The increasing demand for forest products and restricted use of natural forests has resulted in a shortage of high-strength wood fiber. The area covered by plantation forests is steadily rising, but the fiber produced by these forests is often unsuitable for high-strength applications. One attempt to combat this problem is the viscoelastic thermal compression (VTC) process, which can dramatically increase the strength and stiffness of any wood species. To advance VTC wood from the concept evaluation stage to the development stage, concept testing interviews were conducted with individuals in the forest products industry. Opinions, ideas, and insights were gathered from interviewees concerning potential applications for VTC wood, as well as advantages and barriers to commercialization. As a whole, interviewees thought the most viable uses for VTC wood were laminated veneer lumber, plywood, concrete forms, transportation components, and flooring. The most frequently mentioned advantages to commercialization included increased mechanical properties and the utilization of a low-value wood species; barriers to commercialization were cost and the forest products industry's resistance to change. Overall, interviewees thought VTC wood would be successful as long as it was not markedly more expensive than similar products.
To develop bending failure mechanics and establish the bending strength prediction models, fiberboards with both uniform and “bowl-shaped” vertical density profiles (VDPs) were manufactured, and their bend loading–deflection relations were evaluated and compared. The bending modulus of elasticity (MOE) and rupture (MOR) of fiberboards with bowl-shaped VDP (BS-fiberboard) were predicted using the sheet laminating theory. The results indicate that when fiberboards are of the same average density, the bending performance of BS-fiberboard is at least 40 percent stronger than uniform fiberboard. The MOE and MOR prediction models of BS-fiberboard correlated with thickness of panel, average density, surface density, density of sandwich layer, and thickness of sandwich layer and had a very strong predictive ability.
Reusing decommissioned utility poles and other preservative-treated wood reduces the total amount of preservatives in the environment and the need to fall the trees in the forest, offering economic and ecological advantages. In a previous study, the pentachlorophenol (penta) retention and mechanical properties of decommissioned penta-treated southern pine utility poles and pole sections were investigated. The current study evaluated the mechanical and delamination properties of laminated beams made of penta-treated utility pole wood. A total of 45 laminated beams and 15 solid-sawn beams were fabricated from decommissioned penta-treated utility pole wood and untreated southern pine virgin wood. Three composition schemes and two surface preparation methods were investigated for their effects on penta retention, bending, glue-line shear, and delamination properties of the laminated beams. Penta-treated utility pole wood absorbed more penta than virgin wood during retreatment. The bending strength of the laminated beams met American National Standard Institute Standard 05.3. However, percent delamination of the laminated beams failed to meet the standard requirement set by ASTM Standard D2559, and thus, penta-treated utility pole wood beams consolidated by resorcinol phenol formaldehyde resin cannot be used in exterior exposure conditions.
Heat treatment has been assessed as an eco-friendly means to reduce wood's dimensional instability and biodeterioration under varying ambient conditions. However, irreversible losses in mechanical properties have been reported to occur when wood is subjected to elevated temperatures as a result of the autocatalytic breakdown of the cell-wall constituents. The reduced strength of heat-treated wood is a disincentive for its extensive use in structural applications where high-strength quality is important. Thus, improved durability must be balanced with the preservation of the mechanical properties of heat-treated wood. The strength properties of heat-treated loblolly pine (Pinus taeda), sweetgum (Liquidambar styraciflua), and water oak (Quercus nigra) were assessed to quantify the effects of varying temperature levels, up to 204°C, and duration, up to 8 hours, on flexural strengths, compression strengths, shear strength, and hardness. Two-factor analysis of variance (ANOVA) and 1-factor ANOVA (where there is temperature–duration interaction) of results coupled with Tukey's pairwise comparison (α = 0.05) indicated effects ranging from indicative differences in modulus of elasticity to significant increment and decrement in other strength parameters. Generally, strength properties for the three species were optimally preserved, or peaked and dominantly improved in specimens treated at 149°C for 8 hours. This study provides a knowledge base for process optimization in heat treatment industries and for the use of heat-treated wood in structural applications.
This research investigates sources leading to productivity changes for the US forest products industry during the time period from 1997 to 2009 using the contemporaneous and global Malmquist productivity index (MPI) approaches. Under the assumption of variable returns to scale, the global MPI breaks down into new measures of decomposition, such as efficiency change, best practice change, and scale efficiency change. Overall, the productivity change for this industry shows progression in both approaches. The technical and scale efficiency changes are main sources of productivity growth. However, compared with the contemporaneous MPI, the global MPI can reflect the real-world situation in terms of productivity change. Within the US forest products industry, the annual growth rates in housing starts and in real export value significantly affect the productivity growth in the wood product sector. In contrast, the real export value's growth rate is the only notable effect on the pulp and paper sector's productivity growth.
This study provides an overview and analysis of China's timber market trends over the last two decades, along with projections to the year 2020. An econometric model (simultaneous equations regression) is applied to estimate China's timber supply and demand. Key variables influencing China's timber market are identified. Corresponding coefficients are estimated and can be applied to other studies and sophisticated timber market models. Results show that timber supply in China increases at a slightly higher rate than timber demand, but timber consumption is projected to triple between 2008 and 2020, which will result in significant growth of timber imports (also nearly tripling by 2020).
