Environmental stresses and adaptation processes of woody plants in the current urbanized environment

Abstract

Aims. The need to understand the adaptability strategies of perennial woody plants in urbanization, in particular their potential not only for survival but also for performing sanitary and hygienic functions of air purification from dust and smoke, from vehicle exhaust gases, and protection of citizens from various types of noise, while maintaining decorative effect for many years, led to the study of representatives of native and introduced flora used in landscaping, and also searching for means to reduce anthropogenic loads on plants and searching for the plants' selection criteria that can adapt and withstand these loads without significantly reducing their decorative and sanitary-hygienic functionality. Materials and Methods. In the process of studying the sources of environmental stresses and mechanisms of post- traumatic regeneration that promote the adaptation of woody plants to biotic and abiotic factors of urbanized areas, we analyzed relevant publications by scientists from different scientific schools and other publicly available scientific sources. The information obtained was studied using the methods of theoretical analysis, systematization, comparison, and generalization, and the authors used their methodological developments. The empirical observations with woody plants cultivated in cityscape streets and other green spaces were performed according to generally accepted methods. Results and Discussion. The widespread use in the middle of the preceding century of Acer negundo, Acer platanoides, Aesculus hippocastanum, Tilia cordata, Robinia pseudoacacia, Ulmus pumila, Ulmus laevis, and other trees with strong apical dominance for urban street landscaping, which were often planted in the city electricity network's immediate vicinity, led to the introduction of the erroneous practice of radical pruning of skeletal branches touching the wires. Improper pruning of street trees, especially if it is carried out using topping technologies, can significantly reduce the total leaf surface area of pruned trees, distort their growth pattern, weaken their ability to improve the microclimate, and significantly reduce the resistance of plantations to major anthropogenic pollutants, with a simultaneous increase in the number of plants affected by pathogens, damaged by pests, and various abiotic environmental stress factors. The article discusses the prospects of using plants with limited apical dominance, in particular Corylus avellana ‘Pendula’, Morus alba f. pendula, Robinia pseudoacacia f. umbraculifera, and other ornamental woody plants in street gardening and of the design of entrance areas to various institutions. Conclusions. A current shift is imminent in the emphasis of the approaches to understanding stress tolerance, and the mechanisms of their synergy must be tested in plants. The future work must include more emphasis on the woody plants' adaptability studies in urbanized environments.