| The north area of Hebei province is located in the semi-arid to sub-humid transition zone belonged to the northern pastoral area, the problem of land degradation is serious and lack of water resources.The forest ecosystems in North Mountain of Hebei Province had an important role in conserving soil and water and improving ecological environment, but aslo for"building a green screen for Beijing and Tianjin". This paper studied three typical forests (the mixed forest of Larix and Betula,the mixed forest of Populus and Betula,the mixed forest of Pinus and Mongolicain) of the region, and analyzed the hydro-ecological effects of forest canopy,litter layer and soil layer. Finally, the hydro-ecological effects were comprehensive evaluated, to show the forest hydrology and ecological mechanism and to provide technical support for forest management. The results showed that:(1) With the increase of rainfall, throughfall rainfall, stemflow and canopy interception were increased, but canopy interception rate droped.the canopy interception of the mixed forest of Larix and Betulahe and mixed forest of Pinus and Mongolicain was more than the mixed forest of Populus and Betula. The canopy interception ability of coniferous forest was stronger than broadleaf forest.?Finally, the effect of simulating the process of simulated canopy interception with the revised Gash model is better.(2) The litter reserves: the mixed forest of Pinus and Mongolicain(64.28t·hm-2)>the mixed forest of Larix and Betula(39.49t·hm-2)>the mixed forest of Populus and Betula(35.80t·hm-2). The maximum litter water-holding ratio: the mixed forest of Populus and Betula(354%)>the mixed forest of Larix and Betula(272%)>the mixed forest of Pinus and Mongolicain(240%). Litter effective storing amount: the mixed forest of Pinus and Mongolicain(128.15t·hm-2)>the mixed forest of Populus and Betula(82.27t·hm-2) > the mixed forest of Larix and Betula(69.22t·hm-2), Litter interception: the mixed forest of Pinus and Mongolicain(15.55mm)>the mixed forest of Populus and Betula(10.56mm)>the mixed forest of Larix and Betula(8.86mm).(3) Soil bulk: the mixed forest of Pinus and Mongolicain>the mixed forest of Populus and Betula>the mixed forest of Larix and Betula.Field capacity: the mixed forest of Populus and Betula>the mixed forest of Larix and Betula>the mixed forest of Pinus and MongolicainSoil infiltration rate, the mixed forest of Larix and Betula: downslope>midslope>upslope, the mixed forest of Populus and Betula: upslope>midslope>downslope, the mixed forest of Pinus and Mongolicain: midslope>downslope>upslope.Soil water content of June,August and September was bigger than July. Soil water content of the mixed forest of Larix and Betula and the mixed forest of Pinus and Mongolicain concentrated in the 0-30cm soil layer mainly, upslope and downslope>midslope. Soil water content of the mixed forest of Populus and Betula concentrated in the 0-20cm soil layer mainly, upslope>midslope>downslope.(4) Transpiration of trees was low in May and June.Transpiration of trees was growing in July and August. Transpiration of trees reduced in September.In the year of 2010, transpiration of trees of the mixed forest of Larix and Betula was 100.70mm,the mixed forest of Populus and Betula was 129.78mm,the mixed forest of Pinus and Mongolicain was 105.48mm.Using the multiple linear regression method to regress correlation of environmental factors and flow rate, total radiation,air temperature and humidity were the main factors on a sunny days, total radiation and air temperature on a cloudy day, soil water content an a rainy days.(5) Evaluate 3 forest of the mixed forest of Larix and Betula,the mixed forest of Populus and Betula,the mixed forest of Pinus and Mongolicain in North Mountain of Hebei Province with the method of AHP, it showed that: the mixed forest of Larix and Betula(1.0511)>the mixed forest of Pinus and Mongolicain(0.9880)>the mixed forest of Populus and Betula(0.9251). The water conservation of the mixed forest was greater than the broadleaf forest.
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