A Study of Growth Characteristics of Cupressus torulosa Plantations in Jiange County

The research was conducted on the growth characteristics of Cupressus torulosa plantations in Jiange County in Sichuan province by using the stem analysis method.The results showed that the height,DBH and volume of 27-year-old Cupressus torulosa were trees 18.13 m,25.8 cm,0.407 55 m³,respectively.Their mean annual increments were 0.67 m,0.96 cm and 0.015 09 m³ .The fast growing period of tree height was in 12 years old to 21 years old and the current annual increment was 0.73 m·a^-1~0.93 m·a^-1.While the DBH had two fast growth periods,which were from 9 years old to 15 years old and from 21 years old to the 24 years old,respectively.The current annual increment was 1.17 cm·a^-1~1.22 cm·a^-1 and 1.09 cm·a^-1~1.21 cm·a^-1.Average increment curve and current annual increment curve of volume increased with the age.After 27 years,average increment and current annual increment of volume reached 0.015 09 m³·a^-1 and 0.034 28 m³·a^-1,and that didn't intersect.So Cupressus torulosa trees had not reached the quantitative maturity of volume.The logistic equation was good to fit the growth regularity of height、DBH、volume of Cupressus torulosa plantations,getting the relative values were 0.997,0.992 and 0.999.So it could be used to guide the production practice of Cupressus torulosa plantations.