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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 green spaces 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 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.

Greening of Paris

Paris is the densest city on the continent. Paris has an enormous problem to live up to the European standards of microscopic particles and CO2 content of the air. For the first time a coalition of social democrats and the green party has been formed in 2001. From a changed political approach by the local government, an offensive has been developed to tackle the environmental problems of the city with the whole range of all that can help. On the one hand measures have been taken to reduce individual traffic and increase public transport and to stimulate the use of bikes (meanwhile a famous and very successful bike-approach). On the other hand a broad green-campaign. This started with an animation campaign for citizens to make Paris green - to extend vegetation wherever possible, and it has taken shape in a range of green strategies by the local government which has even led to new tasks and change of structures within the administration.

In 2007 the city started with a spectacular exhibition inside and in front of the city hall. During the summer months the large square in front of the city hall was changed into a temporary garden. The city gave information about all its green initiatives and new gardens and demonstrated the possibilities of how residents themselves can contribute to increasing Paris’ greenery. In the summer of 2008 the garden has been laid out again, even with a lake in front of the city hall, the heart of Paris.

All green activities by and in the community are also broadly described on the website of the department of gardens and parks. There one can read as a leading principle:

“Les Parisiens sont régulièrement encouragés à participer à la végétalisation de la ville par la création de jardins partagés, concours de fleurissement des balcons et fenêtres, cours et conseils de jardinage, un guide pour jardiner bio…“ (the parisians are regularily encouraged to contribute to the greening the city, by the creation of community gardens, balcony and window flower competitions, lessons and advice for gardening, a manual for bio-gardening... ) What is expressed here - and to my mind is really exceptional and exemplary - is that the local authorities think and work from a shared point of view. This vision is propagated to the citizens and is the basis for generating acceptance of the strategies developed in the various fields. In this way all these activities reinforce each other.

A consistent strategy encompassing all urban green activities also has its positive effects within the civil services. Many activities are executed by more than one department in close cooperation, apparently running smoothly. I know of other communities how much opposition green initiatives often experience from other departments. In my interviews in Paris I always received relaxed answers. Here the departments seem to cooperate better than elsewhere. This has all to do with the autorities´ strategy of propagating initiatives unitedly and broadly.

As to the details, there are only a few points in which Paris is exceptionally progressive. The strategy on vertical green is exceptional. This is regarded a cornerstone in the strategy to make Paris greener. Paris is a densely built city. As there is little horizontal space, the idea has been developed to include vertical surfaces in the efforts to green up the city. For this innovative vertical green an extra department was formed. Citizens, proprietors as well tenants, can apply for the greening up of the outer wall of their building.

This request is then checked and, if approved, the plants are supplied and the city takes over the maintenance (!).

In this way remarkable vertical gardens have been created: 92 green walls in the past few years. In this number de ‘murs végétalisés’ outside this program are not included. The most famous are the creations by Patrick Blanc on outer walls of the new museum Quai Branly, a tourist attraction, and at the wall of BHV Homme, Rue de Verrerie. (See also several articles and interviews in BIOTOPE CITY JOURNAL on vertical gardens in Paris.)

The great number of new public gardens – often pocket gardens – and parks laid out in the last few years must also be mentioned. Paris is a very dense city but also a city with a tradition of many parks and public gardens. Meanwhile there are 485 in number, 36 of them made during the last years.

A famous example of a nieuw garden in the center of the city where no space for gardens at all, is the garden on the roof of Gare Montparnasse, a crouwded station which now offers silent green space in a beautifull garden on it's roof .

The strategy to realise so called jardins partagés, community gardens is new. These are gardens in the middle of the dense city, that have been laid out by the local residents themselves in small plots of public space, made available by the local authorities. These are a great success among citizens. Meanwhile they are spread over the whole city and there are long waiting lists. Concerning trees: Paris has 96.000 trees along streets and another 87.000 in small parks and churchyards. That sounds a lot but in comparison with Amsterdam it is not so impressive. Amsterdam, being far smaller, counts 350.000 trees in the streets, not counting those in parks, churchyards en wooded areas. The number of trees in Paris increases with almost 1 % a year. That is an additional 900 trees. They are replaced every sixty years, which means 1,6 % a year. They are replaced by six year old trees. Here the new policy is to introduce a far reaching diversification.

Since 2001 each tree has a chip, fixed in the foot of the tree from which a digital device can read information about it. Detailed information about every tree is digitally stored. (This way of registration is considered outdated in Amsterdam. The chips are encapsulated by the growing trees. After six years they are no longer legible and have to be replaced by boring new holes in the trees. In Amsterdam each tree is recorded in a GPS system without having to mark the tree itself.)

Greening of Moscow

Moscow Greening ECOLOGICAL CONDITION OF MOSCOW AREAS  Green plants take up 30% of the territory, and this, according to scientists, a fairly high level for a multi-million metropolis. Despite this, the current state of green space in Moscow is poor. Green areas and forests of Moscow are heavy influences of technological and human pressures. Near the ferrous and nonferrous metallurgy, machinery and printing in plants accumulate lead, tin, vanadium, cobalt, copper, zinc, etc. As a result of their green weight decreased chlorophyll content. The leaves become yellow and ocher color, covered with patches of reddish-brown or brown.

Areas with the most severely damaged plants in the industrial south-east of the city. The reason for summer leaf fall - high content of carbon monoxide in the air.

Severely damaged, and forests of Moscow. They almost universally is "greening" the trunks and lower branches of trees. Elevated airborne levels of nitrogen oxide contributes to the intense escalation of the bark of trees, small green algae. They get they need plenty of nitrogen nutrition directly from the air. Acid precipitation has led to the disappearance of forests fruticose lichens. In its most weakened state are coniferous forests - pine and spruce. Many trees observed browning and shedding of needles, thinning crowns, and suhovershinnost. Deciduous trees and forests are more resistant to the effects of various contaminants. Damage to the hardwood forests are most clearly seen along major highways and in areas of direct influence of industrial emissions.

Significant adverse impact on the vegetation of forests and parks provide recreational increasing load. Soil compaction in the field of mass festivities impairs its water-air properties and is accompanied by destruction of plants, including trees. In order to protect plants from such influences, in forests and parks should be laid track with a hard surface. They take on the mainstream leisure and thereby to protect vegetation from damage. Green gardens, forests and parks can be preserved and developed only in general favorable environmental conditions. Therefore, all measures aimed at improving the environmental quality of air, water and soil, a favorable effect on vegetation.

In the city there are specific problems of the protection of green space. So, on the streets to combat icing throw a lot of chlorides. Salt has a negative impact on plants. Therefore, to combat salinity held their gypsum. In addition, since the tree leaves accumulate a salt, in the autumn leaves should be collected from saline sites and destroy them. And they need to dump, as the burning of all harmful substances accumulated in the leaves, go into the atmosphere. In saline soils can be planted salt tolerant plant species. Among them is the Balsam Poplar, elm, ash, birch. Today, under the greening of Moscow often have in mind the "green area", rather than gardens, parks or gardens and parks.