“Wood in Design and Engineering” is a new course at Mississippi State University that is specifically designed to demonstrate how the philosophies and functions of all three departments in the College of Forest Resources interact with regard to the resource, material, and utilization of wood and forest products, while making a tangible contribution to both the university and the community. The course brings together undergraduate and graduate students from all three departments and uses hands-on methods of teaching concepts and interrelationships, ideas often discussed but rarely encountered in the overall context of forestry, wood science, and wildlife biology. A recent group project was to design and construct a cutaway of a 19th century joiner shop and two display cases based upon variations of the trestle table to showcase antique woodworking tools for the “Treasures from the Vault” exhibition at Mississippi State. Personal projects included tables, bows, settles, desks, memorial crosses, and turkey calls, among others. The students gained a greater appreciation about forestry, forest products, markets, wood, woodworking, teamwork, safety, and themselves.
Ultraviolet (UV) light is high-energy radiation that induces degradation of organic compounds, such as wood. To prevent UV damage, several strategies have been used, including creating a UV light barrier at the wood surface. The most common strategy is to apply a coating to the wood surface. However, coating alone may not be effective enough to protect wood exposed outdoors. For example, clear coatings often contain additives to protect the material from UV radiation (hindered amine light stabilizers, quenchers, UV absorbers). This article reports work on the photostability of wood surfaces coated with waterborne nanocomposite urethane-acrylate systems in outdoor conditions. The wood color variation of sugar maple (Acer saccharum Marsh) was measured following accelerated aging. Different types of nanoparticles (ZnO, CuO) were used in water in predispersed and powder forms. Once cured, the nanoparticle dispersions were characterized by transmission electron microscopy. The best photoprotection was obtained with ZnO predispersed in water. Our major conclusion is that ZnO nanoparticles are better than CuO nanoparticles as additives intended to reduce the discoloration of clear-coated wood exposed outdoors. The highest increase in gloss was achieved with the mixture of inorganic and organic UV absorbers, which appear to show synergistic behavior.
The effect of copper naphthenate treatment on electrical resistance of Douglas-fir utility poles was compared with similar poles either left untreated or treated with pentachlorophenol (penta). Penta-treated and untreated wood had similar electrical resistance shortly after treatment and after a 3-month outdoor weathering period. Electrical resistance of copper naphthenate–treated wood was more variable but consistently greater, indicating that poles treated with this chemical would not pose an increased risk to utility personnel working on them.
Hemicellulose is the most hydrophilic polymer of wood, and as a polysaccharide, it has potential applications in conversion to biofuels. The objective of this study was to enhance properties of flakeboard by extracting hemicellulose. Hot-water pretreatment was performed to extract hemicellulose under different temperatures (140°C, 155°C, and 170°C) and times (30 and 60 min). The flakes were blended with 5 percent liquid phenol-formaldehyde resin and 1 percent wax emulsion. The mat was pressed at 200°C for 5 minutes. The physical and mechanical properties and the susceptibility of flakeboard to mold were studied. Panels made from the hemicellulose-extracted flakes showed remarkable decreases in water absorption and thickness swelling without a decrease in mechanical properties. Resistance of the panels to the mold growth also increased with increasing mass loss due to extraction. The most severe condition of extraction (170°C, 60 min), in addition to having the lowest water absorption and thickness swelling, showed the highest mold resistance.
Reusing decommissioned wood utility poles will extend the service life of the treated wood and offer economic and ecological advantages. The aim of this study was to evaluate pentachlorophenol (penta) retention and distribution, together with physical and mechanical properties of penta-treated southern pine (Pinus spp.) utility poles for reuse and recycling. Fifteen penta-treated decommissioned southern pine utility poles and pole sections were collected and studied. As expected, residual penta retention decreased from outside to the pith and from the top to the bottom of the poles. Of the 15 poles tested, penta retention averages at the two outer test zones varied from 3.9 to 5.6 kg/m3, while the overall penta retention averages of these poles varied from 3.2 to 5.4 kg/m3. The modulus of rupture (MOR) and modulus of elasticity (MOE) averages of the 15 poles and pole sections were 33.7 and 68.1 percent lower, respectively, than the published MOR and MOE values of virgin loblolly pine (Pinus taeda) wood. MOR and MOE varied in an M shape across the diameters of the poles due to surface aging. The shallow, aged surface layers, particularly of older poles, had low strength and relatively high penta retention, suggesting that surface layers should be removed from the recycled poles. However, most of the remaining pole portions had medium to high strength and were therefore reusable for other products.
The Asian longhorned beetle, Anoplophora glabripennis, is an invasive pest that poses a serious threat to many species of North American hardwoods. An efficacious heat treatment schedule for this insect is crucial to allow wood to move from quarantined areas in the United States. A series of experiments were conducted using naturally infested trees to evaluate the International Standards for Phytosanitary Measures Rule No. 15 heat treatment schedule (56°C core temperature for 30 min) on overwintering A. glabripennis larvae. Results indicate that this treatment is effective, as no overwintering larvae were observed to survive. Overwintering larval stage, heating rates, oven load factors, and treatments are reported.
