关键词: 水分循环, 北京土石山区, 同位素, 侧柏, 栓皮栎

Abstract: Currently, urban nitrogen metabolism is a hotspot of the urban metabolism research, the framework of which is to regard the urban region as an organism of nitrogen metabolism, exploring the human impacts on the process of the anthropogenic reactive nitrogen metabolism in urban regions as well as the related potential environmental problems. Based on elaboration of the concept and the research background of urban nitrogen metabolism, this paper attempts to introduce the progress of the research of urban nitrogen metabolism by application of material flow analysis, and to reveal the prospect of the modeling research of urban nitrogen metabolism by application of system dynamics models. Finally, the future development in the research of urban nitrogen metabolism is discussed from three perspectives as follows: The nitrogen metabolism analysis within an urban region, the fate of industrial nitrogen in urban nitrogen metabolism, and the application of nitrogen footprint in the research of urban nitrogen metabolism. The definition in the boundaries of survey regions and the fate of nitrogen flows is the key to accurately analyze the processes of urban nitrogen metabolism at different scales. At present, there are few researches on the analysis of the urban nitrogen metabolism in China. Therefore, to explore the methods of multiscale analysis and the indexes for evaluation of the urban nitrogen metabolism can provide theoretical support for the reduction of anthropogenic reactive nitrogen emissions in urban
regions.

Key words: Quercus variabilis, water cycle, rocky mountain area of Beijing, isotope, Platycladus orientalis