bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical and Mechanical Properties of Young-Growth Douglas-Fir and Western Hemlock from Western Washington
Authors: Langum Christopher E. , Yadama Vikram , Lowell Eini C.
Published: October 2013

Diversity in land management objectives has led to changes in the character of raw material available to the forest products industries in the US Pacific Northwest. Increasing numbers of logs from small-diameter trees, both plantation grown and those from suppressed or young stands, now constitute a large proportion of logs coming into the mill yard. Wood coming from plantations or young stands has different properties than wood coming from older, suppressed stands. This research examined wood properties of small-diameter plantation-grown Douglas-fir and western hemlock with the goal of a better understanding of utilization of small-diameter, fast-grown trees for use in manufacturing engineered wood composites. Twelve trees of each species were harvested and three bolts cut from each tree. Each bolt provided samples for X-ray densitometry profiles, compression, and tension parallel to grain and flexure tests. Both species were found to have a very high proportion of juvenile wood. Most wood properties decreased with increasing vertical position and increased with increasing distance from pith for both species. Increased competition for wood fiber, which accounts for as much as 25 to 35 percent of total wood composite (such as particleboard, medium-density fiberboard and oriented strand board) manufacturing costs, necessitates an understanding of raw material properties and their variations. This knowledge could assist in optimizing the manufacturing process and maximizing efficiency of wood raw material use, thus increasing profits.
A Regression-Based Method for Estimating Rip-First Rough-Mill Lumber Yield
Authors: Buehlmann Urs , Kline D. Earl , Wiedenbeck Janice K.
Published: October 2013

Estimating yield from lumber cut-up in rip-first rough mills for material management and job costing purposes is uncertain unless simulation models are used. To augment the toolbox for industry practitioners, a novel yield estimation model was derived using linear least squares techniques and data derived from an orthogonal, 220–11 fractional factorial design of resolution V.

The model estimated 450 of 512 cutting bills tested within 1 percent absolute yield. However, cutting bills that do not adhere to the model’s framework suffer a larger estimation error. The least squares estimation model thus is a helpful tool in ranking cutting bills that adhere to the model’s framework for their expected yield levels and facilitates the selection of part sizes to be included in cutting bills. Further research is needed to make the model useful for a wider range of cutting bills.
Use of Fiberboard as Substrate in Floating Engineered Wood Flooring
Authors: Bouffard Jean-François , Blanchet Pierre
Published: October 2013

Because it offers good milling properties, especially for self-locking tongue and groove, medium- and high-density fiberboard (MDF and HDF) have gained acceptance as a substrate in the manufacture of engineered wood flooring (EWF). Depending on the component selected, delamination in the fiberboard or severe cupping deformation have, however, been observed. The aim of this study was to identify key design parameters in EWF made with MDF and HDF substrate, taking into account the density of the fiberboard, the characteristics of the face layer, and the type of backing process selected to meet quality requirements. A sliced face layer led to lower cupping deformation than a sawn face layer. With a sawn face layer, denser HDF provided a better substrate for EWF. The use of melamine-impregnated paper as a backing layer significantly contributed to reduced cupping deformation in all cases.
People’s Perceptions of the Visual Appearance of Wood Flooring: A Kansei Engineering Approach
Authors: Nordvik Enar , Schütte Simon , Broman N. Olof
Published: October 2013

Evaluations of products based on visual stimuli are at the same time both subjective and important. The aim of this study was to examine the relationship between the visual properties of wood flooring and people’s reactions to computer visualization of interior wood products. The research strategy involved showing digital pictures of the same room, but with different wood floorings. The impressions of potential consumers were measured by means of rating scales for each descriptive word. This was done using the method of Kansei engineering, in which statistical connections between properties and semantics (descriptions) were analyzed. The research presented here contributes to theory and practice in two important ways. First and most important, the study shows that the chosen method is suitable for measuring people’s preferences on visualizations of interior wood. Second, the results indicate that certain properties are important for a floor to be judged as ‘‘good-looking’’ and others for a floor to be deemed ‘‘modern’’ or ‘‘vivid.’’
Brand Association Transfers between Corporate and Product Building Material Brands: Perceptions of Homebuilders
Authors: Kolarova Elizabeth Scott
Published: October 2013

This article focuses on branding in the forest products industry. It examines corporate and product cobranding. Traditionally, in the forest products industry, uses of new industrial product brands have been promoted in a cobranding context with their better-known corporate brands. This research, using data collected from residential homebuilders in the northwestern United States in the spring and summer of 2007, explores the brand associations of quality, leadership, and environmental stewardship related to corporate and product brands in this cobranding context. Specifically, the research explores the transfer of the noted brand associations from the corporate brand to the product brand as well as the transfer of these brand associations from the product brand to the corporate brand. Resulting analysis of the data noted that stronger rated brands significantly improve ratings of weaker brands generally, while weaker brands do not significantly devalue stronger brands in the cobranding context.
Demands on Lumber Suppliers within the US Prodealers Channel
Authors: Robichaud François , Lavoie Patrick , Gaston Christopher
Published: October 2013

