尾巨桉纸浆材人工林轮伐期研究

Rotation of Eucalyptus grandis ×E. urophylla Plantation for Pulp and Paper

试验设造林密度和追肥 2因素 ,每个因素 6个水平 ,4次重复。在参试的处理范围内 ,初植密度越大 ,其数量成熟和轮伐期的年龄越小 ;密度处理从 1到 6达到数量成熟的年龄分别为 5 5、6 2、6 6、6 7、6 8、6 4a ;最佳轮伐期分别为 5、6、7、7、7、6a ,这时的内部收益率分别为 2 4 8%、2 3 9%、2 3 5 %、2 2 8%、2 1 6 %、2 4 1%。施肥处理 1到 6的数量成熟年龄分别为 6 3、6 6、6 5、6 .5、6 .5、6 .6a ,全部在6 .3 6 .6a之间 ,而轮伐期分别是 6、7、6、6、6、7a ,这时的内部收益率分别为 2 0 4 %、2 1 5 %、2 3 6 %、2 5 0 %、2 6 6 %、2 3 1%。所有施肥和密度处理在 4a时均可进行采伐 ,这时采伐各处理的内部收益率都已超过 18% ,经济效益十分可观。

A spacing and fertilizing trial with 4 replications and six levels each were established. The results show that within the range of the trial, the more the initial spacing, the younger the age to get quantitative maturity and rotation; quantitative maturity of spacing levels from 1 to 6 are 5.5, 6.2, 6.6, 6.7, 6.8 and 6.4 a respectively; the length of rotations are 5, 6, 7, 7, 7 and 6 a respectively, while the rates of economic benefit are 24.8%,23.9%,23.5%,22.8%,21.6% and 24.1%. The results also show that quantitative and economical maturity of fertilizing levels from 1 to 6 are 6.3, 6.6, 6.5, 6.5, 6.5 and 6.6 a, all between 6.3 a and 6.6 a, the length of rotations of all the levels are 6, 7, 6, 6, 6 and 7 a respectively and the rates of economic benefit are 20.4%, 21.5%, 23.6%, 25.0%, 26.6% and 23.1% respectively. All the levels of two treatments could be harvested at age 4 which the rates of economic benefit are all over 18%.