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Urban Greening

The development of greening in urban areas

Green areas of a functional purpose are an organic part of the city as within buildings, and beyond.

Placing green plantations in cities

Accommodation in terms of various categories of plantations is directly dependent on their function: to create conditions for recreation of the urban population, to protect the city from strong winds or to protect residential areas from industrial waste, to improve microclimatic conditions for decorating the city streets, squares and neighborhoods . Plantations of common use within the city should be placed uniformly in some areas, in proportion to population density in each of them, at a distance from home, allowing all people to enjoy them with minimal time to travel to these plantations. These provisions do not apply to areas of public recreation, nature reserves, national parks, botanical gardens and ethnographic park. All these objects are among the plantings in general use, but their placement is determined by natural conditions, existing facilities, transport links with the city and others For the uniform provision of the city stands is not enough to create approximately equal to the square green areas at specific intervals, as different areas of the city are not the same population density, and the area stands to be directly proportional to the number of people in the area. In addition, in some areas of the city are usually concentrated large institutions, industrial enterprises, railway stations, big shops, etc. In this connection, in such areas accumulate large numbers of people, far exceeding the number of permanent residents.

The system of urban greening

The system of green areas of the city - is interlinked, even distribution of urban spaces, defined by the existing system for further development, providing for communications with the country stands. Preserved in the city area of natural landscape, at least in the form of a small inclusion in the urban environment, usually creates a unique identity of the city and sometimes more memorable than the urban ensembles. Modern Theory of Urban Development contains the concept of a system of green areas, which permeates the city, have the primary purpose - improvement of the urban environment.

The role of plants in the environment

Features of urban environmental In urban areas creates a specific and largely unfavorable for human life the eco-logical situation. Air basin city is constantly polluted industrial wastes, exhausts of cars and dust. If you compare the city's air with the air atmosphere of a suburban area, then it contains much less oxygen there is an increased number of bacteria and germs. The degree of air pollution depends on the following environmental factors: wind speed and direction, air temperature and humidity, terrain and character of vegetation. In the major industrial cities in calm weather is often a so-called smog, or fog that contains a high concentration of industrial emissions. Smog often causes serious disease in humans. Solid particles of dust being suspended, and to interact with water vapor, and saturating the atmosphere, are compounds harmful effects on the respiratory organs. Dusty air reduces the illumination of the earth's surface and thus reduces the amount of mineral rights to the ultraviolet rays of the sun. Temperature conditions in urban air and moisture prone stronger fluctuations than in non-urban areas. This often creates uncomfortable conditions for the urban population, especially in hot or cold days. Significant negative factor for human life in an urban setting is the urban noise. Often the level of urban noise is much higher than permissible limits, which adversely affects human health. Lately, the noise level in the large cities increased greatly, and the process of increasing the noise continues.

The role of green spaces in the environment

• The absorption of green plantation of carbon dioxide and oxygen evolution

Green plantations absorb carbon dioxide from the air and air enriched with oxygen. For 1 h, 1 ha of green plants absorb 8 liters of carbon dioxide. 1 ha of forest, into the air oxygen in sufficient quantities to sustain 30 people.

• Green spaces - a factor governing the city reduce the heat

Green plantings significantly affect the air temperature in the city. This is particularly noticeable in hot weather when the air temperature is much lower in green plants than on open ground. This is because the leaves have a higher reflectivity than other types of coatings. Missing a significant portion of radiant energy that leaves of trees and shrubs have a certain transparency. In addition, plants evaporate a lot of moisture, increasing humidity.

• The impact of green space in the formation of winds

Green plantations contribute to the formation of air currents. On hot days, warm air rises up urban areas, and in its place comes a more cold air from areas of greenery. These air currents are most often on the outskirts of the city. In the cool days of air currents do not arise. The penetration depth of air currents in urban development depends on its nature. With a dense perimeter building air currents were rapidly deteriorating and under free - air currents penetrate into the city much farther.

• The impact of green space in humidity

An important factor influencing the thermal regime in the city, is the humidity. The surface of the leaves of trees and shrubs more than 20 times larger than the area occupied by the projection of the crown. Heating plants evaporates into the air a lot of moisture. If we take the relative humidity in the street, at 100%, in the leafy residential quarter of humidity will be 116, on the Boulevard - 205, in the park - 204%.

• Windproof role of green spaces

In the practice of designing green space there is the need to protect urban areas from the adverse winds. In this case, across the main wind flow arrange shelter belts of greenery. The protective role of these strips is determined by their design and layout, as well as the type of building. Wind-proof properties are often green areas have a relatively low altitude and an openwork design. The degree of openwork must be at least 30-40%. The mechanism of action is windproof in that part of the air flow going over the plantations, meets with the airflow passing through the protective strip. Upon meeting the air flow relatively blanked. Planting of greenery dense construction does not justify the windshield functions, as well as contributes to the turbulence of air flow in the area of development.