Pengaruh Karakteristik Kimia terhadap Sifat Mekanis dan Keawetan Alami Tiga Jenis Kayu Kurang Digunakan (Effect of Chemical Characteristics on Mechanical and Natural Durability Properties of Three Lesser-Used Wood Species)

Chemical, mechanical, and natural durability properties of three lesser-used wood species from North Kalimantan, namely nyatoh (Palaquium lanceolatum), pisang putih (Mezzettia leptopoda), and sepetir (Sindora wallichii) woods,were analyzed to seek the interrelationships amongthem and give an overview related to their utilization. The results showed that pH values of three wood species were categorized into moderate to weak acid levels. The extractive contentsin hot and cold water as well as in NaOH 1% of sepetir wood were higher than those of nyatoh and pisang putih woods. In contrast, the solubility in ethanol-benzene of nyatoh wood was the highest. The ash content in the three wood species were categorized intomedium level. Lignin contents in sepetir and nyatoh woods were classified as moderate, while lignin content in pisang putih wood was high. Holocellulose and hemicellulose contentsin sepetir wood were higher than those in nyatoh and pisang putih woods, whereas alpha cellulose in sepetir wood was the lowest. MOE values of the three wood species were classified as strength class of IV‒V, while MOR and compression parallel to the grain were classified as strength class of IV. The hardness value of nyatoh wood was higher than that of other woods.The durability of the three wood species was classified into poor (low durable). The relationship between chemical characteristics and mechanical properties of wood was primarily influenced by its major components (cellulose, hemicellulose, and lignin), whereas natural durability was influenced by its minor components (extractives and inorganic materials).Keywords: lesser-used wood species, mechanical properties, natural durability, parameters interrelationship, wood chemical characteristics