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The anatomical characteristics of the stem of belangke bamboo (Gigantochloa pruriens), which is native in North Sumatra, Indonesia, were examined to attain valuable information for identification and effective utilization. The number and type of vessel bundles and the fiber and metaxylem dimensions in the longitudinal (bottom, middle, and top) and radial (outer, central, and inner) directions of the bamboo culm were investigated by optical microscopy. The vascular bundles were distributed unevenly and arranged alternately, as shown by cross-sectional images of the culms. The proportion of vascular bundles in the culm decreased from the outer layer to the inner layer and tended to increase from the bottom to the top. Most vascular bundles were classified as type IV at the bottom and as type III in the middle and top parts. Fiber length and cell wall thickness tended to increase from the bottom to the top and from the inner layer to the outer layer. Metaxylem length and diameter increased from the outer layer to the inner layer and from the bottom towards the top of the stem. It was revealed that the anatomical characteristics of the belangke bamboo varied significantly in the vertical and radial directions.

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This study aimed to analyze the basic properties (chemical composition and physical and mechanical properties) of belangke bamboo (Gigantochloa pruriens) and its potential as a particleboard reinforcement material, aimed at increasing the mechanical properties of the boards. The chemical composition was determined by Fourier transform near infrared (NIR) analysis and X-ray diffraction (XRD) analysis. The physical and mechanical properties of bamboo were evaluated following the Japanese standard JIS A 5908 (2003) and the ISO 22157:2004 standard, respectively. The results showed that this bamboo had average lignin, holocellulose, and alpha-cellulose content of 29.78%, 65.13%, and 41.48%, respectively, with a degree of crystallinity of 33.54%. The physical properties of bamboo, including specific gravity, inner and outer diameter shrinkage, and linear shrinkage, were 0.59%, 2.18%, 2.26%, and 0.18%, respectively. Meanwhile, bamboo’s mechanical properties, including compressive strength, shear strength, and tensile strength, were 42.19 MPa, 7.63 MPa, and 163.8 MPa, respectively. Markedly, the addition of belangke bamboo strands as a reinforcing material (surface coating) in particleboards significantly improved the mechanical properties of the boards, increasing the modulus of elasticity (MOE) and bending strength (MOR) values of the fabricated composites by 16 and 3 times.

Iswanto AH, Siregar YS, Susilowati A, Darwis A, Hartono R, Wirjosentono B, Rachmat HH, Hidayat A, Fatriasari W. 2019. Variation in chemical constituent of Styrax sumatrana wood growing at different cultivation site in North Sumatra, Indonesia. Biodiversitas 20: 448-452. Kemenyan Toba (Styrax sumatrana) is known as endemic resin-producing trees that naturally grow in North Sumatra and distributed throughout five districts within the province. Different growing site may constitute to different characteristics of the species, e.g. morphological differences, chemical constituent, bioactive substances, etc. Different characteristics of wood chemical constituent are an important factor determining further utilization and potential use of wood in wider spectrums. Information about wood chemical constituent of Styrax sumatrana growing from different site has not been determined yet. Therefore, the objective of this research was to analyze the characteristics of chemical constituent of Styrax sumatrana wood originated from North Tapanuli and Pakpak Bharat according to axial direction of stem (bottom, middle, and top). Chemical properties such as hollocelulose, α-cellulose, hemicellulose, Acid Soluble Lignin (ASL), acid insoluble lignin (AIL), and non-structural component (extractive content in ethanol benzene 1: 2 and ash content) were observed. Results showed that different growth location would yield in different wood chemical constituent. The wood chemical constituent from North Tapanuli and Pakpak Bharat were 52.72 and 69.80% (hollocelulose), 25.94 and 39.87% (α-cellulose), 26.78 and 29.92% (hemicellulose), 5.49 and 4.33% (Acid Soluble Lignin), 4.37 and 20.43% (Acid-Insoluble Lignin), 10.95 and 2.42% (extractive content), 1.37 and 0.8% for ash content.

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