| In the mutual function and influence of forestry vegetation and ecological system, the process of hydrology is one of the most important aspects. However, Forest and water have an intently relationship with each other. It depend on the development of forestry ecological system itself, and space variability such as landforms geology, soil pattern, vegetation and meteorological phenomena such as rain, interpenetration, vaporizing. So the relationship between them is still the hot topic of bionomics and Hydrology. For the past decades, from the traditional areas of comparative test basin, the study develop into other areas of the comprehensive study which are changes in forest ecosystems, the formation mechanism of forest slope of the impact of runoff to the watershed scale, dynamic mechanism of forest influencing basin biogeochemistry, establishment based on process forest hydrology simulation, tracer study of fluent way.This research selects two type places in Chang Sha horizon range tree farm woodland Liquidambar formosana artificial forest, each type place area is 20 X 30 m2, each type place selects 10 different stem levels of the Liquidambar formosana to take the standard tree to carry on the long-term localization observation. From May,2007 to March,2008,1 have carried on 11 month-long hydrology data collections and the reorganization to study the moisture content law of motion of Liquidambar formosana planted forest ecosystem and the content tendency change rule of chemical element. Below this research obtains the main conclusion:(1)The total precipitations of this system are 817.8mm in 11 months, in the forest precipitation only accounts for the total precipitation 81.99%, the forest crown interception quantity per year to account for the year precipitation 18.01%. The rain water which enter in the Liquidambar formosana artificial forest mostly are the water percolation, accounting for only the precipitation 80.3%, the water volume which enter in the forest as the bough stem manifold type is 13.8mm, accounting for the year precipitation 1.69%.(2)Outside the forest the precipitation change is quite obvious in different season, precipitations of the fall and the winter are small, precipitations of the spring and the summer are big; the rate of water percolation is the highest in the spring, lowest in the winter, the seasonal variation scope is not big; The bough stem rate of discharge's seasonal variation scope is smallest, which is the highest in spring and lowest in the winter, which show bough stem class's seasonal variation is not obvious. The forest crown interception rate happen to be opposite with the rate of water percolation and the bough stem rate of discharge, which is highest in the winter, lowest in spring, the change scope are nearly two times, the seasonal variation scope will be most obvious.(3)When precipitations are below 10mm, the Liquidambar formosana forest penetration coefficient is 59.23%, the main current rate is 1.03%; When precipitation located between 10mm and 20mm, the penetration coefficient is 74.7%, the main current rate is 1.39%; When precipitations are above 20mm, the penetration coefficient is the biggest, achieving 84.16%, the main current rate also maximize 1.61%. Regarding the different rainfall magnitude, the penetration coefficient and the bough stem rate of discharge increases along with the precipitation increases. But the forest crown interception quantity increases along with the precipitation assumes the decreasing progressively tendency.(4)Moisture content of various soil layers soil presents the regular change in a year:moisture content of the surface layer soil is quite high, along with soil layer depth's increase, the water content reduces gradually. Soil layer water content is biggest between 0cm and 15cm, next best between 15cm and 30cm, the smallest in Soil layer water of above 30cm.(5)After the precipitation arrives at the forest, various components in the hollow, the bough, the underbrush and the soil level and so on occurs redistributes, during this process, the pH value changes. Outside the horizon range tree farm forest the pH value of the precipitation, the through-fall, Stem-flow respectively is 6.40,6.31 and 6.27. pH value's change of various processes is not obvious, the overall tends to the neutrality. In the process of precipitation redistribution, the PH value has the obvious seasonal variation, the average value of PH value of the precipitation, through-fall, stem-flow vary from low to high according to the winter, the autumn, the spring, summer's arranged in order. The change of PH value's average value of the spring, the summer and the autumn is not obvious. In the precipitation redistribution process, the pH value has little relations with the rainfall.(6)Precipitation outside the forest is highest by the Ca element content and lowest by the Cu element content. Inorganic condition N (NO3--N and NH4+-N) is primarily by NH4+-N, and is higher than nearly 4 times compared with NO3--N. The order of various chemical element content in the precipitation outside the forest is:Ca >NH4+-N>Zn> K>NO3--N>Mg>Fe>Cd>Mn>P>Cu. The content of NH4+-N,NO3--N,P,Ca,K,Mg,Cu,Mn in through-fall and stem-flow assumes the trend of escalation, the element content of Mn increases the scope to be biggest, the order is Mn>K>Mg>NH4+-N>P>Ca>NO3--N>Cu. The element content of Fe, Zn, the Cd in through-fall and stem-flow assumes the declining trend, and the decline rate is various. Inorganic pollutants heavy metal element Cd which is big toxicity in the precipitation outside the forest, it can not be examined in through-fall and stem-flow, which explain the level and the bough of Liquidambar formosana have the adsorption to heavy metal element Cd and have certain purification to the mospheric water. And the declining rate of element content of Zn surpasses 8 times, that of Fe is 2 times. All of which explain the Liquidambar formosana has the strong absorption, adsorptive capacity of the element of Zn and the Fe.(7)For the synthesized influence of rainy condition, the environmental condition, the meteorological condition, the human activity, various chemical element content change has the big randomness in the different time'atmospherical depreciation at the identical area, input value of each month is obvious. The overall displays are that it is low in the micro rainy season and high in the dry season. In the process of precipitation redistribution, various elements content increases along with the precipitation reduces, various chemical element content is low in the rainy season and high in the dry season, the majority element content display the obvious season dynamic change along with the precipitation season.
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