• Journal of the Korean Wood Science and Technology
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• v.52 no.4
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• pp.331-342
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• 2024

Rubberwood (Hevea brasiliensis) has excellent physical and mechanical properties and is one of the most widely used species in Southeast Asia. However, it has poor resistance to subterranean termite attacks due to its high sugar and starch contents. The objective of this study was to evaluate the termite resistance of experimental wood-plastic composite (WPC) panels manufactured from rubberwood flour, polyethylene terephthalate, and silica in three different weight ratios (1/2/7, 1/3/6, and 1/4/5). The panels were exposed to Coptotermes curvignathus subterranean termites in a no-choice test under laboratory conditions based on Indonesian standards. Solid rubberwood used as control samples presented poor resistance, exhibiting 23.1% weight loss due to subterranean termite attack, as indicated by low termite mortality and high wood weight loss. In contrast, the WPC samples demonstrated extreme resistance, with weight loss ranging from 0.19% to 0.23%. Based on the findings of this study, the high termite mortality and overall low mass loss of the samples indicate that such manufactured panels could provide a high level of protection with regard to Indonesian standards.

• Journal of the Korean Wood Science and Technology
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• v.51 no.3
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• pp.183-196
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• 2023

Recently, the morphological and molecular features of five stain fungi infecting rubberwood (Hevea brasiliensis), namely Paecilomyces maximus, Paecilomyces formosus, Penicillium crustosum, Paecilomyces lecythidis and Aspergillus chevalieri, have been studied. Prior to this study, the authors revealed that catechin from gambir (Uncaria gambir) could inhibit the growth of the white-rot fungus Schizophyllum commune, and it was important to determine the bioactivity of the aforementioned agent against A. chevalieri. The efficacy of the biocidal agent was examined using a laboratory wooden block test. Rubberwood blocks, 8 mm in thickness, 20 mm in width, and 30 mm in length, were impregnated with catechin solution at concentrations of 6%, 9%, 12%, and 15% (w/v) using the vacuum-pressure method, and their bioactivity was monitored over three weeks through visual and scanning electron microscope assessment of fungal growth as well as the discoloration intensity of the wood samples. The results showed that catechin treatment increased the resistance of wood samples to A. chevalieri. Overall, the higher the catechin concentration, the lower the fungal growth. The lowest fungal growth was observed in the wood samples treated with 12% and 15% catechin (score of 0), demonstrating no discoloration. In contrast, the fungal growth score of the untreated wood samples reached 4, indicating severe discoloration. Catechins appear to be adequate biofungicides against stain fungi in rubberwood.

• Journal of the Korean Wood Science and Technology
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• v.52 no.1
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• pp.70-86
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• 2024

Termites are a serious threat to wood-based products in Indonesia. This study investigated the termite resistant property of glulam made from polystyrene-modified wood. Three tropical fast-growing wood species, namely mangium (Acacia mangium), manii (Maesopsis eminii), and rubberwood (Hevea brasiliensis), were prepared for flat-sawn laminae. After getting air-dried condition, the laminae were impregnated with polystyrene using potassium peroxydisulphate as a catalyst followed by polymerization at 80℃. Polystyrene-impregnated and control glued-laminated lumbers (glulams) were manufactured, and solid wood was provided. Three wood species and three wood products with six replicates were exposed in a field in Bogor, Indonesia, for four months, and before the tests, their density and moisture content were measured. At the end of the field tests, the weight loss and protection levels of each test sample were determined. A completely randomized factorial design was used for data analysis. The weight percentage gains for mangium, manii, and rubberwood were 22.30%, 18.22%, and 10.44%, respectively. The results showed that manii belonged to low-density wood, whereas the other two woods were medium-density wood, and the moisture content was the ambient moisture content, typical of the Bogor area. Regarding weight loss and protection level, mangium was the most durable against subterranean termite attacks, followed by rubberwood and manii. Among the wood products, the polystyrene-impregnated glulam presented the highest durability, followed by the control glulam and solid wood. Therefore, mangium and rubberwood polystyrene-impregnated glulams are recommended for future product development.

