ABSTRACT
Climatic changes, timber harvesting, and fires are the main factors that determine the structure, functions, and dynamics of forest ecosystems all around the world. Long time development of the Ural Mountains contributed to the wealth and diversity of natural complexes. The Ural Mountains have a unique location. This mountain system is located in the center of Eurasia. These mountains are distinguished by high biodiversity, the preservation of which is extremely important for the biosphere. The geographical location, large extent, great age of the Ural Mountains and the heterogeneity of landscapes make the Ural Mountains a unique object for studying the effects of climate change, timber harvesting, and fire on vegetation. The objective of the research is to study the effects of climate change, logging and fires on boreal forests in order to predict their dynamics. We conducted our study in Zauralsky (Trans-Ural) hilly piedmont province (Russia, the Middle Urals): coordinates 57°00’–57°10’ N and 60°10’–60°30’E. The district is subdivided into foothills formed by alternating meridional low mountains and ridges with wide, intermountain elongated low lands, in which are marked large lakes surrounded by moors. The mountains have altitudes of 30180–450 m a.s.l. The climate is continental and humid. Frostless periods last 90–115 days, the mean annual temperature does not exceed 1°C, and usual snow cover is not less than 45 cm. All major mountain habitats are included in our study. We visited the most-capped mountains. The steep and gentle slopes of the northern, southern, eastern, and western exposure were investigated by us. Swamp forests and marshes were not left unattended by us. All forest types were investigated. It is diverse of light coniferous and dark coniferous forests. The number of trees on the plot was not less than 200. The age by the annual rings was identified. Tapes 4 × 20 m were laid for the study of young generations of woody plants. A total of 10–20 accounting sites with the size of 1 m2 were used to study the productivity of the herbaceous layer. It has been established that climatic and topographic conditions are significant factors determining the composition and productivity of forest communities. The influence of climate leads to a shift in the range of forest types and the replacement of one forest community by another, which is more in tune with new climatic conditions. Forests growing on the border of its spread of habitat are the most vulnerable. Harvesting and fires are superimposed on climate change. The forest dynamics becomes extremely difficult. Timber harvesting leads to the emergence of many plant communities within the same growing conditions (climax forest). Over time, differences between these ecosystems persist. The differences relate to both the dominant species in the tree stand and the grassy layer, development trends and succession rates. Therefore, the management of such ecosystems should have its own specifics. The results of the research reflect the modern evolution of forest vegetation as an adaptation to clear cutting and other impacts in a continuously changing climate.
