The growth pattern of Pinus elliottii Plantation in central subtropical China

Based on tree ring measurement,stem analysis and stand investigation,the growth pattern of slash pine(Pinus elliottii),one of the most common exotic tree species in southern China,was examined in this study for improving the plantation management and forest ecosystem service evaluation.Slash pine was introduced to the Qingyuan mountains,Ji′an city in Jiangxi province as early as in 1948,where the mean DBH(diameter at breast height) and tree height were 34.2(ranged from 18.4 to 58 cm) and 19.5 m(ranged: from 9 to 33m),respectively,in 2005.In the past 50 years,tree ring width increased about 0.34 cm per year,while the largest annual increment was no more than 1.14 cm.Generally,the diameter growth experienced a decreasing trend and showed fast growth rate in the first 20 years with the maximum growth rate appeared at about 10 years old.The trees grow extremely slow when the forest exceeded 40 years old.At the Qianyanzhou Ecological Station,located approximately 100 km southwest of the Qingyuan mountain,the average height and DBH of slash pine are 11 m and 15.9 cm,respectively,with an annul DBH increment of 0.86 cm at the age of 20 years.Compared with native species,the biomass of slash pine forest was lower than that of Masson pine(Pinus massoniana) forest of the same age at Qianyanzhou station,and it was also significantly lower than that of Cinnamomum camphora growing in Hunan province.The While in the original place of slash pine,in Florida of America,The growth rate and carbon sequestration ability in subtropical China were apparently lower than those in Florida,USA,the original place of slash pine,where it is considered as the most suitable area for slash pine growth.