Mechanical Properties and Termite Resistance of Acacia Hybrid 5-Year-Old Grown at Lad Krating Plantation, Chachoengsao Province

Abstract

Acacia species have increasingly been cultivated as economic tree species, particularly the Acacia hybrid, which demonstrates fast growth and good resistance to diseases. This study investigated the mechanical properties of Acacia hybrid wood from the Lad Krating plantation in Chachoengsao Province. The objective was to evaluate the modulus of rupture (MOR) and modulus of elasticity in static bending (MOE) after subterranean termite attack. Two clones, K4 and K19, aged 5 years, were selected. Three trees were randomly chosen from each clone, and each tree was divided into three sections-base, middle, and top-each with three replications. Mechanical properties were tested both before and after subterranean termite attack.The results revealed that clone K4 had an average modulus of rupture (MOR) of 111.97 MPa and an average modulus of elasticity (MOE) of 10,625.52 MPa. Clone K19 showed an average MOR of 102.73 MPa and an average MOE of 9,051.03 MPa. According to the book Characteristics of Thai Wood, wood with a MOR value higher than 95 MPa is classified as high-strength wood. Therefore, both Acacia hybrid clones K4 and K19, with MOR values above 95 MPa, can be categorized as high-strength wood. Moreover, the MOE of clone K4 was higher than that of clone K19, indicating that the wood of clone K4 possesses greater toughness than that of clone K19.Mechanical property tests after exposure to subterranean termites for 21 days, following the JIS K 1571:2010 standard, showed that clone K4 had an average MOR of 94.92 MPa, representing a 15.40% reduction, and an average MOE of 10,540.78 MPa. Clone K19 had an average MOR of 89.46 MPa, representing a 13.30% reduction, and an average MOE of 8,962.29 MPa.

Keywords: Acacia Hybrid, Mechanical property, Termite, Subterranean termites