Research on Growth and Economic Benefit of Eucalyptus Clones with Different Density in the Middle Region of Guangxi

The growth and economic benefit of five-year-old Eucalyptus clones with different density were researched. The results showed that most of diameter of test clones belonged to 13 or 14 diameter class,the distribution of the number of diameter in each diameter class tended to normal distribution,although planted with different density. The average tree height and DBH of three clones were slightly different,which had a slight increase with the reduction of density. The average tree height and DBH of DH32-29 clones,under 2. 0 m × 4. 0 m afforestation density,reached 20. 2 m and 14. 9 cm,respectively. The volume of DH32-29 clones,planted with 2. 0 m ×3. 0 m was the highest,reached 213. 9 m3 per hm2. The financial net present value of DH32-29 clones,planted with 2. 0 m × 3. 0 m,was the largest,which was the most profitable. Internal rate of return,return on investment,profit and tax investment ratio and input and output ratio under 2. 0 m × 3. 5 m planting density could obtain maximum,which was 63. 32%,41. 89%,41. 89%,46. 54% and 14. 94%,respectively.