Factors of pine-stand transformation in the city of Yekaterinburg

详细

The relationships between the health of Pinus sylvestris trees and stands and the levels of anthropogenic stress and fragmentation of habitats have been studied based on the example of pine stands of natural origin in Yekaterinburg and its vicinity (48 sampling plots located at different distances from the center of the city). The distances from the city center and from the boundary of a built-up area to a sampling plot and the population density around this plot are taken to characterize the level of anthropogenic stress. The area and perimeter of a forest site; the distance from the boundary of a sampling plot to the forest edges; and the shape of forest edges are used to characterize the level of fragmentation of habitats. We have found that the average morphological metrics of trees have slight changes, while the traits of tree health are significantly altered under urban environment. The overall performance of stands decreases by 22–35% in the urbanization gradient. The health of stands is most substantially influenced by the forest-site area. The population density around sampling plots and the distance of these plots from the megalopolis center have a lower effect on the health of trees and stands. Fragmentation of forests in the city leads to a decrease in the size of forest sites, which causes a decrease in wood stocks and the diameter and height of trees and the deterioration of their health. The lowest area of the forest to make it sustain an urban environment is about 30 ha. The untransformed core of forest is located no less than 70 m from the forest edge.