A STUDY ON DIAMETER DISTRIBUTION OF SOME ARTIFICIAL PINUS TABULAEFORMIS STANDS BY USING THE WEIBULL FUNCTION
The three-parameter Weibull function is used to fit the diameter distributions of artificial Pinus tabulaeformis stands, as shown by the X2 test, for goodness of fit the three-parameter Weibull distribution is as good as the Normal distribution.In this paper, the method by Issos was improved. The new method present almost same result with the Issos' method for Weibull diameter distribution. Weibull parameter prediction equations were developed by regression of characteristics of 20 stands against the same parameters by Issos'method. The Weibull diameter distributions were predicted from staud mean diameter, the coefficient of variation of stand diameter, stand mean height, stand age and number of stem per unit (O.1he) . But, the effect is not good enough. Which distribution is suitable for fitting the diameter distribution of artificial Pinus tabulaeformis stand. This task will discuss further.