In this study, rated plywood, oriented strand board, laminated strand lumber, and laminated veneer lumber were thermally modified as a posttreatment at 140°C, 150°C, 160°C, 170°C, and 180°C using a closed, pressurized treatment method. Eastern larch oriented strand board manufactured from heartwood and sapwood was also thermally modified as a posttreatment at 160°C and 180°C. All specimens were subjected to laboratory soil block durability tests according to American Wood Protection Association E10‐12 utilizing Gloeophyllum trabeum (brown rot) and Trametes versicolor (white rot) fungi. Heat treatment caused a reduction in weight loss for most substrate and fungi combinations.Abstract
Surface finishes change the characteristics of volatile organic compounds (VOCs) released from wood-based panels. This research studied the effects of different finishes on the VOCs released from particleboard (18 mm thick). Various materials, such as polyvinyl chloride (PVC), melamine paper, and water-based paint, were compared with unfinished particleboard. A 1-m3 climate chamber and gas chromatography–mass spectroscopy were used to examine the types and rates of release and the percentages of various VOCs released by decorative particleboard over 28 days. By comparing the characteristics of VOCs released from unfinished particleboard, the effects of different surface finishes were determined. The VOC substances of concern released from particleboards were analyzed by their type and concentration until they reached a state of equilibrium on day 28. Results showed that none of the surface finishes changed the variety of total VOC (TVOC) released from particleboard, but they had a prominent influence on the rate of TVOC released, especially in the early stages. Acrylic water-based paint increased the TVOC release rate from the particleboard, whereas the PVC and melamine finishes decreased the rate. Surface finishing greatly influences the concentration of various VOCs. Although the same types of VOCs were released by the various finished particleboards, they each had different release rates and different variations in their release-rate tendencies. Surface finishing can change the percentages of various VOC components, so that the amounts were different depending on the finish, and different types of VOCs were controlled better by certain types of finishes.Abstract
The objective of this study was to compare the characteristics and bonding performance of phenol-formaldehyde (PF) resins modified and blended with crude bio-oil. For modified PF resins, crude bio-oil from the pyrolysis of pinewood was synthesized with phenol and formaldehyde at 10, 25, 50, and 75 percent phenol substitution percentages, respectively. For blended PF resins, crude bio-oil was physically blended with PF resin at 4, 13, 23, and 38 percent addition percentages, respectively. The physical properties of crude bio-oil and PF resins, such as viscosity, pH value, gel time, water content, and solid content, were measured. The bond strength of plywood was evaluated. The results indicated that incorporating crude bio-oil into PF resin either by synthesis or by blending at certain amounts could improve the bonding performance of PF resins. For blended PF resins, the best crude bio-oil addition percentage was 13 percent, while for synthesized (modified) PF resins, the best phenol substitution percentage was 25 percent. Further increment of the crude bio-oil content level decreased the bond performance of both modified and blended PF resins. This was mainly due to the increased viscosity and the acidity of blended PF resins at a high crude bio-oil addition percentage and a shortage of reactive phenolic compounds in modified PF resins at a high phenol substitution percentage. Plywood bonded with the resins could generally meet the requirement of Chinese National Standard GB/T 17657‐2013 and be suitable for outdoor applications.Abstract
The purpose of this study was to evaluate the impact of glue line thickness on joint strength properties while using two types of PVAc adhesive (i.e., one-component Rhenocell 3W, 4B Plus, resistivity class D3, and two-component Protovil VP244/2C, resistivity class D4) belonging to the group of thermoplastic adhesives intended for nonconstruction joints. Joint strength testing was carried out using the transverse tensile test for estimation of the joint strength method. It was proven that if specimens were conditioned for 7 days at 20°C ± 2°C and a relative air humidity of 65 ± 5 percent, when testing one-component Rhenocell 3W, 4B Plus (D3) adhesive, increasing thickness of the glue line results in falling strength of the bonded joint. When testing the two-component Protovil VP244/2C (D4) adhesive, increasing thickness of the glue line always results in increasing joint strength, even under conditions when water is directly affecting the joint or under increased temperatures.Abstract
Growing environmental awareness is leading to an increased interest in the use of biobased adhesives and proteins such as vital gluten. The purpose of this study was to investigate the influence of the wood-particle moisture content, water application, and press time on the internal bond strength, thickness expansion, and thickness swelling of particleboards glued with vital gluten. Green and dried wood particles with similar moisture content were achieved through drying or water addition and were blended with vital gluten powder and pressed for 1 to 3 minutes. The results show that not only the pressing time and moisture content, but also the way of achieving the moisture content, has a strong impact on the performance of the boards. At comparable moisture content, never-dried (green) particles with high moisture content in combination with a dry adhesive application produced boards that performed better than boards made of dry particles with water addition to simulate liquid adhesive application.Abstract
