Condition and growth of pedunculate oak (Quercus robur L.) in irrigated forest belts of Saratov Trans-Volga steppe

Abstract

The research aim was to establish the regularities of condition and growth of pedunculate oak (Quercus robur L.) in the irrigated forest belts in the steppe of Saratov Trans-Volga Region. The study object is a system of forest shelter belts under conditions of irrigation of dark chestnut soils of Saratov Trans-Volga steppe with tree species of the main and accompanying purpose - pedunculate oak, lanceolate ash (Fracsinus lanceolata L.) and squat elm (Ulmus pumila L.). The research in the field and materials processing were carried out in accordance with the methodology of specialized research institutes and leading scientists in the field of agroforestry. Forest belts located on agricultural land protect crops from the negative effects of drought and dry winds, optimize snow distribution in winter and irrigation regimes for crops during the growing season, and increase the crops productivity. Irrigation has the most important positive effect on growth and condition of tree species in forest belts and, as a result, on durability and reforestation efficiency of forest belts. The studies have shown that the average height and diameter of oak in the. irrigated forest belts mixed with different species are higher than those without irrigation by 15-26% and 34-39%, respectively. The oak growth in height in irrigated areas of forest belts exceeds its growth in height in areas of forest belts without irrigation by 1.5 times. The vital condition of oak in the irrigated forest belts is characterized by the prevalence of “slightly oppressed” (48%) and “healthy” oak trees (40%).