Abstract:

Taking 258 plots of Larix plantation as the experimental material, probability density function parameters fitted to Weibull distribution of every plot were calculated. It was found that the parameters increased with increasing of upper height and diameter, but decreased with increasing of density. Thus, the Richards model extended relations between stand factor and parameter, among parameters was established. The combination of parameter model with density, upper height, and diameter model was determined the best, after precision, significance, applicability, and the average diameter of basal area were tested. The tree distribution of a forest stand can be predicted by the model. And the model can provide the base for intermediate cuttings at different growth stages and intensities, and predicting stand volume.

Key words: Weibull distrbution, Parameter, Density, Diameter, Upper height, Model