Domestic and world experience of assessment of urban green areas and search for ways to optimize the quality of the urban environment was analyzed.
It was characterized the natural and climatic conditions of the research area, the anthropogenic impact on the dendroflora is analyzed, the city 's vulnerability to climate change is assessed. It was found that the greenery in Rivne cover an area of 414.2 hectares, including 329.4 hectares of public use. It is established that the residents of the western and northern districts of the city are the least provided with recreational areas. It is determined that in the studied area of the city grows 177 species of trees and shrubs belonging to 82 genera, 38 families, 31 orders, 4 classes, 3 divisions: Magnoliophyta, Pinophyta and Ginkgophyta, of which 28.8% of species belong to the natural flora, 65.0% are introducers and 6.2% are species of hybrid origin. It was found that 85.9% of dendroflora belongs to the division Magnoliophyta and 14.1% – Pinophyta, 0.002% – Ginkgophyta, Division Magnoliophyta has 37544 individuals from 34 families, 70 genera, 139 species, the most common is the family Rosaceae. The Pinophyta division is represented by 6167 individuals from 11 genera, 3 families, 37 species, among which Taxus baccata and Larix polonica are listed in the Red Book of Ukraine, the Ginkgophyta division is represented by a relict species of Ginkgo biloba.
Analysis of the ecological structure of the dendroflora showed that mesophytes and mesoxerophytes predominate in terms of moisture requirements due to the lack of optimal moisture conditions. The range of the studied dendroflora in general corresponds to the lighting conditions with the predominance of light-loving and shade-tolerant plants. The predominance of megatrophs and oligotrophs indicates about different edaphic confinement of the dendroflora.
It has been found that the main factors of anthropogenic impact on green areas are emissions of pollutants into the atmosphere, inefficient economic activities, untimely care of affected trees and shrubs, which weaken plant growth, reduce their resistance to pests and contribute to infectious diseases. Most of the main species of shrubs (74.6%) are in satisfactory condition, 15.0% – in good and 10.4% – in unsatisfactory. As a result of climate change in the city, the facts of re-blooming of Sorbus aucuparia, Aesculus hippocastanum, Swida alba and Swida sanguinea, Catalpa bignonioides have been recorded. The mass damage of Aesculus hippocastanum by the pest Cameraria ohridella is threatening for the city. Defeat of deciduous species by the semi-parasite Viscum album is characteristic of 1323 trees and is 5.9%.
It is established that sanitizing functions are inherent in 42 species of trees and shrubs with dust-resistant, 71 species with phytoncide properties and 41 gas-resistant species. The main dust load is on Tilia cordata, Betula pendula, Salix alba and Syringa vulgaris. High and medium bactericidal properties are characteristic of 57 species of deciduous and coniferous species. It is established that the maximum values of ecological indicators are determined in the western district of the city at the lowest degree of its landscaping, and in the central district – low values at the highest degree of landscaping.
The set of action of the parameters of the studied phytocenoses is reflected by the coefficient of phytomeliorative efficiency, which varies from 2.5 to 8.7 for parks and 0.6 – 10.9 for public gardens (mini parks). The phytocenoses of the studied areas were characterized by five levels of efficiency from "very low" to "very high" within the I – V classes with a high level of efficiency in the central and northern districts of the city. Established the average correlation between the area of phytocenotic coverage and the coefficient of phytomeliorative efficiency at R = 0.4067. Scales for assessing the phytomeliorative and environment-forming efficiency of green plantations have been developed and tested and evaluated. It is established that the environment-forming efficiency of greenery of common use in Rivne is characterized by a low and sufficient level of efficiency within the second and third classes. A set of conservation, restoration and reconstruction measures directed at optimizing, preserving of public greenery and increasing their environment-forming efficiency is proposed.
