Study On Community Features And Dynamic Of Public Welfare Forest In Central Zhejiang

The construction of ecological public welfare forest was the main part of ecological construction inZhejiang province.Carrying out this study to master public welfare forest community structurecharacteristics and community succession dynamic rule for the guidance of the central region inZhejiang province and vegetation restoration, public welfare forest management and ecologicalconstruction is of great scientific and realistic significance.Using two order sampling method set up517public welfare forest typical sample plots in thisstudy, Application of vegetation ecology quantity analysis method, to quantitative analysis differentcommunity types of structure characteristics. Basing on space instead of time to analysis of the dynamicrule of community succession.The results were as follows.（1） Studying six types of forest communities in Central Zhejiang; pine, fir, broad-leaved coniferousand broad leaved mixed, phyllostachys pubescent, and scrub growth forests,It shows that dueing to thehuman to the central region of the excessive use of forest resources, the original forest vegetation washuge damage, leaving behind only a small amount of major diameter level of trees, the public welfareforest community in horizontal structure have a consistent trend, all present inverse "J" type, that withthe increase of diameter at breast height, tree species number of proportional decrease gradually.Overall, the community advantage species were relatively single, especially the tree layer dominant treespecies composition, less relatively concentrated, species conservation ability and community stabilitywere needed to improve. But the major advantage of population in central Zhejiang province publicwelfare forest changed with community positive succession law, in the future, paying attention to thepublic welfare forest management in succession Schima superba, Cyclobalanopsis glauca etcadvantages in population tending to transform and upgrade the quality of broad-leaved forest, acceleratecommunity positive succession was particularly important.（2） The biomass and carbon storage, productivity and biodiversity were the quantity reflectof structure and function in public welfare forest.Biomass and carbon storage estimate were evaluationof public welfare forest quality, especially the key link of carbon sequestration ability, this study appliesbiomass model method estimated the biomass and carbon storage in Central Zhejiang province publicwelfare forest. The results show that the unit biomass of the public welfare forest was99.30t·hm^-2,existing total biomass was16430.25×10⁴t, Vegetation carbon density for an average of49.59t C·hm^-2,the total carbon storage was8205.54×10⁴t C.Since2006, biomass and carbon storage of public welfareforest have been growing rapidly, the annual net growth of biomass was6.39t·hm^-2·yr^-1and thecumulative growth of carbon storage was4291.25×10⁴t C, which plays a significant role in keepingforest ecological system stability in central Zhejiang. The analysis also demonstrates that while thecarbon density was seriously affected by human interference. Finally, the study establishes a modelcomposed by stand age and density of tree to estimate the carbon density of public welfare forest incentral Zhejiang which could guide the forestry operation and management.（3）A study of Zhejiang public welfare forest net primary productivity has found that the vegetationrecovery effective, the NPP of pine, fir, broad-leaved coniferous and broad leaved mixed forestcommunity was5.52t·hm^-2·y^-1,6.47t·hm^-2·y^-1,7.09t·hm^-2·y^-1and8.56t·hm^-2·y^-1. Besides, vegetationbiomass and NPP has a high correlation, but the advantage of this relationship on a larger scaleprediction community productivity has a great uncertainty, so getting productivity estimation value more reliable need the local parameters by type classification for detailed statistics, which the publicwelfare forest management has higher guidance significance.（4）The richness, diversity index, evenness index and dominance index of different public welfareforest community types and different layer species diversity in central Zhejiang were calculated. Theresults showed that Patrick index and Gleason index of public welfare forest community speciesrichness description in central Zhejiang was consistent, the sequence of community species richness wasbroad leaved mixed> broad-leaved coniferous> phyllostachys pubescent> fir> pine> scrub growthforests.For different levels of species richness, two index of pine,fir, phyllostachys pubescent,scrubgrowth forests community all represent the shrub layer> herb layer> tree layer; Broad leaved mixedand broad-leaved coniferous forests were mixed in the tree layer has higher abundance. In addition, thepublic welfare forest shrub layer and herb layer plant species diversity in central Zhejiang were higherthan others, it was close to or higher than southeast China climax of Gleason index, but the abundanceof tree layer was relatively low, and the gap is expected to gradually narrowed as public welfare forestvegetation restoration progressing.The effect of the community types and structure force on the biological diversity index isremarkable. Shannon-Weiner index, Pielou evenness index and Simpson’s dominance index wereconsistent with the public welfare forest community biodiversity description in central Zhejiang.Species diversity index in different community were different, Two reasons for this kind of differenceswere community development stage and habitat conditions; And there were also some fluctuations thatdifferent levels of species diversity index have different laws, but it conform to the forest woody plantspecies diversity was obviously higher than the tree layer which was an universal law.Comprehensivedifferent community, different levels of species diversity index can be concluded that the broad-leavedevergreen forest especially as subtropical areas of the zonal vegetation in the community, has a hugeadvantage with Shannon-Weiner index, Pielou evenness index and Simpson ’s dominance index, whichis of great significance to protecting the diversity of ecological environment in central Zhejiang.