Worldwide usage of plywood, the original engineered wood panel, has continued to grow, However, North American plywood production and consumption has finally stabilized (2012–2016) after steadily declining since the 1987 peak. The decline was particularly sharp from 2007 to 2009 during the years of the Great Recession.

Abstract

Modeling and projecting timber supply requires a good understanding of how supply responds to price. The price elasticity of supply (PELS) reported in the literature varies greatly, indicating that conclusions regarding price signaling in the timber market are mixed. Therefore, we conducted a meta-analysis to determine the key factors associated with the heterogeneity of PELS of primary timber product supply by examining data from numerous studies conducted around the world. Twelve “moderator” variables were examined to explore differences in PELS. Moderators with significant impacts on variation of PELS included forest products, geographic regions, econometric models, and data type. Furthermore, two-level categorical variables contained within the econometric models including standing stock were found to have significant influence on the heterogeneity of PELS. Variation in PELS also depended on whether or not the supply models accounted for price inflation, and the time period when the study was conducted. These findings may improve the understanding of the dynamics of price signaling in timber markets, and further improve the efficiency of timber supply and forecasting models for market participants and policy makers.

Abstract

Kaizen events are used in business organizations to lower manufacturing costs and increase product value. However, little research has focused on measuring the effectiveness of Kaizen events as a continuous improvement tool. The goal of this article is to introduce an empirical tool to measure the effectiveness of Kaizen events on the basis of employees' perceptions of their knowledge of, barriers to, motivators for, drivers for, and effectiveness of Kaizen. The design of the tool included a questionnaire for the upper management and a questionnaire for production and nonproduction employees, and it was implemented in a wood products company located in the United States where Kaizen events had been conducted for several years. The interview with the Kaizen manager revealed critical aspects related to strategic issues, structure and support, and implementation of Kaizen events. The analysis of the questionnaire implemented with production and nonproduction employees indicated that perceptions regarding motivators and barriers did not differ among the type of employee. In addition, statistical analysis revealed that only the driver “teamwork efforts” was a predictor of Kaizen effectiveness. The design of a Kaizen effectiveness tool and its implementation in a case study firm is an important contribution in the area of continuous improvement to help practitioners and researchers measure the effectiveness and impacts of Kaizen events.

Abstract

Developing tools and methodologies for the evaluation of sustainable buildings is essential to promote transparency in the building design community. Building sustainability includes attributes from the built, natural, and social systems and inherently requires a series of trade-offs. These complex and often competing priorities require consideration at each stage of a building's life cycle.

A total of 24 environmental, social, and economic indicators were developed and applied to three alternative building systems: cross-laminated timber (CLT), steel and glass, and reinforced concrete.

The goal of this study was to demonstrate the use of a multi-attribute decision support system (MADSS) that uses a series of indicators, assigns numerical values to these indicators, and then allows for systematic evaluation and ranking of alternatives. A case study approach was used to demonstrate the utility of the MADSS approach in identifying “hot spots” and trade-offs for the three building systems. Portland, Oregon, was selected as the location for the alternative buildings. The functional unit for this study was a mixed-use nine-story building with an area of 19,000 ft². All processes from extraction of raw materials to end-of-life operations were considered in this study. The CLT building was found to have a higher rank compared with concrete and steel in all three attributes of environmental, economic, and social sustainability.

The results of this study are intended to serve as a demonstration of the MADSS tool for building systems and to identify hot spots in the various indicators utilized for sustainability evaluation. The ranking of environmental, social, and economic attributes of building materials on specific indicators will vary with the interests of stakeholders and the building's location, type, design, and other factors.

Abstract

In this article we discuss the impact of the recent housing crisis and economic recession on the southern US softwood sawmill industry. We use the first difference model to quantify the impact of market conditions on the performance of independent sawmills including their adjustments and responses between 2006 and 2012. Our results show that lumber and log price change, adjustment in product mix and labor input, and export strategy were key factors influencing production and capacity utilization levels during and after the housing crisis. Furthermore, these factors contributed in different magnitudes in the housing crisis and recovery periods.