After the decrease in southern pine (Pinus spp.) design values, concerns were raised over the design values of Douglas-fir (Pseudotsuga menziesii), the most important structural species in the Pacific Northwest of the United States. Moreover, species need to be re-evaluated every 5 years for properties by the grading agencies. Variability within Douglas-fir lumber may have increased over time because of changes in the silvicultural practices and management techniques including the shift from government to private plantation. The compression parallel to the grain design values took the greatest hit for southern pine. To assess if there is any decrease in the compressional design values, No.2 grade Douglas-fir, of dimensions 38 by 89 by 2,438 mm, were attained from 36 different locations and were cut into 229-mm sections with 20 samples from each location. A total of 720 samples were tested to failure in compression parallel to grain according to ASTM International D4761. Additionally, 288 clear specimens were also tested. The compression strength was calculated and was compared among locations. The data were pooled to calculate the design values for compression parallel to the grain and compared with listed values in the National Design Specification. Variation of compressive strength within locations was observed, but even after accounting for the variation the calculated values are above the average reported value for clear wood specimens and higher than the code-recommended design value for nonclear specimens.Abstract
This article provides an efficient and intuitive way to predict the long-term (12-h) compression creep behavior of wood by a finite element method (FEM). In this study, oriental beech (Fagus orientalis L.) was used as an example. First, a short-term (3-h) compression creep experiment was conducted to obtain the original creep data of beech, and then a Kelvin model (KM) with two elements in series was applied to fit the curve of creep strain and time to calculate parameters used in FEM. Second, long-term compression creep behavior was numerically analyzed by the FEM based on the short-term creep data. Finally, the results of the FEM and the KM were compared with that of the long-term creep experiment. The results showed that the creep deformations increased in the order of longitudinal (L), radial (R), and tangential (T) directions under the same loading level, and the creep behavior of beech in the L direction stopped after a short time and stayed constant. Additionally, in the same orientation, the creep deformation increased with the growth of loading levels below the ultimate creep strength. In addition, the KM did not work well for predicting the long-term creep behavior of beech. By contrast, the results of FEM were highly consistent with those of the experiment, and errors in L, R, and T directions were all less than the standard deviation. As a result, the numerical method provided acceptable accuracy to predict the long-term creep behavior of wood construction and wood products.Abstract
Aiming to provide economical equipment support for nondestructive wood testing, we developed a wood computed tomography (CT) imaging system to aid wood researchers in accurately understanding wood internal structures and defect characteristics. The wood CT system consists of an X-ray source, an X-ray detector, an electric rotational stage, and a computer. The X-ray source projects a fan-shaped X-ray beam to the wood, and the X-ray detector captures the penetrated X-ray intensity data when the wood is at different angles of rotation. The projection data were preprocessed before they were used for image reconstruction. An improved filtered back-projection (FBP) algorithm specialized for wood cross section CT image reconstruction was proposed. The traditional Ram-Lak (RL) filter and Shepp-Logan (SL) filter were replaced by a Butterworth filter. The Butterworth parameters were determined to achieve a desirable compromise between spatial resolution and image noise. Two pieces of cylindrical log (Thuja sp., Pinus sp.) and a block of laminated timber were scanned. The reconstructed images clearly revealed the internal structures of wood, and the fine features such as pith, annual growth rings, radial cracks, knots, and outer edge were enhanced, while the image noise and blurring effect were suppressed.Abstract
In this research, the anatomical characteristics and physical–mechanical properties of bamboo between internodes and nodes were investigated to evaluate the influence of nodes on the properties of bamboo culm. The results indicate that node sections had lower vascular bundle frequency, shorter fiber length, and wider parenchyma lumen diameters in comparison with internodes. The compressive strength parallel to grain, shear strength parallel to grain, and modulus of elasticity of bamboo culm internodes were significantly higher than those of the nodes. The basic density, volumetric shrinkage, and modulus of rupture of the former were also higher than the latter, although the difference was not significant.Abstract
