Bioecological characteristics of unique natural and artificial oak populations on semi-desert landscapes in the Volgograd Region

Introduction. The article presents the results of studying the pedunculate oak, which is one of the most valuable species for use in forest plantations for various purposes – from protective to anti-erosion and landscaping. Despite the wide range and ecological plasticity, plantations with oak trees very often cannot be restored naturally, which makes the work especially relevant. The last decades have been marked by a comprehensive study of the genetic resources of natural oak populations, as the threat of their loss arises with all evidence. The purpose of the research was to study the growth and development of oak forests in specially protected natural territories of the Volgograd region for the selection and preservation of parent species with a high degree of adaptation to local climatic conditions when creating nurseries and forest-seed facilities. The objects of the research were populations of the oak tree – Quercus robur L., the observation points were the lost complex reserve “Pereshchepnovsky”, “Kozlovskaya forest dacha”, protected areas “Tingutinskaya forest dacha” and “Chapurnikovskaya beam” with different soil and climatic conditions. Materials and methods. During the research, phytogeography methods were used for spatial study of vegetation of territories, the growth of oaks, their crown projection, shoot growth, number of leaves, weight of acorns during shedding, resistance to freezing and drought were studied. Results. As a result of the research, it was revealed that in the natural conditions of the Kotovsky and Rudnyansky districts, the petiolate oak is characterized by the best growth and frost resistance, but its drought resistance, electrolyte yield and turgorescence are noticeably less than those of oaks growing in the conditions of the Svetloyarsky district, which is explained by the adaptation of species to drought and, as a consequence, high drought resistance. It was found out that in the conditions of the Pereshchepnovskaya ridge, oaks are in satisfactory condition and low productivity, shrinking stands make up 15%. On the territory of the Tingutinsky forest cottage, the oak has no undergrowth and natural renewal, which is due to the strong erosive dissection of the landscape and the close level of groundwater occurrence. The results of the research are promising when using zoned improved and varietal seeds in solving the problem of the organization system of oak forest seed production, for this it is necessary to create nurseries and seed facilities for mass production of seeds with improved hereditary properties, preservation of oak collections in areas of specially protected natural territories, replenishment of lost populations. Discussion. Petiolate oak is the most valuable species for afforestation, its wide range indicates great plasticity, large differences in natural and forest-growing conditions in the areas of the studied specially protected and lost natural territories are the reason for its form diversity. Oak forms a lot of climatic races differing from each other in morphological and biological characteristics in different regions of the region and soil varieties. One of the main tasks is the preservation of oak forests, especially in the territories of protected areas, taking into account genetically valuable plantations and oak trees, including individuals with valuable forestry properties. Hybridization proposed by the authors will make it possible to obtain oak hybrids for the dry-steppe and semi-desert zones that have rapid growth, resistance to drought, to phytoand entomological pests. The study of the physiological features of oaks in geographically separated experimental plots showed that the intensity of transpiration in the species of Kotovsky and Rudnyansky districts is significantly higher than in the species of Svetloyarsky district adapted to drought. However, they are characterized by much more vigorous growth and development. The mass reproduction of genetically valuable oak species and the preservation of oak forests in areas of specially protected natural areas should be the next stage of work on the selection of trees with increased viability. Conclusion. The article presents the results of many years of extensive research on the growth and development of populations of the oak tree (Quercus robur L.) in the existing and lost areas of specially protected natural territories of the Volgograd region – the lost complex reserve “Pereschepnovsky” (Kotovsky district), the botanical nature monument of republican significance “Kozlovskaya forest cottage” (Rudnyansky district), the protected area “Tingutinskaya forest dacha” (Svetloyarsky district), a lost natural monument “Chapurnikovskaya beam” (Svetloyarsky district). Resume. As a result of the research, it was revealed that in the natural conditions of the Kotovsky and Rudnyansky districts, the petiolate oak is characterized by the best growth and frost resistance, but its drought resistance, electrolyte yield and turgorescence are noticeably less than those of oaks growing in the conditions of the Svetloyarsky district, which is explained by the adaptation of species to drought and, as a consequence, high drought resistance. It was found out that in the conditions of the Pereshchepnovskaya ridge, oaks are in satisfactory condition and low productivity, shrinking stands make up 15%. On the territory of the Tingutinsky forest cottage, the oak has no undergrowth and natural renewal, which is due to the strong erosive dissection of the landscape and the close level of groundwater occurrence. Suggestions for practical application and direction of future research. The research results can be useful when using zoned improved and varietal seeds in solving the problem of the organization system of oak forest seed production, for this it is necessary to create nurseries and seed facilities for mass production of seeds with improved hereditary properties.