NATURAL REGENERATION IN THE SUBURBAN BROAD-LEAVED STANDS IN UFA

The aim of the work is to study the natural regeneration in suburban stands of the Republic of Bashkortostan with the participation in them both European white elm and an invasive species, ash–leaved maple. To carry out the study, an analysis of the characteristics of stands in 23 habitats near Ufa was carried out according to the data of the 1996 forest management tax descriptions. Trial plots were established on each of these sites (in each, on a total area of 0.0605± 0.0222 ha, with changes, depending on the density of undergrowth, from 0.0353 to 0.4320 ha). The main 1-2 canopy levels of stands and undergrowth previously included 14 species, of which broad-leaved forest trees were characterized by a composition formula in decimal units 3,6 (smooth elm) : 2,4 (small-leaved linden) : 1,2 (holly maple) : 0,7 (pedunculate oak) : 0,1 (mountain elm). In the undergrowth of this formation’s main representatives, their composition (2,2 (smooth elm) : 2,1 (holly maple) : 1,5 (small-leaved linden) : 1,0 (ash–leaved maple) changed towards a decrease in the place of aboriginal broad-leaved tree species due to the appearance of invasive ash-leaved maple, the proportion of which reached in the studied areas to 8,8 decimal units. The species has good opportunities to further strengthen its position due to the presence of larger undergrowth with a height of more than 1.5 m (65.6% of the young generation of this plant) in the total sample, second in number to this group only to mountain elm. The undergrowth of the ash–leaved maple is most often found in pure elm forests or stands with the dominance of this species (3.1–8.8 units of composition) and less in mixed stands of other species. Stands with lower density had a more frequent occurrence of the young generation of this species (the Spearman correlation coefficient was statistically significantly negative: R=-0.60, p<0.01). The problems of threats to the species diversity of native broadleaf forests are discussed.