Penentuan Daur Teknis Kayu Sengon Berdasarkan Sifat Fisis-Mekanisnya

Abstract

INTRODUCTION. Wood demand in Indonesia is mostly fulfilled by wood supply from natural forest area. Exploitation of this forest without any commitment to sustain our natural resources has resulted in high rate destruction of the forest. Therefore, wood supply decreasing year by year. One alternative to solve this problem is by relying upon the supply of timber from timber estate. Species planted in such kind of forest is usually fast grown species, and sengon (Paraserianthes falcataria(L) Nielsen) is one of them. The objective of this research was to determine the technical rotation of sengon wood, based on its physical and mechanical properties, as building and construction materials. Moreover, effect of age on these two kind of properties was also investigated. METHOD. The main material in this study was sengon wood from Ciamis district, West Java. The samples were in the form of log, from five different ages of standing tree. Each age is represented by 3 trees. Physical properties tested are moisture content (MC), specific gravity (SG) of wood, and shrinkage (S) while mechanical properties tested are static bending strength (MOE and MOR), compressive strength parallel to grain, shear strength parallel to grain, and hardness. The testing of physical and mechanical properties of wood was referred to ASTM standard D143-94 (2006). RESULTS AND DISCUSSION. Result of this study on physical properties showed that tree age has no effect on MC but it has to SG and S. The highest SG was found on wood of 10 yr-old (0.37), while the lowest on 9 yr-old (0.29). The lowest radial shrinkage was found on wood of 9 yr-old (2.85%), while the highest on 6 yr-old (3.60%). The lowest tangential shrinkage was found on wood of 5 yr-old (5.64%), while the highest on 10 yr-old (6.11%). In case of mechanical properties, it could be said that wood from 10 yr-old tree has the highest value. The largest of MOE, MOR, compressive strength parallel to grain, and the hardness -at the end, radial and tangential, were found on wood of 10 yr-old (35,908, 262, 137, 127, 80, and 85 kg/cm2, respectively), while the lowest on 9 yr-old (24,711, 211, 113, 112, 62, and 65 kg/cm2, respectively). The largest value of shear strength parallel to grain at radial and tangential directions was found on wood of 10 yr-old (23 and 25 kg/cm2, respectively), while the lowest on 5 yr-old (19 and 21 kg/cm2, respectively). Analysis of variance showed that tree age also affects the MOE, MOR, compressive strength parallel to grain, and the hardness of the side. However, it has no effect to the shear strength parallel to grain and hardness at the end. Based on its physical and mechanical properties studied, the technical rotation of sengon wood for building and construction materials was 10-year due to the highest of total scoring.