As an important means of urban greening, what are its main forms?

Ground greening is to use all the green spaces in the city to plant trees, plants flowers and plants, and cover and dress the bare ground. The ground greening should make scientific use of tall trees with good ecological functions, form an approximate natural forest with trees, shrubs, vines and grass as the main body, make full use of woodlands with different heights, and improve the filling quality of woodlands.

1. 1 urban road greening

In urban road greening, it is necessary to build a boulevard and combine green trees with belt-shaped green belts. Greening trees should be dominated by trees, with flowers and shrubs in the middle, forming a staggered tree community. Introduce tall trees, such as paulownia, fast-growing poplar, ginkgo, Pistacia chinensis, melia azedarach and cedar. Tall trees should be pruned less, and the height under the branches of trees should be increased by pruning to form a huge umbrella crown. This can alleviate the air quality problems caused by poor air, avoid the obstruction of business premises caused by low crown, and play the role of shading and cooling. At the same time, in the selection of tree species, we should pay attention to the collocation of fast-growing tree species and long-lived tree species, and use fast-growing tree species to occupy space quickly and maintain the sustainable effect of tall buildings.

1.2 public green spaces such as city parks, squares and street parks.

For urban parks, squares, street parks and other public green spaces, the proportion of lawns should be reduced and the proportion of trees and shrubs should be increased. With natural ecological configuration, scientifically collocate arbor, shrub and flower, trim arbor and shrub neatly, form a loose multi-layer structure of arbor, shrub and grass and a multi-functional plant community, promote the mutual prosperity of plants and animals, animals and microorganisms, ensure the smoothness of "insect path" and "bird path", and create a four-season landscape of "spring flowers, summer shade, autumn fruits and holly".

1.3 residential area and unit courtyard greening

Residential areas and units in courtyard greening should adhere to the principle of "people-oriented, one residence and one scene". For modern residential quarters, the most important thing is to produce more green on limited land, create a quiet and leisure environment, and meet the ecological requirements of greening in residential quarters. Plant community is the foundation of green space environment, and plant landscape is the main component of green. Therefore, the green space should be patchwork, mainly with tall trees with dense crowns and shady trees, and give full play to its functions of shading, cooling, humidifying, dust retention and noise reduction, and then be separated by flowers, shrubs and hedges to form different leisure spaces. According to the seasonal changes, considering the collocation of tree species, evergreen plants and deciduous plants, trees and shrubs, woody plants and herbs, flowering plants and foliage plants are combined to form a plant landscape with flowers in three seasons and evergreen in all seasons.

As an integral part of urban greening and environmental construction, unit courtyard greening plays a vital role in improving urban ecology and beautifying urban environment. Combined with the standard-reaching activities in courtyard greening, a "garden-style unit" was established. Clear the principle of "inserting green in every seam, tearing down the wall to penetrate green, seeking beauty in green", and greatly increase the green area. Give priority to planting trees, so that conifers and broad-leaved trees, trees and shrubs can be reasonably matched and planted scientifically, so as to maximize the ecological benefits of unit green space. Street-facing units should plant at least 1-2 rows of trees on the street-facing side of the courtyard to form a continuous green belt and form a landscape effect with lush plant growth, rich layers and stable structure.

1.4 stereoscopic flower bed

In open squares, parks, amusement parks, streets and other places, all kinds of three-dimensional flower beds are built as central attractions to display the rich colors of flowers and form a strong visual impact. Generally, three-dimensional flower beds belong to the high-grade, high-cost and most flexible and rich types in three-dimensional greening. In most cases, it is necessary to design a skeleton as a carrier for placing flowerpots and planting flowers. Herbaceous flowers, five-colored grass, flowering shrubs, vines and other plants are densely planted or placed on installed frames to complete specific landscape shaping. The three-dimensional flower bed makes full use of the landscaping function of plant flowers and leaves, and can be made into animal and plant modeling or abstract sculpture flower bed through careful design and collocation. The common forms are styles, flower stands, flower balls, various geometric shapes and distinctive styles. The plant materials used are mainly Petunia, colorful grass, chrysanthemum, asparagus and so on. By building three-dimensional flower beds with different shapes, a beautiful scenery can be added to the city.

2. Greening of building walls, fences, fences, columns and flower racks.

2. 1 wall greening

Build flower beds under the walls of buildings, plant climbing plants, and choose plants with climbing roots, such as Parthenocissus tricuspidata, Parthenocissus quinquefolia, ivy, wisteria, etc. , covering the whole wall, forming a large area of green curtain. Ling Wei Xiyang, with poor cold tolerance, can be planted under the sunny south wall; Sidestone likes shade and has strong cold resistance, which is suitable for planting under the north wall of the house; Parthenocissus tricuspidata grows fast and has many branches, which is most suitable for planting under the Western Wall. You can also choose wisteria, grape, rose, radix aucklandiae, honeysuckle, iris, morning glory, pumpkin, loofah, pumpkin, etc. It is reported that the vertical greening wall can reduce the temperature by 2 ~ 7℃, especially the cooling effect is more obvious after the western greening wall is covered, which has played an ideal energy-saving effect. Moreover, after the wall is covered with greening, the air humidity 10% ~ 20% can be increased, which is of great benefit to people to eliminate fatigue and increase comfort in hot summer.

