[Comparison of leaf decomposing rate in a headwater stream in Xiangxi River catchment]

With the litterbag method, the decomposition of leaf of 4 tree species growing in riparian forest in a headwater stream was investigated in 90 d consecutively in Xangxi River catchment. The results showed that the loss rate of dry weight of leaf differed among 4 species. The loss rate of dry weight of Pterocarya insignis and Cercidiphyllum japonicum was 77% and 71%, and shat of Fagus engleriana and Cyclobalanopsis multinervis was 43% and 42%. Using exponential equation, the loss process of dry weight of leaf was modeled. According to the value of constant k, 4 species could be divide into to fast group and medium group. The invertebrate was also collected, and there were 22 species, belong to 3 classes, 6 orders, and 21 families. The quantity of invertebrate differed in each tree species litterbag and different periods. The invertebrate was rich in number and small in body during early time of leaf decomposing, and it was less in number and big in body during middle and late time of decomposing.