EFFECT OF AGE ON VARIATION IN PHYSICAL AND MECHANICAL PROPERTIES OF Acacia mangium PLANTED IN THAI NGUYEN
Abstract
This study aimed to investigate the effect of age on some physical and mechanical properties of Acacia mangium planted in Thai Nguyen province such as air-dry density (AD), modulus of rupture (MOR), and modulus of elasticity (MOE). The small specimens with dimensions of 20 (radial) 20 (tangential) 320 (longitudinal) mm were cut at breast height of 7-, 10-, 14-year-old sample trees. The mean values of AD at 12% moisture content of 7-, 10-, 14-year-old A. mangium were 0.48, 0.51, and 0.53 g/cm3, respectively. The mean values of MOR of 7-, 10-, 14-year-old A. mangium were 64.38, 71.59, and 73.46 MPa, respectively, while these values of MOE were 7.31, 8.77, and 9.10 GPa, respectively. AD had a significant positive linear relationship with mechanical properties at all age levels. This suggests that AD could be a useful parameter to predict static bending strength of A. mangium wood. AD, MOR, and MOE exhibited a considerably increasing trend from age 7 to age 10 before stabilizing to age 14. This result will be an important reference for forest growers whether to extent planting time of A. mangium after 10 years or not.