Preliminary Exploration on Design of Green Landscape of Urban Streets: A Case Study of Guangchang East Road in Xihu District of Nanchang City

Yiqian YANG

Jiangxi Normal University, Nanchang 330022, China

Abstract Urban streets are the main public places for outdoor activities in urban areas. Urban street landscape is the core content of urban landscape, and urban street greening is an essential part of urban landscape streets. With the rapid development of cities, humans have higher and higher requirements for surrounding environment. To this end, this paper makes a preliminary exploration on the green landscape of urban streets. Based on the analysis of the basic concepts and components of green landscape of urban streets, this paper puts forward the role of green landscape of urban streets: practical function, landscape creation function and environment optimization function. Taking the Guangchang East Road in Xihu District of Nanchang City as an example, through field survey, observation and data collection, it found that the main problems of Guangchang East Road, and came up with the recommendations that the design of the greening landscape of Guangchang East Road in the planting and color block matching. It is expected to provide references for the planning and design of urban street greening landscape in the future.

Key words Street greening, Landscape design, Plant configuration

1 Introduction

As an important part of the city, urban streets can not only promote people’s communication, but also continue the urban context and promote the social and economic development. With the improvement of people’s living standards and the expansion of urban areas, people’s time consumption on urban streets is higher than in the past, and people become increasingly aware of the importance of urban street greening. People are eager to live in a good environment, starting from the simple traffic requirements of the past to increase the need to optimize the environment and improve the ecology. Excellent urban street greening can not only purify the air, but also isolate the noise. It can also make people feel at ease, improve the social atmosphere, and make people’s public social activities continue to be enriched, and increase people’s social activities such as recreation, walking and communication on urban streets.

2 Basic concepts and components of urban street greening landscape

2.1 Basic concepts of urban street greening landscapeIn theDesignofUrbanStreetLandscape, urban street landscape suitable for outdoor activities such as external courtyards, gardens, green spaces, and squares are landscapes belonging to street areas outside the indoor landscape space surrounded by a group of physical buildings[1]. According to the literature we collected, different scholars have different understandings of the concept of urban street greening landscape. For example, Lu Zhenghua believed that the urban street greening landscape is the visual landscape composed of trees, flowers, shrubs and other plants within the urban street green area and the seats, flower beds and fountains that have the function of leisure and recreation within the green space[2]. In the opinion of Yang Shuqiu, the street greening and beautification refers to the use of garden plants to decorate different types of streets through different layouts and planting methods[3]. As stated by Xu Chongyong, through the scientific, reasonable and artistic design, plants can be planted on streets of different natures and categories in order to achieve the purpose of assisting transportation, optimizing the environment, creating space suitable for people’s activities, so as to bring into full play the comprehensive function of the roads[4].

In summary, we believed that the basic concept of urban street greening landscape is the rational layout and planting of garden plant materials on different types of streets, and the green landscape is organized in a skillful and harmonious manner into urban streets to create suitable outdoor space for people.

2.2 Structural components of urban street greening landscape

2.2.1Vegetation greening. The green landscape is an essential part of the urban street greening landscape. Green plants can reduce noise, regulate air temperature, purify the air, and protect the ecological environment. They play an important role in the circulation of urban biological flow, material flow and energy flow[5]. Scientific and appropriate design for road greening can enhance the ornamental value and continuity of the road landscape, and can cover or decorate the unsatisfactory landscape in urban areas. Choosing appropriate tree species can fully reflect the regional characteristics and also manifest the urban scenery of different regions.

2.2.2Road space structure. The road space structure refers to the main body structure of the road, including the type of urban road, the linear design of the road and the road surface. These form the elements of the road space and are also factors to be considered in creating a scientific, reasonable and comfortable urban road space suitable for human beings. The main landscape of the street greening landscape is laid on the sidewalk, which is the passage of pedestrians and is closely related to people’s behavior. The most basic requirement for paving on the sidewalk is to provide a comfortable and safe road surface, which should be non-slip in wet weather and easy to drain, and should be safe in harsh weather conditions, and also should have appropriate color, dimension, and texture[6].

2.2.3Buildings along the street. The main part of the boundary of urban road space is building, and the shape of the building is a very important factor in forming the characteristics of the urban landscape. Building is the most important artificial factor in road landscape design. It not only plays the role of surrounding the vertical interface of road space, but also the main part of road space boundary[7]. Different natural geographical conditions, different building materials and technologies, and different architectural views of people bring about colorful architectural forms, which also form different urban styles[8].

3 Functions of urban street greening landscape

The planning and design of urban street greening should be based on the precondition of ensuring road safety, giving play to the functional effects of greening landscape and creating beautiful street landscape. The urban street greening has three main functions: practical functions, creating landscape and optimizing environment[9].