Abstract

In an effort to identify opportunities for regional economic development for western North Carolina, this study investigated the economic impacts generated by collocating a 10,500-ton/yr wood pellet mill alongside a 10-million board foot hardwood sawmill in the Asheville–Brevard combined metropolitan statistical area. Using the analysis-by-parts methodology within the input–output analysis framework, a custom production function was built to describe a small-scale pellet manufacturing facility operating alongside a hardwood sawmill. The additional economic effects generated by a pellet mill collocation are described, along with upper and lower bounds that represent potential variability in the estimates caused by raw material price fluctuation. Last, the impacts generated by the collocated mills are compared with a similar increase in demand distributed among all forest products manufacturing sectors existing within the study area. The study found that wood product firms existing within the region had the opportunity to utilize excess woody biomass for pellet production and could diversify their product lines, create additional jobs, and stimulate value-added economic activity for the region.

Abstract

The potential development of a Canadian forest-based bioeconomy requires an assessment of both fiber availability and associated marginal supply costs. To a large extent, the bioeconomy is expected to rely on wood fiber made available through primary products, sawnwood, and pulp production processing streams. Therefore, it is important to understand the regional wood fiber flows and mill residue availability through various processing streams. In this study, we developed a spatially explicit Forest Fiber Cascade Model (FCM) to estimate regional fiber flows and availability of untapped residue surplus. The FCM was calibrated to 2013 production levels, and we evaluated the wood fiber cascade through existing forest industry in Canada. The results show that, under current conditions, there is limited availability of surplus mill residues in Canada, especially in the Eastern provinces. It is therefore critical to consider the impacts on regional fiber flows and feedstock availability to the secondary industries when designing feedstock supply strategies and policies for the emerging forest-based industries.

Abstract

Decisions in the forest products sector have economic, environmental, and social impacts, and involve multiple stakeholders. The complexities and variations in the sector, such as equipment interactions and seasonalities, make discrete-event simulation an attractive decision-support tool. This article reviews the relevant literature to highlight the extensive applications and benefits of discrete-event simulation in forestry. Discrete-event simulation allows one to perform “what-if” scenarios and assess the impact of changes on processes, overall throughput, and productivity. It has been used to compare harvesting systems, evaluate the impacts of machine interactions in the forest and in mills, conduct bottleneck analyses, determine the feasibility of machine replacements, assess log transportation methods, and analyze biofuel supply chains. No studies considered the combined interactions of workers and machines, which could be considered in the future. Future work could also consider multiple objectives, the combination of optimization and simulation, the combination of different simulation methods, and the use of simulation for training and performance evaluation.

Abstract

Programs aimed at developing clones of hybrid trees are commonly established in Brazil to meet the demands of various forest-based industries. These programs have continually improved the quality of eucalyptus wood, which has the potential to reduce deforestation by lowering demand for other high-value species. This is particularly true in the lumber market, but little is known about the resistance of eucalyptus wood to biodegradation. This study evaluated variation in natural resistance of seven Eucalyptus grandis × Eucalyptus urophylla hybrid clones to decay by four wood-rot fungi and feeding by subterranean termites. In addition to mass loss, the relationship between density and durability was also examined. Results showed significant differences among the various clones in density as well as in resistance to fungi and termites, although none of the clones were resistant to Trametes versicolor. Mass loss in wood specimens ranged from 9 to 61 percent in the fungal tests and from 6.9 to 20.5 percent in termite tests. Average density measurements among clone groups were calculated to be between 461 and 659 kg/m³. Among the clones, five of the seven showed resistance to fungal decay and termite feeding, which was correlated with increased wood density. Based on these results, we suggest that certain clones, particularly those with higher density values, may be considered for production of various lumber products.

Abstract

To simulate fuel oil spills occurring during catastrophic floods, short-term absorption of two chemicals, n-hexadecane (representative of semivolatile organic compounds in fuel oil) and water, into southern yellow pine was gravimetrically monitored as a function of time at ambient conditions. Different scenarios were run on the basis of (1) the order of contamination (n-hexadecane followed by water or vice versa) and (2) whether the wood lateral sides were covered with epoxy. The experiments were designed to evaluate fast initial sorption, allowing separate estimation of the end-grain (i.e., total longitudinal) and lateral (i.e., surface longitudinal) liquid penetration. Presaturation of wood with water did not significantly impede the subsequent penetration of n-hexadecane, whereas the presaturation of wood with n-hexadecane led to a significant decrease of the subsequent water uptake. This difference in penetration on the basis of the order of application was explained by the differences in the polarities of the two penetrating liquids and their impacts on the interactions with the wood matrix. Calculated apparent diffusivities for end-grain and lateral penetration were similar at ca. 3 × 10⁻⁷ m²/s, indicating that filling of easily accessible near-surface voids does not have a substantial impact on the overall penetration of contaminants into wood. The n-hexadecane distribution profiles based on penetration into wood blocks (obtained by means of gas chromatography) showed that water and n-hexadecane appear to use different (although overlapping) penetration paths owing to the differences in their physical properties.

