History of study and genesis questions of pine forests (<i>Pinus kochiana</i>) in the Caucasus
On the territory of Russia, forests formed by Pinus kochiana are common in the mountains of the Caucasus and Crimea, and grow in dry and wet habitats at altitudes from 400 to 2700 m above the sea level. Forms pure pine and mixed forests in the regions of the Eastern, Central and Western Caucasus; the belt of pine forests is well expressed in the eastern part of the Caucasus. In similar edaphotopes, but under warmer climatic conditions, in the Crimea and Transcaucasia (Arkhipo-Osipovka village), they are replaced by Pallas pine communities, and in colder habitats, in the western and central Caucasus and western Transcaucasia, by fir or spruce forests, as well as subalpine shrubs or meadows. Pinus kochiana is of East Asian origin, it penetrated the Caucasus at the end of the tertiary period and is a relic of the ice age. The formation of forests from Pinus kochiana , as well as in the entire Euxine province, is associated with paleogeographic processes that took place during the Pleistocene. Further distribution of pine was determined by intraspecific relationships and soil and climatic conditions of a particular region.