A preliminary model for annual ring density of plantation Chinese fir

A preliminary physical and mathematical model (along with its associated MATLAB R2011a computer code) was developed to describe the density distribution in the tree radius. The relationships between density and the growth rate as well as the relationship between the growth rate and the environment parameters, such as ambient temperature and rainfall, have been established respectively in the model. The finite difference scheme was used to solve the first order ordinary differential equations. Good agreement was obtained between experimental results of density and ring width profiles of Chinese fir measured by radiation densitometry and the numerical results in the heartwood area.