International Wood Products Journal

The present study was conducted to investigate the influence of heat treatment temperature and duration on the dimensional stability of chir pine (Pinus roxburghii Sarg.) and mango (Mangifera indica L.) wood. For this purpose, wood was heated at different temperatures for periods of 4, 8 and 12 h in an inert atmosphere. Differential responses of both wood species to different parameters, namely, volumetric swelling and shrinkage, water absorption and equilibrium moisture content (EMC) at different relative humidities, were observed. Results revealed that increase of heat treatment temperature in conjunction with time leads to a significant drop in the shrinkage of mango wood, whereas a reverse trend prevailed in chir pine until 210°C for 12 h treatment. Least values of EMC were recorded for chir pine and mango wood treated at 190 and 210°C for 4 h respectively. Further, increase in temperature and/or time of treatment significantly decreased the water absorption capacity of mango wood.

The ISO 9001 quality system is being advocated as a management tool to boost the performance of wooden furniture manufacturers in the South East Asian region. A study was therefore conducted to evaluate the status and challenges of the ISO 9001 quality system adoption among wooden furniture manufacturers in Malaysia and Vietnam. The data were compiled through direct-interviews of 100 wooden furniture manufacturers (of which 25 were ISO 9001 certified companies) using a structured questionnaire, which had four parts. The results found that ISO 9001 adoption was relatively low among furniture manufacturers due to its high implementation cost and lack of market demand, although the ISO 9001 certified companies were much more productive than their non-certified counterparts. It was also apparent that the certified furniture manufacturers were focused on producing quality furniture cost effectively, derived primarily from their lower degree of operational inefficiencies. Nevertheless, the demand for ISO certification is market-specific, as Japanese, Korean, European and Middle Eastern furniture buyers show preferences for dealing with certified companies. Therefore, the benefits of ISO 9001 quality system through greater market access and increased productivity in the mills must become more apparent, before significant adoption among wooden furniture manufacturers can be realised.

In this study, the mechanical properties of laminated strand lumber and oriented strand lumber were investigated. Two species of fast growing; Poplar (Populus deltoides) and Paulownia (Paulownia fortunei) were used. Urea formaldehyde resin was used to manufacture these products and this resin was reinforced with four levels of nanoclay (0, 2·5, 5 and 7·5%) based on dry weight of resin. Press temperature, press time and press pressure were 120°C, 5 min and 11 kg cm⁻² respectively. Statistical analysis showed that the effects of species and nanoclay on the panel properties were statistically significant at 95% confidence interval. Modulus of rupture, modulus of elasticity, internal bond, shear strength and screw holding strength were analysed in boards. It was found that if nanoclay content was increased to 5 or 7·5%, all properties were significantly improved, when Populus deltoides was compared to Paulownia fortunei, the poplar panel had excellent performance.

Twenty-one wood species native to the Pacific Northwest region of the United States, including conifers, were tested to determine if any of the commonly utilised melanin producing spalting fungi could generate sufficient spalting coverage to compete within the decorative woods market. Zone lines were readily produced by Xylaria polymorpha on Douglas fir, redwood, myrtle, and cottonwood. Blue stain from Scytalidium lignicola was prolific on myrtle and ash. These results indicate that a number of Pacific Northwest native wood species are suitable for controlled spalting, including two conifers. The prevalence of spalting on these wood species should lead to their increased value, and allow the Pacific Northwest to compete within the spalted woods market.

Prediction of basic timber properties like moisture content and density is an important factor for quality control in timber industry. This paper deals with the detection of moisture content and density of spruce (Picea abies). It describes the calibration and validation of the newly developed microwave prototype on the basis of 480 measurements for moisture contents between 8 and 19% and densities between 340 and 600 kg m^–3. The calibration and first validation set lead to R²≥92% in both cases. The prediction for a second and third validation decreases as especially the range of moisture content for these pieces was limited. Compared to other moisture and density measurement systems, the prototype showed good performance. With this technology it is possible to detect moisture and density of a piece of timber contact free and non-destructive with high prediction accuracy for both parameters in one pass.

Two model rooms were constructed out of OSB and CLT and applied as a large scale test method for emissions of volatile organic compounds (VOC) from wood based building products over a period of 23 weeks. The measured VOC emissions show terpene and aldehyde emissions in both model rooms. Emissions from all identified substances declined over time to a low value. In the CLT model room terpene emissions exceeded aldehyde emissions. Terpenes declined from 65 to 11 μg m⁻³ (83%), whereas aldehydes declined from 28 to 5 μg m⁻³ (82%). In the OSB model room aldehyde emissions were higher and declined from 247 to 51 μg m⁻³ (79%). Terpene emissions decreased from 59 to 23 μg m⁻³ (61%).

Polyvinyl acetate (PVAc) adhesives present several advantages: ready to use, short setting time, flexible joint, easy to clean and long storage life. On the other hand, formaldehyde-based adhesives are less expensive and give a rigid bond.

In this work, the combination of a PVAc glue and UF resin for surfacing MDF with wood veneer was assessed. The reactivity of different mixing ratios was evaluated using ABES (automated bonding evaluation system) machine as well as the wettability of beech veneers after different heat pre-treatments. The obtained results have shown that a mixture of PVAc/UF could be used for surfacing MDF with beech veneer without loss of mechanical properties, when compared with pure PVAc.

This study reports on a detailed investigation into the greenhouse gas emissions associated with the construction process of multistory wooden buildings relative to the other life cycle stages: the material production and operation stages. The results showed that the construction stage accounts for 20–30% of the initial embodied emissions and 6–10% of the total emission of the included life cycle stages. Especially the transport process of building components seems to have higher potential to mitigate the emissions than the actual construction work. In addition, the emissions from different construction systems were studied based on the reference buildings. Although definitive conclusion would be difficult to be drawn from this study alone due to the small sample size and the assumptions made, prefabrication work seems to be a more efficient construction method compared to on-site work for wooden buildings.

Ten-ply high pressure paper laminates were prepared by impregnating filter paper with mimosa tannin solution mixed with furfuryl alcohol and formurea concentrate. Abrasion resistance tests, a cross-cut test, and water vapour resistance measurements were carried out. The effect of 10-ply paper laminates on the shear strength of plywood was also determined. It was demonstrated that 10-ply paper laminates with mimosa tannin resin may increase the dry shear strength of plywood and reduce the absorption of water into the plywood. 10-ply paper laminates pressed at 140°C temperature at 120 kg cm⁻² pressure for 600 s gave the best appearance compared to other laminates.

Without any adhesive and other chemical additives, the mechanically induced welding can make good wood joints satisfying the relevant requirements for application. The bonding performances of the wood Tauari (Couratari oblongifilia) welded joints in three different directions were studied here: parallel to the wood grain, perpendicular to the wood grain and end grain to end grain. The results show that the compression shear bonding strength of the perpendicularly welded joints was the best, parallel welded joints took the second place while the strength of the end grain butt joints was so small that it could not resist the sewing machine. The figures of scanning electron microscopy and the density profiles show the different structures and density distributions of the welded joints which indicate the reasons behind the big differences of the compression shear bonding strength.