Study On The Relation Between Garden Ornamental Plants And Urban Ecology In Changsha

With the further development of urbanization, people's life becomes more and more convenient. Industrial development has made society economy developing higher and higher. But, industrial waste pouring off, and automobile tail gas giving off, have also brought about very big contaminating by atmosphere, water hereof at the same time. With the CO2 blowing off, the feasible air temperature are higher and higher. The city puts in changing soft and floury under buildings, the feasible city forms a heat island effect. The flood and fire cause extremely large damage to people's life. In order to relieve the secondary effect of urban heat island, the city virescence is necessary. Study of relation between ornamental plant and city organism is significant.This paper discusses the following aspects, including the disposition of pavement plants in Changsha streets, the effect of greenbelt to release urban heat island effect, the intrusive alien plant in Changsha. Results discover that the most two popular pavement trees in Changsha city are Cinnamomum philippinense and Magnolia grandiflora, and the most widely used shrubs are Camellia japonica, Ligustrum quihoui, Rhododevdron simsii, which have good ability to absorb and clear polluting gas. But in some areas, there are few plants which have good clearing capability of contaminating gas. To enhance the purifying ability on polluting gas, we can apply more plants, sush as Osmanthus fragrans, Ginkgo biloba, Koelreuteria bipinnata, Pittosporum tobira.Investigating different parks, we observe that compound type greenbelt has maximal fuction to relieve heat island effect;Greenbelts with big edge rate have larger function on reliving heat island effect than that with small one. The small amount distribution of Changsha city roof gardens can not get up big ecology effect. Network construction of city roof gardens ought to be taken consideration seriously.There are 36 common intrusive alien plants in Changsha city, most of which are herbs and few wines, no arbor. And they are mainly from South America and North America, which commonly distribute in disturbed places. The most serious damage plants among them are Alternanthera pungens,Conyza canadensis,Phytolacca Americana,Erigeron annuus,Bidens pilosa,Euphorbia maculate. Appropriate plant dispostion not only can bring aesthetic feeling to people's life, but also reduce temperature, increase the humidity, eliminate pollution and defend disaster, making people's life more comfortable. Therefor, to enlarge the urban afforestation step, expand urban afforestation's area is desperately imperative. Protecting local ecosystem, defending the endanger of alien plant invasion should not be ignored.