Differences of technological properties on sapwood and heartwood of short rotation teak wood

Short rotation teak has been developed to overcome the limited supply of long rotation teak. The characteristics and technological properties of sapwood and heartwood of short rotation teak are not well studied. The purpose of this study was to evaluate the effect of sapwood and heartwood differences on technological properties for short rotation teak. The short rotation teak woods used were Plus Perhutani teak of 15 years old with a sapwood proportion of 30% and Biotrop teak of 8 years old with a sapwood proportion of 18%. The following technological properties of sapwood and heartwood were studied: extractive content, chemical composition, volumetric swelling, water-sorption isotherm, modulus of elasticity, modulus of rupture, decay resistance, termite resistance, surface roughness, surface free energy, wettability, and weathering performance. The results showed that the extractive content of heartwood was higher than sapwood. The main compounds in the extractive content of heartwood were lapachol and 9,10-anthracenedione; meanwhile the main compounds of sapwood were mostly single sugars and derivatives. The extractives present could contribute to technological properties of short rotation teak wood, particularly for improved dimensional stability, reduced water-sorption, higher decay and termite resistance, and better photostability. Sapwood presented lower quality especially in dimensional stability and durability, which could restrict its utilization for both indoor and outdoor applications. Therefore, sapwood should require certain treatments, especially for wood exposed to outdoor conditions.