Abstract

Quality Indexes for red oak (Quercus rubra) and white oak (Quercus alba) logs were established using multivariate regression models developed by the US Department of Agriculture (USDA) Forest Service that predicted green 4/4 lumber grade yields from hardwood sawlogs. Past Quality Indexes were based on air-dried lumber grade yields, but these yields can be affected by mill-specific factors. Considering green lumber as the finished product isolated the drying process and any subsequent changes in lumber product value from the analysis. Lumber grades were consistent with National Hardwood Lumber Association specifications, while log grades were based on the USDA Forest Service grading rules. Input data into the models included log scaling diameter, log length, and percent scaling defect. Green lumber grade yields were then used along with price relatives developed from 5-year lumber grade price averages (nominal) to develop Quality Indexes for each species. Two applications of the Quality Index are illustrated.

Abstract

Log rules estimate the volume of green lumber that can be expected to result from the sawing of a log. As such, this ability to reliably predict lumber recovery forms the foundation of log sales and purchase. The more efficient a sawmill, the less the scaling methods reflect the actual volume recovery and the greater the overrun factor. Using high-resolution scanned log data and the RAYSAW hardwood log sawing simulator, we compared recovery results for a 32-log sample with data from other mills and examined the overrun factors for common log scaling methods. With the sample logs, we saw underruns as low as −31.9 percent and overruns as high as 159.4 percent depending on log rule and log characteristics. Given the measurement accuracy of laser profiling systems and computing speed, it is relatively easy to determine log volume and recovery both quickly and with heretofore unknown accuracy. The log rules commonly in use today were all developed over 100 years ago: Doyle in 1825, Scribner in 1846, and International ¼-Inch in 1906. Both the logs from the forest and processing methods and equipment in the mills have changed since then. As such, the log rules are not as relevant to modern mills and today's timber supply as they once were. Given modern developments in laser measurement systems, mill operators have much better tools available to access log supply.

Abstract

The goal of this project was to investigate the efficacy of vacuum–steam technology to sanitize low-quality ash logs and ash firewood. It is difficult to heat treat logs and firewood because of the relatively large cross-sectional dimension. Compared with hot air, steam has a greater heat capacity, and the condensation, without reducing the moisture content of wood, results in more efficient heat transfer. Also, the pressure gradient created by the vacuum accelerates heat transfer through the wood cross section. The vacuum–steam system consists of a vacuum source, a controlling device, a flexible container, and a steam generator. The white ash logs and firewood were harvested in Montgomery, Virginia. Ash log diameters ranged from 16.5 to 27.9 cm on the small end. The logs were cut into lengths of 1.82 m. After the vacuum was drawn to 300 or 500 mm Hg inside the container, steam was injected into the container. The steaming continued until 56°C was reached at the center of the lengths. The treatment time for all the logs varied from 5.5 to 14.5 hours, including a vacuum and a holding time of 30 minutes. The 1.82-m logs were cut into 40.6-cm-long bolts and then split into firewood, rarely larger than 15.2 cm on the wider side. The treatment time for firewood varied from 80 to 137 minutes, including a vacuum and a holding time at 56°C for 30 minutes at the core. There is no effect on quality, and the process can be tailored to different treatment capacities and is easily portable.

Abstract

Spatially resolved measurements of moisture content (MC) in black spruce (Picea mariana Mill.) logs were undertaken by unilateral magnetic resonance (UMR) and magnetic resonance imaging (MRI). The goal of this study was to understand drying behaviors of the different regions in black spruce wood logs. Results indicate that water is lost from the entire length of the log as drying progresses. Diffusive drying from both sapwood and heartwood was observed at the log ends. The most significant drying in the log interior was through the bark. The magnetic resonance signal has an amplitude that depends on water content and a lifetime that depends on the water environment, namely, cell wall or cell lumen. The UMR measurement distinguished signal from cell wall and lumen water. The MRI measurement spatially resolved, in 3D, total water content in the wood. This was important in order to differentiate the water content and drying behavior in sapwood and heartwood. The MC in the black spruce sapwood was significantly higher than the MC in the heartwood. The water content in the cell wall does not change significantly until lumen water is depleted.

