The paper presents the results of the geographical analysis of the dendroflora of Cheboksary. The landscaping system of Cheboksary is represented mainly by woody vegetation, which grows in public areas, in limited-use plantings, as well as along the streets and main highways of Cheboksary. Woody vegetation is represented by 73 species, which, according to the generally accepted systematics of plants, belong to 43 genera and 20 families. The geographical analysis of the dendroflora of Cheboksary is based on archaeological data from various reports. In the dendroflora of Cheboksary, 7 groups of the area have been identified, depending on their natural distribution: 1) aboriginal group, 2) cultural group, 3) hybrid group, 4) North American group, 5) East Asian group, 6) Mediterranean group, 7) European group. The dendroflora of Cheboksary is dominated by introducents, which account for 44 species. The most numerous of the introducers is the East Asian group, which makes up 41% of the total, the North American and European groups 25% each, the Mediterranean group 9%. The geographical composition of the dendroflora, depending on the element of the system of green spaces, showed that the largest number of introducers were identified in public plantings, which were represented by 40 species of trees and shrubs, in limiteduse plantings 29 species, along streets and main roads 28 species. The analysis of the dendroflora by the ratio of hygromorphs has revealed that mesophytes predominate in the dendroflora of Cheboksary 54,7%, xerophytes 17,8%, mesoxerophytes 12,3%.

The paper presents the results of research to assess the quality of the urban environment in the areas we have identified by the functional and economic significance of Cheboksary using a method of fluctuating asymmetry of Betula pendula Roth leaves and a scale of gas resistance of tree and shrub plants. The studies have showed that the integral indices of fluctuating asymmetry of Betula pendula leaf plates of all surveyed green planting objects vary from 0,038 to 0,054. The highest levels of asymmetry were found in the eastern and southern parts of the city, where the values of leaf asymmetry fluctuations range from 0,050 to 0,054. Based on an assessment of the quality of the urban environment the authors have developed recommendations to improve and expand the range of resistant woody plants to anthropogenic stress of Cheboksary. Depending on the nature of the urban environment and the degree of woody plants resistance to anthropogenic pollution, we offer a range of woody and shrub plants for landscaping, it contains 73 species. The recommended range of trees and shrubs for landscaping in the Central zone of Cheboksary is 68 species (asymmetry coefficient 0,040 to 0,044), in the Coastal and Suburban areas 62 species (asymmetry coefficient 0,046 to 0,049), in the Industrial zone 29 species (asymmetry coefficient 0,050 to 0,053).

The paper presents the results of a comprehensive analysis of the species composition of Cheboksary. The analysis of the dendroflora of the urban environment was carried out according to 3 indicators: the territory of woody plants, the occurrence of woody plant species in landscaping, the structure of the landscaping system. The arboreal vegetation of Cheboksary is represented by 73 species belonging to 43 genera and 20 families. The predominant part of the dendroflora is represented by the covered-seeded plants (86,3%), the gymnosperms - 13,7%. In the dendroflora of green areas of the city, the most widely represented families are Rosaceae, Pinaceae, Salicaceae (48%). The analysis of the species composition of woody plants showed that in the functional and economic zones of Cheboksary plantings of general use are represented by 65 species, plantings of limited use - 52 species, plantings along the streets and main roads - 50 species. The analysis of the species composition of woody plants depending on the share of their participation in landscaping revealed that the greatest number of woody plants is used with low (51 species) and medium (50 species) share. The analysis of the degree of participation of woody plants in landscaping in the four identified functional and economic zones of Cheboksary found that the greatest number of taxa prevail with an average participation in the central zone (37 species), the coastal and suburban zones (36 species). The largest number of species of woody plants grow in the green areas of the central functional and economic zone, where the landscaping involved 66 species, the smallest number grow in the green areas of the industrial area (36 species).