The Influence of Climatic and Edaphic Conditions on the Development of Thuja occidentalis ‘Smaragd’ Under the Urban Conditions of a Large City

Abstract

The negative effects of the urban environment on the morphological and physiological states of Thuja occiden- talis ‘Smaragd’ have been investigated. For comparison, two plots were selected for the cultivation of eastern arborvitae cultivars: one in a public garden (the control plot) and the other one in street planting with its posi- tive vertical temperature gradient associated with overheating and dehydration of the soil. This situation had a negative impact on the biometric and physiological parameters of the plants, and, in the end, the level of their vitality. If, under optimal growth conditions, the vertical temperature gradient is negative (the air temperature in the crown is higher and the soil temperature in the rhizosphere zone is lower), the physiological processes in Thuja ocidentalis ‘Smaragd’ (transpiration, water-holding capacity) proceed in a normal mode.