Prodealers are building materials suppliers whose client base comes mostly from the homebuilding industry. Because they represent an important channel for wood products, a 2007 survey of US prodealers examined (1) lumber attributes demanded, (2) products and suppliers requirements, (3) trends in substitution between countries supplying lumber to the United States, and (4) trends toward prefabrication of structural components. Forty-six prodealers were surveyed; most answered for multiple stores. On average, respondents purchased 60 million board feet of lumber in 2007, and their overall consumption was estimated at 2.76 billion board feet. By far, the most common grade in the prodealer segment is dimension lumber (No. 2 and Better), and the most common type is the spruce-pine-fir species group (SPF). Within the sample, 5 percent of US lumber imports came from offshore. Canada supplied 51 percent of the lumber purchased by respondents, and the United States supplied 47 percent. Wane as well as warp and twist were consistently identified as the most challenging lumber attributes for prodealers. Product quality was identified as a primary reason for changing lumber suppliers. In characterizing properties of the dimension lumber imported from Europe to the United States, it was found that European lumber stands out mostly for visual appearance and low wane. For customer support and timely deliveries, respondents tended to favor US mills. The study suggests that customers are not fully satisfied with lumber, especially with regard to wane and straightness, and that lumber quality issues may be more important today than in the past.
Penetration of Boron from Topically Applied Borate Solutions
Authors: Lebow Stan , Lebow Patricia , Halverson Steven
Published: October 2013

Borate penetration relies on diffusion when borate and glycol-borate preservatives are applied to the surface of wood. This study evaluated the extent of borate penetration in framing lumber as a function of preservative formulation, wood moisture content, and diffusion time after treatment. In Phase I of the study, end-matched specimens were conditioned to target average moisture contents of 15, 25, or 35 percent, briefly immersed in borate formulations, and then placed into wooden frames to minimize air exchange during diffusion. Penetration in these specimens was generally less than 5 mm (or 35% of the cross section) regardless of treatment solution, target moisture content at time of treatment, or diffusion period (2, 4, or 8 wk). Assay of boron concentrations after 8 weeks of diffusion also indicated that the boron was concentrated in the outer 5 mm of the wood. Diffusion appeared to have been limited by the relatively rapid drying of the specimens, even with the restricted air movement within the wooden frames. In Phase II of the study, specimens were conditioned to a target average moisture content of 20 percent prior to dip immersion and then placed in a room that maintained an equilibrium moisture content of 19 to 21 percent. Penetration in these specimens was assessed after 6, 13, and 26 weeks of diffusion. After 6 weeks of diffusion, average boron penetration exceeded 5 mm, and after 26 weeks of diffusion, penetration exceeded 11 mm, or over 70 percent of the cross section. Little difference in diffusion was observed between the types of borate formulations evaluated in either phase of this study. The results of this study indicate that rapid drying conditions may limit penetration of boron from spray applications; however, in situations where high humidity is maintained in a structure, substantial diffusion is possible.
Occurrence of Preservative-Treated Wood in a Wood Recovery Center in Western Oregon
Authors: Morrell Jeffrey J.
Published: October 2013

The amounts of treated wood present at a wood recycling center in western Oregon were surveyed over a 10-year period. Treated wood was found at 106 of 112 inspections, but the levels never exceeded 2 percent of the volume present. The amount of treated wood averaged 0.15 percent of the total volume over the 10 years. These values were considerably lower than those found in surveys in Virginia and Florida, reflecting a lower overall use of treated wood and, with respect to Florida, a lower risk of decay in Oregon. The results indicate that treated wood is a minor component in the recycling stream studied and does not pose a risk to those using the material.
Emissions of Hexanal and Terpenes during Storage of Solid Wood Fuels
Authors: Granström Karin Maria
Published: October 2013

The purpose of this study was to investigate emissions during storage of solid wood fuels by measuring both the emission of monoterpenes and the formation of aldehydes during storage of undried sawdust, dried sawdust, and pellets. Sawdust is commonly stored up to several months at pellet plants. Pellets are stored due to seasonal demand variation and wood fuel trade. Freshly sawn sawdust from Scots pine (Pinus sylvestris) was dried and pelleted. The fuel was stored in a controlled laboratory setting to avoid undue influence of temperature and humidity fluctuations. The emission of volatiles was analyzed with static headspace and gas chromatography–mass spectroscopy. The content of terpenes in undried sawdust decreased dramatically in the first days of storage, with 10 percent of the original amount left after 10 days. In dried sawdust, about two-thirds of the terpenes that remained after drying were released in the first 10 days. In sawdust, the hexanal concentration was negligible at first, became equal to the terpene concentration after 15 days, and reached a maximum after 40 to 50 days. Hexanal was then found in an equal amount to the remaining terpene content in undried sawdust; in dried sawdust, it was found in a much higher amount than the remaining terpene content. In pellets, hexanal content was consistently higher than the terpene content. The wood fuels were low-emitting for both terpenes and hexanal after 2 to 3 months. In conclusion, although terpenes have been assumed to be the predominant volatiles emitted during storage of solid wood fuels, hexanal from fatty acid oxidation is also of importance.
Strength Performance of Prestressed Glass Fiber–Reinforced Polymer, Glued-Laminated Beams
Authors: Silva-Henriquez Rodrigo , Gray Howard , Dagher Habib J. , Davids William G. , Nader Jacques
Published: October 2013

