The Studies Of The Function Of Resisting Wind, Stabilizing Sand And Fixing Carbon Of Vegetation In The Middle And Lower Reaches Of Tarim River

Tarim River is the biggest interior river in China, which green vegetation corridor along coast is the last barrier for preventing desert invasion. Studies on the function of vegetation growing in the lower reaches of Tarim River, such as resisting wind, stabilizing sand and fixing carbon can help us know the function of destroyed ecosystem and offer important theory support for the vegetation restoration in this region. The results of the researching are shown as followed:According to investigation data on protective effect of six different plant species in the middle and lower reaches of Tarim River, the order of the ratio of protection effect is Karelinia caspica>Poacynum hendersonii> Alhagi sparsifolia> Tamarix ramosissima>Halostachys caspica >Populus euphratica. As regard to three life-form of vegetation tree, shrub and herb, the order is perennial herb>shrub>tree.With the degree of vegetation coverage increasing, the windproof potency of vegetation increases. In addition, vegetation can enormously reduce sand transport. By using investigation data on spot and Matlab5.3, this paper established the model of quantitative relationship between vegetation coverage in the lower reaches of Tarim River and effective wind encroaching velocity:V 1 = Vexp( ?0.00722c?0.000116c2), also induced the effective vegetation coverage in the middle and lower reaches of Tarim River. Under the common wind velocity (10～15 m/s), the effective ratio of vegetation coverage should be over 50% for preventing wind erosion.Through decreasing wind velocity of the windward and leeward, the shrub clumps of Tamarix spp could accumulate sand along the bottom of vegetation. The order of correlation coefficient between accumulated sand volume and morphology variables of Tamarix spp is: crown>dry weight of leaves>aboveground biomass>height>basal diameter>number of basal branchs.The protective effect of forest belt is focus on leeward side, while pear orchard's is focus on inside The order of the two artificial vegetation on sand resistance is pear orchard>forest belt.The Carbon storage and the quantity of fixed CO₂ every year in Ying Bazha section of middle reaches of Tarim river ecosystem are 99.68 t/hm² and 7.61 t/hm² respectively。The two indexes referred above of lower reaches of Tarim River are far below that of middle reaches. In addition, with the distance to river increasing, both Carbon storage and the quantity of fixed CO₂ every year gradually drop in lower reaches of Tatrim River, however, the Carbon storage of vegetation debris shows ascending trend on the contrary.