here, a young solitary tree grows on a small fragment of fine earth among a stone placer covered with epilytic lichens (Lichenes ) . Its stem has a height of 1.3 m. The area we are considering is in the Ozernoe Gorlo River basin, can serve as a reference for monitoring observations of age-old changes in the altitude boundary of forest vegetation.