With economic globalization and the diffusion of corporate social responsibility (CSR), firms are increasingly moving from using reactive to more proactive strategies in their environmental, social, and governance (ESG) strategies. Wood-based panel processing enterprises, which are particularly sensitive to environmental and social issues, are increasingly developing their CSR strategies. Previous research on environmental protection and responsibility in this industry focused mainly on single aspects, such as the control of volatile noxious gases, while neglecting comprehensive social environmental responsibility strategies, especially in emerging economies. This article adopts a case study approach that analyzes the main CSR strategies of four leading Chinese wood-based panel processing enterprises. The study provides a reference for similar enterprises in China and other developing economies on CSR/ESG strategies. Even though context specific, our findings can provide further impetus for research and discussion on other emerging economies that share similar institutional characteristics.Abstract
The value of aggregate forest product exports to India has increased from about $1.5 billion in 2003 to about $5.4 billion in 2013. Although many of the forest product resources can be sourced from within India, the subcontinent must also source forest products from trading partners, in the form of wood product exports. This presents many economic challenges and opportunities for wood product markets and trade, as India is the second-largest importer of wood products in the world. In this study, we focus on the effect of regulatory quality on forest products exports by partner countries to India. Using a panel of trade flows during 2009 through 2013 of 143 partner countries exporting forest products to India, we estimate an augmented gravity trade model to capture the effect of relevant variables on the outflow of aggregate forest products and disaggregate paper and paperboard, wood pulp, fiberboard, veneers, sawn wood, industrial roundwood, and plywood products from partner countries to India. Results from the analysis are mixed; regulatory quality is found to have positive correlation with exports to India in some cases (paper and paperboard products and wood pulps) and no correlation in a few instances (fiberboard, veneer sheets, sawn wood, industrial roundwood, and plywood). Other explanatory variables such as the distance between the partner country and India, forest area of partner country relative to forest area of India, gross domestic product, population, and trade agreements are mostly found to have positive or negative significant effects on trade, varying across different sectors.Abstract
Our study examined relationships among pellet mills, bulk delivery companies, and high-efficiency pellet boiler equipment firms in northern New England as they relate to homeowner satisfaction, using social network analysis and the concept of supply chain management. The continual growth of supply and demand for automated pellet heating requires a careful match between innovative technologies and homeowner needs; these involve multiple factors and require collaboration among firms. Using interview data with managers from pellet mills, bulk delivery companies, and equipment firms in Maine, New Hampshire, and Vermont, we found 15 firms that are connected through both a transaction network and an informal business interaction network. The networks were characterized by short paths and no obvious sign of centralization. Network statistics reported for each network included density, clustering coefficient, and degree, closeness, and betweenness centrality. Most firms in the supply networks shared customer satisfaction information (average number of information sending ties = 3) and considered collaboration in customer services important (mean = 4.4, on a 5-point scale). However, equipment firms initiated more information sharing than other types, and bulk delivery companies were in the best position in the supply network to promote collaborative customer services. Opportunities exist to improve communication between pellet mills and equipment firms, leading to a robust automated pellet heating supply chain, strong demand, and subsequent homeowner satisfaction.Abstract
A two-step method was developed to estimate the economically available biomass from forest operations in the Pacific Northwest. Step 1 measures the amount of biomass in piles from a variety of logging operations. Step 2 applies logistics models to determine the amount of biomass that is recoverable by computing the extraction costs depending on the distance from the landing. Cable units included only the biomass piles located at the landings, while ground-based units computed the collection and transport of each pile to the most cost-effective landing using geographic information system and simulation tools. This approach was applied to operations on state and private timberlands in Oregon and Washington. For the cable logging units, the average pile size was 46.7 green tonnes of residue, and this material was either on or next to the roadside landing. It produced few large piles with an average of 24.75 green tonnes per ha. For ground-based operations, approximately 54 percent of the residue in the harvest units was 90 m or less from the landing. Collection cost increases as the material is farther from the landing and ranged between about $17.6 per green tonne at distances of 15.2 m to $37 per green tonne at distances of 213 m from the landing. Depending on the distance from the landing to the bioenergy facility, it is possible to estimate how far from the landing into the forest to reach to economically collect the biomass.Abstract