The Research and Construction on Plant Landscape Characteristics of Urumqi

XIE Yang（School of Architecture，Xi'an University of Architecture Technology，Shaanxi Xi'an 710055 School of Engineering and Architecture，Xi'an University of Technology，Shaanxi Xi'an710048）

Characteristics and construction of city plant landscape，means making the city green to meet its special functions and technical requirements.And at the same time，it can inherit the historical influence of the plant landscape to the city image，develop city plant resources positive effects and the potentiality of the city image and outstand the city characteristics.It ultimately achieve two goals，one of which is to create the green city to improve living conditions，and another of which is to promote the city environment quality and figure the city concept and characteristics.

There are many examples of using plant landscape to enhance the city quality in our country.For example，many towns or administrative divisions make the plants for their names，such as Zhangshu in Jiangxi Province，Huadu in Guangzhou Province，Huangmei in Hubei Province，Yulin and Shenmu in Shaanxi Province，Guilin and Liuzhou in Guangxi Province etc.Surpassing its own geographical range，some plant names have more widely cultural meanings.Such as“old pagoda tree”in Hongdong is the symbol that people of Shaanxi living in other provinces or countries are attached to hometown；“Jing Chu”has become the core of Jianghan Plain and the concepts of cultural geography，including most parts of Hubei，Hunan，parts and the majority of Henan，Jiangxi and Anhui Province.In addition，some cities in our country make the plants as their aliases，such as Guangzhou and Fuzhou that are also called Huacheng and Rongcheng，Luoyang that has a nickname of“Peony Capital”，Xianning that is called“the homgtown of sweet－scented osmanthus” .Coming to a climax ，some plant landscape become the core idea of the city，area and even the national image of the country，such as pine trees in Huangshan Province and the spirit of pine trees of Huangshan，the plum blossom of Wuhan and the spirit of strong proud and aloof，the Hongkong redbud and its flag and badge，etc.

1 The present situation of Urumqi plant landscape

1.1 The present situation of natural vegetation

1）The desert plants Belonged to the north desert region，Urumqi is not only the contact zone of Central Asia flora and Central Asia flora，but also the demarcation line of two desert type vegetation which are half shrub——desert shrubs and subshrubs desert Ephemerals.The regional vegetation of Urumqi is desert vegetation，which are mainly constituted by xeric，xerophytic woody plants and shrubs.The barren mountains are mainly desert，scrub and grassland vegetation.The low index diversity of vegetations，the severe ecological environment of barren mountain and the lack and uneven distribution of species reflect that the barren mountains vegetations are instability and the environment conditions of barren mountains vegetation plant communities are terrible.According to the results of barren mountain and vegetation survey，the natural vegetation can be divided generally into 6vegetation type groups，which are desert，grassland，shrub，meadow，marsh and deciduous broad－leaved forest，and 19 kinds of plant community types.Among of them the distribution area of small Peng formation，slender Seriphidium formation，in c.acanthophylla formation and camel Chenopodiaceae formation is larger and boarder.

2）The wetland plants In Urumqi，there are 21612hectares wetland altogether，accounted for 1.94%of the total wetland，which is mainly made up by lake，river，swamp，reservoir，and some sewage pool，pond，irrigation field （including rice），salt marsh，sedimentation basin.Because of the great impact of the surrounding environment，even belonged to the same type of wetland，the species composition，the system structure and function of the wetland，are also have some difference.Research shows that，the surrounding wetlands are mainly river wetland，lake wetland，meadow wetland and pond wetland.Wetland plants are mainly distributed meadow wetland in Dabancheng flat，salinization wetland in Chaiwopu，swamp wetlands，Salt Lake wetland，desertification meadow wetland and meadow wetland in Tianshan Wild Zoo.Wetland plant in Urumqi totally include 45families，134categories and 270species of seed plants，in which monocotyledon species，including 17types form and forming rich plant communities，are dominant.

3）The forest plants The surrounding area of Urumqi is the intersection zone of Eurasian forest area，Eurasian grassland area，and the Central Asia desert subregion.The vertical zone distribution of mountain vegetation is significant.At the altitude of 1500－1800m，there are mountain grassland and valley deciduous broadleaf shrub.The mountain grassland is small and discontinuous and valley deciduous broadleaf shrub are mainly willow，honeysuckle，Tianshan mountainash branchlet and fruit and osamultiflora，etc.At the altitude of 1800－2800m，there is the mountain forest，and the constructive species of it is evergreen aciculiailvae mainly made up of picea schrenkiana.At the altitude above 2800m，there are subalpine and alpine grassy marshland，which are mainly wormwood and head of grass formation.

