Suitability Evaluation And Selection Of Urban Landscaping Tree Species In Wuwei

The urban greening is very important for construction of modern city, urbancivilization and development symbolization. It can enrich urban landscape, improveurban ecological environment and raise urban life quality. The choice of urbangreening tree species bases on ecological function and diversification landscape, it isalso very important sign of the level of urban landscaping greening. The suitabilityevaluation and investigation of trees may offer scientific foundation for urbanlandscaping greening, it may enable urban landscaping greening construction morerational, more standard and more scientific.According to consulting data and overall investigating of trees of urbanlandscaping in Wuwei, using landscape dendrology, forest ecology, landscapeaesthetics and methods of Analytical Hierarchy Process(AHP),analyses andcomprehensive evaluation of 105 species of urban landscaping trees in Wuwei weremade. The results and conclusion are summarized as follows:(1)There are 38 families, 70 genera, 105 species of current trees for urbanlandscaping greening tree species in Wuwei.(2)It indicates that numerous floral elements compose in the trees in Wuweithrough flora analysis. Six familes, including Rosaceae(10 genera,20 species),Salicaceae(2 genera,13 species), Leguminosae(5 genera,7 species), Cupressaceae(4genera,7 species), Oleaceae(5 genera,6 species),and Pinaceae(4 genera,6 species),which are considered as obviously advantage families in trees for urban landscapingand the total is 30 genera,59 species, each accounting for 17.59%,42.86% and 56.19%of total number of families, genera and species.(3) In Wuwei, the comprehensive evaluation index system of landscape treeswere established through index choice from three hierarchies. The goal layer (A): thecomprehensive evaluation index system of Wuwei landscape greening trees; Thecriteria layer (B): ecological adaptability ,view and admire capability, cleaningcapability and growth capability; The variable layer (C): including 24 evaluationfactors, they are crown type; height; strange shape; colour; sapor fragrant; differentform; alkali endurance; high temperature endurance; cold and frozen endurance;dryness endurance; shield; plant diseases and insect pests; SO₂ absorbability; HFabsorbability; CI₂ absorbability; wind resistance; dust-blocking; bacteria; length andheight; canopy diameter; sprouting; Porosity; longevity; and suckering.(4)According to the results of the weight value of landscape trees by means ofAHP, the weight value of ecological adaptability is the most important part oflandscape trees comprehensive evaluation index system and the first choice ofchoosing landscape trees, view and admire capability is less important, which will bea considerable factor of choosing and using landscape trees. The last is growthcapability, which shows that growth capability has least influence on comprehensiveevaluation index system. The weight values of cold and frozen endurance, drynessendurance, high temperature endurance, coronal type, and tincture in variable layerare obviously higher than the others. It can be regarded that those factors haveimportant influence on the comprehensive evaluation of landscape trees in Wuwei. The factors of penetration and scattering and germination have slight influence on thecomprehensive evaluation of landscape trees species in Wuwei.(5)The comprehensive index of each landscape trees can be calculated accordingto the weight value of various evaluation from AHR With the distribution of variouscomprehensive index, four grades of landscape trees in Wuwei can be determined.The results show that the number of first class trees is 28, the second is 53, the thirdis 16, and the fourth is 8, all of them are graded according to their integralperformance.(6)According to light favored, drought resistance, low temperature resistance,wind resistance, ecological nature was evaluated to recognize basic ecologicalcharacteristic about landscape trees in Wuwei.(7) According to tree shape, leaf, flower, fruit and limb of garden trees, the viewvalue of garden trees species in Wuwei City was evaluated.(8) Trees of different kinds include: grassland in parks, such as Picea crassifolisKom, Pinus tabulaeformis, Platycladus orientalis,Larix gmelini and Populus albacv.Pyramidalis,grassland to defend, such as Populus alba cv.Pyramidalis, Populussimonii, Ulmus pumila, Fraxinus chinensis,and Eleagnus angustifolia, grassland incourtyard, such as Picea crassifolis Kom,Pinus tabulaeformis, Populus tomentosa andPopulus simonii, grassland on road, such as Pinus sylvesris L.var.mongolica, Populusalba cv.Pyramidalis, Populus tomentos,Populus simonii, Salix babylonica, and othersas Picea crassifolis Kom,Pinus sylvesris L.var.mongolica, Platycladus orientalis,Populus alba cv.Pyramidalis, and so on.(9) By investigating and analyzing garden trees species in Wuwei City, the mainproblems existing in the process of city greening were the singleness of garden treespecies, the lack of evergreen tree species, the lack of characteristic native tree species,more grass and less trees, emphasizing coverage rate while ignoring ecologic benefitand the singleness of structure of city grassland and type of greening.(10) In terms of the main problems above, the principles were brought forward inthe process of choosing and disposing garden tree species in Wuwei City, We shouldpay more attention to the principle of ecology and local environment, native species,culture, sustainable development and so on. In addition, we should build up the ideaof whole and unity and the function landscape-making of plant. According to the localenvironment and different characteristics of garden greening in different zone, manyconstruction countermeasures were put forward to improve the level of administratinggarden greening.