Retrospective analysis of spatial patterns of ash-leaved maple settlement in the protective zone of the Yamskaya steppe (Belogorye nature reserve)

In the fall of 2014 and 2015, in the protective zone of the Yamskaya Steppe (Belogorye nature reserve), near the border of the second quarter, a grove of dangerous introducer - ash-leaved maple was cut down. After felling, we mapped the position of the trees and estimated their age by the number of annual rings on saw cuts. Based on these data, we studied the history of settlement of ash-leaved maple. The source of bringing is the planting of ash-leaved maple in the village of Zagorny, located near the border of the reserve. The entire study area is in the zone of wind transfer of seeds. But the first trees were fixed in 1980 only locally - in the most humid part of the boundary ditch. Further resettlement initially took place along the boundary ditch, and then to the sides of it. The resettlement process can be divided into three stages, which have their spatial patterns of settlement. The first stage (1980-1990) is characterized by a random spatial distribution of trees. The border of the forming thicket expands slightly, but the density of trees inside it increases. The second stage (1990-2000) is characterized by a group spatial distribution. The border of the emerging grove is actively expanding. At the third stage (2000-2015), a continuous closed thicket is formed, covering the entire studied area. The group type of distribution is preserved, but over time its severity weakens. The appearance of new trees is noted mainly within the boundaries of the thicket. In 2015, presumably, a new expansion stage began, which was artificially interrupted. At this stage, the spread of ash-leaved maple could again go beyond the thicket, including the territory of the reserve.