Wood Chemical Compositions of Raru Species Originating from Central Tapanuli, North Sumatra, Indonesia: Effect of Differences in Wood Species and Log Positions

Abstract

Raru is a lesser-known plant species originating from North Sumatra, Indonesia. Information on the characteristics is still limited, especially its chemical component. Therefore, this study aims to examine the chemical composition information of Cotylelobium lanceolatum, Cotylelobium melanoxylon, and Vatica pauciflora woods based on their axial log positions (bottom, middle, and top). The wood chemical analysis was performed in terms of the Indonesian National Standard (SNI) method. Furthermore, the analysis measured holocellulose, α-cellulose, hemicellulose, lignin content, alcohol benzene extractive content, the extractive substance in hot and water, and solubility in NaOH 1%. The results indicated that the species and their log axial positions affected different chemical components, which included α-cellulose, hemicellulose, and lignin of C. lanceolatum amounting to 41.88%, 19.39%, and 28.68% respectively. Meanwhile, for C. Melanoxylon, they were 42.01%, 21.11%, and 24.76% respectively; and for V. pauciflora wood, they were 42.95%, 23.24%, and 30.11% respectively. The average values of the extractive contents including the solubility in 1: 2 ethanol benzene, NaOH, and hot water for C. lanceolatum, C. melanoxylon, and V. pauciflora wood were (10.58%, 27.62%, 8.13%), (14.54%, 28.22%, 7.82%), and (10.95%, 28.60%, 7.57%) respectively. The wood species had a significant effect on chemical components including lignin, cellulose and hemicellulose, and extractive solubility in cold water. Furthermore, the axial log position had a significant effect on all the parameters of the chemical composition of the wood being tested.