Roof greening is a kind of greening form which is not connected with the ground soil and is based on the building facade space. Flowers and trees are widely planted on roofs, terraces, rooftops or balconies, and green grass is planted to create a garden landscape. Wang Xianmin said that the concept of "roof greening" began in the Babylonian "hanging garden" in the 6th century BC. Since 1950s, Germany, the United States, Canada and other developed countries have tried roof greening projects in urban centers. Since 1970s, domestic cities in China, such as Guangzhou and Peking, have also carried out roof greening experiments. Nowadays, because of its advantages of environmental protection, land saving and beauty, roof greening has been paid more and more attention by cities.
The value of roof greening is not only to add green to the city, but also to reduce the radiant heat of building materials roofs and weaken the urban heat island effect. If it can be well used and popularized to form an urban aerial greening system, it will greatly improve the urban environment.
Roof greening is usually divided into two categories. One is the roof lawn, which is generally uninhabited, with light load, suitable for planting Sedum and perennial ground cover plants, and extensive management. One is the hanging garden, which is a green space for people's leisure and entertainment. There are trees, shrubs, flowers, pavilions, bridges and sports facilities.
The cheapest way of urban greening
Wang Xianmin believes that roof greening has no land cost and is the cheapest greening method in the city at present.
Roof greening can degrade dust, absorb inhalable particles and purify the air; In summer, the roof temperature can be reduced by 20℃-40℃, the indoor temperature can be reduced by 4℃-6℃, the urban heat island effect can be reduced, and the electricity consumption of air conditioning can be saved by 50%; It can also prolong the service life of roofing waterproof materials by 3-5 times.
Roof greening has restored the water and soil circulation, and provided a space for creatures to play, and also provided a space for people to play. At present, the urban ground greening is close to saturation, and the cost of demolition and construction of green space is too high. Therefore, roof greening is worth advocating.
Please take the soil back to the city.
The rapid expansion of cities has destroyed the soil system, water circulation system and animal and plant habitat system. Wang Xianmin called for bringing the soil back to the central area of the city. "If we can better restore the function of water and soil circulation and give birds and small animals living space, we can greatly improve the quality of life of urban people and expand living space. In Beijing, some large institutions, such as the Chinese People's Political Consultative Conference, the Central Organization Department and the State Administration of Radio, Film and Television, have built hanging gardens and rooftop lawns, which have played an exemplary role in the country. "
Wang Xianmin praised Shanghai's practice of "wrapping" garbage stations with flowers and plants, which turned the stinkiest and dirtiest place into "Huaguoshan".
Related links Brief introduction of roof greening abroad
Oakland, California, USA built a beautiful hanging garden on the roof of a six-story building in Kaiser Center in 1959, which was regarded as a wonderful mixture of architecture and greening art. After the success of 1959 in the United States, the roof greening technology became more and more mature, and it is now in the ascendant in developed countries such as Europe and America.
Germany pays special attention to roof greening and is in a leading position in the world in the research of new technologies. 1982, Germany legislates to force roof greening. By the end of 2003, the total area of roof greening was close to 1 100 million square meters. By 2007, the roof greening rate in Germany reached about 80%, which is the best country in the world.
In recent years, Britain has paid more attention to roof greening, especially the increase of biodiversity brought by roof greening. It makes full use of the ecological function of vegetation roofs in its zero-energy buildings, and collects plants from all over the world for screening research.
The Japanese government especially encourages the construction of roof greening buildings. Tokyo is one of the most densely populated cities in the world, and it is quite difficult to improve its vegetation coverage. In May, 200 1 year, Tokyo put forward the "Roof Greening Facilities Allocation Plan" in the revised Urban Green Space Protection Law, stipulating that the area of new buildings should reach 1000 square meters or more, and 20% of the roofs must be covered with green plants, otherwise they will be fined.