3.1 Practical functionsOrganizing traffic and shading are the most important practical functions of street greening. Using different planting methods, roads can be diverted to create a safe and orderly traffic environment; tall trees, especially street trees, can effectively cool pedestrians during the summer; some street greening also has space and facilities for leisure and recreation, then they become a leisure place for pedestrians.

3.2 Creating landscapeStreet greening is an important part of the street landscape. In the street landscape, plants are the most special and vivid elements. The natural beauty of plants makes the city closer to nature. The changes in plant growth make people in the city experience time and seasonal changes, accordingly making the street landscape more natural and active. Generally, both sides of the street lack a good natural environment, but are mainly buildings and artificial facilities, making the street landscape lack of affinity and difficult to coordinate. Among all kinds of street landscape elements, green plants are the most ideal soft landscape materials[10]. Through the color, texture and shape of plants, a unified tone can be formed, so that all kinds of hard landscape can be coordinated, and soft and hard landscapes from contrast, so as to achieve a rich and harmonious landscape effect.

3.3 Optimizing environmentThe ecological environment of urban streets is more harsh than other urban areas, while greening is the most effective way to improve the ecological environment of the streets. The main benefits of street greening in improving urban ecological environment include absorbing dust, cooling, increasing and reducing temperature, absorbing harmful gases, reducing noise, fire prevention, wind protection, and maintaining water and soil[11].

4 Analysis on current situation of greening landscape for Guangchang East Road in Xihu District of Nanchang City

4.1 General situation of Guangchang East RoadIn this study, we selected Guangchang East Road in Xihu District of Nanchang City to analyze. As shown in Fig.1a and Fig.1b, Guangchang East Road is a one-way eastbound street. It is on the east side of the landmark building Bayi Square. It connects to the Guangchang South Road and Dinggong Road. It is adjacent to Yingshi Square and only 500 m from Dinggong Road Subway Station. In the end of the Guangcheng East Road, it is Yingshi Square and Bayi Square, and the inside is residential area and one building is being relocated.

For the field survey and research on the greening landscape of the Guangchang East Road, the main observations are the three types of street planting forms, plant selection and color, and green plant height. Street trees can be planted in many ways. Common methods include belt planting and pool planting[12]. For belt planting, a planting belt is provided between the sidewalk and the driveway in the roads with low traffic flow. For pool planting, pool shape green space is provided through planting flowers, grasses and trees in square, rectangular, and circular form in narrow roads with high traffic flow. Guangchang East Road is a life-type street. Through the field survey, it is found that the main road traffic of Guangchang East Road is only 468 person/time, and the traffic volume is 1 955 vehicles/time, so it belongs to the roads with small traffic flow. In both sides of the road, a row ofCinnamomumcamphoraare planted, belong to belt type planting method.

The selection of street greening requires understanding the local natural conditions, physical and chemical analysis of soil conditions, and firstly considering local backbone tree species. At the same time, it is necessary to consider the laying of pipelines in underground space, planting plants with small and shallow roots, keeping the scale of trees and space suitable, ensuring the safety of engineering pipelines, adapting to people’s psychology of seasonal and temperature changes in color selection; in summer, it is hot, so the color should be cold; in winter, it is cold, so the color should be warm, but should be green first[13]. The green landscape of Guangchang East Road has only two rows ofC.camphoraas street trees. Although theC.camphorabelong to evergreen trees, there is only one kind of green landscape on one street. The color of the species is single. The green landscape of the whole street is not rich enough, the level is monotonous, and its greening plant height is 9-12 m. The north sidewalk is narrow and the greening plants are too high to block the indoor lighting of the street residents. The street trees on both sides are intertwined and connected on the roadway. Pollutants such as automobile exhaust gas do not diverge well, which poses a certain harm to the health of pedestrians. Besides, they are intertwined with wires. Once the lightning occurs, there will be certain safety risks for people and cars coming and going.

Fig.1 Location (a) and surrounding area (b) of the Guangchang East Road

4.2 Main problems of the Guangchang East RoadThe street trees and electric wires are intertwined, posing potential safety hazards; plants block the indoor sensitivities of residents and affect the life of street residents; the color selection of street greening plants is monotonous, the level is monotonous, the visual landscape is not good; the street greening is not properly maintained in the later period.

