Global warming increasingly more interferes in the natural ecosystems. It sufficiently noticeably influences forests. Meanwhile, forests play a greater role in the maintenance of the regulation of the gas composition of the atmosphere , stability of a soil cover and a hydrological network, and also in preservation of a biological variety. The Russian forests, which compose 22% of all forest territories of the world, influence a condition of all of these world parameters considerably. But how much seriously global warming threatens to forests?
Among all types of forests, which exist on the planet, the massifs, located in coniferous and mixed areas of Eurasia and Northern America are object of the greatest transformations in conditions of the climate changes. This is explained by displacement to the north of borders of “forest- tundra” and “the forest- steppe”. According to the Fourth estimated report of the Intergovernmental Panel on Climate Change (IPCC), with the retention of the existing tendencies toward an increase in the world emissions of greenhouse gases, temperature by 2100th will increase almost to 4°C. If the stabilization of anthropogenic emissions will occur, growth of temperature will make no more than 2°C.
In the first case (increase in the temperature by 4°C) in the entire territory of Russia will begin the process of the retreat of forests from the south to the upper latitudes, and it will be additional sort than the advance of forest boundary to the north. Natural deforestation will envelop almost entire middle strip of European Russia and West Siberia. But if an increase in the temperature comprises not more than 2°C, then “green” migration will affect only the south of West Siberia, but the total area of forest cover will increase due to the propagation into the contemporary tundra zone. The boundaries of plant zones do not change instantly and several “are late” a little in its motion on the comparison with the climatic trends. For renovation of specific structure of a vegetative cover time estimated in tens, and sometimes and hundreds years is required. The scientists of the institute of physics of the atmosphere of the Russian academy of sciences have preformed a detailed study of changes in the plant cover of Russia with an increase in the temperature by 1°C, which is expected in the next decades (30’s -50’s) of 21 st century.
Global warming actively is discussed for the last 20 years; however it began more than a century ago. It is sufficient time for the successions, and in some regions territorial changes of plant zones are already obvious. The studies, carried out in the zone of the polar Urals by the scientists of the institute of the ecology of plants and animals of Ural department RAN -Russian Academy of Science, have revealed absolutely noticeable changes in the spatial distribution of plant communities. For example, for 90 years (1910th -2000th) the share of tundra in this region has decreased from 76 %, which it usually occupied, to 59%. The zone of enclosed woodlands at the same time grew, from 1% to 10%. The light forest has increased also, from 11 % up to 18 % and larch forest was taken away into the mountains to 60 meters, after engaging the mark of 320 meters (instead of former 260 m.). The reasons for such changes in the plant cover in the polar Urals are connected with the local warming, which amplitude somewhat exceeding “curve” of global warming. The degree of disappearance of Russian forests by this time it is not predicted, but victims nevertheless will be. In the Volga- Vyatsky interfluves and the upper flow of river Ob the small areas of pine forests will die out. On 70% of areas of pine forests and on half of the territory of fir will begin groves the processes of succession (transformation of plant communities). The mixed woods and oak groves are less sensitive to warming - there succession will touch only 1/5 of territories. The steadiest will be larch forests of Eastern Siberia (less than 5 % succession). These results are quite comparable to forecast of the Intergovernmental Panel on Climate Change (IPCC) , predicting disappearance of 30 % pine and fir forests of a planet by 2100th.