Ecological Researches On Sprout Regeneration Of Evergreen Broad-leaved Forest In Tiantong

The Tiantong National Forest Park is located in eastern Zhejiang province, it is a rare region-specific vegetation type in this hilly region, and preserves China's eastern region typical subtropical evergreen broad-leaved forest. However, as frequent forest harvesting in a long times, makes this region's evergreen broad-leaved forest belonging to secondary vegetation types. But as a result of the interference is not catastrophic, the logged area generally has a lot of residual stakes. Therefore, create a good test condition for our sprouting regeneration study. This thesis mainly focuses on the growth characteristics of sprouting individuals after logging disturbance, and its important function in community recovery process. The results are as follows.(1) Apply stem analysis method to analyze the growth characters of the four common dominant species, mainly focusing on their height and basal diameter growth of the two different regeneration patterns. We found that in the early stages of growth, especially in the first four years is the rapid growth period. This attributes to the abundance remnant nutrients remaining in the stump. However, in later growing stage the difference between the two regeneration patterns gradually shrinks, in tree height the seeding individuals even exceed the sprouting ones. This reflects that the sprout forest exist premature senility phenomenon. In the leaf structural characteristics we also found that in the early stages of growth sprout individuals generally have a higher leaf nitrogen and phosphorus content, and have lower SLA, with the growth process the difference in the leaf level is also gradually disappeared.(2) After logging because of the rapid growth of the sprouting branches, making the sprouted community can form secondary population in a short time. During the four selected restoration series, Castanopsis fargesii population developed from stepwise development type to maturation and stability type. Schima superba population developed form growthing population to intermittent development type. Castanopsis carlesii and Castanea gracilis population showed instability in the later restoration stage. Namely in the 60-year stage after logging disturbance the community has already closed to the maturity community in Tiantong region.(3) From the species composition and the alternation of dominant species in communities, in the early stage of the community formed mainly by sprouting, dominant species combination is pioneer species + dominant species, it is a special combination compared with the early community formed by seeding regeneration. When sprouting community restored to 20-year, the dominant species of each layer were already the dominant species composition of climax community. From this we can see that as to the sprouted community, during the process of restoration the changes in species composition were small, and the replacement of the dominant species was also more stable.(4) In the species diversity of community, the secondary communities mainly formed by sprouting also expressed their own characteristics: in the early stages of recovery with the highest number of species and the highest species diversity. And to the secondary communities mainly formed by seeding, species number and diversity is the lowest in the early stage.(5) Whether from the research of community or population, sprouting individuals all play an important role in the early restoration. Along with the progress of resumption, the percentage of sprouting in the population and the community level all show descending trend on the whole, namely in the later stage of restoration, if there is no further large-scale anthropogenic interference, seeding individuals will play an increasingly larger role in the process of restoration and regeneration of communities.