Hydrologic Effect of Canopy Layer of Typical Vegetation in Ecological Rehabilitation Region in the Upper Stream of Huangqian Reservoir

It studies the hydrological effect of canopy layer of typical vegetation type in the ecological rehabilitation region of soil and water conservation in the upper stream of Huangqian Reservoir in Tai’an City of Shandong Province, by using the principle of forest hydrology and water balance and the method of fixed sample plot. The outcomes show that ①under the conditions of P=18 mm, the sequence of the canopy interception of different trees in the ecological rehabilitation region is Pinus tabulaeformisPinus densifloraPlatycladus orientalisQuercus acutissimaRobinia pseudoacacia, but the similar law has not been found in the amount of stemflow and the throughfall in forest area, and the canopy interception of the coniferous forest is greater than that of the broadleaf forest. ②The main influencing tendency of different afforestation density to the canopy interception is the greater density the more canopy interception, conversely, the less interception; the variation law of the throughfall in forest area and the canopy interception shows contrary character. ③The forest stand of different canopy density and different afforestation density is the same to the precipitation redistribution. ④The sequence of interception of forest stand in different mixed patterns is mixed Pinus tabulaeformis, Quercus acutissima and Robinia pseudoacaciaPinus tabulaeformismixed Pinus tabulaeformis and Quercus acutissimamixed Pinus tabulaeformis and Robinia pseudoacaciaQuercus acutissimaRobinia pseudoacacia; the regular pattern of the amount of stemflow and the throughfall in forest area is not obvious. ⑤When precipitation is smaller(P=4.50 mm), the canopy interception of typical vegetation in the ecological rehabilitation region is very obvious and the rate of canopy interception is greater; the amount of stemflow increases gradually along with the increase of rainfall and the rate of canopy interception is the trend of decrease.