Effect Of Forest Canopy On Redistribution Of Rainfall And The Characters Of Litter Form On Liupan Mountains

In the paper, the canopy interception, stemflow and rainfall and the characters of litter-form in main forest stand of Liupan Mountains are studied.The main results are shown as follows:(1) The interception capacity increased along with precipitation, but the interception ratio decreased along with precipitation. When the precipitation was 0～5mm, the interception ratios were about 50%～65%. When the precipitation was greater than 20mm, the interception ratios of most forest vegetation were below 20%.(2) The relation between stemflow and precipitation was linear function. When precipitation was little, the stemflow was hardly. When precipitation was more, the stemflow also was more. The diversities along different tree species were larger and the stemflow changed in different season.It had a critical precipitation when the stemflow happened and many factor, such as former precipitation and tree spcies, could influenced the stemflow happened. The stemflow ratios were difference in different vegetation types. Many factor can influenced stemflow ratios, such as shape structure, bark features, the degree of angle between branch and tree trunk, and so on.(3) The rainfalls in stand had close relation between precipitations out of forest stand. The greater of the precipitations and its intensities, the more of the rainfalls in stand. When the rainfall beginned, rainfalls in stand also increased with nonlinear function. When the interception capacity of forest canopy near to saturation, the rainfalls in stand increased with linear function. The relation between rainfall ratios and precipitations out of forest stand were nonlinear function. When the rainfalls were less or the rainfalls just beginned, the rainfalls ratios in stand increased with the precipitations increased. With the precipitations increased to fixed level , the rainfalls ratios in stand increased slowly and finally tended to steady figure.(4) The amount of litter-form in different stands has a large gap. The stand of Quercus liaotungensi has the largest storage, reached 34 t/hm~2,next is Pinus tabulaeformis , Betula albo-sinensiand Pinus armandii, the smallest is shrub,which only is 13.38t/hm~2. there is great difference in water holding capacity between half-decomposed and un-decomposed litter form, which show the degree of decomposability has great influence.