The Investgation And Evaluation Of Street Trees' Application Status Of Baoding Arterial Streets

The people's demands on urban greening is developing with material living standards. Road greening is the most frequent form in the people's daily life, and is an important manifestation of economic, social development and spiritual civilization. The street tree as the backbone of road greening connect the dotted green areas in the city forming a complete urban greening system which plays an important role in improving the ecological environment, dust shade, amenity, traffic organization, etc. Baoding is a city with long history, profound culture, ancient civilization and rich tourism resources, urban greening is gradually strengthened in the tide of eco-city construction, and the city needs to improve the image from the road landscape. In order to solve the problems in the function of street tree in urban greening and the application of street tree in arterial roads, through the investigation of the status of street tree in arterial roads this paper analyzed the species structure and landscape aesthetics, set up an adaptability evaluation index system for street tree species with Analytic Hierarchy Process(AHP), evaluated the adaptability of the street tree in arterial roads, then summarized the problems in the applications of street tree, and proposed solutions as well as a reasonable selection and planning of street tree based on the greening status, climate and culture of Baoding as references for road greening construction and ecological environment construction. The main findings were: (1) Species structure: 13 species of 12 genera of 11 families such as Chinese scholartree, chinar, heaven tree, white wax and so on with a total of 40,078 involved in arterial roads of Baoding; the ratios of native species and exotic species, fast-growing species and slow-growing species, evergreen trees and deciduous trees were 1.5:1,13:1,1:131; the roads with good species diversity were Tianwei Road, Lekai Street, Sanfeng Road and Fuxing Road, and those with bad species diversity were Qiyi Road, Xiangyang Street and Hengxiang Street; the important value of species in descending order were Chinese scholartree, chinar, heaven tree, white wax, ginkgo, walnut, Chinese white poplar, cedar, silk tree, catalpa ovata, goldenrain tree, sabina chinensis and catalpa bungei; age structure of species deflect to infancy; the vertical structure was simple, mostly single-layer structure and dual-layer structure, only a few were triple-layer structure. (2) Adaptability evaluation: the adaptability of the street tree in arterial roads of Baoding consisted of stress resistance, growth performance and appearance performance, flexibility index in descending order were Chinese scholartree, heaven tree, chinar, koelrenteria paniculata, white wax, Chinese white poplar, catalpa ovata, walnut, catalpa bungei, sabina chinensis, ginkgo, silk tree, cedar; heaven tree, Chinese scholartree, koelrenteria paniculata had best stress resistance index, the tree Sophora japonica, and Luan, Chinese scholartree, chinar, Chinese white poplar had best growth performance index, and koelrenteria paniculata, Chinese scholartree, white wax, had best appearance performance index. (3) Analysis of landscape aesthetics: the overall landscape effect of green belts in the arterial roads of Baoding was prominent, but in lack of shrubs; the green belt width was not in coordination with height of trees, surrounding environment; the configuration was monotonous; the colors match was not reasonable; the local culture was not enough, and there was not prominent features. (4) Investigation and evaluation showed the following problems in application of street tree in Baoding: species structure was irrational; individual species were not flexible, while excellent species was not used; landscape aesthetic value was not so high. (5) Solutions to the existing problems: mining plant resources, optimizing the species structure; employing scientific selection of tree species to improve the level of road greening; enhancing the landscape aesthetic value, formation of the landscape characteristics of the roads.