• Advances in Energy Research
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• v.8 no.4
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• pp.223-231
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• 2022

An ex-situ gravitational fixed bed pyrolysis reactor was used over Al₂O₃ supported Ni₂P based catalyst with various Ni/P molar ratios (0.5-2.0) and constant nickel loading of 5.37 mmol/g Al₂O₃ to determine the hydrodeoxygenation of rubberwood sawdust (RWS) at atmospheric pressure. The 3D catalysts formed were characterized structurally as well as acidic properties were determined by hydrogen-temperature programmed reduction (TPR). The Ni₂P phase formed completely on Al₂O₃ for 1.5 Ni/P ratio, although lesser crystallite sizes of Ni₂P were seen at Ni/P ratios less than 1.5. Additionally, it was shown that when nickel loading level increased, acidity increased and specific surface area dropped, probably because nickel phosphate is not easily converted to Ni₂P. When Ni/P ratio was 1.5, Ni₂P phase fully formed on Al₂O₃. The catalytic activity was explained in terms of impacts of reaction temperature and Ni/P molar ratio. At relatively high temperature of 450℃, the high-value deoxygenated produce was predominantly composed of n-alkanes. Based on the findings, it was suggested that hydrogenolysis, hydrodeoxygenation, dehydration, decarbonylation, and hydrogenation are all part of mechanism underlying hydrotreatment of RWS. In conclusion, the synthesized Ni₂P/ Al₂O₃ catalyst was capable of deoxygenating RWS with ease at atmospheric pressure, primarily resulting in long chained (C₉-C₂₄) hydrocarbons and acetic acid.

• Journal of the Korean Wood Science and Technology
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• v.50 no.6
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• pp.458-474
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• 2022

Many methods have been explored to increase the palatability of pine (Pinus merkusii), the most common wood used for termite baiting. However, because of the undersupply of pine in Indonesia, it is crucial to vary the wood species for termite baiting and look for potential alternatives. Furthermore, various studies have shown that baiting time influences the intensity and pattern of termite attacks. Therefore, the present research aimed to study the preferences of subterranean termites and find the ideal baiting time among community wood species from Bogor, West Java, as a baiting alternative to pine. The woods tested were Acacia mangium (acacia), Falcataria moluccana (sengon), Anthocephalus cadamba (jabon), Maesopsis eminii (manii), Swietenia mahagoni (mahogany), Hevea brasiliensis (rubberwood), and P. merkusii (pine). Field tests were carried out based on the American Society for Testing and Materials D 1758-06 at the Arboretum, Faculty of Forestry and Environment, IPB University, with a baiting time of one to six months. The results led to the identification of four species of termites, namely Microtermes sp., Macrotermes sp., Shedorhinotermes sp., and Capritermes sp.. The frequency of termite attacks on the test site reached 93.1%. Rubberwood was the most potential wood bait for subterranean termites, indicated by the highest average weight loss value (65.8%) with a shorter optimal baiting time (up to one month) than that of other tested woods.

• Journal of the Korean Wood Science and Technology
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• v.48 no.5
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• pp.641-650
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• 2020

In this study, the chemical components and termiticidal activities of bamboo vinegar against subterranean termite were evaluated. Bamboo vinegar used in this study were produced from Mayan (Gigantochloa robusta Kurz.), Balcoa (Bambusa balcooa Roxb.), and Taiwan (Dendrocalamus latiflorus Munro). It was analyzed by gravimetric methods. Rubberwood (Hevea brasiliensis) was soaked for 24 h and tested against Coptotermes curvignathus Holmgren according to the Indonesian National Standard (SNI 7207-2014). The bamboo vinegar demonstrated antitermite activities against subterranean termite. Vinegar of 400℃ recorded higher total phenol and acid than that of 300℃. Results from this study suggest that the phenolic and acidic component of the bamboo vinegar contributed to 100% mortality rate of the termite, some wood weight loss, and a decrease in the termite feeding rate. These results strongly recommend that bamboo vinegar from D. latiflorus Munro is a potential environmentally friendly preservative.

• The Plant Pathology Journal
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• v.37 no.3
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• pp.243-257
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• 2021

Bacillus pumilus is the causal agent of trunk bulges disease affecting rubber and rubberwood quality and yield production. In this study, B. pumilus and other closely related species were included in B. pumilus group, as they shared over 99.5% similarity from 16S rRNA analysis. Multilocus sequence analysis (MLSA) of five housekeeping genes and repetitive elements-based polymerase chain reaction (rep-PCR) using REP, ERIC, and BOX primers conducted to analyze the diversity and systematic relationships of 20 isolates of B. pumilus group from four rubber tree plantations in Peninsular Malaysia (Serdang, Tanah Merah, Baling, and Rawang). Multi rep-PCR results revealed the genetic profiling among the B. pumilus group isolates, while MLSA results showed 98-100% similarity across the 20 isolates of B. pumilus group species. These 20 isolates, formerly established as B. pumilus, were found not to be grouped with B. pumilus. However, being distributed within distinctive groups of the B. pumilus group comprising of two clusters, A and B. Cluster A contained of 17 isolates close to B. altitudinis, whereas Cluster B consisted of three isolates attributed to B. safensis. This is the first MLSA and rep-PCR study on B. pumilus group, which provides an in-depth understanding of the diversity of these rubber-pathogenic isolates in Malaysia.