Aracteristics And Simulation To Canopy Interception In Typical Natural Forest To Greater Xing’an Mountains South

The present study area which is located on the typical natural forest of the important water conservation in the Greater Xing’an mountains south Xiliao River upstream, researched at aspen forest and white birch forest, analyzed and compared the characters of the canopy interception, stemflow and penetrating rain measured by wild long-term positioning observation method in the both simples, and revealed the characters of typical natural rainfall redistribution in this study area. We used the revised Gash model to simulate the canopy interception of the typical natural forest in the research area, and also analyzed the sensibility of the model parameters. Then we discussed the applicability of the revised Gash model in this study area. According to rainfall data observed in natural experimental areas in 2013 and 2014, combined with laboratory data analysis, we obtained the main results as follow:1. Compared the rainfall characters in the natural aspen forest and the natural white birch forest:the rainfall times, rainfall capacity(including total rainfall, mean rainfall per time and maximum rainfall), mean rainfall intensity of the natural aspen forest experimental area are all less than the natural white birch forest experimental area, but the total rainfall duration and mean rainfall duration per time of the natural aspen forest experimental area are greater than the natural white birch forest experimental area.2. In natural aspen forest, penetrating rain total volume accounted for 69.13%out of forest rainfall during the same period, stemflow total volume accounted for 2.61% rainfall during the same period, canopy interception volume accounted for 28.26% rainfall during the same period; in white birch forest, they are 72.54%,2.47%and 25.00%, respectively.3. In natural aspen forest, penetrating rain volume (R2=0.9647) and stemflow volume (R2=0.9166) were a linear correlated with out of forest rainfall(P＜0.01), for the regression model, there is the greatest stemflow when the out of forest rainfall is 2.07mm; in white birch forest, penetrating rain volume (R2=0.9647) and stemflow volume (R2=0.8462) were also a linear correlated with out of forest rainfall(P<0.01), for the regression model, there is the greatest stemflow when the out of forest rainfall is 2.09mm; thereby, the canopy interception of the natural aspen forest(R2=0.7114) and the white birch forest(R2=0.7077) have a cubic function with out of forest rainfall. From the perspective of canopy interception volume, natural aspen forest is greater than white birch forest.4. In natural aspen forest, canopy water-holding capacity(S) is 0.1327mm, trunk water-holding capacity (St) is 0.0904mm, and stemflow coefficient (Pt) is 0.0437. In natural white birch forest, they are 0.1297mm(S),0.0712mm (St) and 0.0340(Pt), respectively. In natural aspen forest, the simulated value of canopy interception volume and stemflow volume are both decreased 6.25% and 19.30% than the real value, but the simulated value of penetrating rain volume is increased 3.28% than the real value. In natural white birch forest, the simulated value of canopy interception volume is decreased 7.04% than the real value, but the simulated value of stemflow volume and penetrating rain volume are increased 12.42% and 2.15% than the real value, respectively. The revised Gash model is possessed of stronger applicability for the two kind of natural forest in this study area during a certain time, and the model is mainly affected by the ratio of canopy evaporation rate and rainfall intensity (E/R).