铁坚油杉天然林生长规律的研究

采用树干解析方法对广西国有雅长林场30 a铁坚油杉天然林生长规律进行研究。结果表明，30 a铁坚油杉树高、胸径和材积生长量分别为14.4 m、32.80 cm和0.479 9 m3。树高和胸径快速生长期分别为1~12 a和6~14 a，连年生长曲线与平均生长曲线分别相交于12~13 a和14~15 a。材积连年生长量在26 a达到最大值0.030 0 m³·a^-1，之后逐渐降低，模型分析得出材积连年生长曲线与平均生长曲线相交于38~39 a之间。借助系统聚类分析将材积生长期划分为生长缓慢期（1~8 a）、生长加速期（9~19 a）和生长快速期（20~30 a）3个阶段。树高、胸径和材积生长回归方程分别以理查德、理查德和威布尔模型拟合效果最好。

Growth Regularity of Keteleeria davidiana Natural Forest

The growth regularities of Keteleeria davidiana natural 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 14.4 m, 32.80 cm and 0.4799 m³, respectively. The fast growing periods of tree height and DBH were in the 1^st to 12^th and the 6 to 14^th year, respectively. The curves of current annual growth and and average growth of tree height and DBH intersected in the 12 to 13^th and 14 to 15^th year, respectively. Current annual increment of volume reached the peak value, which was 0.0300 m³·a^-1 in the 26^th 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 38~39^th year. The volume growth period was divided into three stages based on the results of cluster analysis, period of slow growth (1~8 a), the growth acceleration period (9~19 a) and the period of rapid growth (20~30 a). The optimal model of tree height, DBH and volume was Richard, Richard and Weibull model, respectively.