Reseach on the Growth Characters of Toona sinensis Plantations in Jianyang City

The research on forest growth characteristics was conducted on the Toona sinensis planted in Jianyang town in Sichuan province by using stem analysis method. The results showed the DBH, tree height and tree volume growth of the 27-year-old Toona sinensis were 26.03 cm,17.9 m and 0.4530 m³, respectisely. Their mean annual increment were 0.96 cm,0.66 m and 0.01678 m³,respectisely. The current annual increment reached the maximum at the age of 24,and they did not intersect at the age of 27, which meant that the Toona sinensis growth process did not reach its quantitative at the age of 27. The growth dynamic models of DBH, height and volume of Toona sinensis were established with the Logistic Equation. Three regression equations were:y=27.7189/(1 + 6.4415 ^* e^-0.1635x), y=16.7421/(1 + 4.2965^* e^-0.2387x) and y=0.5797/(1 + 42.9833 ^* e^-0.1866x), and the correlation coefficient of fitting curve(R²)were 0.9993,0.9978 and 0.9994.