Research On Three-dimensional Vegetation Quantity Of Different Green Community Type With Spectral Measurement

"Three-dimensional vegetation quantity" was proposed as a new mentality and theory in the research of urban green space and its indices. It is a scientific method and instrumentality to weight the ecology function of urban green space and urban greening needing grosses in practice of urban planning and urban greening .Leaf Area Index (LAI) as an important evaluation basis of three-dimensional vegetation quantity, for the attention by more and more researchers at home and abroad, become the most important indicators of three-dimensional vegetation quantity. Along with the superiority of spectroscopy measurements was showed in urban research day by day, spectroscopy have showed their characteristics, such as efficient, scientific, precise, visual. They were already became important way and method in the research of urban green space.In this paper, leaf area index (LAI) study as a basis for trying to use urban green spectral index inversion different green community types of three-dimensional vegetation quantityTest selected exuberance communities in Wuhan east lake scenes as a study area and choose nine plots (total of 39 samples) of grassland, woodland, forest of three different types of communities as a study. First, we used Hemiview Canopy Analysis System measurement LAI, as a reference. Then spectrometer measured the spectral index, using spectral index inversion LAI, compared with the former. The results show that spectral index can be good invert LAI. The main findings are as follows:(1) Accurate measurement of leaf area index (LAI) of the turf: 0.66. Proposed the inversion model between leaf area index (LAI) and the spectral index within two kinds of community type in study area:woodland: Y=1.84+0.47Xå’ŒY=2.29e^0.11xforest: Y=9.37X-1.34 (x>0.14)å’ŒY=4.75e^0.65xIn the investigation of three sample in the region, and quantitative estimates leaf area index of the study area, detect four-leaf area estimation accuracy under 95% degree of confidence, respectively: 0.81, 0.81; 0.82 and 0.78. The light of domestic and international experience in the relevant calculations, the accuracy of more than 80% can be applied, the above equation and research methods in the promotion of Wuhan City.At the same time, show the relevance of the spectral index: grassland > woodland > forest. (2) The content of chlorophyll has good correlation with the photosynthetic capacity, developmental stages and condition of nitrogen of vegetation, and usually is the indicator of nitrogen stress, vegetation photosynthetic capacity and the development stage. In order to monitor the growth environment of the community,using model:(?)to in versed chlorophyll contentof the urban green plant in the 95% confidence level, the estimated accuracy is 86.4%, which shows that the model can be inversed the chlorophyll content of green plants very exactly.(3) We analyzed the leaf area index of three-storied plantation communities types of grassland, woodland, and forest. Three types of leaf area index are 18.9 0.66and3.17 respectively, and different obviously.(4) The inversion of leaf area index (LAI) and chlorophyll content Cab showed that spectral reflectance of red edge position ,where is about 700 nm is superior to green peaks position, where is around 550-600 nm.(5) The inversion of chlorophyll content Cab showed that, the infection of the leaf structure can be ignored to the spectral inversion of leaf chlorophyll content, as the result itself, including reflectance spectroscopy of chlorophyll A, B chlorophyll, arytenoids and the lutein.(6) The spectral index GM and Vog, which is not commonly used, can inverse LAI very exactly, but the correlation of NDVI, common normalized vegetation index, is not satisfactory, indicates that NDVI is not sensitive to spectral features, when sensitive to remote sensing spectroscopy.(7) The data analysis of community canopy density and leaf area index showed that: the leaf area index of woodland and forest with their canopy density was positively correlated, the higher the closing of the community, the higher the leaf area index, the closest to index relationship. Canopy density of forest between mainly concentrated in the 0.85-0.95...