Evaluating trees and shrubs for multifunctional plantations to enhance agro and urban landscape greening in arid zone environments

Green plantations in arid and low-forest regions often lack sufficient decorative quality and multifunctionality. Enhancing these systems requires updating species composition with well-adapted trees and shrubs. However, limited research has systematically evaluated taxa within dendro collection genera for their ecological, sanitary, and aesthetic traits. This study addresses that gap by assessing species groups to guide the development of multifunctional plantations in agricultural and urban landscapes. Therefore, a group of characteristics was refined, and a scale was developed to assess the decorative properties of plants. The research objects grow in the arboretum of the Nizhny Volga Station for the Selection of Woody Plants (Volgograd Region, Russia), which was founded in 1931 in the zone of dry steppes with chestnut soils. The assessment involved 95 taxa from the genera of the families Aceraceae, Berberidaceae, Cupressaceae, Fabaceae, Oleaceae, Pinaceae, and Rosaceae. It was found that against the background of a significant warming, the rapid accumulation of effective temperatures (above +5°C and +10°C) on the earlier onset of the initial phases of development: the beginning of sap flow, swelling and budding, and flowering. The average dates (for 2022-2024) of the onset of the main phases of woody plant development have been established, which indicates a shift in the flowering period and a 12% increase in the number of species with early spring and spring flowering periods. From the point of view of the ornamental value of plantations, the earlier and longer vegetation of adapted woody plants allows for extending the aesthetic appeal of landscaping objects up to 35-45 days. At the same time, there are also risks of reducing the ornamental value of both individual species and the plantations due to spring frosts.