The Development and Use of Economic Value concerning Urban Landscape Plants in Shijiazhuang City in the Context of Ecological Civilization Construction

Chenxia HAN

College of Resources and Environmental Sciences，Shijiazhuang University，Shijiazhuang 050035，China

1 Introduction

With the acceleration of urbanization，the situation of resource constraints，environmental pollution and ecosystem degradation is becoming increasingly grim.The vigorous development of urban ecological civilization is an effective means to solve the problems of urbanization.Urban landscape construction must stick to the ecological civilization concept of nature protection and choose the path of sustainable development.The urban landscape plants can improve and beautify the urban environment，and some of them have edible， medicinal， forage and industrial functions［1－4］.However，most landscape plants are mainly used for ornamentation and greening in urban construction，and other economic values are not fully developed and utilized，resulting in aw a ste of resources.Presently，there are few studies on the development and use of economic value concerning urban landscape plants.In 2013，the area of new garden plot was 6 mill ionm2in Shijiazhuang City，and the rate of urban greening，green coverage and per capita green area reached 39.5%，43.5%and 14.8 m2，respectively；until 2017，the rate of urban greening，green coverage and per capita green area will reach 40.5%，44.5%and 15.3m2.In addition to ecological and ornamental value，other economic values of landscape plants in Shijiazhuang City are mostly ignored，and with the growth of the garden area in the future，there is a need to carry out effective development and management，to achieve effective integration of ecological and economic benefits，and to meet the needs of sustainable development strategies and conservation-oriented society building.In this paper，taking Shijiazhuang City for example，we conduct survey and analysis of landscape plant species and their economic value，and explore the principles and programs about development and use of economic value concerning landscape plants in Shijiazhuang City，in order to provide a reference for the full utilization and sustainable utilization of landscape plants in Shijiazhuang City.

2 Analysis of economic value concerning landscape plants in Shijiazhuang City

Shijiazhuang City is located in the central part of North China，and it features a warm temperate semi-humid continental monsoon climate，with abundant plant species.There are about 100 kinds of landscape plants in Shijiazhuang City，and most of them have high economic value.According to the economic use，these landscape plants can be divided into medicinal plants，edible plants，nectar plants，forage plants，fiber plants and aromatic plants（Table 1）.Most of these plants are native plants，such asSophora japonica，Robinia pseudoacacia，Diospyros kaki，Punica granatum，Salix babylonica，Malus domestica，andJasminum nudiflorum.

2.1 Medicinal plantsThere are 65 kinds of medicinal plants among landscape plants in Shijiazhuang City，and the common medicinal plants includeGinkgo biloba，Ophitopogin japonicum，Lonicera Japonica，Calendula officinalis，Tageteserecta，Paeonia suffruticosa，Jasminum，Forsythia suspensa，Rosa chinensis，Cercis chinensis，Chaenomeles speciosa，Broussonetia papyrifera，Sophora japonica，andRobinia.

2.2 Edible plantsThere are 25 kinds of edible plants among landscape plants in Shijiazhuang City，includingGinkgo biloba，Nymphaea tetragona，Malus domestica，Rosa chinensis，Sophora japonica，Robinia pseudoacaciaia，Malus micromalus，Diospyros kaki，andChaenomeles speciosa.

2.3 Nectar plantsThere are three common nectar plants among landscape plants in Shijiazhuang City：Lonicera maackii Loniceramaackii，Sophora japonica and Robinia pseudoacacia.In Shijiazhuang City，Sophora japonicaandRobinia pseudoacaciaare widely planted and there is also sophora flower honey for sale in the market.

Table 1 The landscape p lant species and economic use in Shijiazhuang City

2.4 Forage p lantsThere are only three main forage plants（Phragmites australis，Trioflium repensandMedicago sativa）among landscape plants in Shijiazhuang City，andMedicago sativa，known as＂king ofgrass＂，is favored by all kindsof livestock.

2.5 Fiber p lantsThere are three main fiber plants（Yucca gloriosa，Broussonetia papyriferaandPhragmitesaustralis）among landscape plants in Shijiazhuang City.Yucca gloriosaisa rigid fiber used most widely in the world，and it can be widely used in producing the ropes for voyage，mining and transportation.Meanwhile，it has important medicinal value.

