Effects of different afforestation density on growth of Acacia mangium × A. auriculaef Ormis.

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.