Features of the meteorological regime species composition and renewaltrees on the slopes in the urban environment

Abstract

It is known that tree plantations can have a significant effect on a number of meteorological parameters. The most significant manifestations of this effect are reduced insolation, stabilization of temperature and humidity. Plant transformation of these and other meteorological factors was called phytoclimate. The object of the study of phytoclimate was, as a rule, large vegetative communities, influencing both the local microclimatic conditions and the regional climate In the conditions of large cities, the importance of such an effect of plants on the environment increases many times. Large, devoid of vegetation of space, a considerable area of asphalt and concrete cover, walls and roofs of houses lead to a significant violation of the natural temperature and humidity balance, which, as a consequence, negatively affects the comfort of the microclimate of the urban environment. In the conditions of Kiev, which, unfortunately, loses the former glory of one of the greenest cities, the plantations of the slopes of the least developed territory of the urban landscape are becoming increasingly important in the formation of the urban microclimate.

The purpose of our research is to study the local features of a number of meteorological parameters within the plantations of the slopes of Kiev, to establish their species composition and natural renewal.

        The obtained data testify to the essential features of the meteorological regime of plantations on the slopes (see Table 1). Thus, the level of illumination on all test areas was lower and varied significantly within the range from 2.8 to 32.6% of the control. The most shady were the test areas of the Siretsky and Mariinsky parks, the tract "Kirillovsky grove", located on the eastern and northern slopes. Here the level of illumination was mainly in the range of 3.5 to 9.2%.

The illumination of slopes of predominantly southern orientation was higher and averaged 12.8-21.5%, reaching 24.4 - 32.6% of the total value in rarefied plantations. Plants of these slopes are characterized by relatively rich species composition, complex spatial structure and a good resumption of predominantly of seed origin both in relatively open areas and under the canopy. In general, the light regime depended most strongly on the coherence and leveling of the planting, its composition, and the orientation of the slope.

The temperature regime of the surface layer of air was also lower than the control values, but in general was characterized by greater stability. Thus, the lowest temperatures are noted in the lower parts of the northern and northeastern slopes of Syritsky Park and the Askold's Grave tract, where the deviation from the control was 11.9-12.7 ° C (trial area 7, 8 and 24).

        The upper and middle well-lit sections of the slopes were the hottest ones, where the temperature of the air relative to the control values decreased by 2.4 - 3.4 ° C (test areas 6 and 32). In general, the temperature background depended more on the location of the test area on the slope and its orientation, less on the nature of the vegetation.

         The relative humidity of air on all test areas significantly exceeded the control values and varied within wide limits. The most "dry" were, as a rule, the upper parts of slopes predominantly southern orientation. Minimum deviations from control (4.0 - 18.8%) were recorded on the southern slopes of the tract "Kirillovsky grove".

            It was established that the humidity of the air was largely determined by the spatial structure of the planting (closeness and tieredness), and also depended on the location on the slope and its orientation. Exit to the surface of groundwater, the presence of streams and reservoirs significantly increased the humidity of air. In addition, this factor significantly correlated with the temperature background, to a lesser extent with the illumination.

The woody vegetation of the slopes is represented mainly by natural and mixed plantings of seminal and porous origin. Analysis of the taxonomic structure showed that these plantations are mostly formed by native species of tree plants (except parks, where the proportion of introducts is significantly higher).

Our studies have shown that the meteorological behavior of the surface horizon significantly affects the natural renewal of plantations. Most successfully this renewal is observed with sufficient illumination and humidity, which is characteristic of the upper northern horizons or the bases of the eastern slopes. Qualitative teenage growth is formed at illumination of 20 - 30% of the full value. Such conditions are characteristic for plantations of low closeness or open areas of multi-tier stands (test areas 2-4, 9 and 18).

For a reliable renewal of the plantations of most of the examined slopes, sanitary felling, clearing cuttings on re-condensed areas, cleaning of manure and dry land are required. In order to reduce trampling and excessive local recreational load, it is necessary to equip the rest areas and optimize the road-tropical net.

The conducted studies allowed to establish a number of features of the meteorological regime of the surface layer in plantations on the slopes of Kiev. This mode is characterized by a significant decrease in the illumination and temperature of the air, increasing its relative humidity, which is most characteristic of the northern slopes. This regime is conditioned by orographic and hydrological factors, as well as taxonomic and spatial features of the plantings.

Dendroflora of investigated territories is represented mainly by aboriginal deciduous plants. Natural renewal of plantations is marked only with sufficient lighting and humidity. Actual forestry activities are continuing to promote natural regeneration of plantations, improve sanitary conditions and expand the species diversity of plantations, taking into account local environmental conditions.