3 Discussions on the development and use of economic value of landscape plants

3.1 Analysis of the factors influencing the development of economic value of urban landscape plants

3.1.1 The impact of main functions of urban landscape.The main function of urban garden plants is to improve the urban ecological environment，which determines the differences in planting mode and spatial distribution between landscape plants and natural vegetation or agricultural vegetation，thereby influencing the development of economic value.

3.1.2 The impact of the spatial distribution of urban landscape plants.In the urban landscape construction，in terms of spatial distribution，the urban landscape plants have small-scale and scattered distribution characteristics.Compared with agricultural vegetation，the small cultivation amount of each plant but large amount of cultivation varieties per unit area，will reduce the economies of scale and increase the difficulty in development and use.

3.1.3 The impact of the urban environment.The environmental problems are rife in cites and especially industrial cities，and some landscape plants use their ecological function to absorb and transform pollutants.These plants are mostly distributed close to the pollution sources，undoubtedly increasing the difficulties in the development and utilization of economic value of urban landscape plants.

3.2 The principles for development and use of economic value of urban landscape plants

3.2.1 The principle of being oriented by ecological landscape benefits.The main purpose of landscape plants is to beautify the urban environment，and the disorderly and uncontrolled development and use of landscape plants will cause damage to the landscape and inflict adverse impact on the urban environment.Therefore，in the development and use of these landscape plants，it is necessary to maintain orderly and rational development and use without affecting the garden landscaping and ecological benefits.

3.2.2 The principle of output value greater than input value.When developing and using the landscape plants，if the input value is greater than the output value，then the development of these resources will not yield any benefit，that is，there is not any development and use value.So it is unnecessary to develop and use these scattered and sparse plant species，but for those widely distributed and centralized plant species，it is necessary to fully and rationally develop and use these plant resources in order to obtain the proper value of plant resources.

3.2.3 The principle of safe use.In the development and use of landscape plants，there is a need to pay attention to the impact of environmental pollution on plant value.Some landscape plants play an important role in absorbing and purifying the air and water pollutants，and they are mostly planted near roads and factories that discharge pollutants.If these plants are wrongly developed and used，it is likely to cause hazards to mankind.Many landscape plants around polluting enterprises also play a role in absorbing and purifying pollutants.The development and use of these plants may cause harm to humans through the food chain.Therefore，when developing and using the landscape plants，it is necessary to pay attention to the impact of environmental pollution on plants，to avoid harm to human health.

4 The development and use programs for the economic value of landscape plants in Shijiazhuang City

4.1 Determining the geographical range suitable for development and useIn accordance with the different roles of different urban landscape plants in the urban construction layout，the geographical distribution of landscape plants are divided into three categories.（i）Streets and industrial areas.The landscape plants in these areas mainly play a role of landscaping and pollutant purification in urban construction，but they may contain toxic and hazardous substances，so they are not suitable for use.（ii）Parks，schools and residential areas.The plants in these are as are suitable for utilization due to good habitat environment.（iii）Outside of the city.The environment in this area is good，and the plants are widely distributed and can be effectively utilized.The current landscape plants that can be developed and used in Shijiazhuang City are mainly concentrated in parks，universities and country areas.The large-scale and concentrated distribution of these plants facilitates the use and development.

4.2 Determining the landscape plant species suitable for development and useThere are rich landscape plant resources with economic value in Shijiazhuang City，and different plant species have different economic use.It is necessary to focus on the development and utilization of those plant species with high economic value.The nectar plants should not be developed within the city lest the bees might sting.It is necessary to consider the medicinal and edible value of plants to be developed and used.For example，Ophitopogin japonicumis a perennial herb，and its root tuber can be used as medicine，but it is widely planted in some parks，schools and residential are as as lawn for greening and ornamentation in Shijiazhuang City.It has not been rationally developed and used for many years，and for this important medicinal plant，it is a big waste.It is recommended to divide the lawn into several parts to be developed and used.

4.3 Strengthening the routine maintenance and unified management for the landscape plants with high development and use valueThe city is densely populated，and there are large differences in the quality of different individuals，causing difficulties in the maintenance and management of landscape plants，so relevant administrative departments should adopt reasonable measures.

