A Study on Felling Age of Chinese Fir Plantation

The felling age of Chinese fir plantation was systematically studied in Daganshan Area. Richards function was selected as the basic growth model of Chinese fir plantation, and site index was introduced into chis model to establish a polymorphic growth model with 7 parameters, using the site index and tree age as the varibles. The quantitative maturity was calculated based on the principle of growth and yield compatibility, and stand structure model on Weibull function, technical maturity on the cultivated timber assortment, acceptable return on investiment was calculated by the readjusted timber shadow price. By means of discounted measure, economic analysis was analysed and economic maturity was determined by the maximum net present value. Two alternative felling age models were proposed on the basis of technical maturity with a emphatical considering of economic maturity and an approprite considering of quantitative maturity. The model has a notable economic return. Comparing the felling age determined by our models with the current felling age, the internal rate of return can be raised and the maximum profit rate can be increased by over 8%.