Today it is impossible to imagine a large city without islands of greenery. Flowerbeds, parks, squares are an integral part of the modern metropolis. Green spaces are, first of all, a natural filter that purifies the air and saturates it with oxygen. Gas pollution is a sore problem in large cities, so more and more measures are being taken to plant trees and greenery and improve park areas and squares. In this article, we will consider the creation, maintenance of green spaces, their role in settlements.
The main purpose of green spaces and their classification
Based on the functions performed by plantations, they are divided into several classes:
- Public use - recreational parks, boulevards, squares and other green areas with open access for residents. Often such places are used for culturalmass events. Various holidays, rallies and other city events are held here. Public green spaces are a decorative element of the city, making it more comfortable and beautiful. In addition, they are also an excellent natural filter that reduces the concentration of impurities in the air.
- Restricted are green spaces that are not available to anyone. These include hospitals, universities, sports and cultural institutions, sanatoriums. In such places, events aimed at medical treatment and sports activities are often held.
- Green spaces for special purposes. These are places located in industrial areas, near roads, nurseries, fields. The maintenance of green spaces of this type is aimed at protecting against fires, cleaning the air from exhaust gases and harmful substances emitted during production.
Types and varieties of plantations directly depend on the role that they will subsequently perform. Thanks to special plantings, the danger of the spread of fires in the fields is significantly reduced, the risk of dust storms and snow storms, the consequences of which can be very destructive, is minimized. In addition, such planting beautifies the roads and becomes an important element of the natural landscape.
Dust reduction
Trees help filter the air from exhaust gases and dust. This is due to the slowdown of the air flow when it enters the green mass encountered on the way. However, its speedsignificantly decreases, and the dust remains in the form of sediment on the bushes and leaves of trees. When it rains, everything is washed to the ground. Thanks to green spaces in the city, the air is purified from 70% of harmful impurities. In addition to shrubs and trees, the lawn also takes part in the process of air purification. It slows down the forward movement of wind-blown dust. Trees help reduce dust even without leaves.
Gas protection
In addition to cleaning the air from dust, urban green spaces reduce the concentration of exhaust gases. Plants absorb them, and aerosol particles with a solid structure settle on the crowns of trees and shrubs. The green array, which gets in the way of the air flow with impurities, breaks it, directing it in different directions. Due to this, polluted air is diluted with clean air and the concentration of harmful substances is significantly reduced. Not all plants are suitable for a gas-protective role. For example, plants with intensive photosynthesis are less resistant to gases and therefore will not last long. Experts call the best species such as: elm, spruce, willow, aspen, poplar, ash maple, acacia, lilac. These trees can be planted near roads and industries where most emissions occur. Birch, mountain ash, Tatar maple and Engelman spruce are perfect for the territory of green spaces for common use.
The key feature of the green massif is its ability to absorb carbon dioxide and release oxygen. Scientists have proven that 1 hectare of green spaces absorbs 8 liters of carbon dioxide in one hour. Deciduous trees with a large crown emit oxygen much more than conifers.
Reducing the amount of gases in the air depends not only on the number of trees, but also on how closely they are planted together. If green planting with dense planting is arranged near sources of emission, this can cause stagnation of air, which entails the concentration of gases. Therefore, it is recommended to place well-ventilated plantings near enterprises and highways.
Planting - protection from the winds
As design practice shows, green spaces are not only a decorative element and an air filter in the city, but also an excellent protector from strong winds. In order to solve the problem of dust and snow storms, strips of green spaces are being arranged across the streams.
The protective function of the green massif is determined by the density and location of plantings. For example, a windbreak with eight rows of trees, whose size does not exceed 17 meters, can reduce the wind speed by up to 70%. If we consider the specific width of forest plantations, then 20-30 meters wide strips are sufficient. Such green spaces can significantly reduce wind speed. Trees are able to reduce it to zero. So, in the depths of the forest, at a distance of 200-250 meters, calm sets in.
Phytoncidal action
The main part of plants is able to secretevolatile, substances that can kill bacteria harmful to the human body and prevent their development. So, for example, phytoncides contained in oak leaves kill pathogens of dysentery. The ability to form phytoncides is most pronounced in poplar, oak, birch and bird cherry. In addition, such substances can produce, but in smaller quantities, about 500 more types.
Influence on wind formation
Green plantings have a positive effect on the appearance of air currents. This is due to the fact that the warm air of the city, under the influence of hot weather, rises. In turn, less warm air from the area where the trees are planted takes its place. Air currents can form only when the temperature difference is at least 5 degrees. In most cases, this occurs on the outskirts of settlements. Streams are formed only in warm weather, in cool weather it is impossible.
Role in noise control
Scientists have proven that trees located between a residential area and noise sources significantly reduce its level. The green array is able to reduce noise up to 10%. At the same time, deciduous trees with a large crown can absorb up to 26% of sound energy, and shrubs planted 40 cm wide can reduce noise to 20-23 decibels. An interesting fact is that the grass on the site also reduces the noise level by 5-7 backgrounds. However, when placing green spaces near noise sources, it is worth considering the location of trees in relation to them,otherwise, you can get the opposite effect. For example, if you plant trees along the axis of a busy street, the plantings will become a screen that reflects sound waves towards the residential area.
The role of plantings on a personal plot
To live and spend time surrounded by beautiful and useful plants is desirable not only for residents of large cities, but also for people living in small towns. In them, green spaces are the basis of the landscape of any yard. When planting, preference is usually given to fruit trees, which will not only decorate the site, but also allow you to enjoy fresh fruits. But besides such trees, breeds with an exceptional decorative look are also in demand. These include: pine, fir, oak, linden. Equipping the territory with these plants, you can give a unique appearance to the site for many years.