This article focuses on assessing the strength performance of glued-laminated (glulam) beams with E-glass fiber–reinforced polymer (GFRP) prestressing (prestressed GFRP-glulam beams) through bending tests and cross-sectional analysis. In addition to fifteen 6.7-m-long prestressed glulam beams, 15 GFRP-reinforced glulam beams and 15 unreinforced glulam control beams with nominally identical layups and 6.7-m lengths were tested to failure in four-point bending to provide direct performance comparisons. Load-displacement data and strains in the prestressed GFRP were monitored. The results of the tests show that the prestressed GFRP-glulam beams exhibited a 38 percent increase in allowable bending stresses compared with reinforced GFRP-glulam beams without prestress and an approximately 95 percent increase compared with unreinforced glulam beams. Both the prestressed and reinforced specimens exhibited an 8 percent increase in stiffness relative to the control specimens. Loss of prestress due to creep was examined for one specimen by monitoring GFRP strains over a 12-day period following fabrication. The total loss of prestress over this 12-day period was less than 2 percent, and the rate of prestress loss decreased during monitoring. The GFRP stresses predicted by a cross-sectional moment-curvature analysis of the prestressed and reinforced beams agree well with stresses inferred from measured strains. The results of this study show that prestressed GFRP reinforcement of glulam beams shows significant promise for practical applications.
Bending Strength and Modulus of Elasticity of Squares with Wane as Compared with Round Timber of Scots Pine (Pinus sylvestris)
Authors: Vestøl Geir I. , Høibø Olav
Published: October 2013

A comparison of bending strength and modulus of elasticity (MOE) of squares with wanes to round timber was performed as part of a project on the use of round Scots pine (Pinus sylvestris L.) timber in structural frameworks. The study was based on 125 squares and 124 round logs from two sites at high altitudes and two sites at low altitudes in southern Norway. The effects of wanes were estimated by means of reduction in second moment of area and section modulus. Wanes had significant effect on both bending strength and MOE, but in both cases the effects were minor when compared with the effects of material properties. The reduction of bending stiffness due to wanes was almost as much as expected from lack of section, while the reduction of moment capacity was smaller. Squares with ⅓ wane had both lower bending strength and lower MOE than round timber. According to how bending strength and MOE are calculated, differences due to wane were expected. The observed difference in bending strength was larger than expected through the lack of section, indicating that it was affected by material properties as well. The difference in MOE between round timber and squares with ⅓ wane could be explained by the lack of section according to how these values are calculated. Origin had a significant effect on both bending strength and MOE.
The Theory and Mathematical Model Underlying the Radial Sawing Simulator—RadSawSim
Authors: Ištvanić Josip , Piljak Krunoslav , Antonović Alan , Luˇić Ružica Beljo , Jambreković Vladimir , Pervan Stjepan
Published: October 2013

Gaining additional knowledge of sawing methods that produce sawn boards with a radial grain is a significant problem today because such methods are rarely used. The current technology in Croatian sawmills is adapted to the standard live and cant sawing methods. Experimental in-mill sawing studies designed to monitor yield are subject to financial and technological restrictions. Therefore, simulated sawing is often required. This research presents the calculation method used to formulate a mathematical model that simulates sawing. The objective was to produce as many radial sawn boards as possible.
Assessment of Microwave Bending Capabilities for Australian Wood Species
Authors: Ozarska Barbara , Daian Georgiana
Published: October 2013

An innovative wood bending technology has been developed by the University of Melbourne, within the Cooperative Research Centre for Wood Innovations, which involves the microwave softening of wood components to make them pliable for bending, the use of an automated bending machine, and microwave drying of bent furniture components. This article presents the results of a study that assessed bending quality and that determined the minimum radius of bending curvature of eight plantation and regrowth Australian timbers using the microwave wood bending process: Eucalyptus nitens, Eucalyptus saligna, Eucalyptus marginata, Eucalyptus diversicolor, Pinus radiata, Nothofagus cunninghamii, Atherosperma moschatum, and Acacia melanoxylon.

Based on the results of the study, the microwave bending performance of the wood species was rated as follows: (1) E. diversicolor, very good (sanding or small amount of machining was required); (2) P. radiata, Atherosperma moschatum, and E. nitens, decent (machining was needed); (3) Acacia melanoxylon and N. cunninghamii, satisfactory (fairly large failures occurred but these were removed by machining); and (4) E. saligna and E. marginata, very bad (large failures which could not be removed by machining).

