DYNAMICS OF SPECIES CHANGE OF LIVING ABOVE GROUND COVER IN YOUNG CULTURES OF ZHEREBKIVO FORESTRY

Abstract

The species composition of herbaceous vegetation in oak plantations before their closure were analyzed. It was found that after cutting down the mother stand, the diversity of plants from different families begins to increase already in the first year. According to the results of field observations, a sharp reduction of shade-tolerant species and an increase of light-loving and drought-resistant species was revealed. As a result, non-forest edifiers increase and the change of tree communities by grassy non-forest formations, uncharacteristic for forest biocenoses. Representatives of the Poaceae family, as well as Fabaceae and Rosales, characteristic of the steppe zone, begin to actively appear on a fresh log. In the following years, the dominant position is occupied by the family of Asteraceae. In the first year after felling, about 40 species were identified, over the years their number decreases, and already in the sixth year, the number of species is about 17 species. Analysis of the coenomorphic structure shows that in the first years the number of sylvans significantly decreases, some species disappear altogether from the plantations. Instead, ruderants (from 55% in the first year to 35% in the sixth) and pratants (from 28% to 35%) begin to dominate. In the trophomorphic structure of the living ground cover on the lands not covered by forest, there is a significant decrease of mesotrophic species between 1–2 and 3–5 years. A significant decrease in oligotrophs (from 6% to 0%) and mesomegatrophs (from 3% to 0%) is also observed. No significant difference in the change of megatrophic species was found. According to the hygromorphic structure, mesophytic vegetation (46%-58%) is dominant in all studied areas. The greatest floristic similarity of grass cover is characterized by 2-3-year crops with 45% similarity of species composition, 4-5-year crops (46%) and 5-6-year crops (46%). The same types of grass vegetation grow on these Фlogs, acting as indicators of ecological conditions in the forest phytocenosis.