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| Spatial variability of throughfall in forest canopy layer of Chinese Pine(Pinus tabulaeformis) plantation in Northern China |
| Zhan Weiqing1,Zhang Zhiqiang1,Wu Jun2,Xiao Jinqiang1 |
| 1.Key Laboratory of Soil and Water Conservation & Desertification Combating,College of Soil and Water Conservation,Beijing Forest University,100083;2.Beijing Water Conservation Forest Experimental Station,100029: Beijing,China |
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Abstract The interception of rainfall by vegetation and the subsequent evaporation of intercepted water from canopy surface play an important rule in hydrological processes,water and energy balance of forest ecosystem.Spatial variability of interception has different effects on runoff yield from watersheds located in different climatic and biome regions.In order to indicate spatial distribution characteristics of interception,rain-gauges were installed by grid-sampling method to measure throughfall.Results show that the coefficient of variation(Cv) of throughfall tends to be declined as rain intensity increases.After canopy is saturated,Cv of throughfall was(remained) at a constant value,which is close to the Cv of leaf area index(LAI) value 0.18.So the Cv of LAI is regarded as extremum of that of throughfall.Because of the special characteristic of Chinese pine(Pinus tabulaeformis),and the lower droopy branches,negative values for interception account for 13% of the total samples,thereinto the max is above 70% of gross rainfall.
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Received: 01 June 2005
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