Overall, the results of the study on the bending performance capabilities of plantation and regrowth Australian timbers showed several differences compared with the literature data relating to the bending abilities of the relevant old growth timbers.
Second-Order Polynomial Model to Solve the Least-Cost Lumber Grade Mix Problem
Authors: Buehlmann Urs , Zuo Xiaoqiu , Thomas R. Edward
Published: October 2013

Material costs when cutting solid wood parts from hardwood lumber for secondary wood products manufacturing account for 20 to 50 percent of final product cost. These costs can be minimized by proper selection of the lumber quality used. The lumber quality selection problem is referred to as the least-cost lumber grade mix problem in the industry. The objective of this study was to create a least-cost optimization model using a design that incorporates a statistical approach to address shortcomings of existing models using linear optimization methods. The results of this study showed that optimal solutions tend to use as much low-quality lumber as possible to minimize costs. Comparison of results from this new least-cost grade mix model with other existing least-cost lumber grade mix models has shown that the new model results in lower-cost solutions.
Characteristics of Virginia's Logging Businesses in a Changing Timber Market
Authors: Bolding M. Chad , Barrett Scott M. , Munsell John F. , Groover Miles C.
Published: October 2013

The forest products industry is a vital component of Virginia's economy, and logging businesses, as the suppliers of raw material, are an extremely important part of this industry. How they operate, their challenges, and their ability to adapt to changing economic conditions are of interest to the entire forest products industry. To further our understanding of how Virginia loggers operate their businesses, we developed and mailed a repeatable survey instrument during the summer of 2009 to participants currently enrolled in the Virginia Sustainable Harvesting and Resource Professional logger program. Due to Virginia's distinct geographic makeup and its impact on logging system design and characteristics, results were segmented by three physiographic regions: mountains, piedmont, and coastal plain. Ninety-eight percent of respondents were men, 94 percent were Caucasian, and 49 years was the average age. Logging businesses operated with an average of 1.2 crews and 3.3 workers per crew, which varied across each region of the state. The type of harvesting system used also varied between regions as did the products harvested, production levels, use of technology, and time spent planning harvests and implementing best management practices. Business owners also indicated that their greatest challenges were finding markets for their products, the increasing costs of fuel and operation, and the prospect of fewer markets in the future. Survey results provided further insight into the characteristics of Virginia logging businesses and the challenges they face, while establishing a baseline dataset for future comparison.
Appalachian Hardwood Product Exports: An Analysis of the Current Chinese Market
Authors: Wang Jingxin , Wu Jinzhuo , DeVallance David B. , Armstrong James P.
Published: October 2013

A mail survey of Appalachian hardwood product exporters was conducted in the fall of 2008 to analyze the export practices for Appalachian hardwood products, specifically the volume of hardwood products exported to the Chinese market, their preferred species, and potential and existing trade barriers between US producers and Chinese customers. Results of the survey showed that the most frequent export destinations of Appalachian hardwood products were Europe, China, Canada, Mexico, and Japan. In 2007, approximately 11.4 million board feet (MMBF, Doyle scale) of hardwood logs and 145.3 MMBF of hardwood lumber were exported to China by the respondents. Approximately 37 percent of the respondents who exported hardwood products to China exported red oak logs, followed by white oak, black walnut, black cherry, and hard (sugar) maple. The top species of hardwood lumber exported to China were red oak, white oak, yellow poplar, black walnut, hickory, cherry, hard maple, and soft maple. Respondents indicated that transportation freight costs and payments are the limiting factors when considering expanding business overseas. The continued decreasing hardwood price has put more pressure on hardwood products exporters to maintain profit margins. Because of the current economic downturn, hardwood production in the Appalachian hardwood region has declined by more than 40 percent. Exports of hardwood products to China will be affected to some extent. However, it is expected that China will remain an important overseas market in the near future.
Trends in Lumber Processing in the Western United States. Part I: Board Foot Scribner Volume per Cubic Foot of Timber
Authors: Keegan Charles E. , Morgan Todd A. , Blatner Keith A. , Daniels Jean M.
Published: October 2013

This article describes trends in board foot Scribner volume per cubic foot of timber for logs processed by sawmills in the western United States. Board foot to cubic foot (BF/CF) ratios for the period from 2000 through 2006 ranged from 3.70 in Montana to 5.71 in the Four Corners Region (Arizona, Colorado, New Mexico, and Utah). Sawmills in the Four Corners Region, Alaska, and California had the highest ratios, with each state's BF/CF ratio greater than 5.0. Among the states using the Eastside Scribner scale, the Four Corners Region had the highest BF/CF ratio (5.71), followed by California (5.03). Among states using primarily the Westside Scribner scale, Alaska had the highest ratio (5.29). All states or regions, with the exception of Alaska, have shown declines in BF/CF ratios over the last three decades. Montana has had the largest estimated decline (29%), followed by Oregon (23%). The increase in Alaska was the smallest change among states (<2%). Two major factors in the western United States appear to have largely influenced BF/CF ratios: changes in log diameter processed by western sawmills and the use of Westside versus Eastside variants of the Scribner Log Rule.
Length Effect on the Tension Strength between Mechanically Graded High-and Low-Grade Chinese Fir Lumber
Authors: Zhou Haibin , Ren Haiqing , Lu Jianxiong , Jiang Jinghui , Wang Xueshun
Published: October 2013

