Ecological adaptations among spruce species along an environmental gradient in urban areas

Abstract

Knowledge about current state of the trees in urban areas may be important for foresting and green planting of city landscapes and for improving environmental quality in these areas. The object of this study were to screen a range of morphometric, physiological and biochemical parameters among species of the genus spruce (Picea A. Dietr.) in urban areas of Kryvyi Rih City and to assess the ecological adaptations among species of the genus spruce (Picea A. Dietr.) along an environmental gradient in urban areas of Kryvyi Rih City. During 2017-2021, the 7 research plots in Kryvyi Rih City urban areas along an environmental gradient (low, moderate and high levels of the environmental impact) and 1 research plot in the background area (control) were established. The 30–40-year-old trees of indigenous spruce species (Norway spruce (Picea abies (L.) Karst.)) and non-native spruce species (Colorado blue spruce (Picea pungens var. ‘Glauca’)) were investigated. The morphometric characteristics of trees, vitality of trees and chlorophyll a, chlorophyll b content in needles were studied. The results showed that in background area the tree height (14.5-15.1 m and 11.7-12.5 m for Norway spruce and Colorado blue spruce), diameter at breast height (25.3-28.1 cm and 24.6-27.2 for Norway spruce and Colorado blue spruce), chlorophyll a content (0.75-1.04 mg/g of wet weight and 0.96-1.24 mg/g of wet weight for Norway spruce and Colorado blue spruce) and chlorophyll b content (0.33-0.41 mg/g of wet weight and 0.42-0.50 mg/g of wet weight for Norway spruce and Colorado blue spruce) were typical of mature 30-40-year-old spruce trees. In Kryvyi Rih City urban areas the ecological stress along an environmental gradient decreased the values of growth, vitalyty and photosynthetic activity of the trees by 15-50%. Colorado blue spruce trees (non-native species) exhibit greater ecological tolerance and ecological adaptations than Norway spruce trees (indigenous species). Colorado blue spruce is less sensitive to environmental impact and have a better ecological adaptive balance of pigment content than Norway spruce. Our results confirm that from a sustainable development of the urbane areas perspective it is necessary to using the Colorado blue spruce for greene planting.