| Jinyun Mountain is an ideal natural laboratory for studying and evaluating on water and flood regulation by forest. It conserves the integrated subtropics evergreen broad-leaved forest types in the three-gorge reservoir area. In 1999, the forest ecology beneficial monitoring station of Chongqing Jinyun Mountain, starts to construct, provided with automatic forest hydrological monitor. It can tell the living process of forest ecological changes. In this dissertation, there are 8,619,840 effective firsthand monitoring data from June, 2001 to July, 2003, with 4 heavy rainstorm days, 8 rainstorm days, 23 heavy rain days, 43 middle intension rain days, and 293 rain days.When rain falls into forest environment, the forest and soil can be expressed by a reservoir, which regulates water. We call the action water and flood regulation by forest. This forest service has timeliness, extensity, and variability, complexity, coupling, and predictability, changes with its growth and rain temperament.The simulation by WEPP model is rather better on runoff changing with rainfall and the growth situation of vegetation in the field. One way is gived for translating climate data into WEPP. WEPP model acts as very efficient fictitious interfaces to study and evaluate on water and flood regulation by forest.When artifical neural net (ANN) model views ( study, recollection ) the nonlinearity appearance of water and flood regulation by forest, it remembers regular pattern (training ),and forecasts the forest circle function dissectionally.When there is fog or little rain, the crown can catch fog or little rain together, so in forest environment the rainfall by fog drip is more than the open air at Jinyun Mountain.The relationship between canopy interception storage Y (mm) and rainfall X (mm) at Jinyun Mountain isIf the inputs of BP model are crown closure, DBH, H, age, under branches height, density, crown breadth, rainfall, rain intensity, wind velocity, air temperature, humidity, and the output is canopy interception storage, the rights in order are: 0.988053, -0.0358021,0.406472, -0.0675435, 0.225698, 0.412862, -0.00698586, -1, 0.652695, 1, -1, -1, -0.154032,but the real weights in order are: 0.0718,0.0772,0.0837, 0.1600,0.0210,0.0008, 0.1849,0.2406,0.0428,0.0523,0.0325,0.0325.The stemflow of Mao bamboo can be observed when the rainfall is over 0.3mm, and it almost flows along the same route. The rate of stemflow to rainfall is 26.3%, and the largest stemflow is over 19.8L/h in a tree. The relationship between stemflow and rainfall is 4 stairs multiple nonlinearity (R2>0.9), and for the age of it is Weibull (7.5,1991.9,4.8,1.4). If the inputs of BP model are DBH, H, under branch height, age, and the output is stemflow, the rights in order are: 1.91161,1.88262,1.99452, -3.83706, -3.37618, -1.98549, -2.1501, and the real weights in order are:0.088,0.186,0.197, 0.17,0.103,0.256.Mixed forest (Pinus massoniana Lamb, x Gordonia acuminata H. T.Chang) reservoir throws away its water for 300 days in a year. In a day, the minimal erosion rainfall is 12.76mm, interception is 6.9mm,and the average rate of surface flow is 0.044.The trees rain when rainfall is 0-4.3mm,and start 0.3h earlier, 8.0h later than the open air.Broad leaved forest (Gordonia acuminata H. T.Chang) reservoir throws away its water for 320 days in a year. In a day, the minimal erosion rainfall is 13.22mm, interception is 7.8mm,and average rate of surface flow is 0.017. The trees rain when rainfall is 0 -5.3mm,and start 0.5h earlier, end 10.Oh later than the open air.Mao bamboo forest reservoir throws away its water for 220 days in a year. In a day, the minimal erosion rainfall is 11.40mm, interception is 4.8mm, and average rate of surface flow is 0.036. The trees rain when rainfall is 0-3.3mm,and start 0.2h earlier, end 6.0h later than the open air.In a day, minimal erosion rainfall of brush and slope field is 12.76mm and 10.76mm, and the average rate of surface flow is 0.038 and 0.028.The indexs of evaluation on water and flood regulatio...
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