1.2 The present situation of garden plant

According to the general investigation data by Afforestation Committee，there are about 300types garden plants in Urumqi，including 40families，78categories and 191species，in which 42species of native plants accounted for 46.15%and 49types alien species accounted for 53.85%.Categorized according to the types of growth environment，there are 88types temperate deciduous broadleaf tree species，accounted for 87.12%，13types evergreen conifer tree species，accounted for 12.88%，and without evergreen broadleaf tree.Among the garden plant species，there are 50%macrophanerophytes，42.42%arbuscle and 70%herbag，which are all introduction species.

The advantage families of garden plants are mainly Salicaceae，Leguminosae and Rosaceae，and the advantage categorie of garden plants are mainly Populus，Rosal and Ulmusl.The Urumqi Tree is elm with large leaf，and Urumqi Flower is rose，both of them reflects the garden plant characteristics of Urumqi.

2 The problems of Urumqi plant landscape

2.1 The problems of natural vegetation

（1）The problems of natural vegetation are heavy grazing，grassland degradation and soil desertifi－cation.“Urumqi”means“beautiful pasture”in Mongolian，and it was a lush，scenery and pleasant place at one time，but in recent years，due to heavy grazing and grassland degradation，people have not seen the beautiful meadow landscape.

（2）The expansion of city leads the vegetation area being reduced.Because of the rapid expansion and the economy development of surrounding area，it has brought the demand of construction land rising rapidly.At the same time，the surrounding woodland，grassland，desert occupied and exploited，and the vegetation damaged severely.Because of human intervention，it has changed the original environment，especially caused the natural habitat fragmented，the result of which is a large number of peripheral plant species reducing.

（3）The capital investment to natural vegetation protection and restoration is limited，and extensive use has also caused negative effects to natural vegetation resources.

（4）It is difficult to form a harmony biological relationship because of the destruction of original natural vegetation，the relatively simple species structure of artificial vegetation in space，age and variety，and the lowness of biological diversity degree.At the same time，the low stability of the ecological system，need much more persistent and higher cost of artificial management.

2.2 The problems of city garden plant

（1）Garden plant species are less.There are about 400plant species in Urumqi，including 210 kinds of trees and shrubs，but the common species of city plants are less than 100.It is a big disparity between domestic and foreign cities with better afforested❶.

（2）The structure of ecological plant community is single.Because of fewer plant species and the fragile ecological communities structure，the single structure of plant community cause the lawn degeneration and the diseases of tree pests increasing.

（3）There is less use of native plants.In the main areas of urban district afforested in Urumqi，with the exotic species as dominated and the native species as a supplement，the City Trees and Flowers of Urumqi are less use.Because of many wild native plants having been cleared from the garden，there are rare area with highlight native plants and the urban district afforested are lack of cultural connotation.It is not only against the diversity conservation of landscape plants，but also lack of local characteristics.

（4）There are lack use of City Tree and City flower.In addition to that rose is susceptible to pests and elm resistance is weak，there are some other reasons for the lack use of City Tree and City flower.We should not ignored the cultural value of the City Tree and Flower，Because they are the symbol of plant landscape core and can promote the image of the city❶❶The Research of the Urban Characteristics of Urumqi－Book2.Xin Jiang Architectural Design Institute Wang Xiaodong Studio，2011：55－70..

（5）There are lack of cultural connotation landscape plants in different city green spaces.At present in Urumqi，all kinds of green plants are in pursuit of visual beauty，and the plant selection is more or less the same.There are no features landscape of regional culture，because most of the plants are common shrubs without history culture.

3 The construction of Urumqi City plant landscape characteristics

3.1 The concepts of construction

1）Plant landscape with native vegetation and characteristic vegetation The natural characteristics of native vegetation geographical environment are unique and cannot be copied，because it is the result of adaption to the regional natural environment❶.The characteristics are not only one of the significant physical performance and distinguished different from other cities，but also an important carrier of the city characteristics.It is one of the most important parts of city characteristics.

2）The concepts of practical environmental—suit one's measures to local conditions According to the actual condition，take the methods of“conservation”，“noninterference”or“interchange”to construct the peripheral green landscape of Urumqi，improve the environment quality and the ecological environment safety of Urumqi，in order to curb the deterioration of the ecological environment.

3）The concepts of biological diversity protection The aim of protecting plant landscape is to maintain the stability of the ecological system and achieve the sustainability of landscape.It is also an important part to construct ecological garden city of Urumqi.

4）The concepts of green landscape by the method of inside and outside complementing with each other It should take the natural vegetation of peripheral city as the base background of the construction of city green landscape❶.On the basis of protecting the natural environment，we should ensure the inside and outside green of city contact with each other，and at the same time protect and recover the natural environment.It should also make the use of zonal plants and endemic plants to build city plant landscape with local characteristics and local cultural connotation.

