Radial Variation in Selected Wood Properties of Indonesian Merkusii Pine

Abstract

Merkusii pine wood (Pinus merkusii) was extensively planted throughout Indonesia, where it is only indigenous in northern Sumatera, by the Dutch during colonial times. The demand for this wood species, especially in the domestic market, has increased notably, despite its limited durability regarding decay resistance. The purpose of this study was to investigate the occurrence of juvenile and mature wood on merkusii pine and to analyze its radial features from pith to bark based on density, shrinkage, static bending in modulus of rupture and modulus of elasticity, fiber length, microfibril angle, and durability. A segmented modeling approach was used to find the juvenile-mature transition. The graveyard test was performed to characterize the termite resistance from pith to bark of merkusii pine. The maturations were estimated to start at radial increments of 15 cm from the pith by fiber length and of 12 cm from the pith by microfibril angle. The projected figures for the proportion of juvenile wood at breast height were around 65%. The results also indicate that the pine wood was 0.52 g/cm3 in density, 1.45 in coefficient of anisotropy, which indicates its good stability, 7597 MPa in modulus of elasticity, and 63 MPa in modulus of rupture. Natural durability against subterranean termite of the merkusii pine wood was rated to be grade 4 to 0 from pith to bark. However, after being treated by Entiblu and Enborer preservatives, its rating increased to grade 10 to 9.