A Study Of Chinese Fir Plantation Forest Structure And Growth On Different Density Control

This paper takes Chinese Fir Plantations on jiangle state-owned forest farm in Fujian as the research object, took four different thinning intensity by 50%,33%,25%and 20% management measures, Analysis the change of forest spatial structure and spatial structure in different thinning intensities, From the level of the stand structure to provide a guidance for the business units of production. The preliminary conclusions of the study are as follows:(1) Whether it is stand for thinning operations or no thinning operations, All of the diameter distribution is like peak mountain shape curve that stand average breast diameter as the peak point, the amount of middle diameter of trees is the largest, the number of trees by both ends of curve decreased gradually.(2) the growth of stand average diameter at breast height that thinning intensity were 20%,25%, 33% and 50% is 0.99cm,1.05cm,1.25cm,1.30cm, is greater than the growth of the 0.83cm no thinning, the trees were classified as dominant, medium and inferior wood, comparative and analysis the various grades of forest growth under different thinning intensity, DBH growth are the dominant outweigh medium outweigh inferior wood, at the dominant wood and inferior wood grades, the great thinning intensity was a significant difference with the small thinning intensity, there was no significant difference between the medium wood.(3) Using 5 kinds of theoretical growth equations about Weibull distribution function, Gompertz equation, Mitscherlich equation, Logistic equation and Korf equation and 4 kinds of distribution functions are denoted as Fuzzy-1, Fuzzy-2, Fuzzy-3, Fuzzy-4 to fitting before and after thinning of the diameter distribution, Results show that the Weibull equation was precision fitting to fit diameter structure before thinning, after thinning, different fitting equations fit different thinning intensity.1 years after thinning, Weibull equation and Fuzzy-4 were well fitted to 5 kinds of different density stand diameter structure.(4) the growth of stand average height after thinning intensity were 20%,25%,33% and 50% is 0.94m,0.91m,0.89m,1.01m, the growth of no thinning was 0.92m,no difference with each other, the stand density had no effect on the growth of tree height.(5) Form stand volume structure analysis, found that after thinning and 1 year after thinning, stand volume was less than the no thinned stands, the volume growth rate with increasing thinning intensity.(6) Little change in forest average neighborhood pattern before and after thinning, the distribution pattern is consistent, which is related to artificial forest as the experimental object. At the same time, it will also affect the neighborhood comparison, thinning will moderate release competition wood around reference tree, reduce the competition to reference tree, and it is conducive to the reference tree growth.