Study On Green Quantity And Ecological Benefits Of Landscape Plants In Main Urban Area Of Nanjing

In recent years,with the accelerated process of urbanization in China and the increasing demands of urban greening level,people pay more attention to the study of green quantity and ecological benefits of urban green space.Therefore,how to improve ecological benefits of urban green space and achieve a low-carbon garden city is the responsibility and challenge to all the garden people.The ecological benefit value is the core content of urban green land ecological benefits,which is based on carbon sink(nitrogen fixation and oxygen release)and cooling humidity increasing.The Nanjing City(Xuanwu District,Qinhuai District,Gulou District)of four types of greenland(Campus green space,Road green space,Park green space,Attached green space)in a total of 70 plots as the object of study by investigation of typical plant communities,in plant growth(DBH,tree height,plant density)parameters and green quantity and ecological benefits,in order to provide the basic parameters for the quantitative analysis of green ecological benefits,trying to establish the quantitative relationship between green quantity and ecological benefit and provide scientific reference to Nanjing green plants green quantity study on the correlation between,and to provide a scientific basis for Nanjing urban greenbelt plant community configuration.The results are as follows:(1)Scientifically define green quantity and the concept of green quantity's index,set LAI and total leaf area into the green quantity indicator systems,use the product of LAI and crown projection area instead of green biomass values,establish the foundation for the future of Nanjing's deep green quantity research.(2)Count five common trees and shrubs in Nanjing(Cinnamomum camphora,Magnolia grandiflora,ginkgo,cherry,Acer palmatum),record 70 plots' quantity,diameter,crown width and tree height.According to crown width,calculating green quantity and analyse the correlation between diameter,tree height and green quantity,then compare green quantity and ecological benefits value in five species.We found that the relationnship between green quantity and DBH of camphor,Magnolia grandiflora is strong.The relationship between green quantity and tree height of Cherry,Acer palmatum is strong.Camphora has the best ecological benefit value in five plants.(3)Discuss four types of green-plant community index(type,quantity,height,DBH,plant density)and make classification statistics,found that Nanjing's tree DBH mainly concentrated in the 10-30 cm interval,average DBH of campus green space is maximum and park green space is minimum;tree height concentrated in the<5m.5?10m and 10?15m three range and distribution of each range ratio is basically equal;four types of gree-space plant community's plant density mainly concentrated in 500 plants/ha?1000 lines/ha,road green space plant density is maximum and attached green space plant density is minimum.(4)Calculate all plots' green quantity of four types of Greenland,and according to plots' square count values of every unit green area,found that four types of green-plant community green quantity is basically equal.The plot number of green quantity value in the range of 1000 to 2000 m2 is maximum.The plot number of green area value in less than 5 m2 range the number of plant community is maximum,accounting for 41%of the total.According to the survey results,the main urban area of Nanjing's plant community unit green area is 6.8%,the survey of 70 plots the average quadrat greening for 2432.4m2.From the point of view of four types of green lands,campus green space due to the sample size is bigger,and have larger plots the total green quantity(4927.2 m2);road green space of unit green area values reached a maximum of 9.4 m2.(5)According to the plant communities of the green value and green plant ecological benefit calculation method,the calculated plots to carbon(nitrogen fixation and oxygen release)cooling and humidification for the index of the comprehensive ecological benefit value and ecological benefits per unit area value.It is found that the Nanjing city greenbelt plants of unit area of solid carbon content is 59.27 g/d per unit area and oxygen release were 43.47 g/d per unit area.The cooling rate is 1.73'C/d per unit area,and the humidification amount is 9051.80 g/d per unit area.The campus green space ecological benefit value and road green space of the unit area ecological benefits are maximum.