Distribution of Acer negundo L. in the Karasye-Ozersky forest park of Yekaterinburg

02028


Introduction
Of the 3.9% of the species of the Earth's flora that have naturalized in regions new to them [1], the greatest threat to the diversity of indigenous communities is associated with transforming plants, which can block the normal course of succession [2][3][4][5][6].It is no coincidence that the ash-leaved maple (Acernegundo L.) was chosen as the object of study, since it is one of the most aggressive tree species in the forest zone of Eurasia [7].Therefore, the study of the processes that occur in the forest park zone of Yekaterinburg when ash maple is introduced into them seems very relevant.
The purpose of the study is to study the distribution and comprehensive assessment of the condition of the ash-leaved maple in the Karasye-Ozersky forest park of Yekaterinburg.

Materials and methods
According to the botanical and geographical zoning of the Sverdlovsk region, the city of Yekaterinburg is located in the southern taiga boreal forest subzone [8], it is surrounded by forest parks and urban forests.The study of Acernegundo was carried out in 2022 in eight habitat fragments (HF) in the Karasye-Ozersk Forest Park in Yekaterinburg.When studying maple, standard methods were used [9][10].

Results
Currently, the undergrowth of forest parks in Yekaterinburg is greatly changed in species composition.The tree stand in the Karasye-Ozersky Forest Park is represented by a natural pine phytocenosis, the age of which is 120-140 years.According to taxation data, the ashleaved maple has invaded 13 of 15 forest parks in Yekaterinburg, and forms a secondary habitat [9].On the territory of the Karasye-Ozersky Forest Park it grows only in mixedgrass pine forests on an area of 34 hectares, mainly with a tree stand density of 0.6-0.7 (Figure 1).The density of individuals in habitats varies from 767 to 1422 individuals per hectare (Table 1).The maximum number of maple individuals was found in a mixed-grass pine forest with a canopy density of 0.5 (FM1).In the Karasye-Ozersky Forest Park, the morphometric parameters of the plant vary in height from 0.63 to 1.01 m, with a projection from 0.11 to 0.43 m² and crown volume of 0.04 to 0.53 m³.The vital state of plants is established from 72 to 93% (Figure 2), while the vitality spectrum in habitats is represented mainly by healthy plants.In maple ontogenesis, two periods have been identified: pregenerative and generative; five ontogenetic states have been identified (Figure 3).The share of the generative fraction consists of young generative individuals (from 3.5 to 6) and mature generative individuals up to 6%.The pregenerative fraction is represented by juvenile plants from 3.5 to 10%, immature plants from 6.5 to 47 and virginal plants from 40 to 87.In six habitats (FTP 1-6) they consist entirely of pregenerative individuals, and with FTP 7.8 the proportion of these individuals decreases slightly, and the proportion of generative individuals increases accordingly.
A left-sided single-vertex spectrum was established in all fragments of the maple coenopopulation.All eight fragments from L.A. Zhivotovsky [9] belong to: young populations (Figure 4) (FTP1-8).In the dominant part of the habitats, the maple has not achieved good regeneration capacity, this is confirmed by the restoration and replacement indices, which are less than 1 and are in the initial stage of colonization, but in two habitats a high invasive potential was revealed, which is confirmed by the restoration and replacement indices, and a high density of fragments.The predominant part habitats are normal, but with an intermittent spectrum, with the exception of FTPs 7 and 8, there are full cenopopulations.
When assessing the condition of the maple in the Karasye-Ozersky Forest Park, an integrated approach was used based on organismal and population indicators (Figure 5).The maximum values of organismal parameters were established in a mixed-grass pine forest (FTP 8) (15 points) and population characteristics in a mixed-grass pine and birch forest (FTP 1.4) (16 points).
It was revealed that the best conditions in the Karasye-Ozersky forest park for the growth of ash-leaved maple are in a mixed-grass pine forest (26 points) (FTP1) with a tree canopy density of 0.5.This is confirmed by the category of vitality and high organismal parameters.It was revealed that the best conditions in the Karasye-Ozersky forest park for the growth of ash-leaved maple are in a mixed-grass pine forest (26 points) (FTP1) with a tree canopy density of 0.5.This is confirmed by the category of vitality and high organismal parameters.

Discussion
According to Vinogradova Yu.K. [2] The ash-leaved maple has formed an extensive secondary range on the territory of Russia; it emerged from cultivation and invaded the native flora.In 1897, A. negundo first appeared in the Urals and successfully naturalized [9], penetrated into the forest park zone of Yekaterinburg [10], which is confirmed by our research.Eight fragments of ash-leaved maple coenopopulations were studied in the Karasye-Ozersky forest park.Possessing high shade tolerance, seed With its productivity and growth rate, Acernegundo forms multi-tiered thickets, displacing and complicating the regeneration of indigenous species in this forest park.This is consistent with other data [2].Despite the wide amplitude of its growth, some patterns of distribution can be identified in the forest park under study:  Ecological nichemixed-grass pine forest with canopy density of 0.5. The strategy of the species during expansion in the Karasye-Ozersky Forest Park has a general tendency -introduction begins from open habitats, gradually penetrating deep into the forest stand, displacing indigenous species.

Conclusion
As a result of studying the distribution of ash-leaved maple in the Karasye-Ozersky Forest Park, similar patterns of distribution of this species in any habitat were established.When studying the biological characteristics of Acer negundo, active penetration into the forest park was revealed.Based on a comprehensive assessment, it was determined that the ecological niche for maple in this forest park is mixed-grass pine forests, which is confirmed by the data from the Lesfond program, despite the wide geographical and ecological-cenotic range of its growth.The obtained population and organismal parameters of maple growth in habitats are of scientific interest, as they allow one to make a forecast regarding the further development of the species, and also contribute to the understanding of the fitness and development of a given species in environmental conditions specific to the region.

Fig. 5 .
Fig. 5. Assessment of the condition of Acernegundo habitat fragments (in points) in the Karasye-Ozersky forest park.

Table 1 .
Characteristics of habitats of A. negundo L. in the Karasye-Ozersky forest park in Yekaterinburg.