2.2 fence, fence greening

Combined with the removal of the fence along the street, the fence and fence can be decorated with vines, honeysuckle, morning glory, vines, Berberis, thorn plums, boxwood, pearl plums, hibiscus flowers, medlar and so on.

2.3 scaffolding greening

Parks and leisure squares generally have scaffolding greening, which is the most widely used vine landscaping method in urban three-dimensional greening. Scaffolding greening can form a variety of landscapes, and commonly used vines generally include wisteria, lingxiao, rose, gourd, loofah, grapes and so on. These plants are flourishing, which can form a flowery and fruitful plant landscape, not only enjoying flowers and fruits, but also providing a place for leisure and entertainment.

2.4 overpass bridge, bridge column greening

Building flower beds or hanging baskets on both sides of the overpass and planting drought-resistant climbing plants such as ivy, Parthenocissus tricuspidata and Euonymus fortunei can vacuum, reduce noise, cool down and increase the green area.

2.5 Street lamp post greening

Planting morning glory under the street lamp can form a green style and give people a pleasing feeling. You can also hang a flowerpot in the middle of the lamppost, and plant drought-tolerant grass flowers in the flowerpot, such as sunflower and petunia, just like a flower gallery in the air.

2.6 Slope protection greening

Slope protection greening is an effective way to protect exposed slopes. Parthenocissus tricuspidata, Lingxiao, Euonymus fortunei, Euphorbia humifusa and Lonicera japonica should be selected for slope protection greening. Planting these plants can not only cover hillsides and beautify the environment, but also reduce rain erosion and prevent soil erosion and landslides.

3 windowsill and balcony greening

Planting vines, flowers and bonsai on balconies and windowsills not only makes the facade of residential buildings decorated with green, but also decorates doors and windows like green curtains and vases, allowing beautiful and harmonious nature to penetrate indoors and increase the aesthetic feeling of living environment. The greening of windowsill balcony should choose plants with lush foliage and beautiful flowers, so that the color and texture of flowers and windows can be contrasted and complement each other. There are many flowers and plants suitable for potted plants on the windowsill, as well as some drought-tolerant grass flowers, such as sunflower, geranium, Petunia, begonia, Bidens bipinnata and so on. , can be the first choice for windowsill gardens; Geranium and Petunia are also common balcony flowers and plants; Some short shrubs, such as miniature roses and upside-down golden bells, can also be planted in flowerpots in front of the window. Ivy and American Parthenocissus are also suitable for windowsill planting. In addition, you can also grow mint and lettuce.

4 roof greening

Roof greening, also known as "hanging garden" and "roof garden", is to selectively plant flowers, trees and grass on the roof to create a garden landscape. Roof greening can increase the area of urban green space, improve the appearance of urban environment, reduce the indoor temperature, effectively alleviate the suffering and pain brought by the heat island effect to the city, effectively restrain the floating dust on the roof, and add a touch of coolness to the impetuous city. Roof greening can be made into a small garden, which is mainly composed of low shrubs, lawns, ground cover plants and climbing plants. In principle, there is no need for big trees, and a small number of drought-tolerant small trees can be planted when conditions permit. Joe, shrub and grass are skillfully matched to create a rich and intimate rooftop plant landscape that integrates landscape and ecology. Also pay attention to choose plants with developed fibrous roots, rather than plants with strong root penetration, to prevent plant roots from penetrating the waterproof layer of buildings; Choose plants that are easy to transplant, resistant to pruning, resistant to extensive management and slow to grow; Choose plants that are resistant to wind, drought and high temperature; Choose plants with strong ability to resist pollution, tolerate, absorb and retain harmful gases or pollutants. In order to meet the needs of plant root growth, the planting soil should be 30 ~ 40 cm thick, and the planting layer is generally made of vermiculite, perlite, peat, humus, peat soil and sand. Leaf-watching plants suitable for roof greening in northern China include purple-leaf plum, purple-leaf dwarf cherry, red-leaf Berberis, golden-leaf Ligustrum lucidum and so on. Flower-watching plants, such as magnolia, pearl plum, yellow thorn rose, canna, etc. Fruit viewing plants, such as hawthorn, begonia, grapes, etc. ; Lianas, ground cover plants such as honeysuckle, Euphorbia pentaphylla, Euonymus microphylla, etc. Sedum sarmentosum is the main grass for roof greening, and the lawn will not be yellow all year round, and no additional protective measures are needed in winter.