Water Holding Characteristics of Coarse Woody Debris in Abies georgei var.smithii Forest of Sygera Mountains of Tibet

REN Yihua; HOU Lei; MA Haoxia; ZHA Xilamu

doi:10.3969/j.issn.1003-6504.2017.03.012

Abstract：Coarse woody debris (CWD) is a very important structural and functional unit of forest ecosystem,which plays an important role in the water conservation function of the ecosystem.In order to understand the water holding characterstics of coarse woody debris in Abies georgei var.smithii forest of Sygera Mountains of Tibet,typical sample plot method was utilized to survey and sample coarse woody debris in the ecosystem,then measure its water absorption,water absorption rate and water holding potential with soaked-simulation method.Water absorption,water absorption rate and water holding capacity of CWD in the process of their absorption water showed that high decay level higher than the low decay level.The relationship between water absorption and soaking time presented logarithmic function y=alnx+b,and the relationship absorption rate and soaking time power function y=ax-b,both reached a significant level (p＜0.01).CWD density decreases with the level of decay increase,the saturated water absorption increased with the level of decay increases and the saturated water absorption raised with decreasing density,those relationships were binomial function y=-0.004 7x2-0.034 3x+0.443 6,binomial function y=0.393 2x2-1.569 3x+2.070 5 and the power function y=0.153x-1.661 respectively,the first two significant level of p＞0.05,and the later reached a significant level (p＜0.05).CWD reserves was 60.363 t/hm2,the maximum water storage capacity 98.420 t/hm2,the effective storage capacity 83.657 t/hm2,equivalent to 8.366 mm of rain.The results provided a solid foundation for further research on eco hydrological function of coarse woody debrisin Abies georgei var.smithii forest of Sygera Mountains.