Diameter distribution modelling of plantations Pinus kesiya Royle ex Gordon on II site class based on weibull and richards distribution functions
Keywords:
Plantation Pinus kesiya, site class,, Weibull distributi, Richards distribution function, location parameter, scale parameter,, shape parameteAbstract
The objectives of research is to determine the goodness-of-fit of Weibull and Richards distributions to model and predict the diameter distibution of the plantations Pinus kesiya from the age classes 6 to 20 years. Collected data on diameter of plantations Pinus kesiya is 8 typical sample plots with size 0.2ha; in which each class of age one sample plot. The parameters of the Weibull and
Richards distribution functions is estimated according to the nonlinear method. The meaning of the parameters of the Richards distribution function is assessed through a relationship with the characteristics of plantations Pinus keysia. Research results have shown that the diameter distribution of plantations Pinus kesiya from the age classes 6 to 20 years on II class can be modeled by
using the Weibull and Richards distributions; including Richards distribution function more suitable than Weibull distribution function. The three parameters of the Richards distribution function have a relationship with characteristics of plantations Pinus kesiya. The location parameter of the Richards distribution function can be approximate estimate based on the average diameter at breast height and average height of plantations Pinus keysia. The scale parameter of the Richards distribution function can be estimated based on age of plantations Pinus kesiya. The shape parameter of the Richards distribution function can be estimated based on location parameter.
References
1. Bailey, R.L., Dell, T.R., 1973. Quantifying diameter distribution with the Weibull function. For. Sci., 19, 97 - 104.
2. Duan, A.G, Zhang J.G, Tong S.Z, 2004. Studies on dynamic prediction of stand diameter structure of Chinese fir plantation. Sci. Sil. Sin., 40, 32 - 38.
3. Duan, A.G, Zhang, J.G, Zhang, X.Q, He, C.Y, 2013. Stand Diameter Distribution Modelling and Prediction Based on Richards Function. PLoS ONE 8(4): e62605. doi:10.1371/journal.pone.0062605.
4. Gove, G.H, Patil, G.P., 1998. Modelling the basal area-size distribution of forest stands: a compatible approach. Forest. Science, 44, 285 - 297.
5. Nguyễn Hải Tuất, 1982. Thống kê toán học trong lâm nghiệp. Nxb. Nông Nghiệp, Hà Nội, 185 trang.
6. Nguyễn Văn Trương, 1984. Quy luật cấu trúc rừng gỗ hỗn loại. Nxb Khoa học và Kỹ thuật, Hà Nội, 240 trang.
7. Vancley, J.K., 1995. Growth models for tropical forest: A synthesis of models and methods. For Sci, 1995, 41, 7 - 42pp.
