Growth, biomass, and energy quality of Acacia mangium timber grown at different spacings

The objective of this work was to assess the effect of spacing on the growth, biomass allocation, and wood quality for energy purposes of Acacia magium. A randomized complete block design was carried out with three replicates and five treatments consisting of trees planted at different spacings: 2.0x2.0, 2.5x2.5, 3.0x2.0, 3.0x2.5, and 3.0x3.0 m. At 67 months after planting, the following species parameters were evaluated:  performance (mortality, diameter growth, height, bark factor, and bark and biomass volume yield) and wood energy quality (basic density, higher-calorific value, ash, fixed carbon, and volatile materials) through the analysis of variance. Plant spacing did not affect volume and biomass production per hectare nor wood quality for energy purposes. The widest spacing (3.0x3.0 m) provides better individual growth, and the narrowest one (2.0x2.0 m) produces smaller trees, but with the highest percentage of dry biomass in the trunk, and can show the best energy potential at a rotation age from 40 to 50 months.