An experimental study was conducted to evaluate the length effect on the parallel-to-grain tensile strength of Chinese fir (Cunninghamia lanceolata) lumber. In all, 473 pieces of mechanically graded lumber were tested at gauge lengths of 150, 200, 250, and 300 cm. The lumber was sorted into matched groups according to the dynamic Young's modulus as measured using the longitudinal vibration method. The averages of the dynamic Young's modulus of high-grade (H) and low-grade (L) specimens were 11.8 and 8.9 GPa, respectively. Using nonparametric estimates, the estimated length effect parameters of H and L were 0.188 and 0.226, respectively, for the 50th percentile and 0.185 and 0.318, respectively, for the 5th percentile. It was then concluded that the different length effect factors between H and L could be used when using the lumber for practical purposes. The effect of increasing length on the tensile strength was a little larger in H but smaller in L for the 50th percentile compared with the 5th percentile. When two-parameter Weibull distribution functions were fitted to the strength data, the estimated shape parameters of the Weibull distribution by the parametric method were almost identical to the inverse of nonparametric parameters. The influence of defects such as knots on the lower tail of the strength distribution in H may be different than that in L.
Effects of Dead Load and Multiple Earthquake Loadings on Seismic Performance of Wood-Frame Shear Walls
Authors: White Kevin B. D. , Miller Thomas H. , Gupta Rakesh
Published: October 2013

Goals of this preliminary study are to better understand (1) earthquake performance of wood-frame shear walls carrying gravity loads, compared with walls without gravity load, and (2) performance of walls subjected to a sequence of earthquake motions, compared with walls subjected to a single earthquake.

Tests with simulated earthquake ground motions were conducted on 2,440 by 2,440-mm (8 by 8-ft) walls with 38 by 89-mm (nominal 2 by 4) Douglas-fir studs at 610 mm (24 in.) on center. Two oriented strand board (OSB) panels were installed and fastened vertically to the frame, and two gypsum wallboard panels were installed opposite the OSB. Partially anchored (PA) walls had two anchor bolts on the sill plate. In addition to the anchor bolts, fully anchored (FA) walls included hold-downs installed at the end studs. Ground motions were scaled to the 10 percent in 50 years probability of exceedance design level for Seattle, Washington, the traditional level associated with life safety performance.

For PA walls with dead load, failure modes were consistent with tests without dead load; however, additional fastener damage, common to FA walls, resulted from the additional resistance to overturning. PA walls realized a greater improvement in performance from dead load application compared with FA walls; performance appears to approach that of FA walls when dead load is applied. FA and PA walls subjected to a sequence of earthquake motions showed wall performance about the same as that of walls subjected to a single scaled earthquake motion.
Laminated Crossarms Made from Decommissioned Chromated Copper Arsenate–Treated Utility Pole Wood. Part I: Mechanical and Acoustic Properties
Authors: Piao Cheng , Monlezun Charles J.
Published: October 2013

In recent years, rising concern over the disposal of preservative treated wood has generated interest in the reuse and recycling of this biomass resource. The primary objective of this study was to evaluate the bending strength and stiffness of laminated crossarms consisting entirely of virgin wood, entirely of decommissioned chromated copper arsenate (CCA)–treated utility pole wood, or a mixture of virgin wood and decommissioned CCA-treated utility pole wood after treatment with pentachlorophenol (penta). The secondary objective was to correlate acoustic properties of the laminated crossarms with their mechanical properties. Solid sawn virgin wood crossarms, solid sawn crossarms cut from decommissioned CCA-treated utility pole wood, and the laminated crossarms were evaluated for strength, stiffness, strain, and acoustic properties. The solid sawn virgin wood crossarms and all compositions of laminated crossarms met the American National Standards Institute minimum strength requirement. Only the solid sawn decommissioned CCA-treated utility pole crossarms failed to meet the minimum strength requirement. Both crossarm composition and surface preparation had no significant effect on the strength of laminated crossarms. Maximum strain decreased with an increase in the number of utility pole wood plies in the laminated crossarms. Cubic relationships were found between stress wave acoustic velocity and the number of utility pole plies contained in the laminated crossarms. Both before and after penta treatment, a linear relationship was found between bending modulus of elasticity and stress wave acoustic velocity of the laminated crossarms. Penta treatment significantly reduced stress wave acoustic velocity for all categories of crossarms, both laminated and solid sawn.
Residual Strength and Stiffness of Lumber from Decommissioned Chromated Copper Arsenate–Treated Southern Pine Utility Poles
Authors: Piao Cheng , Groom Leslie
Published: October 2013

