CHARACTERISTIC OF COMPOSITE PINE FORESTS ON VOLGA TERRACES OF TATARSTAN
N. B. Prokhorenko1, S. G. Glushko2
1Kazan Federal University, Kremlyovskaya str., 18, Kazan, Republic of Tatarstan, 420008 Russian Federation
2Kazan State Agricultural University, Karl Marx str., 65, Kazan, Republic of Tatarstan, 420015 Russian Federation
Keywords: древние террасы р. Волга, сосняки сложные, видовое богатство, структура и возобновление древостоя, мозаичность травяного покрова, эколого-ценотическая структура, ancient Volga terraces, composite pine forests, species richness, structure and renewal of the stand, mosaic of grass cover, ecological and coenotic structure
Abstract
The structure of pine forests in various natural areas of European Russia depends on environmental conditions, specifics of soil and underlying parent rock. Types of pine forests are distinguished by such features as their species composition of the lower layers, structure of grass-shrub layer and the nature of its mosaic. The purpose of the study are regional features of the composite pine forests, distributed on ancient terraces of left bank of the Volga River in north-western Tatarstan, considering specifics of their position in the contact zone of coniferous-deciduous forests with steppes. The structure of the communities of the pine forests on such indicators as species richness, quantitative participation of species, their occurrence and horizontal structure of grass cover were analyzed, and detailed description of the stand and of its renewal was given. In addition, ecological and coenotic structure of communities of pine forests was investigated. It was found that group of types of composite pine forests on the slopes and flat sections of high Volga terraces in northwest of Tatarstan are distinguished by age and completeness of the stand, but is characterized by similar composition of dominant species of lower layer and microgroups in grass layer composition. These communities are characterized by high participation of meadow-steppe plants. This feature distinguishes them from composite pine forests that are found in the central part of the European Russia. This is due to the fact that the area of our study takes position of a buffer, with broad invasion of meadow and meadow-steppe species in the communities of pine forests, especially when anthropogenic disturbances take place. The probability of further transformation of pine stands in the direction of their xerophytization has been identified.
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