Forests of the Khan-Khukhii Mountain Ridge in Mongolia

The results of complex forest-ecological studies at the Khan-Khukhii Mountain Ridge in the territory of National Natural Park Khan-Khuhii-Khyargas-Nuur, Western Mongolia are presented. The forests at the Khan-Khukhii Mountain Ridge are isolated from the north by the desert, and from the other sides – by dry steppes. The location of the stands makes it possible to study climatic, geomorphological and economic factors, affecting forest formations along the border of forest distribution. Five sample plots in accordance with the variety of forest vegetation and geomorphological locations were established during the field surveys. Sample plots were placed at the lower forest boundary in the old-growth larch sparse stand experiencing the greatest pasture load, and in the herbaceous larch stand with zoogenic inhibition of undergrowth and fragments of selective felling of the lower part of the northern slope. Larch forests of green moss-red bilberry type with the participation of the Siberian stone pine are characteristic of the upper part of the slopes. The Siberian stone pine stand with dead ground cover is bordered by watersheds and a steppe southern slope and a herbaceous larch stand in the north. An intrazonal object was categorized as yernik (dwarf birch) on permafrost grounds. The geomorphological affiliation of the Siberian stone pine and larch formations to elevations above the sea level and slope exposition is shown. The zoogenic factors determining silvicultural processes limit forest restoration and lead to the formation of a savannah type of vegetation. Under adverse climatic conditions, primary pests of larch needles and root pathogens are detected. Forest logging leads to the growth of grass cover and movement of livestock into the forest zone, followed by the cessation of forest restoration. In the forests of the Khan-Khukhii Mountain Ridge there are no signs of fires (no cinder and fire scars on tree stems), which indicates a long pasture load and the impossibility of accumulation of combustible material. The results of the study made it possible to recommend the directions for silvicultural operations on the territory of the National Natural Park Khan-Khukhii-Khyargas-Nuur. First of all, it is necessary to identify factors of the curtain and highly dense forest regeneration on the border between the forest and steppe. If there is a continuing intensive pasture load, forest compartments will remain within the present boundaries or will be reduced. The impact of global climate change on the current distribution of forests has not been revealed.