What aspects does road greening include?

The selection of urban road greening plants mainly considers artistic effect and functional effect.

1. tree selection. Trees are mainly used as street trees in street greening, and their functions are mainly to shade pedestrians and beautify street scenes in summer. Therefore, when selecting varieties, we mainly start from the following aspects:

(1) The plants have neat shapes and high ornamental value (or flowers, leaves and fruits are strange, or colorful, or have a long flowering period). It is best that the leaves change color in autumn, and branches can be seen like trees in winter.

(2) strong vitality, few pests and diseases, easy management, low management cost, and no peculiar smell of flowers, fruits and branches;

(3) Trees germinate early and shed leaves late, which is suitable for normal growth in this area. When leaves fall in late autumn, the leaves can fall off in a short time, which is convenient for centralized cleaning; (4) Street trees have neat crowns, high enough branch points, stretched main branches, and an included angle of not less than 30 degrees with the ground, with close leaves and shade; (5) It is easy to propagate, survive and recover after transplantation, and is suitable for transplanting big trees; (6) It has certain anti-pollution and anti-smoke ability; (7) The life span of trees is very long, and the growth rate will not be too slow. At present, cedar, Sophora japonica, Albizia Albizia, Luan tree, weeping willow, steamed bread willow, Eucommia ulmoides and Fraxinus mandshurica are widely used.

2. Selection of shrubs. Shrubs are mostly used in parking lots or sidewalk green belts (green belts between the edge of the roadway and the building red line), which can block the line of sight and reduce noise. Pay attention to the following aspects when choosing:

(1) Full branches and leaves, perfect plant type, long flowering period, and more flowers exposed to prevent excessive sprouting from blocking traffic;

(2) The plant has no thorns or fewer thorns, the leaf color changes, and it is resistant to pruning. In a certain period of time, the shape and height of the tree can be controlled by manual pruning;

(3) Easy to raise, easy to manage and resistant to dust and road radiation. Buxus macrophylla, purple leaf tiller, rose, purple shade, clove, bauhinia, forsythia and so on are widely used.

3. Selection of ground cover plants. At present, most cities mainly choose cool-season turf as ground cover plants, so it is very important to choose suitable turf grass species according to climate, temperature, humidity and soil conditions. In addition, various low flowering shrubs can also be used as ground cover plants, such as Tang Di.

4. Selection of herbaceous flowers. Generally, perennial flowers are the main flowers in the open field, skillfully matched with arbor, shrub and grass, and rationally arranged: annual and biennial herbal flowers are only decorated in key parts, so it is not suitable for multi-use.

Design form of roadside tree planting in road greening

(1) tree belt. In the road section with less traffic and more people, an unpaved planting belt with a width generally not less than 1.5m can be set aside to plant a row of big trees and hedges. If the width is appropriate, you can plant two or more rows of trees and hedges respectively. Sod should be laid under the trees, and people or cars should be parked on the sidewalks.

(2) Tree pool type. Square, rectangular or circular open spaces are designed to plant flowers and trees on sections with heavy traffic, many pedestrians and narrow sidewalks to form pool-type green spaces. The side length of a square is 1.5m, the length and width of a rectangle are 2m and 1.5m respectively, and the diameter of a circular tree pool is not less than 1.5m: the planting point of roadside trees is located in the geometric center, and the pool edge is 8 cm- 10 cm higher than the sidewalk to avoid pedestrian trampling. If the tree pool is slightly lower than the road surface, a pool wall with the same height as the road surface should be added to increase the width of the sidewalk to avoid trampling, and rainwater can penetrate into the pool; The pool wall can be cast iron or reinforced concrete, and the design should be simple and generous.

When planting street trees, we should fully consider the spacing between plants and the fixed stem height. Generally, the plant spacing should be determined according to the crown size, ranging from 4m, 5m, 6m and 8m. If the diameter of the trunk is more than 5cm, the spacing between plants should be 6m to 8m. The green area from the edge of the roadway to the building line is collectively called sidewalk green belt. In order to ensure that people in the car can see pedestrians and buildings on the sidewalk when driving on the roadway, planting trees on the sidewalk green belt must keep a certain distance. Generally speaking, the spacing should not be less than 2 times of the crown.

Plant configuration of urban trunk roads

Urban trunk roads have three functions: realizing traffic, organizing street scenes and improving microclimate, which affect urban landscape space and landscape sight with rich landscape effects, diverse greening forms and changeable seasonal colors. Urban trunk roads are divided into general urban trunk roads, landscape recreation trunk roads, protective trunk roads, expressways, elevated roads and other types. The greening design of all kinds of urban trunk roads should follow ecological principles, arrange plants according to aesthetic characteristics and human behavior recreation principles, and reflect their own characteristics. Plant configuration should have its own characteristics according to different locations.

(1) Plant Configuration of Landscape Recreation Trunk Road

The plant configuration of scenic and recreational trunk roads should give consideration to their ornamental and recreational functions, and design the road for tourists to participate in sightseeing from the perspective of human needs and the naturalness and systematicness of plant communities. There is a green belt with a width of 2 1 m in the middle of Zhaojiabang Road, which is known as "City Avenue". A large number of tall trees such as Cinnamomum camphora, Metasequoia glyptostroboides and Ligustrum lucidum are planted, and various shrubs and flowers are arranged under the forest. At the same time, leisure trails are set up in the green space, dotted with various sculptures and garden sketches, and their ornamental and leisure functions are brought into play.

