The Comparative Experiment on Afforestation of Three Acacia Species

Experiments on afforestation of Acacia crassicarpa,A.mangium and A.mangium×A.auriculiformis were carried out in the Forestry Science and Technology Demonstrate Farm of Guangxi.Three random block were set respectively on the upper slopes,middle slopes and lower slopes on the trial.Each block includs three plot of 400m2 planted with one tree species.The results showed that the average tree height were 13.4m,12.4m and 11.0m respectively,the former was 7.5 and 17.9 percent higher than that of the two latter.The average DBH were 13.7cm,12.8cm and 11.2cm respectively,the former was 6.6 and 18.2 percent larger than that of the two latter.Both the tree height and DBH of the three Acacia species had a characteristic of rapid early growth.The rapid growth stage was between 1 to 3 year.The annual tree height were 3.0～3.6m and the annual DBH were 3.8～4.7cm.The volume accumulation were 122.3m3/hm2,100.7 m3/hm2 and 70.7 m3/hm2 respectively,the former was 121.5 and 173.0 percent of the two latter.The pure income were 10620.0 yuan/hm2,7695.0 yuan/hm2 and 3645.0 yuan/hm2 respectively,and the former was 1.38 and 2.91 times of the two latter.Comprehensive analysis of the growth and static economic benefits,A.crassicarpa is the best tree species for industrial timber plantation in short-term rotation,and then A.mangium.