为了找出杂交相思人工林合理的种植密度,以达到较佳经济效益,笔者选用5种不同密度,采用单因素、随机区组设计进行杂交相思密度试验。对经过5年的观测资料进行分析表明:杂交相思不同造林密度对胸径、材积的生长有一定的影响,随着密度增大,胸径、单株材积表现出与密度间的负相关,每公顷833株林分的平均胸径为107 cm,每公顷1 666株林分的胸径为9.6 cm；每公顷833株和1 000株林分的5年生林龄时平均单株材积较高,分别为0057 566和0.051 79 m3;5年生每公顷1 666株的林分材积为63.922 1 m3，分别比其他4种密度林分的高190%、52.0%、58.3%和103.3%。造林密度对树高生长无显著影响。

In order to find out reasonable afforestation density of Acacia mangium×A.auriculaef Ormis, which would bring the best economic benefits, we selected 5 kinds of different densities, used the single factor and the randomized block arrangement experimental design to carry on Acacia mangium×A.auriculaef Ormis density experiment. After 5 years’ observation, the results showed that different densities had a certain effects on diameter at breast height(DBH) and single tree volume of Acacia mangium×A.auriculaef Ormis. With the increase of afforestation density, DBH and single tree volume showed negatively correlation. The DBH was 10.7 cm at the density of 833 trees/hm2, and the DBH was 9.6 cm at the density of 1 666 trees/hm2. When the planting densities were 833 trees/hm2 and 1 000 trees/hm2, the tree volumes were 0.057 566 m3, 0.051 79 m3. The 5 years’ tree volume was 63.922 1 m3/hm2 at the density of 1 666 trees/hm2, separately higher than the other four afforestation density 19.0%, 52.0%, 58.3% and 103.3%. The planting density had no significant effect on tree height.