Edge Effect: Growth and Morphogenetic Features of Scots Pine Trees in Forest Parks and Natural Stands

The degree of development and depth of edge effect are studied in some fragments of forest-park stands under long-term urbanization impact (in the city of Yekaterinburg, Russia) and in natural forests using the method of transect investigation. The method of quantitative assessment of tree stem and crown growth features by a set of morphological characteristics was used. The objects of the research included the edges of Scots pine stands. The edge effect was determined by two of the five studied characteristics: foliation and branchiness, which characterize the level of the development of the tree assimilation apparatus. The general trends indicate an increase in the development of these characters in natural stands and decrease in the forest park at increased distance from the edge. The nonlinear development of morphological characteristics along the transects is due to different types of tree responses on the impact of determining morphogenesis factors. Four statistically significant different zones were identified in the natural stands at distances of 0–75, 100–125, 150–175, and 200–225 m from the forest edge and only two zones were differentiated in the forest park. The unified approach to data analysis suggests the edge effect in both habitats at a distance of 75–100 m from the forest edge according to branchiness and 100–125 m according to foliation. Several types of morphogenetic tree responses, distinguished by the degree of foliation and branchiness variation under edge effect impact, are revealed.