What Is Control Banding?

The greening control zone refers to the green vegetation zone built around the city. This concept was first proposed by Howard in "A Rural City of Tomorrow". He designed a circular green belt with a width of 8m or more around the city to limit the urban area and protect the cultivated land.

Green belt

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The greening control zone refers to the green vegetation zone built around the city. This concept was first proposed by Howard in "A Rural City of Tomorrow". He designed a circular green belt with a width of 8m or more around the city to limit the urban area and protect the cultivated land.

The Green Belt Act was passed by the British Parliament in 1938, and a green belt of about 10km in width was constructed around the city of London from 1944. Its main purpose is to control the unrestricted spread of urban built-up areas, evacuate the urban population and industry and improve city environment. The green belt of the city around London has played an important role in guiding the orderly development of the urban pattern formation and built-up area. Since the 1950s, some major cities in the world, such as Paris, Berlin, Moscow, Frankfurt, have planned and constructed urban green belts. Judging from the effects of the green belt around the megacities around the world, the green belt around the city plays a significant role in controlling the urban pattern, improving the urban environment, and improving the quality of life of urban residents.

In the planning and construction of green belts in large foreign cities, they are usually based on the city's own conditions, such as terrain, hydrology, climate, historical and cultural characteristics of the city, and the relationship with surrounding areas and urban development. Functional greening control belt (Table 1). The form and structure of the greening control belt are various. The overall structure can be divided into 6 types, namely the ring-shaped green belt, green wedge, and corridor green belt , Satellite satellite green zone (green zone), buffer green zone (green buffer) and central green space (green heart). (1) Ring-shaped green belt: The green belts are distributed in a circular pattern around the built-up area. The green belts of many cities in the world are planned and constructed with this type of control belt as the basic pattern. Its typical representative is the London Green Belt. The initial purpose of planning and constructing the London Green Belt is to evacuate population and industry, restrict the expansion of the urban area, promote the reconstruction of the city center, and connect London with the surrounding area through green spaces.

(2) Wedge-shaped green belt: green areas such as forests, wetlands, and grasslands are arranged around the city, with the green area surrounding the built-up area as the skeleton, and the industrial areas, residential areas and satellite cities are distributed radially. The greening control zone of Moscow and Berlin is a typical wedge-shaped greening control zone. The industrial area and satellite cities are distributed along the main transportation lines. Large-scale suburban forests and forest parks isolate Moscow and Berlin from their surrounding cities, forming a harmonious The landscape pattern mainly focuses on nature protection, leisure and entertainment, and some scattered residential areas are appropriately arranged and developed.

(3) Satellite green space around the city: Large green areas such as forests or wetlands and grasslands are arranged around the city, but these green areas are separated from each other. The urban green belt of Paris is composed of several typical green areas such as large-area forests.

(4) Buffered greenbelt: Forests and other types of greenbelt are distributed between cities in the urban agglomeration. The greenbelt becomes a buffer zone to isolate the city. The urban green belt of the Ruhr area in Germany is a typical representative of the urban buffer green belt.

(5) Central green space: A large area of green land is located in the city center, and the built-up area is distributed around the central green space, and the built-up area is isolated by a green belt. Randstad, the Dutch metropolitan area, has a typical central green space.

(6) Corridor green belt: The green control belt is distributed in a network pattern. The green control belt around the city and the urban green space are connected through a green corridor to form a complete green space system.

Comprehensive analysis of the structure and distribution of urban greening control zones in the world can be seen that the greening control zones of large cities have the following characteristics: Most of the greening control zones surround the urban built-up area. The main goal is to control the disorderly expansion of the city and ensure the formation of a reasonable urban pattern. . The width of the greening control zone is mostly between 5-15km, and the total length of the greening control zone in large cities is more than 100km. The area of greening control zone is large. Large cities such as Paris, London and Moscow are more than 800km2. The area of greening control zone of medium cities is more than 100km2.

The urban green belt is a public green space planned by the government. Its initial main goal is to control urban expansion, avoid the integration of large urban expansion with surrounding cities, and protect the characteristics of urban and rural landscape patterns. In the 1970s, the environmental protection movement emerged. Protecting and improving the quality of the urban ecological environment became the new main goal of the urban green belt. It emphasized the protection of the natural ecological environment in the process of urbanization, providing healthy leisure and entertainment places for human life. Historical and cultural landscape pattern, especially historical and cultural resources based on natural landscapes.

Ecological function of green belt

The ecological essence of urban development is the process of changing the natural ecosystem into an artificial system. The original ecological structure and ecological process are usually completely changed, and the natural energy flow process and material metabolism process are replaced by artificial processes. The construction of urban green belts is conducive to enhancing the city's natural ecological functions, improving the city's atmospheric and water environments, protecting the surface and groundwater resources, regulating the microclimate, reducing the bare ground around the city, reducing urban sand and dust, and can be a wild animal. Plants provide habitats and habitats to increase urban biodiversity.

(1) Purification of the environment: The urban green belt has a strong ability to absorb CO2, SO2, NOX and dust reduction to remove air pollutants, which plays an important role in improving the urban environment.

(2) Improve microclimate: The urban green belt helps to improve the energy radiation balance of the city, increase the humidity of the local environment, and reduce the urban heat island effect. At the same time, the urban green belt is also an urban shelter belt, which can reduce the impact of wind and sand on the city.

(3) Protection of water resources: The urban green belt plays a positive role in protecting the city's surface water and groundwater resources. For example, it plays an important role in protecting, restoring and managing important water sensitive areas such as rivers, floodplains, groundwater recharge areas and wetlands. In addition, the construction of urban green belts can also improve the purification capacity of water bodies and protect and improve the quality of river systems.

(4) Restoring degraded ecosystems: The suburban transition areas around cities in China are often areas with poor ecological protection, and forests, grasslands, and wetlands are usually severely damaged. The construction of urban green belts can promote the restoration of these degraded ecosystems, reduce bare land, help control urban sand and dust, and enhance urban ecological regulation capabilities.

(5) Providing habitats for wildlife: Urban green belts can protect and provide habitats and habitats for wild flora and fauna, and maintain or increase urban biodiversity to the greatest extent. The green belt is also an important landscape ecological corridor, which has an important impact on urban biological flow, material flow, and energy flow. The green belt can connect the isolated green space of the city, which is conducive to the migration of wild animals from one isolated habitat to another, providing a migration corridor for wild animals. The green belt can also enable animal and plant populations to remain healthy during natural evolution through long-term gene exchange or provide local species with an opportunity to recover after being destroyed.

Functions of green belts to control urban development patterns and development patterns

The original purpose of the urban green belt is to prevent the disorderly expansion of the city and to ensure that the urban structure develops according to a certain planning direction. This is the most direct reason for the planning and construction of green belts in many large cities. The practice of London, Paris, Moscow, and some large cities in Asia also proves that the urban green belt has played an irreplaceable positive role in the orderly development of the city, ensuring the formation of urban forms and urban patterns.

Green control with leisure and entertainment functions

With the process of urbanization, the urban population is expanding day by day, people's living and working pressures increase and their relative free time increases. It is urgent to find leisure and entertainment space to eliminate troubles and relax. The green belt is able to provide people with a place of leisure and entertainment based on natural landscapes. People can carry out recreational activities such as walking, cycling, ice skating, horse riding and so on.

Aesthetic and educational functions of green belts

In addition to leisure and entertainment, the social functions provided by the green belt also have aesthetic and educational functions. Like other types of parks and natural areas, the "urban green belt" can increase the beauty of urban landscapes and provide a place for urban residents to recognize the importance of harmony between humans and nature.