The reusability of decommissioned treated wood is primarily dependent on the residual strength of the wood after service. Determining the residual strength can provide useful information for structural design and reuse of the decommissioned treated wood. This study evaluated the residual strength of decommissioned chromated copper arsenate–treated utility pole wood. Eleven decommissioned southern pine (Pinus spp.) distribution poles and pole sections were evaluated, using small clear samples, for bending strength and stiffness across and along each pole. Results showed that the strength of the decommissioned treated wood varied across and along each pole and among the poles. Average modulus of rupture (MOR) was 80.9 percent of the typical MOR of longleaf pine (Pinus palustris) virgin wood, and average modulus of elasticity (MOE) was 83.9 percent of the typical MOE. Average MOR of the samples in the outer surface (first test zone) was 7.5 percent lower than the average MOR of the adjacent samples toward the pith (second test zone) on each side of the pole surfaces, but average MOE showed no significant difference between the two zones. Older poles lost more strength in the first test zone. Results demonstrated that spiral grain substantially reduced the strength of utility pole wood.
Microwave Wood Modification Technology and Its Applications
Authors: Torgovnikov Grigory , Vinden Peter
Published: October 2013

The use of microwave (MW) technology is growing in all industries. This increased use has resulted from the high efficiency of converting electricity into MW energy; energy savings associated with rapid, in-depth heating of materials; specific interactions that can be achieved between MW energy and materials; radical acceleration of technological processes; reductions in MW equipment costs; and improvements in the reliability of industrial MW equipment. The new technology of MW wood modification is based on the supply of high-intensity MW power, up to 135,000 kW/m3 at frequencies of 0.922 and 2.45 GHz. Such power induces significant changes to the microstructure of wood and a dramatic increase in wood permeability. A number of commercial applications have been developed based on the fundamental changes in wood structure. These include the treatment of refractory wood species with preservatives, rapid drying of hardwoods, relief of growth and drying stresses in timber, manufacture of the new wood materials Torgvin and Vintorg, and modification of logs, sawn timber, and woodchips for pulping. MW equipment and processing parameters have been developed for three applications that are ready for commercial use. The technology provides significant material and energy savings and will give a new impetus to product development in a very traditional industry. The costs of microwave timber processing range from AU$22 to AU$69 per m3. These costs are acceptable to industry and potentially provide wide appeal for use in the timber, biocomposite, and pulp and paper industries.
Soil and Sediment Concentrations of Chromium, Copper, and Arsenic Adjacent to a Chromated Copper Arsenate–Treated Wetland Boardwalk
Authors: Lebow Stan , Foster Daniel
Published: October 2013

Environmental accumulation of preservative adjacent to a chromated copper arsenate (type C)–treated wetland boardwalk was evaluated. The site is considered a realistic “worst case” because of the large volume of treated wood, low current speeds, high annual rainfall, and environmental sensitivity. Soil and sediment samples were collected before construction and 0.5, 2, 5.5, 11, 24, 60, and 131 months (11 y) after construction and analyzed for total chromium, copper, and arsenic concentrations. This article updates the findings after 11 years of exposure. Environmental concentrations varied with time, with proximity to the treated wood, and between riparian and aquatic locations. Concentrations of leached components in the soil developed slowly, were greatest at the 60-month sampling, and declined at the 131-month inspection. Soil samples with elevated levels of copper and chromium were confined to directly under the drip line of the boardwalk, and arsenic appeared to be limited to within 0.3 m (1 ft) of the structure. Concentrations of leached components in the sediments increased more quickly than those in the soil and tended to reach maximum or near maximum levels within the first year. However, concentrations of arsenic and copper in sediments directly under the walkway reached maximum levels after 60 months, before declining at the 131-month sampling. Elevated concentrations of copper, chromium, and arsenic were occasionally found in sediments as much as 3 m (10 ft) from the boardwalk.
Wood Degradation after Windthrow in a Northern Environment
Authors: Ruel Jean-Claude , Achim Alexis , Herrera Raul Espinoza , Cloutier Alain , Brossier Benoît
Published: October 2013

Severe windthrows often require salvage operations that can lead to increased costs. Given these extra costs, it is of paramount importance to make sure that wood degradation does not become so advanced that significant value loss is incurred. The rate at which wood deteriorates is a function of many factors, including species and climate.

The study was conducted in a northern area affected by two partial windthrows. Logs from the damaged area were collected for two species, balsam fir (Abies balsamea) and black spruce (Picea mariana). Logs were classified into one of three degradation classes based on visual assessments. A sample of logs from standing trees was also collected. In total, 167 logs were sampled. Each log was sawn and one piece of lumber was selected from each to determine the bending strength and stiffness and the visual grade.

