Comparatively Study On The Characteristics Of Litter Of Different Forest Types In Tongguling National Nature Reserve On Hainan Island

Tongguling Nature Reserve is located in the northeast coast of Hainan Island, it has rich vegetation types, the shrubbery and tropical evergreen monsoon elfin forest were the major vegetation types, and the latter was the climax vegetation types. The physiognomy, floristic composition and composition structure of Tongguling community are different from those of other tropical forest in Hainan Island. Litter characteristics and its influencing factors were studied in the shrubbery and monsoon elfin forest, compared with the montane cloud forest, Pinus latteri forest in Bawanglin Nature Reserve and the mountane rainforest in Wuzhishan Nature Reserve. The results showed that:(1) The annual litter and organ composition were different in different forest types, and the order of1annual litter: The shrubbery (6.227t/hm2)> Monsoon elfin forest(5.636t/hm2)> Pinus latteri forest(5.403t/hm2)> Montane cloud forest(5.305t/hm2)> Montane rainforest (3.753t/hm2). In the shrubbery, The litter of leaves, branches, fruit accounted for the proportion of the total litter is60.93%,18.31%,17.18%; and the three proportion of monsoon elfin forest is68.16%,19.31%,7.84%; The Pinus latteri forest is56.79%,30.42%,10.32%; the three proportion of montane cloud forest is72.26%,21.74%,5.89%; the mountain rainforest is64.42%,25.34%,5.58%. A comparative study has fully demonstrated that the total forest litter is closely related to forest types and its fruit composition, and the relationship between the leaf litter amount and total litter amount is most closely related; in addition, the total litter of coastal forest was more than the non-coastal forest. Further studies showed that, There was no significant correlation between litter characteristics and stand characteristics of the shrubbery, but in the Monsoon elfin forest, leaf litter and stand density was significantly positively related(R=0.495, n=25), the total litter and stand density is significant positive correlation (R=0.477, n=25).(2)60kinds of leaf litter species were collected in the shrubbery plots and78kinds were collected in monsoon elfin forest plots, the leaf litte of each species was accounted for the proportion of total leaf litter, found that the amount of Aeronychia oligophlebia, Oligostachyum nuspiculum, Aporosa yunnanensis and other15species accounted for77.72%in the shrubbery, which is the dominant species and main species of litter; the amount of Syzygium tephrodes, Syzygium acuminatissima and Aeronychia oligophlebia and other17species accounting for71.84%in monsoon elfin. Further studies showed that, the leaf litter amount of dominant species and main species and tree density were significantly positive correlation (R=0.826, n=12), and were significantly positively related with the total basal area (R=0.970, n=12), and also significantly positively correlated with the crown area (R=0.955, n=12); In monsoon elfin forest, the leaf litter and the species composition is significantly positive correlation (R=0.607, n=17). Fully explain the amount of forest litter is closely related to the species composition of leaf litter.(3) The seasonal dynamics of the litter production were different in different forest types, the results showed that: A double-peaked curve described the dynamic of the annual litter production in the shrubbery and monsoon elfin forest, and the highest point occurred in spring and autumn; Leaf litter was double peak in the shrubbery, and it peaked in autumn, exhibited a single peak in monsoon elfin; Besides the montane rainforest, the branch litter were single peak; Besides the shrubbery, the others dynamics of fruit litter showed a single peak. In the dominant species and major species of litter of the shrubbery and monsoon elfin forest, most of them peaked in the autumn and winter affected by the typhoon, but the seasonal dynamic of different leaf litter were different. According to its seasonal dynamics of leaf litter, they can be classified into four types: the deciduous trees had a peak of leaf litter in the autumn and winter; the evergreen trees had a peak of leaf litter in the spring; the evergreen trees had a peak of leaf litter in the autumn or winter; the evergreen trees had a peak of litterfall in both winter and autumn.(4) Jaccard similarity coefficient were used to evaluated the similarity of litter composition and community species composition.The results showed that:The composition of forest communities have a different influence on the composition of leaf litter in different forest types.The Jaccard similarity coefficient is20%in the shrubbery, and25.93%in monsoon elfin forest, indicating that the two kinds of forest communities, the consistency of community species composition and leaf litter composition is not very high. In tropical forest communities with more superior, forest dominant species is not the same as the dominant species litter, need specific conditions.(5) In the shrubbery and monsoon elfin forest, take the three topographic factors (aspect, slope, bare rock) to analyze the influence for total litter, leaf litter, branche litter, fruit litter. The correlation analysis showed that: there was no significant correlation between the litter characteristics and the terrain factor in the shrubbery and monsoon elfin forest, the results explained the litter characteristics is not related to micro-topography in160m x160m square of two different forest types, therefore, if we want to study the relationship between litter characteristics and terrain,we may require a large sample area to conduct more study.