Study On The Correlativity Between The Nanning City's Greening And The Environmental Quality

Urban greening, guided by the principle and method of ecology, means the planning, designing, management and construction to the urban green area, and is also one important part of urban construction as well as a criterion of the modernization and civilization to a city. Through the investigation to the Nanning greening situation, and measuring the green area's structure, such as the plant's height, quantity, coverage, diameter of breast height, and it's microclimate factors, such as temperature, relative humidity, light intensity, wind speed, as well as it's air environmental quality factors, such as CO2, O2, CO, SO2, NOx and total floating dust, this paper studied the difference, the efficience and the correlativity among them, especially the correlativity.Contents: I . The greening state of Nanning City. Investigation was carried on tweenty-four sample stands of four districts in Nanning City, including (1) college area: the Subtropical Conservative Rainforest, the omni-tree Woods, the Pinus massoniana Woods in Guangxi Ethnic College, the TaoLi Garden, the Centre Garden, the Nurture Garden, the sod Garden, the Eucalptus woods, the Osmanthus fragrans Woods and the Livistona chinensis green Belt in Guangxi University; (2) residence: the Swiss Villa's two greening sample standsand the Wenhua Villa's three greening sample stands; (3) commercial streets: theXingming Road ,whose prime street tree is Dracontomelon duperreanum , the Yuanhu Road, whose prime street tree is Saraca chinensis Merr.et Chum, the Xingzhu Road, whose prime street tree is Artocarpus nitidus Tree, subsp. Lingnanensis; (4) major traffic roads : the Ethnic Road's two greening sample stands and the University Road's greening sample stands.The results show that: There are forty-five main planting arboreal trees in the tweenty-four sample stands of four districts in Nanning city, the front ten ones are as follows: Dracontomelon duperreanum; Archontophoenix alexandrae;Ficus benjamina; Osmanthus fragrans; Mangifera persiciformis; Livistona chinensis; Cinnamomum burmanii; Pinus massoniana; Mangifera indica; Saraca indica . And there are also twenty-four main planting shrub, the front eight ones are as follows:M玶raya paniculata; Olea cuspidata; Duranta repens; Hibiscus rosa-sinensis; Cordyline fruticosa; Lagerstroemia indica ; Caryota mitis ; Canna generalis . They can be considered as major greening plants often used in Nanning City. Accroding to the green area's comprehensive important value, their ordinations are as follows: the first and best one is the Subtropical Conservative Rainforest, then following the omni-tree Woods, the TaoLi Garden, the Swiss Villa, the Centre Garden, the Eucalptus woods, the Osmanthus fragrans Woods, the Pinus massonianaWoods, theXingming Road, the Wenhua Villa, the Ethnic Road, the University Road, the Nurture Garden, the sod Garden, the Yuanhu Road, the Xingzhu Road, the Livistona chinensis green Belt was listed in the last one. In addition, the author also analysed the correlativity among the green area's structure. The results show that: the correlativity between the plants' total mean diameter of breast height and density is quite obviously negative, while the total plants' coverage, density and the comprehensive important value show quite obvious correlativity among themslves, but others ambiguous.II. The correlativity and the difference among the green areas' structure and their microclimate factors are analysed in this part. The results show that: (1) in the shade, the correlativity among the total plants' coverage, density, comprehensive important value and the temperature is quite obviously negative, while comprehensive important value and relative humidity is obviously positive for their correlativity; (2) in the hiatus, the total mean height and light intensity show obviously positive correlativity, especially with wind speed, their correlativity come to quite obviously negation. In addition, the green areas' struture and their microclimate factors' effects show their correlativity as follo...