桂中地区不同造林密度下桉树无性系生长及经济效益研究

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

桂中地区不同造林密度下5 a生桉树无性系生长及经济效益研究结果表明,各无性系径阶株数多分布在13、14径阶,虽造林密度不同,各径阶株数分布基本趋向于正态分布;3个无性系的平均树高、平均胸径差异不大,总体上随着密度的降低而略有增加,平均树高、平均胸径以2.0 m×4.0 m造林密度下的DH32-29无性系最大,分别为20.2 m、14.9 cm;蓄积量以2.0 m×3.0 m造林密度下的DH32-29无性系最高,达213.9 m3/hm2;DH32-29无性系在2.0 m×3.0 m造林密度下获得的财务净现值最大,相对盈利能力最强;内部收益率、投资利润率、投资利税率和投入产出比则以2.0 m×3.5 m造林密度获得最大值,分别达63.32%、41.89%、46.54%、14.94%。

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 1 3 or 1 4 diameter class,the distri-bution of the number of diameter in each diameter class tended to normal distribution,although planted with differ-ent 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 afforesta-tion density,reached 20.2 m and 1 4.9 cm,respectively.The volume of DH32-29 clones,planted with 2.0 m × 3 .0 m was the highest,reached 21 3 .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 maxi-mum,which was 63.32%,41 .89%,41 .89%,46.54% and 1 4.94%,respectively.