The time since tree death, as determined from dendrochronology, ranged from 1 to 31 years. The visual grade of the lumber was not affected after 1 year but severe downgrades were observed after 4 years. Moisture content decreased rapidly for both species during the first year and continued to decrease until 4 years after mortality. No clear decrease in bending stiffness was identified even though such a tendency was noticed for older black spruce windthrows. Bending strength became variable after 4 years for balsam fir and was reduced after 4 years for black spruce. Windthrows older than 7 years will produce low visual grade timber of reduced bending strength and possibly of lower bending stiffness.
The Practice and Economics of Stewardship Contracting: A Case Study of the Clearwater Stewardship Project
Authors: Kerkvliet Joe
Published: October 2013

The purpose of the stewardship contracting authority is to allow public land managers to achieve land management goals while meeting local rural community needs. The authority's use is on the rise, and many regard stewardship contracting as a win–win mechanism for federal land management and a means of ending the “timber wars” on public land. This report provides an overview of stewardship contracting, with a focus on improvements needed for it to reach its full potential. A case study of the economic impacts of a high-profile pilot project of the new authority, the Clearwater Stewardship Project, is used to illustrate its potential. With impact assessment software (IMPLAN), I find that the project's total economic impact includes a $23 million increase in final sales for 206 industry sectors in eight Montana counties, 148 full- and part-time jobs, $4.6 million increase in wages (2003 dollars), $1.4 million increase in proprietors' income, and $570,000 in indirect business taxes. Over 85 percent of the impacts arise from the harvesting and processing of wood, while 10 percent arise from restoration activities paid for with the receipts from these harvests. The combination of harvesting, wood processing, restoration, administrative, and monitoring activities typical of a stewardship contract serves to spread impacts across a wider variety of economic sectors than timber harvesting alone.
Productivity Standards for Harvesters and Processors in Italy
Authors: Spinelli Raffaele , Hartsough Bruce R. , Magagnotti Natascia
Published: October 2013

The authors developed a general productivity model for the harvesters and processors currently used in Italy. The model consists of a set of mathematical relationships that can estimate the productivity of these machines under the whole range of specific work conditions faced in Italy. Such relationships can provide general directions to prospective users and can contribute to the development of scenario predictions. The original data pool contained more than 15,000 individual time-study records, each representing a single harvesting cycle (most often one tree). The records were extracted from 38 studies conducted with the same methods and by the same principal investigators between 1998 and 2008. Statistically significant models were developed for all cyclic work phases, such as moving, brushing, felling, and processing. Accessory time and delay time were added as percent factors, also estimated from the same studies. Model development aimed at achieving the best compromise solution between accuracy and easy use, avoiding the introduction of an excessively large number of input variables. Selected independent variables were tree volume, tree species, task type (harvesting or processing), machine power and type, density of residual stand and of harvest trees, stand type, and slope gradient. These models could predict a large proportion of the variability in the data and were successfully validated using reserved cycle records, extracted from the same data pool and not used for model development. Comparison with similar Nordic and German standards confirmed the sound structure of the Italian models while highlighting the need for specific productivity norms due to the different work conditions faced by Italian operators.
Impact of Paper Birch (Betula papyrifera) Tree Characteristics on Lumber Color, Grade Recovery, and Lumber Value
Authors: Drouin Myriam , Beauregard Robert , Duchesne Isabelle
Published: October 2013

The aim of this research is to assess the impact of paper birch (Betula papyrifera Marsh.) tree characteristics on wood color variability, grade recovery, and lumber value. Current results are based on 2,284 paper birch boards coming from 168 trees harvested in two different stands in Québec, Canada. Results showed that tree diameter was the most important variable affecting board quality and value. Larger trees were associated with higher board quality and higher lumber value per tree. Lumber value per tree was influenced by tree vigor as well but not by tree age. The most vigorous trees produced higher board value with an average of USD 316.62 per m3, middle vigor classes showed averages of USD 218.28 per m3 and USD 251.84 per m3, while the less vigorous trees had the lowest average with USD 165.94 per m3. Board quality was only partly influenced by tree age and tree vigor. When selected for color, the majority of the board surface area fell under the sap category (50%), while 28 percent was classified as regular presenting simultaneously both colorations, and finally only 4 percent of the board area was classified as red. It was found that the most important variables affecting this board color distribution were tree vigor and tree diameter, whereas tree age also had a significant but lesser impact. In general, older, larger, and less vigorous trees tended to present higher proportions of boards classified in the red category. Finally, the results obtained in this study tend to support the practice of silvicultural treatments aiming to produce larger trees yielding higher value and quality boards.
Effect of Crosscutting Crooked Sugi (Cryptomeria japonica) Logs on Sawing Yield and Quality of Sawn Lumber
Authors: Ikami Y. , Matsumura Y. , Murata K. , Tsuchikawa S.
Published: October 2013

The objective of this study was to develop an efficient method for using crooked sugi (Cryptomeria japonica D. Don) logs by crosscutting the logs prior to sawing. We investigated the effect of crosscutting crooked logs on the sawing yield and the quality of sawn lumber and proposed an effective processing method. The sawing yield and the quality of sawn lumber were improved by crosscutting the logs one time. An economic analysis based on the processing intensity required for crooked logs, subjected to one-time crosscutting, and crook-free medium-quality logs was conducted. When the price of sawn lumber obtained from the crooked logs was equal to that of medium-quality logs, the net revenue obtained from crooked logs became nearly equal to that of medium-quality logs. The results demonstrated that the crooked logs could be used effectively by onetime crosscutting.
A Note on the Effect of Wood Moisture Content and Clear Coating on the Color of Veneer Panels Stained with Solvent-Borne Stain
Authors: Evans Philip D. , Cullis Ian
Published: October 2013

