There has been a great deal of interest in studying the crown of trees using remote sensing data. In this study, crown width was extracted from high-resolution QuickBird images for open Populus xiaohei plantations. Re...There has been a great deal of interest in studying the crown of trees using remote sensing data. In this study, crown width was extracted from high-resolution QuickBird images for open Populus xiaohei plantations. Regression models for predicting the individual stem volumes of Populus xiaohei were established using extracted crown width, as well as estimated tree parameters （i.e. diameter at breast height [DBH] and tree height） as predictors. Our results indicated that crown width could be accurately extracted from QuickBird images using a multi-scale segmentation approach with a mean relative error of 5.74%, especially for wide-spacing stands. Using either extracted crown width alone or with estimated DBH and tree height can successfully estimate individual stem volume of Populus xiaohei with the R2 value ranging from 0.87 to 0.92 depending on different model forms. In particular, the two second-order polynomial models （model 2 and model 6）, based on QuickBird image-derived crown widths and estimated DBH and tree heights, respectively, were the best at describing the relationship between stem volume and tree characteristics.展开更多
Wetlands in urban area are an important part of environment. The status of wetland is tightly related with the security and sustainable development of urban ecosystem and society. Jinan is the capital of Shandong prov...Wetlands in urban area are an important part of environment. The status of wetland is tightly related with the security and sustainable development of urban ecosystem and society. Jinan is the capital of Shandong province, China. It is the centre of culture and economy of this province and famous for its springs. So it has important meaning to survey the wetland resources of the urban parks. In this study, the quantity and location of various vegetation types and water areas were obtained using manual classification on QUICKBIRD images. Study results showed that arbor vegetation was domain green land type in the urban parks, so the vegetation structure in parks was reasonable; water quality of the wetlands in the parks was poor, and eutrophication phenomena was obvious in some water areas; the quantity of the water areas has been declined. Through the surveying, we should think that it is a big challenge for the government to protect and restore wetland resources in the parks from 2 respects of quantity and quality in urban area.展开更多
基金the National Natural Science Foundation of China(No.30230420)
文摘There has been a great deal of interest in studying the crown of trees using remote sensing data. In this study, crown width was extracted from high-resolution QuickBird images for open Populus xiaohei plantations. Regression models for predicting the individual stem volumes of Populus xiaohei were established using extracted crown width, as well as estimated tree parameters （i.e. diameter at breast height [DBH] and tree height） as predictors. Our results indicated that crown width could be accurately extracted from QuickBird images using a multi-scale segmentation approach with a mean relative error of 5.74%, especially for wide-spacing stands. Using either extracted crown width alone or with estimated DBH and tree height can successfully estimate individual stem volume of Populus xiaohei with the R2 value ranging from 0.87 to 0.92 depending on different model forms. In particular, the two second-order polynomial models （model 2 and model 6）, based on QuickBird image-derived crown widths and estimated DBH and tree heights, respectively, were the best at describing the relationship between stem volume and tree characteristics.
文摘Wetlands in urban area are an important part of environment. The status of wetland is tightly related with the security and sustainable development of urban ecosystem and society. Jinan is the capital of Shandong province, China. It is the centre of culture and economy of this province and famous for its springs. So it has important meaning to survey the wetland resources of the urban parks. In this study, the quantity and location of various vegetation types and water areas were obtained using manual classification on QUICKBIRD images. Study results showed that arbor vegetation was domain green land type in the urban parks, so the vegetation structure in parks was reasonable; water quality of the wetlands in the parks was poor, and eutrophication phenomena was obvious in some water areas; the quantity of the water areas has been declined. Through the surveying, we should think that it is a big challenge for the government to protect and restore wetland resources in the parks from 2 respects of quantity and quality in urban area.