(2) Plant configuration of protective trunk roads

High-rise buildings on both sides of roads and streets form long and narrow valleys under the urban atmosphere, which is not conducive to the emission of automobile exhaust, directly endangering pedestrians on both sides and residents in the building, and is quite harmful to people. Road greening with isolation and protection as the leading function mainly plays its function of isolating harmful and toxic gases and noise, and takes into account the ornamental function. Plants with anti-pollution, anti-pollution, dust retention and noise absorption, such as cedar, Sabina vulgaris, osmanthus fragrans, coral trees, oleander and so on. In the greening design, the transition from arbor community to small arbor community, shrub community and lawn is adopted to form a three-dimensional layering, which plays a good protective role and landscape effect.

(3) Plant configuration of expressway

Good highway plant configuration can reduce the driver's fatigue, and rich plant landscape also brings passengers a relaxed and pleasant journey. Expressway greening consists of central isolation belt greening, slope greening and interchange greening. Generally, trees are planted in no rows in the central isolation belt to avoid the shadow projected on the driveway from disturbing the driver's sight, and trees with too large crown are not suitable for selection. Large color block pattern green belts with rich visual rhythm can be planted in the isolation belt. There should not be too many plant varieties, too bright colors, too high repetition frequency and too strong sense of rhythm in the green belt. Generally, it can be repeated every 30-70 meters according to the width of the isolation belt, and 3-6 kinds of color block shrubs can be selected, and various flowering or evergreen plants can be planted in the middle to enrich the landscape.

The main purpose of slope greening is to stabilize soil and protect slope and prevent erosion. Plant configuration should try not to destroy the natural terrain and vegetation, and choose tree species with developed roots, easy survival, convenient management and landscape effect.

Interchange greening is located at the intersection of expressway, which is the focus of people's vision. There are two main forms of greening: one is a large-scale pattern, and flowers and shrubs are planted according to different linear patterns to form a simple plant landscape. The other is the landscape mode of nursery. The artificial plant community is planted in the form of arbor, shrub and grass with high density. It not only plays its ecological and landscape functions, but also gives consideration to its economic functions, which provides a strong guarantee for the seedlings needed for urban greening development.

(4) Plant disposition of roads in garden green space

Garden road is the skeleton of the whole garden, which has important functions such as organizing tour routes and connecting landscape areas. Whether in the choice of plant varieties or in the form of collocation (including color, level, size, area ratio, etc.), the configuration of road plants is more diverse, free and vivid than that of urban roads. ).

Garden roads are divided into main roads, secondary roads and paths. The greening of main roads often represents the image and style of green space, and the plant configuration should be attractive to form the momentum and atmosphere consistent with its positioning. For example, large and tall trees such as Platanus acerifolia, Cinnamomum camphora, Du Ying and Zelkova schneideriana are planted at regular intervals on the main road at the entrance, and plastic shrubs such as azaleas, safflower and cypress are planted under them, which is lively and full of rhythm, forming a magnificent main road landscape. The secondary trunk road is the main road of each district in the park, generally 2 ~ 3 meters wide; The path is for tourists to stroll in the quiet rest area, generally only 1 ~ 1.5 meters wide. The secondary roads of green space often have twists and turns, and the plant configuration should be natural. Visually, roads should be sparse and dense, high and low, covered and open. There are lawns, flowers, shrubs, bushes, solitary trees and so on. Visitors can walk along the road across the lawn, take a nap in the forest, or walk through the flowers to enjoy the flowers. Youzhu Path is a common landscaping technique in traditional gardens in China. Bamboo grows rapidly, has strong adaptability, is evergreen all the year round, is delicate and upright, has cultural connotation, and can still be seen in modern green spaces.

Layout form of urban road greening

The layout of urban road greening is also varied, among which section layout is the main way used in planning and design. The commonly used forms of urban road greening are:

(1) One board with two belts. This is the most commonly used form of road greening, that is, planting street trees on the sidewalk separation lines on both sides of the roadway. The method is simple to operate, saves land and is convenient to manage. When the roadway is too wide, the shading effect of street trees is poor, which is not conducive to traffic management when motor vehicles and non-motor vehicles are mixed.

(2) Two boards and three belts. The middle of the two lanes separated by one-way driving is afforested, and street trees are arranged on both sides of the road. This form is suitable for wide roads, with a large number of green belts and remarkable ecological benefits, and is mostly used for greening highways and sidewalks.

(3) Three boards and four belts. The lane is divided into three parts by two independent lanes, with a motor vehicle lane in the middle and non-motor vehicle lanes on both sides. Together with the street trees on both sides of the driveway, there are four green belts. Although this way covers a large area, it has a large amount of greening, good shading effect in summer, convenient traffic organization, safety and reliability, and solves the contradiction of mixed interference of various vehicles.

(4) Four boards and five belts. The lane is divided into four lanes by three isolation belts and planned as five green belts, so that the up and down of various vehicles do not interfere with each other, which is conducive to speed limit and traffic safety; If the road area is not suitable for the fifth district, it can be separated by railings to save land.

(5) Other forms. According to the geographical location and environmental conditions of the road, green belts are set up according to local conditions, such as the greening design of hillsides and waterways.

As the main part of the city, road greening plays an increasingly prominent role in the construction of modern cities, which is also directly related to the spiritual connotation of a city. Therefore, urban road greening should be regarded as a key issue in urban construction. I believe that as long as we can make more efforts on this issue, the urban road construction in China will be brand-new, the urban landscape will be developed and the urban connotation will be enhanced.