The use of woody biomass has received considerable attention for energy production. However, high production and transportation costs can be a barrier to woody biomass use in some regions. Developing cost-effective transportation systems has become an economically critical issue to expand biomass use. We developed a computer model, named BIOTRANS, to estimate biomass transportation productivity and cost in western Oregon. We used BIOTRANS to evaluate the effects on transportation costs of six different truck configurations, four transported material types, and over 100 travel routes. Different truck configurations, transported material types, and travel route characteristics were found to significantly affect transportation costs. A four-axle truck and single trailer was the most cost-efficient hauling configuration for the conditions studied, and shavings had 30 percent higher trucking costs than other hog fuel, chips, and sawdust.
Persistent concerns about the continued use of foreign labor and the viability of northern Maine's logging industry prompted further research on the cross-cultural logging workforce found in Maine's counties that border the province of Quebec. Two distinct populations of woods workers are employed in these border counties: Maine residents and Quebec residents. This study examined sociodemographic attributes, sense of occupational choice and prestige, and familial attachment held by these two populations of loggers, as well as barriers to business expansion felt by logging entrepreneurs. Significant differences in age, education, logging experience, attitudes toward logging, and perceptions of public image were found between Maine and Quebecois loggers. Additionally, despite an intergenerational labor supply that historically characterizes the logging industry, more than 50 percent of loggers from both countries would not encourage their children to enter the logging profession. These factors may not only pose challenges for logging business stability and labor recruitment efforts in this region but also impact the economic vitality of the forest products industry as a whole. Furthermore, the findings from this research may be of interest and pertinent to those engaged in forest products industries within other cross-border regions.
Whole comminuted trees are known to self-heat and undergo quality changes during storage. Trommel screening after grinding is a process that removes fines from the screened material and removes a large proportion of high-ash, high-nutrient material. In this study, the trade-off between an increase in preprocessing cost from trommel screening and an increase in quality of the screened material was examined. Fresh lodgepole pine (Pinus contorta) was comminuted using a drum grinder with a 10-cm screen, and the resulting material was distributed into separate fines and overs piles. A third pile of unscreened material, the unsorted pile, was also examined. The three piles exhibited different characteristics during a 6-week storage period. The overs pile was much slower to heat. The overs pile reached a maximum temperature of 56.8°C, which was lower than the maximum reached by the other two piles (65.9°C and 63.4°C for the unsorted and fines, respectively). The overs also cooled faster and dried to a more uniform moisture content and had a lower ash content than the other two piles. Both piles of sorted material exhibited improved airflow and more drying than the unsorted material. Looking at supply system costs from preprocessing through in-feed into thermochemical conversion, this study found that trommel screening reduced system costs by over $3.50 per dry matter ton and stabilized material during storage.
A robust supply chain is critical to ensure a sustainable supply of feedstock to the existing and emerging bioenergy and bioproducts industries. Logging contractors are a key group in this process, since they provide harvesting and transportation services, and their success is directly linked to innovation activities. Surprisingly, very little is known about the innovation system in the logging industry—especially about how it relates to biomass supply. Failure to understand how logging contractors adopt and implement biomass production technologies could lead to failed innovation efforts, unmet development goals, and a lack of properly equipped contractors. This article presents results from a series of case studies of highly innovative logging contractors in Maine. All of the firms had some experience producing biomass within their operations. The firms had also used multiple biomass harvesting technologies. This study highlights the variation in challenges that led to the adoption (or rejection) of biomass as a product innovation—with particular emphasis on harvesting technologies. A major finding of this study was the need for a high degree of collaboration between landowners, logging contractors, and biomass consuming facilities in the innovation process. The future development of the biomass industry is highly dependent on contractors adopting biomass harvesting and related technologies. The innovation process of logging firms is an area that is not sufficiently studied, and this research provides valuable insight into this important component of the forest biomass industry.
A survey of six stand-alone wood-based electric power generation plants in Michigan assessed facility operating characteristics, fuel characteristics, sources of wood, and operators' views on wood supply and needed policy changes. Survey results provide insights regarding the role of these renewable energy plants in meeting Michigan's Renewable Portfolio Standard (RPS). The plants have long-term power supply agreements with Consumers Energy Company; they produced the bulk of renewable energy for Consumers in 2009. The six plants were the only wood-burning electric generating facilities operating in Michigan during 2008, the base year for the survey. Each plant employed 22 people, on average, to operate the facility. The three smaller plants generated 18.4 MW on average in 2008 and used 195,954 tons (177,766 metric tons) of wood fuel. Larger plants produced 27.7 MW on average and consumed 323,915 tons (293,851 metric tons) of wood fuel. Green wood from logging residues was the largest source of material. The second largest wood fuel source in 2008 was chips, but managers noted that this was an anomaly driven by depressed activity in the wood products industry. Given the economic downturn in 2008, more logs and chips were available for power generation. Most facilities supplemented their wood fuel with tire-derived fuel. Managers identified several policy changes that would encourage stability and growth in their industry, most related to wood fuel supply.