With the rapid occupation of land by industrial, commercial and residential land, the regional and even global environmental situation is deteriorating. With the global climate change, resource consumption and other issues, the output of garbage has increased significantly, and the urban heat island effect has become more and more obvious. Therefore, it is urgent to increase urban green quantity and improve urban environment, but overall, horizontal development can no longer meet the demand. Opening up garden green space on buildings is an effective way to increase the area of urban green space, create a new urban landscape and improve the urban environment ... Due to the limitation of roof environment, the choice of roof garden plants has great limitations. In many urban roof gardens, the varieties of green plants are single, the collocation is monotonous and the color changes are not obvious. Plants suitable for roof greening need to have strong characteristics such as drought resistance, heat resistance and waterlogging tolerance. Therefore, it is of great significance to summarize the plant materials suitable for urban roof greening. I. Overview of Roof Garden (Greening) can be widely understood as rebuilding and gardening on impervious structures above the ground, planting flowers and trees, including roofs, aerial platforms and balconies of buildings. The biggest difference between it and open field gardening is that plants are planted on artificial buildings or structures, and planting soil and soil are not connected. 2. Study on the Application of Green Plants in Roof Gardens at Home and Abroad19th century, Germany conducted in-depth research on the selection, management and maintenance of plants in view of the large area of vegetation in buildings. Roof greening is divided into "fine" and "rough" greening forms, and the applicable plant species in different greening forms, especially rough greening, are analyzed. According to different cultivation substrate layers above 4-6cm, 6-10/0-15cm and15 cm, Since then, Spain, Czech Republic, Hungary and other countries have also studied the species and stress resistance of green plants in roof gardens, and selected a number of plant varieties that can adapt to the special environmental conditions of roofs. These varieties can withstand the harsh growth environment, do not need fine maintenance, and their roots will not pose a threat to the roof structure. In Asia, the research on roof greening plants in Japan started earlier. At present, nearly 40 kinds of succulent plants have been applied to roof greening, and a standard system for plant selection in grassland roof garden with drought resistance, cold resistance and shallow tolerance as the main indicators has been basically formed, and the important position of some plants in roof garden has been established. Since the 1960s, China began to study the varieties of roof greening plants, mainly selecting plants that produce fruits and vegetables for roof greening, which developed earlier in several densely populated cities, such as Chongqing, Chengdu, Shanghai and Guangzhou. Later, with the acceleration of urban economic development, in order to beautify the three-dimensional landscape of the city, evergreen plants were mainly used for greening, and grass flowers and vines were dotted. It is also matched with some colorful plants and seasonal plants to reflect the beautiful scenery of the roof garden. Third, the ecological factors in the roof environment, such as temperature, light, wind speed, air composition and other ecological factors on the roof, are significantly different from the ground due to the influence of height. Therefore, plants should be selected and matched according to the ecological environment requirements of the roof, so as to achieve the effect of reasonable planting and beautifying the environment. 3. 1 temperature: the roof is relatively high and the solar radiation is strong. After irradiation, the temperature of roof building materials rises rapidly, while the temperature drops rapidly at night. In summer, the roof temperature difference is large, which is beneficial to plant photosynthesis and organic matter accumulation; In winter, the temperature of roof garden is about 5℃ higher than that of ground soil, and frost does little harm to plant roots. 3.2 Daylighting: Compared with the ground, the roof bears more solar radiation and the intensity of ultraviolet rays is greater, so choose plants that like the sun. In high-rise buildings, the roof of the podium is surrounded by surrounding buildings, and the sunshine time is short all year round. In such areas, all kinds of plants should be planted. 3.3 Humidity: Due to the sunlight on the roof, the temperature is high, the wind is strong, and the water evaporates quickly. Especially in summer, plants grow vigorously and have strong transpiration, so roof plants have higher requirements for water. 3.4 Wind power: The space at the top of the building is relatively empty and there is no shelter from the wind, so the wind power on the roof is stronger than that on the ground. At the same time, some buildings will have a strong airflow effect because of their location. Therefore, when choosing plants, we should choose plant materials with strong wind resistance. In a word, the roof environment of urban buildings is worse than the ground planting environment. Therefore, green plants should be selected according to the specific ecological conditions of different areas and different types of roof gardens. Fourth, the principle of roof greening plant selection The survival and growth of plants mainly depend on the environment in which they grow. Therefore, the choice of roof greening plants must start with the environment on the roof, first consider the basic requirements of plant growth, and then consider the art of plant configuration. 4. 1: select shrubs and herbs with strong drought and cold resistance. Because the roof garden has high temperature in summer, poor soil moisture conservation and low temperature in winter, plants with strong drought resistance and cold resistance should be selected. At the same time, considering the bearing capacity of the roof, shrubs and herbs should be selected for planting management. 4.2. Choose plants that are actively barren-tolerant. Most areas of the roof garden have long direct sunlight time and high light intensity. We should try to choose positive plants, but in some small environments with short sunshine time, we should also choose negative-tolerant plants. The soil layer of the roof garden is shallow, so barren-tolerant plants should be selected, and varieties with shallow roots should be selected to prevent the roof building structure from being eroded. 4.3: Choose wind-resistant and waterlogging-resistant plant varieties. Roof environment, the wind is generally stronger than the ground, the roof planting layer is barren, and the soil water storage capacity is poor. In this case, plants suffer the most. Therefore, we should choose some wind-resistant and water-resistant plants as much as possible. In areas with perennial winds above Grade 6, it is not advisable to choose big trees for roof greening. 4.4. Choose native plants as much as possible, which can be well adapted to the local climate conditions. Therefore, in the roof garden with relatively harsh environment, it is more appropriate to choose native plants that meet the local planting environment than to blindly choose exotic species. In addition, you can also choose some small new varieties with high ornamental value, decorate them more exquisitely and improve the grade of the roof garden.
For more information about project/service/procurement bidding, and to improve the winning rate, please click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd