Growth Regularity of Keteleeria davidiana Natural Forest

The growth regularities of Keteleeriadavidiananatural forest in Yachang Forest Farm,Guangxi were studied by using the method of stem analysis.The results showed that the height,DBH and volume of 30-year-old trees were 14.4m,32.80cm and 0.4799m3,respectively.The fast growing periods of tree height and DBH were in the 1st to 12th and the 6to 14th year,respectively.The curves of current annual growth and and average growth of tree height and DBH intersected in the 12to 13th and 14to 15th year,respectively.Current annual increment of volume reached the peak value,which was 0.0300m3·a-1 in the26th year.After that it reduced gradually.According to the growth model of the volume,current annual increment curve and average increment curve didn't intersect until the 38~39th year.The volume growth period was divided into three stages based on the results of cluster analysis,period of slow growth(1~8a),the growth acceleration period(9~19a)and the period of rapid growth(20~30a).The optimal model of tree height,DBH and volume was Richard,Richard and Weibull model,respectively.