| The urban forest is used as a kind of nature resources to take the important ecosystem environment function on existence and life of mankind, the street trees are the important parts of the urban forest ,not only beautify the whole landscape, but also play the important function on living environment quantity of city resident. it rises primarily the balance of carbon oxygen , decontamination air, regulation of city weather, defending breeze and consolidating sand, water and soil of keeping, protect living creature variety on the ecosystem performance. The street trees of ZunYi city which are adopted the sampling method are analyzed theirs distribute structure and ecological functions in the paper, moreover I put forward the reasonable management measures and suggestions. Then research results indicate: ( 1 ) Street tree of ZunYi city has totally 23 kinds, among them laurel blossom, glossy privet , poplar , wide magnolia, parasol tree, orange ,the number of six tree species occupy 85.54% in the total ones , and total index number of living creature variety is 0.924. ( 2 ) The average chest of street trees is low, what is more, chest path which is under 10 cm occupies 47%. ( 3 ) The total biomass of street trees is 1500t, equal to 18.9 hm2 forest, and the total deal in leaf's area amounts to 1018.67*103m2 . ( 4 ) 15 main trunk highways of the City of ZunYi tall trees have the ability of dust absorption and total dust absorption measure is 2283.413 kg, however, bush only 1.076 kg . ( 5 ) The simple leaf's area of parasol tree, glossy privet , wide magnolia, purple leaf Lee is strong, but the dust absorption ability of the gingko, willow, poplar, elm, camphor are oppositely weak. Furthermore, dust absorption ability of parasol tree is particularly strong. ( 6 ) The tree grows to enrich to gather the manifestation to the heavy metals chemical element: Mn> Zn> Cu> Pb> Ni , Glossy privet, purple leaf Lee, willow , parasol tree, azalea , wide magnolia, Ch. fan palm , poplar leaf which have an ability for absorbing heavy metals are strong, meanwhile, and the ability of Ch.ilex, gingko, laurel blossom, orange , palm tree, red bayberry leaf's slice absorbing the heavy metals are weak. At the same time, the contains of heavy metals in the road of WaiHuan FengHuang GaoJiu and HaiFeng, are oppositely higher than other trunk highway. ( 7 ) Glossy privet , little leaf's glossy privet , poplar tree laurel blossom, wide magnolia, orange which have an ability for absorbing SO2 are strong; But the ability of purple leaf Lee, parasol tree, camphor, Ch. fan palm for absorbing are weak. ( 8 ) The average temperature ratio of the sunless are lower 2.41 ℃ than bares road under the same surrounding , degree of humidity higher than 6.56 ℅, at the same time,the gap of temperature and wet from 9-11:00,15-18:00 shows notably . ( 9 ) Comparing to 8 kinds of the most common trees: The result of the adult camphor reducing the heat to increase the wet is most notable , and the next one is parasol tree . (10)The same trees are differently notable on different road ,and the different trees reducing the heat and increasing the wet are also different on the same road. (11) Through synthesizing estimation different trees on the different roads ,the result shows: the grade of reducing the heat to increase the wet belongs to class A( namely very good), the grade of dust absorption ability belongs to class B, the grade of fixing carbon is low; Further computing synthesizing of the grade point value also reflects the same result. (12) The synthesizes of XinHua and ZhongShan road are best, but they still exist the problem of lacking Joe, shrub , grass reunite. The other roads' colligating benefits are low because the age of tree species is young. In one aspect ,it reflects that the biomass of street trees is low, In the other one it discloses the forest structure of ZunYi city still goes unsteady. |
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