Red alder, mahogany, maple, white oak, and pine veneer panels conditioned to 6, 12, or 20 percent moisture content (MC) were stained with red solvent-borne stain, partially coated with clear lacquer, and air dried. All of the hardwood panels stained at an MC of 20 percent were either significantly redder or darker than panels stained at lower MCs. Clear coating made panels darker and redder (except oak). We conclude that large departures from the recommended MC for staining (6% to 8%) can significantly alter the color of hardwood veneer panels stained with solvent-borne stain.
Activated Carbon from Extracted Sawdust Waste with Alkaline Activation by Physical Mixing
Authors: Wang Rui , Liu Shouxin
Published: October 2013

Activated carbon (AC) with high surface area and narrow pore size distribution was prepared from extracted Larix gmelinii (Rupr.) sawdust by alkaline activation through physical mixing. The preparation method has been optimized through the analysis of diverse experimental variables. Among them, type of activating agent and activating agent/sawdust ratio, activation temperature, and precarbonization have been studied. N2 adsorption isotherm and scanning electron microscopy were used to determine the BET surface area, pore structure, and surface morphology. It was shown that chemical activation with KOH can be successfully used to develop an AC with a high surface area from extracted L. gmelinii sawdust. When the raw sawdust was precarbonized at 500°C for 1 hour, physically mixed with KOH (mass ratio of KOH/sawdust, 4:1), and activated at 750°C for 2 hours, an AC with narrow pore size distribution, a maximum surface area of 2,659.4 m2/g, and a total pore volume of 1.21 cm3/g could be obtained. Hg(II) adsorption capacity of AC produced under optimal conditions was 318.47 mg/g, much higher than the compared commercial adsorption value. With a high surface area, narrow pore size distribution, and large Hg(II) adsorption capacity, the AC prepared from extracted sawdust waste appears as a very promising adsorbent for pollution control.
The Durability of Diphenylmethane Diisocyanate– and Phenol-Formaldehyde–Bonded Japanese Cypress Particleboard
Authors: Kojima Yoichi , Nakata Shinichi , Suzuki Shigehiko
Published: October 2013

Particleboard was fabricated using hinoki (Japanese cypress: Chamaecyparis obtsusa Endl.) particles and different amounts of diphenylmethane diisocyanate (MDI) resin (2%, 4%, 6%, and 9%) and phenol-formaldehyde (PF) resin (6% and 10.2%). Four accelerated aging treatment tests were conducted to compare the durability performance of MDI-bonded boards with that of PF-bonded boards: two Japanese industrial standard wet-bending tests, a European cyclic moisture test (V313), and the American Society for Testing and Materials (ASTM) six-cycle test (ASTM-6c). The bending strength of the wet MDI boards increased with increasing resin content, and the strength retention after the treatment was greater than 50 percent, which corresponded to that of high-moisture-resistant boards. After the V313 and ASTM-6c treatments, the thickness swelling of the MDI boards with 6 percent resin content was less than 5 percent, whereas that of the PF boards was about 10 percent. The thickness of the specimens varied according to the resin content and at each step of the treatment for both the V313 and the ASTM-6c tests. The resin content equivalence for the two types of resin was determined based on the internal bond (IB) strength after aging treatments of both types of board. The MDI board required only 50 to 70 percent of the resin required for a PF board with a comparable IB quality. The superior performance of the MDI-bonded board was clear after all the tests except for the boiling treatment, in which no significant difference was observed between MDI and PF.
Kenaf Bast Fiber Bundle–Reinforced Unsaturated Polyester Composites. I: Processing Techniques for High Kenaf Fiber Loading
Authors: Du Yicheng , Zhang Jilei , Toghiani Hossein , Lacy Thomas E. , Xue Yibin , Horstemeyer Mark F. , Pittman Charles U.
Published: October 2013

The fabrication of kenaf bast fiber bundle/unsaturated polyester composites with high (60% to 67, wt/wt) fiber contents was explored in this study. Mechanically ground kenaf bast fiber bundles were preformed into mats with a polyvinyl acetate emulsion adhesive. The preformed mats are easy to handle during subsequent processing with the unsaturated polyester resin and laminate compression molding. Fiber loadings as high as 65 percent (wt/wt) were achieved. The generated composites possessed high elastic moduli, and their tensile strengths were close to specification requirements for glass fiber–reinforced sheet molding compounds. These composites also exhibited higher specific tensile moduli and strengths than glass fiber–reinforced sheet molding compounds' specific modulus and strength lower bounds and those calculated from specification requirements for glass fiber–reinforced sheet molding compounds. If reduced void contents and enhanced interfacial binding can be achieved through improved processing, then natural fiber composites similar to those developed in this work have the potential to possess mechanical properties competing against those of currently used automotive sheet molding compounds.