4.4 Improving the collection of the landscape plants with high development and use valueDue to the differences in economic use and characteristics between different plant species，it is necessary to explore scientific collecting methods，to make landscape plants not only give full play to the landscaping functions，but also realize their economic value.For the collection of medicinal or edible parts such as fruits，seeds，buds and flowers，the parts that are not the ornamental parts are generally collected，such as cypress seeds and locust tree seeds.For the collection of medicinal parts such as stems，leaves and bark，we can collect them in the process of pruning.For the collection ofBerberis thunbergiiandLigustrum lucidum，they are collected after leaves fall such asGinkgo biloba［5］.

4.5 Considering the economic plant types and layout in the green space of urban planning area in advanceWith the increasing future garden area in the city，in terms of the configuration of plants，we can plant more plants with high economic value and development and use potential，to achieve effective integration of ecological and economic benefits.We can build agricultural tourism theme parks with local characteristics in suburban areas，integrating leisure tourism，agriculture exhibition，technological innovation and picking of local characteristic fruits and vegetables，in order to provide leisure and entertainment for people and maximize the economic value of landscape plants.

4.6 Developing the management programs for the rational use of landscape plantsThe income distribution of landscape plant development and use also needs sound management and implementation measures，which requires coordination of relevant departments.It is recommended to invest the economic benefits from the development and use of landscape plants in the landscape construction or public infrastructure construction.In short，different landscape plants have different characteristics and economic value，and the distribution area，surrounding environment and management measures have some impact on the development and use.It is necessary to take into account a variety of factors in the development and utilization.

5 The development and use of typical plants in Shijiazhuang City

5.1 Herbal medicinal plant-Ophitopogin japonicumOphitopogin japonicumis a species ofOphiopogonnative to China，Vietnam，India，and Japan.In traditional Chinese medicineOphitopogin japonicumtuber，known as maimen dong，is the cardinal herb for yin deficiency.According to the Chinese Herbal Medicine Materia Medica，the herb is sweet，slightly bitter and slightly cold，enters the heart，lung and stomach channels and nourishes the yin of the stomach，spleen，heart and lungs and clears heat and quiets irritability.Ophitopogin japonicumis widely planted in some parks，schools and residential are as as lawn for greening and ornamentation in Shijiazhuang City and its medicinal value has not been developed and used.It is recommended to divide the lawn into several parts to be developed and used.Meanwhile，it is necessary to implement unified management of the entire region to form a certain scale of production，which can ensure stable annual production ofOphitopogin japonicum.

5.2 Woody plants-persimmon，crabapple，etc. Persimmon，crabapple and hawthorn are the commonly used garden fruit trees in Shijiazhuang City，distributed in parks，universities and residential areas.For the development of fruit-yielding landscape plants，it is necessary to strengthen the maintenance and management of the existing fruits and implement unified picking after fruits ripen.In the future landscape planning and construction of universities，parks and residential communities，it is necessary to increase fruit tree species，and use local apples，jujube and grapes for the construction of the garden.

5.3 Versatile woody plant-Sophora japonica Linn.Sophora japonicais an important nectar plant.It is used widely in rural areas but almost idle in urban areas，therefore，it is necessary to carry outunified management and maintenance ofSophora japonicain the whole city.ForSophora japonica Linn.in parks，communities and universities，it is necessary to take into account the ornamental value of its flowers，and focus on the development and use of its fruits.After the fruits ripen，we can promptly harvest the fruits to be used as medicine.Robinia pseudoacacia Linn.is leguminous deciduous trees，and about12%of its seeds contain soil.It can be used as soap and paint material.The flowers contain aromatic oil，and can be eaten.Its stems，bark and leaves can be used as medicine，having diuretic and hemostatic efficacy.Meanwhile，it is also a good nectar plant.Compared withSophora japonica，Robinia pseudoacacia Linn.has higher economic value.Taking into account the ornamental value of flowers and the damage of bark and root use to landscaping，so its development is not considered.We can develop and use its fruits，and obtain seeds from the fruits after picking to be used for producing soap and paint.

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