Formation of the Secondary Area of Caragana аrborescens Lam. in the Forest Parks of Yekaterinburg

Abstract

The article is devoted to the analysis of the distribution and features of the ecological and biological confinement of Caragana arborescens Lam. in the forest parks of Yekaterinburg. Caragana plantations have been studied in 14 out of the 15 city forest parks: Kalinovskij, Zheleznodorozhnyj, Karas’ye-Ozerskij, Moskovskij, Nizhne-Isetskij, Sanatornyj, Uktusskij, Shuvakishskij, Yuzhnyj, Shartashskij, named after the Foresters of Russia, Obroshinskij, Central and South-West – on an area of 12,077 hectares based on a standard electronic database. The ontogenesis of the species and its morphological features have been studied in 10 local habitats by the example of 2 forest parks – named after the Foresters of Russia with the largest number of caragana and Uktussky with the minimum. The formation of the secondary area of caragana in the forest parks of Yekaterinburg depends on the presence of generative individuals nearby. The maximum growth area is established in the forest park named after the Foresters of Russia (98.6 ha), the minimum – in the South-West (0.4 ha). The area of distribution is determined by the area of plantings that have been carried out in the 1970s and 1980s, which is confirmed by our research in the forest parks. C. arborescens prefers to settle in mixed-herb (67.8 %) and berry (26.8 %) pine forests with a stand density of 0.6–0.7, being a heliosciophyte. The number of caragana trees in the habitats increases with the increase in the density of the stand from 404 to 1359 plants. When the density of the pine stand is 0.3–0.5, the amount of caragana decreases, and at 0.1–0.2 it disappears. The distribution of C. arborescens depends on the age categories and productivity of forest plantations, it grows mainly in mature pine (68.8 %) trees in high-quality (the 2nd quality class – 62.3 %) plantations. In the ontogeneisis of caragana, 2 periods and 6 age-related conditions have been established, with the pregenirative fraction predominating. The studied habitats are normal, incomplete, but capable of self-maintenance, since under favourable conditions individuals reproduce by self-seeding. The life forms of the caragana tree are formed in open areas as an aeroxylic shrub, and in pine forests as a small tree. The Caragana arborescens introductions in the forest parks of Yekaterinburg are rare and currently pose no biological hazard to forest ecosystems. © 2024, Northern Arctic Federal University named after M V Lomonosov. All rights reserved.