5 Design requirements and recommendations for greening landscape for Guangchang East Road in Xihu District of Nanchang City

5.1 Design requirements for greening landscape for Guangchang East Road in Xihu District of Nanchang City

5.1.1The street greening landscape requires fine details. The road surface of Guangchang East Road is not wide, the speed of the car is slow, and the landscape of the pedestrians on the East Road in the past is slow. It belongs to the slow-moving viewing road. Therefore, in the design process, plants and colors cannot be used in a large area, and fine details are required. In the design process of green landscape, it is necessary to take into account that the landscape pattern created by the plants cannot make the color blocks separated too long. The public cannot see an overall landscape, and only see the partial landscape effect, which is not conducive to the public’s appreciation of the landscape of Guangchang East Road. It is necessary to exquisitely treat the design of the detailed green landscape of each color block or flower bed to meet the exquisite and meticulous requirements of the landscape of Guangchang East Road.

5.1.2Street greening should take into account the practical needs of people. The ultimate purpose of street greening landscape is to serve people. Therefore, when designing the greening landscape of the Guangchang East Road, it is necessary to take into account the practical needs of people. It needs to provide the feelings of the cool summer and warm winter for the pedestrians, so that the green landscape of road presents a lively lifestyle.

5.1.3The street greening landscape should properly coordinate plants. When selecting trees for roads, it is necessary to fully consider the limited street space of the Guangchang East Road, as well as the coordination of the street landscape to the surrounding environment and the landscape feeling of people. In the selection of street trees, in order to be suitable for the road environment, some small and medium-sized street trees can be selected, which can not only enrich the greening of the road, but also achieve the effect of beautifying the landscape. In addition, in order to enrich the road landscape of the city, the selection of the street trees should also pay attention to the matching of plant colors and the matching of different tree species with different seasons. As the season changes, the street landscape of different seasons are presented, and the color of street will also change accordingly[14].

5.2 Recommendations for greening landscape for Guangchang East Road in Xihu District of Nanchang CityAccording to the field survey and observation of the Guangchang East Road, we found out the current situation of the Guangchang East Road and its existing problems. In order to meet the requirements of the green landscape design of the Guangchang East Road, we came up with some recommendations for the design of greening landscape on both sides of the Guangchang East Road, and based on this, we detailed the greening landscape[15].

5.2.1Recommendations for planting street trees. The sidewalk on the south side of the Guangchang East Road is relatively wide. When planting the street trees, it is recommended to take into consideration of the road functions, the plant spacing and cut trunk height should be one of the most important factors to be considered. The selected tree species should have a trunk diameter of 5 cm or bigger, and the branching point height is not less than 3.5 m. The deciduous tree species (such asGinkgobiloba, Platanus×acerifolia, Toona sinensis,etc.) should be separated from the evergreen tree species (such asCinnamomumcamphora,Ligustrumlucidum,FicusvirensAit. var. sublanceolata,etc.). The cut trunk height is the height of the first branch point of the street tree, preferably higher than the pedestrian height, so that the height of the branches and the vehicles on the street will not affect each other[16]. The sidewalk on the north side of the Guangchang East Road is relatively narrow. It is not suitable for planting canopy and broad-leaved large trees. It uses colorful low-lying shrubs such asLoropetalumchinensevar. rubrum,Durantarepenscv. Dwarf Yellow,Buxussinica, and Photinia×fraseri Dress, and the height selected should be in the range of 20-35 cm.

5.2.2Recommendations of color block design. The street green color block in the Guangchang East Road is an intuitive way to express the visual experience of street greening. Generally, the color strips are divided into strips with a width of 5-10 m, and then repeat. The entire living style street of the Guangchang East Road is affected by the width of the road surface. It is suitable for the segmentation of color blocks. At the same time, the color and pattern of the divided color blocks should be rich, so as to increase the ornamental quality. The pattern of color blocks can be selected according to the length of the Guangchang East Road and the east-west direction and the street trees and the lower shrubs.

5.2.3Recommendations for the design of planting with feelings of levels and rhythm. The Guangchang East Road is an east-west street. There is only one large intersection. When making the greening design, it is necessary to match the direction of the street. For example, it is recommended to choose different types of plants to express the rhythm of the landscape, and also use small trees (such asArtocarpusheterophyllusLam,Lagerstroemiaindica), to increase the levels of the green landscape; in the design of the lower shrubs, it is recommended to choose a variety of shrubs for simple auxiliary green design, exquisite detail green landscape, use spherical or cylindrical shrub landscape. At the same time of increasing the levels of the street greening landscape, it is also recommended to express a certain sense of rhythm and enrich the street greening landscape.

6 Conclusions

At the same time of rapid urban development, street greening should receive more and more attention. The beautiful urban street greening environment is an important part of people’s impression of a city. Excellent design of urban street green landscape should be implemented through field survey, comprehensively bring into full play the comprehensive benefits of road green space, should have the support of the citizens, and the coordinated management of various management departments, unified planning, so as to truly create a more beautiful and comfortable street green space for urban residents and make the street green space become a beautiful landscape.