This article presents a study on stress-laminated timber bridges. The technique is useful for the rehabilitation and construction of bridges. It consists of a series of timber planks placed side by side and compressed transversely with high-strength steel prestressing bars. A prototype of this kind of structure was built in the Department of Civil Engineering at the University of Coimbra. The prototype, a stress-laminated timber bridge deck with butt joints, was 6 m long, 2.7 m wide, and 0.20 m thick. The experimental program was developed with two main objectives: to study the evolution of the prestress value applied to the structure and to observe the bridge structural behavior under the effect of loads simulating the action of a standard vehicle. Practical difficulties and/or limitations and potentialities of the system when maritime pine is used as the timber material are also discussed. This article reports the experimental program and the results, with emphasis on the tension losses in the prestressed steel bars.
Compression bending testing, as described in this article, has been used successfully on various advanced composite materials, such as carbon-fiber reinforced plastics, to compute bending properties. This method might be applicable for several wood-based panels, such as medium-density fiberboard (MDF) and plywood, because they are quite thin, and thus the elastica phenomena can be easily induced. In this study, the bending properties of MDF and Lauan five-ply wood were determined by performing a compression bending test. The validity of the compression bending testing was then examined by comparing these results with the results from flexural vibration tests and three-point bending tests. The compression bending test proved effective for measuring the flexural Young's modulus when the length/thickness ratio was larger than 33 because the test method minimizes deflection caused by shearing force. Nevertheless, it was even less effective when the length/thickness ratio was smaller than 33. It was expected that the test would be more effective than the three-point bending test for measuring proportional limit stress and bending strength because the test specimen is independent of the stress concentration around the loading nose; however, this proved not to be the case for the materials investigated in this study. Thus, further research is still needed to devise ways to more effectively measure the bending properties of the materials tested.
As the importance of hybrid poplar plantations continues to increase, these stands may soon represent a strategic source of wood products for many temperate-region countries. Financial success from growing these plantations depends on obtaining the highest value recovery at the lowest harvest cost, which has motivated a gradual shift toward mechanized harvesting. This study compared the harvesting efficiency and cost of different harvesting procedures based on manual, semimechanized, and mechanized system configurations. Overall, 25 sites were sampled with time studies. Average site size varied between 0.3 and 2.5 hectares. Total observation time amounted to 787 hours, during which 6,449 trees were harvested. Mechanized harvesting proved significantly faster and cheaper than traditional manual harvesting, allowing an average saving of about 3 €/m3 for the same tree size. Hence, mechanization may help maintain profitability when harvesting smaller trees, allowing companies to cope with current trends toward shorter rotations for increased cash flow. Semimechanized harvesting did not involve fewer work steps, nor was it less expensive than traditional manual harvesting; its only benefit was a substantial reduction of labor requirements. The concern about reduced value recovery is still the main obstacle to the extensive application of mechanized poplar harvesting.
Quantification of seasonal bark loss for two Oregon commercial tree species, Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa), was conducted at monthly intervals beginning in late October to early November 2009 and finishing in August 2010. All assessments were carried out on harvesting operations that were using mechanized processor heads with chains over rubber feed wheels. A total of 450 stems were assessed. There was a substantial (up to five times) increase in areal bark loss, expressed as a percentage of log surface area, during late spring and early summer compared with the loss in winter. Areal bark loss appeared to be species dependent, with Douglas-fir incurring more than twice as much bark loss as ponderosa pine. Seasonal differences in postharvesting bark volume and weight were determined by accounting for bark thickness and bark density. In winter, bark could be expected to account for 3 to 4 percent more of a stem's weight than in late spring to early summer. There were considerable differences between species in the contribution of bark to total weight, but not in the percent drop in weight between seasons. It is shown that the seasonal changes in bark loss could be expected to lead to changes in solid wood truck payloads, transport costs, bark, and available energy (from bark) delivered to mills.
The forest products industry plays a large role in Michigan's economy. It is one of the largest manufacturing sectors in the state, employing more than 29,000 individuals with an annual payroll of $1.2 billion. However, due to extended economic downturns, the industry is currently facing an adverse business environment, threatening its performance and even the retention of existing mills in some cases. Given this situation, an emerging bioenergy market could provide new opportunities for the struggling industry and help regain its vitality. However, this is possible only if sufficient resources are made available for both the traditional forest products industry, as well as new bioenergy facilities. Failure to do so will weaken already vulnerable forest products sectors. This study uses a mail survey of Michigan's primary forest products industry to provide insight into the state's forest products sector, with the aim of helping stakeholders make informed decisions for promoting bioenergy facilities while strengthening the existing operations within the state. Our findings suggest that there is a positive attitude among Michigan primary mills toward the introduction of wood-energy facilities in their wood basket, and hence there is evidence for a conducive environment for promoting bioenergy. However, careful consideration must be given to existing resource conditions, industry infrastructure, and strategies for maintaining sustained wood availability for promoting bioenergy industry that complements, rather than competes against, the traditional forest products sector.
Results of this exploratory study provide insights into the implementation of advanced manufacturing technology (AMT) in China's furniture industry by using a multiple-case study approach. Qualitative interviews were conducted with upper managers and specialists in production and human resource management from four Chinese furniture firms that are viewed as pioneers in implementing computer-integrated manufacturing (CIM) in China's furniture industry. The findings show that key drivers for implementing AMT in the Chinese furniture firms are problems in production process, the need to reduce dependence on employees' work skills, and difficulties in recruitment arising from increased labor costs and a shortage of skilled workers. In addition, findings of the study reveal that the barriers to AMT implementation in Chinese furniture firms are not only from the technology side but also due to nontechnological aspects. These results could help decision makers in conducting process innovation with regard to both technological and nontechnological aspects, as well as in taking their interactions into account. Moreover, our findings may also help forest products industries in other emerging countries that are moving toward introducing new working systems.