Abstract:
Objective Close-to-nature silviculture of Chinese fir plantations mixed with Phoebe bournei (Hemsl.) Yang is the main management mode in China. Developing diameter distribution model of Chinese fir after close-to-nature silviculture can provide an important basis for accurately predicting the timber output of Chinese fir plantations.
Method Based on the Chinese fir forests mixed with Phoebe bournei in Chenzhou Xishan Forest Farm, Hunan, the diameter distribution of Chinese fir after close-to-nature silviculture was fitted using four commonly used probability density functions, including Normal distribution, Lognormal distribution, Weibull distribution and Gamma distribution. Also, the skewness and kurtosis were used to describe the diameter distribution characteristics of Chinese fir.
Results Compared with pure forest, the close-to-nature silviculture mixed with Phoebe bournei increased the proportion of large-diameter of Chinese fir, and the mean DBH of Chinese fir was positively correlated with the skewness. In addition, according to the χ2 test, both of the Normal distribution and Weibull distribution performed better than the other two distributions.
Conclusion Combined with the adaptability and flexibility of the Weibull function, the Weibull distribution can be used for modelling the diameter distribution of Chinese fir after close-to-nature silviculture mixed with Phoebe bournei. The study plays an important role in accurately estimating the timber output of Chinese fir under close-to-nature silviculture.
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