Role of Extractives in the Durability of Neobalanocarpus heimii and Shorea falcifera Heartwoods

• Main Authors: Nurfarahin, Ajlan, Ismail, Jusoh, Zaini, Assim
• Format: Article
• Language: English
• Published: The Academy of Sciences Malaysia 2019
• Subjects: S Agriculture (General); SD Forestry
• Online Access: http://ir.unimas.my/id/eprint/26572/1/Ismail%20Jusoh.pdf; http://ir.unimas.my/id/eprint/26572/; https://www.akademisains.gov.my/asmsj/

Wood durability refers to the resistance of the wood from decay agents such as fungi, termites, marine borers and weathering. Extractives isolated from the heartwood of durable hardwood species and some other plants species may provide alternatives to pest control because of their bioactive compounds. Wood extractives are known to affect wood resistance against fungi and termites attack. This study was carried out to determine the role of extractives of two natural durable woods namely Neobalanocarpus heimii (chengal) and Shorea falcifera (balau kuning) towards fungal decay and termites attack. A nondurable wood, Dyera polyphylla (jelutong paya), was used as control. Sequential Soxhlet extractions were done by using firstly mixture of 95% ethanol and toulene at a ratio of 2.32:1 (v/v), followed by 95% ethanol, 95% methanol and finally hot distilled water. The extracted and unextracted wood cubes were tested for decay resistance based on soil blocks decay test using white-rot (Trametes versicolor) and brown-rot (Coniophora puteana) decay fungi. A no-choice termite resistance test was carried out using a subterranean termite Nasutitermes sp. The weight loss due to fungal decay and termite attacks were determined after twelve weeks and three weeks of exposure, respectively. Chemically extracted test blocks were compared to unextracted blocks. Extracted durable species were also compared to nondurable controls. Sequential Soxhlet showed that Shorea falcifera yielded the highest amount of extractives at 19.81%. Results showed that non-durable wood recorded the highest weight loss in both fungi and termite attacks. Decay resistance test also showed that all extracted N. heimii and S. falcifera blocks exhibited significantly higher weight loss due to fungi and termites attacked compared to unextracted blocks. Overall results of these tests indicated that extractive content is primarily responsible for durability of N. heimii and S.falcifera.