Abstract

In this study, polyols recycled from decomposed polyurethane (PU) foam wastes were used in preparing adhesives for plywood manufacturing. A polyol was made from chemically decomposed flexible PU foam wastes separated from automobile shredder residue. The recycled polyol was mixed with a commercial polyol at weight ratios of 100/0, 25/75, 50/50, 25/75, and 0/100, respectively. These polyol mixtures were mixed, respectively, with polymeric methylene diphenyl diisocyanate at isocyanate group–to–hydroxyl group (NCO/OH) molar ratios of 1.0, 1.25, and 1.5 to prepare adhesives. The recycled polyol and adhesives were characterized by Fourier transform infrared spectroscopy. Plywood specimens bonded by the adhesives were fabricated and tested. The effects of NCO/OH molar ratio and recycled polyol–to–commercial polyol weight ratio on adhesive gel time and bonding strength before and after water treatments were evaluated. The adhesives prepared from recycled polyol presented shorter gel time and greater dry bonding strength than those prepared from commercial polyol. The adhesives prepared from the recycled polyol–commercial polyol weight ratio of 50/50 and NCO/OH molar ratio of 1.25 showed the best bonding performance after cyclic boiling water treatment. Multilinear regressions showed that NCO/OH molar ratio was the main factor in developing plywood shear strength.

Abstract

In this study, a kind of nanocomposite was prepared using nanocellulose fibril (NCF) aerogels derived from processed bamboo residues composed mainly of parenchymal cells. NCF aerogels were prepared using an ultrasonication method with freeze-drying. The freeze-dried aerogels were swollen with water and then impregnated with aqueous phenol-formaldehyde resin solutions of varying concentrations. The mechanical properties of nanocomposites with 10 percent (by weight) resin exhibited a tensile strength, tensile modulus, and tensile toughness of 150 MPa, 5 GPa, and 17 MJ/m³, respectively. Compared with NCF aerogels, the composites demonstrated lower hygroscopicity at high humidity. This combination of toughness, minimal moisture absorption, and other properties is of technical interest for practical applications.

Abstract

Sr²⁺ was chemically grafted onto the hydroxyl position of bacterial cellulose. Fourier transform infrared and UV-Vis spectroscopy were used to evaluate the chemical bonding of the modified bacterial cellulose structure. Then a chemical bond between Sr-O was formed. The presence of strontium was confirmed using X-ray fluorescence. A significant enhancement in the dielectric properties was observed. Next, a small amount of modified bacterial cellulose was prepared as a binary blend composite. The ratio between polyvinylidene fluoride and the modified bacterial cellulose was investigated. They had superior thermal stability and mechanical properties compared with the neat modified bacterial cellulose. The degradation temperature was higher than 300°C. The outstanding property of the composite was its flexibility. The excellent properties of the composite of modified bacterial cellulose and polyvinylidene fluoride make it a good electroactive biocomposite candidate.

Abstract

The aim of this study was to evaluate the effects of radial growth on wood properties and anatomical characteristics and to clarify the xylem maturation process in Gmelina arborea. Stem diameter, tree height, and stress-wave velocity were investigated for 54 5-year-old G. arborea trees planted in Indonesia. In addition, radial variations of wood properties (basic density and compressive strength parallel to the grain in green condition) and anatomical characteristics (fiber and vessel morphologies) were investigated for nine trees selected from three different radial growth categories (fast, medium, and slow growing). Stem diameter was positively significantly correlated with stress-wave velocity and compressive strength parallel to the grain in green condition. In addition, compressive strength and anatomical characteristics, except for wood fiber diameter, differed significantly among the radial growth categories. Radial variations of the wood properties and anatomical characteristics gradually increased, and then they showed constant values toward the bark. It is thought that the xylem maturation of G. arborea begins at approximately 5 cm from the pith. In addition, in a fast-growing tree species, such as G. arborea, the trees with faster stem diameter do not always form wood with low strength properties.