3.2 The principles of construction

1）The principle of adapting to trees and soil On the one hand，it is the selectivity of plant to land，the specific performance of which are the selective to different soil，water，surrounding environment.On the other hand，it is certain selectivity of land to species.They are the key to create a unique plant landscape.

2）The principle of biodiversity The number of plant species in city landscape，does not only affects the heterogeneity，diversity and naturalness of plant landscape，but also affects the simplification and complication of the animal and plant communities of the city，and ultimately affects the stability of city ecological system.

3）The principle of ecological sustainability The function of garden plants of city are not only the beautification and leisure，but the more important function is the ecological.The selection of plant should not only guarantee good adaptability of its own in the city environment，but also can maintain the development of the city ecological system.

4）The principle of landscape diversity The greening of city should emphasize on the reasonable disposition and the city ecological diversity.The aim is to make that there are not only flowers in spring，shade in summer，fruits in autumn，green in winter，but also different form of different distance and always suitable for heavy or light makeup❶❶The Research of the Urban Characteristics of Urumqi－Book2.Xin Jiang Architectural Design Institute Wang Xiaodong Studio，2011：55－70.❷The Overall City Planning of Urumqi（2009－2020）.Xinjiang Uygur Planning Bureau，2008：20－26..The distribution of city landscape plants in space should combined with the characteristics of city space，and give guidance with system and local recognition，so that make the color changes continue in time，and the space distribution prominent personality.

5）The principle of highlighting the characteristics of regional culture The landscape is the objective carrier of traditional culture and modern civilization，which can provide people with sensory framework of identifying their social attributes.For landscape design，it is the foundation that respecting and embodying the local culture so that to develop and continue the culture.The local native plants，which are long associated with indigene and endowed with certain cultural connotation，have identification function to the formation of the regional plant landscape features and the city characteristics❷❶The Research of the Urban Characteristics of Urumqi－Book2.Xin Jiang Architectural Design Institute Wang Xiaodong Studio，2011：55－70.❷The Overall City Planning of Urumqi（2009－2020）.Xinjiang Uygur Planning Bureau，2008：20－26..

6）The principle of building conservation－oriented garden Water resources are not only the basic conditions to maintain the ecosystem of Urumqi，but also the restriction factor of Urumqi development.Because the economic development of Urumqi is relatively backward，it is necessary to put“the concept of saving”into the garden greening，select drought－resistant plants and improve the utilization of water resources and water reuse❷.

7）The principle of entirety and harmony of landscape Plant landscape should be in order in the performance of city characteristics.Different types of plants have their own characteristics in reflecting city characteristics，but they must be in the framework of plant landscape.It will not be in a mess when pants are unified in general and coordinated in diversity.

3.3 The objects of construction

People should use regional vegetation（deciduous broad－leaved tree species）and plants with characteristics to make plant landscaping and adopt different landscape construction methods in different regions in Urumqi.

1）Construct the natural vegetation in city peripheral areas In the outskirts of Urumqi，on the basis of keeping ecological function，make appropriate landscape optimization with mainly natural plant community landscape❶❶The Overall City Planning of Urumqi（2009－2020）.Xinjiang Uygur Planning Bureau，2008：20－26..At the same time，take ecological measures of protecting and recovering to the natural vegetation and reduce man－made interference，so that make the vegetation recovered naturally and to be the natural ecological barrier of Urumqi.In addition，choose zonal desert plants，such as Populus diversifolia，Chinese tamarisk，Caragana，Rose，Mongolian calligonum herb with fruit，Iris ensata，etc，to imitate the natural community structure of planting，and embody the desert landscape on both sides of traffic and river near the town.

2）Construct the artificial protection forest On the basis of original shelter－forest，increase native plant species，which have some ornamental and economic value，at the same time locust tree and understory shrubs to form a complex planting and enrich seasonal variation.Connect protection forest with the desert plant landscape in outskirts of the city，so that make the nature landscape into city green space.

3）Construct the artificial plant communities in the main city zone Make the artificial plant community to be the main landscape，and appropriately increase some specific ornamental plants adapted to Urumqi environmental conditions，such as shrubs，native plants or naturalized plant［2］.At the same time，make great efforts to cultivate and applicate more varieties City Flowers and Trees to enrich species diversity and form colorful community landscape.

4）Construct the urban agriculture zone Depending on the agricultural industrialization，and make the modern science and technology as foundation，develope urban agriculture with regional characteristics of Urumqi，so that promote the coordinated development of city and countryside［1］.At the same time，exert its functions of ecological，services，tourism，leisure，science and technology demonstration，education，etc.