Some physical and mechanical properties of glue laminated mahang wood (Macaranga triloba)

Nowadays, a lot of commercial timber species in the forest have been replaced by pioneer tree species such as mahang (Macaranga spp.). This species grows naturally in the opened areas. These exposed forestlands in large scale have occurred due to improper logging operation, forest fire and encroachment in the production forest areas. Mahang from Euphorbiaceae family is distributed extensively in all islands of Indonesia. Although many of its wood can be found easily in secondary forests, but the data or information of its uses is very limited. Therefore, investigation on the properties of products from mahang wood becomes necessary for information base and for governing and utilizing of this wood. The aim of this study was to examine the properties of laminated products made manually from mahang wood. The wood samples were obtained from mahang trees growing on secondary forests from the forest concession area of PT Triwira Asta Bharata, Senduru, Melak, Kutai District, East Kalimantan. The adhesive employed in this study was polyvinyl acetate (PVAc). Several iron clamps were used during bonding process conducted manually at room temperature for the period of 24 hours. The results showed that the moisture content, density, specific gravity, modulus of elasticity (MOE) of mahang wood laminated products both two and three layers were tested and found to be comparable to those of their original wood. The modulus of rupture (MOR) of the laminated products tended to be lower than that of the original wood. The bonding strength of the laminated products were lower as much as two-times than the shearing strength of the original wood. The mahang wood laminated products made manually using PVAc adhesive are advisable for interior and non-structural uses. To improve the strength of these bonding products, mahang lumbers should be dried to the moisture content of around 12 percent and harden or cured the bonded wood under pressure more than 24 hours