PATTERNS IN CONDITION, GROWTH AND PRODUCTIVITY OF TREE SPECIES IN FOREST BELTS OF IRRIGATED STEPPE OF SARATOV TRANS-VOLGA REGION
The purpose of the research was to establish regularities of growth and productivity of tree species in forest strips of the irrigated steppe of Saratov Volga region based on 2017-2019 research. The object of research is located in the steppe of the Saratov Volga region on the territory of JSC «Breeding plant» Meliorator» of Marksovsky district of Saratov region. Field research and processing of materials was carried out in accordance with the guidelines of specialized research institutes of Russia (VNIALMI). The studied forest strips have a tree-shadow type of mixing with the main species of oak and elm squat and accompanying species-lanceolate ash. Forest belts, being the ecological framework of the agricultural landscape, protect agricultural land from the effects of adverse natural factors, increasing productivity of crops and ensuring optimal use of irrigation regime. The most important indicator of longevity, biological productivity and, as a result, the effectiveness of forest reclamation impact on the surrounding area is the state and growth of tree species in forest strips. Research has shown that taxational indicators of the cherry oak when it is mixed with ash are 20 % higher than when it is mixed with the squat elm. The growth of oak in height and diameter when mixed with ash, starting from 6 years of age and throughout life exceeds the similar indicators of oak when mixed with elm by 20 %. Taxational indicators of squat elm and its growth when mixed with oak and ash exceed similar indicators of elm in clean stands by 9-11. 5 %. A study of life status of oak in woodlands showed us that when oak and ash were mixed, «low-carbon» trees (46 %) and «healthy» trees (45 %) of oak prevailed, and when oak and elm were mixed, the number of «healthy» oak trees decreased by 6 %, «low-carbon» and «high-carbon» trees increased by 3.6 % and 5.3 %, respectively.