（5）The public welfare forest community dynamic change in Zhejiang province is very quick, ischanging from shrubbery to coniferous forest, and from the coniferous forest to broad-leaved forest. Inthe Succession, succession middle and later population Schima Superba, Castanopsis Sclerophylla, andCyclobalanopsis Glauca succession progress in the community advantage layer, instead of a recessionkind of Pinus Massoniana become a community of dominant species. With this change, the tree densityin internal community improved which change from1207.50plant per hectare increases to2370.00perhectare, about10species increase （every400m2）. In the community succession, the competition wasintense, kinds of quantity and structure are notable changes have taken place, population decline in thediameter distribution of general level number declines, and progress in each diameter level densityrising trend presented instead. On Vertical structure, the high level of progress of density increasegradually, while recession was relative low, at the same time, during to the rapid growth of density oftrees, community average height growth was not obvious, only increase from6.35m to6.78m.It is that community structure defined function changes, the average community biomass increasefrom80.90t.hm^-2to156.12t.hm^-2.Relative to understory biomass which was basic stability, tree layerbiomass change intensely, increase from51.69t.hm^-2to116.11t.hm^-2. The biomass of progress species insuccession later occupy absolute advantage and has an obvious control action which was69.38t.hm^-2,accounting for59.76%.The size of the vegetation carbon density was controlled by forest age anddensity, in the succession, vegetation carbon density increase by pine forest40.34t C·hm^-2to evergreenbroad-leaved forest78.02t C·hm^-2. All levels show different characteristics, tree layer for increasing, herb layer for decreasing, and shrub layer was relatively stable, indicating that tree layer determines thesuccession process changes in vegetation carbon density; Accordingly, the NPP of pine forest was5.66t·hm^-2·y^-1, increased1.71times to evergreen broad-leaved forest9.68t·hm^-2·y^-1.The recovery of species diversity was a key to recovery ecological system function and structureeffectively. From the early succession to the later stages of succession community, species increasedabout ten kinds （every400m2）; Community of Shannon-Weiner index rose from2.38to3.38. Thehomogeneous degree of tree layer rose from0.29to0.96, which suggest that in pure forest of Pinusmassoniana, the number of tree species distribution was non uniform, Pinus massoniana individualswas occupied with randomness in tree space, usually around them window was left, in where the youthin the community could positive broadleaf tree layer; This also reflected in the dominance of tree layers,which rose from0.10to0.72, indicating that tree layer was changing from Pinus massoniana which wasa single strong positive dominated species to the Schima superba, Castanopsis sclerophylla, andCyclobalanopsis glauca etc evergreen broadleaf species whom had an optimal pattern.Niche breadth and niche overlap of major plant in central Zhejiang were studied according to nichebreadth and niche overlap formula of Levins. Analysis shows one of the factors affecting the nichebreadth and the overlap size of species is the distribution frequency. In the data analyzed, the larger thedistribution frequency was, the probability of forming species niche overlap with other plants was larger.Along with the function status changes of main population in the community succession, the populationdistribution frequency, important value appeared more regular change, dominant population have widerniche, the resources are the most widely used; In succession the changes of tree layer species numberand type have a most rapid increase, niche overlap increases more rapidly than niche differentiation,resulting in potential competition strength increases and the niche overlap rise; On the contrary, nichedifferentiation of understory plants is more apparent, overlap value is more stable, because the light isgradually stable.Distribution pattern changes of main plant population in central Zhejiang public welfare forestsuccession were studied according to e deviation index （variance mean ratio）. Research shows thatecological niche and niche overlap value are related to the population distribution in the community,and the internal advantage degree is related. In the community internal changes, the dominant species isusually cluster distribution structure, whereas the second position of the population are randomdistribution. Therefore, population distribution pattern with the population change trend of the presentlaw marked differences in different changes of tree layer of progress with random distribution （or notdistribution） to the cluster distribution change; Recession species are cluster distribution to randomdistribution change; Transition species is a random distribution or random-cluster-random variation.