| In this paper, the characteristics of rainfall interception by Pinus tabulaeformis plantation in Miyun reservoir watershed were studied. By measuring precipitation outside the experimental forest and throughfall, stemflow in the forest located in Beizhuang Forestry Station of Miyun, rainfall interception by canopy of Pinus tabulaeformis plantation in various rainfall events with different intensities in various periods was computed; the relations between precipitation and interception in individual rainfall events were simulated using various statistical models, theoretical models and semi-theoretical models; through analysis of annual rainfall distribution by the forest, proportions of interception components were computed and compared; the generation of stemflow was analyzed; from the statistics of monthly rainfall distribution, the relationships of monthly precipitation with monthly interception, monthly stemflow, monthly interception rate and monthly stemflow rate were analyzed; the characteristics of rainfall interception by Pinus tabulaeformis plantation in Beizhuang were compared with Pinus tabulaeformis plantations in western watershed of Miyun reservoir, Robinia pseudoacacia and Castanea mollissima plantations in Beizhuang by comparison of relevant parameters. The main results of this study were:(1) Rainfall interception by canopy is influenced by multiple factors in meteorology, canopy patterns and site conditions. Therefore, it is almost impossible to conclude the law of interception simply by analyzing the relationship between precipitation and interception. Similar with most domestic and foreign studies, this study could not arrive at stable curve simulation on the relationship between precipitation and interception in individual rainfall events. However, it is obvious that nonlear models can perform more satisfactorily than linear models in the simulation.(2) While indices of climate and canopy were replaced by empirical factors, a simplified semi-theoretical model was advanced on the basis of models advanced by Liu J.G and Aston:(3) The canopy storage of Robinia pseudoacacia and Castanea mollissima plantations were all less than that of Pinus tabulaeformis plantation. The canopy storage of Pinus tabulaeformis plantation in Xiwengzhuang was far less than that of Pinus tabulaeformis plantation in Beizhuang. Greater canopy capacity was reflected in the rainfall interception by Pinus tabulaeformis plantation in Beizhuang. (4) Monthly throughfall and monthly stemflow all had obvious positive relationships with monthly precipitation with higher rates of simulation than those for individual rainfall events. However, monthly interception rate, monthly throughfall rate and monthly stemflow rate did not demonstrate obvious relationships with monthly precipitation.
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