Life Forms of Larix Cajanderi Stems near Northern Tree Line in Yakutia

Abstract

We study life forms of Larix cajanderi stems near northern tree line in Yakutia. Researches are conducted in 2009–2012 on the island Tit-Ary of Bulunsky district of the Republic of Sakha (Yakutia) within a complex expedition of the Institute for Biological Problems of Cryolithozone of the SB RAS. We study dynamics of composition and structure of the most northern forest area in the delta of the Lena River. The island Tit-Ary is one of the most northern points of distribution of larch forest massive in the territory of Eastern Siberia. The studies were performed in accordance with typical forestry and geobotanical methods, on the basis of which 14 test areas for different types of larch forests were incorporated. Forest area of the Tit-Ary Island and its vicinities are presented by pretundra sparse larch forests. We registered four types of life forms of larch trees in the studied area. They are formed as a result of external environmental factors. The most common life form of Larix cajandery is a stem form with a pronounced one straight, tapering trunk. The stand is formed from the stem forms of larch, is mostly sparse, closeness is always thickness than 0,3, there are between 700 to 2750 stems at an average height of 1,45–3,15 m and an average diameter – 1,66–6,17 cm. In Tit-Ary Island there are less common shrub and elfin forms of larch, which are formed as a result of direct zoogenic and wind factors. A study of larch life forms, their varieties, adaptation at the northern boundary of forest is of great importance in the conditions of the climate change.