bluuebunny/crossref_metadata_2025 huggingface dataset:
Protecting Aspen Oriented Strand Board Panels from Biodegradation with White Cedar Extracts and Coatings
Authors: Yang Dian-Qing , Wang Xiang-Ming , Wan Hui , Liu Zhi-Ming
Published: October 2013

Eastern white cedar (Thuja occidentalis L.) is a naturally durable wood species due to toxic compounds present in the heartwood. These compounds may serve as natural fungicides to protect nondurable wood products from biodegradation. This study was intended to improve the effectiveness of posttreating aspen oriented strand board (OSB) panels with white cedar heartwood extracts against mold and decay by co-applying a protective coating. The results showed that aspen OSB samples treated with the white cedar water-soluble heartwood extracts had little mold infection. No mold growth was detected on any samples that were dip treated with the extracts and then brushed with a coating. The decay test showed that most samples treated with both white cedar heartwood extracts and a coating had significantly less weight loss than untreated control samples. Using coating products alone also reduced mold and decay growth on OSB samples; however, adding cedar extracts to the treatment significantly improved the performance of one of the three coating products tested against mold and decay.
A New Slash Bundling Concept for Use in a Southern US Logging System
Authors: Meadows Steven , Gallagher Tom , Mitchell Dana
Published: October 2013

John Deere's biomass bundler unit is an effective machine for harvesting forest residues, which can be used as a source of fuelwood and/or a feedstock for biofuel production. This project explored an avenue that could supply a promising source of readily available energy in southeastern forested lands. Typical southern harvesting operations consist of whole-tree harvesting in which trees are felled and then skidded to a landing. Limbs and tops are usually either deposited over the landscape or piled in windrows. The biomass bundler captures the otherwise nonmerchantable material and maximizes the marketability of the entire tree. In order to reduce costs, maximize efficiency, and implement the bundler in a tree-length harvesting operation, this project tested a prototype harvesting system. This venture (1) adapted the John Deere B380 bundler unit to a motorized trailer, (2) designed an optimum landing configuration, and (3) conducted a productivity study of the bundler unit. The unit produced 13.2 tonnes per productive machine hour (PMH; 14.6 tons/PMH) of 250-cm bundles and 14.9 tonnes/PMH (16.4 tons/PMH) of 350-cm bundles, assuming minor delays at a cost of $12.50 to $14.20/tonne ($11.25 to $12.85/ton).
Bulk Density (Scaling Factor) of 14 Hardwood Species in Arkansas
Authors: Patterson David W. , Doruska Paul F. , Hartley Jonathan I. , Hurd Matthew
Published: October 2013

With the monetary exchange for hardwood trees and logs changing from log-scale board feet to tons, it is important that bulk density values (also called scaling factors) be developed to aid in determining the value of standing trees and logs. This study included 14 species of hardwoods and a total of 325 trees. Ten species were oak, which were divided into a red oak group (seven species) and a white oak group (three species). The red oak group had an average bulk density of 80.7 lb/ft3, and the white oak group had an average bulk density of 79.2 lb/ft3. A significant difference was found between the groups, as were significant differences between species within each group. Southern red oak (Quercus falcate) had the highest value (83.0 lb/ft3), and white oak (Quercus alba) had the lowest (77.0 lb/ft3). Three hickory types had an average bulk density of 79.4 lb/ft3. Sweetgum (Liquidambar styraciflua) had a bulk density of 78.3 lb/ft3.
Hazardous Air Pollutants and Volatile Organic Compounds Emitted during Kiln Drying of Southern Pine Lumber to Interior and Export Moisture Specifications
Authors: Dahlen Joseph , Prewitt Lynn , Shmulsky Rubin , Jones David
Published: October 2013

The emission levels of hazardous air pollutants (HAPs) from wood kilns are needed to comply with the Clean Air Act. Softwood lumber, including southern pine (Pinus taeda, Pinus palustris, Pinus echinata, and Pinus elliottii), is considered kiln dry when the wood moisture content reaches below 19 percent, but it is sometimes overdried or dried to 8 percent moisture content for export or interior applications. To study HAP emissions when drying to 8 percent moisture content, green lumber was obtained from a local mill, and 12 charges were kiln dried using three schedules: a 99°C elevated schedule and 116°C and 127°C high-temperature schedules. Methanol and formaldehyde were collected and analyzed using the National Council for Air and Stream Improvement (NCASI) 98.01 method, “Chilled Impinger Method for Use at Wood Products Mills to Measure Formaldehyde, Methanol, and Phenol,” where formaldehyde was analyzed via spectrophotometry using acetylacetone and methanol was analyzed via gas chromatography with a flame ionization detector. The high-temperature schedules had significantly greater HAP emissions than the elevated schedule. When drying from 19 to 8 percent moisture content, methanol and formaldehyde emissions increased by an average of 48 and 52 percent, respectively. Volatile organic compounds (VOCs) were also measured using a flame ionization detector by the NCASI VOC method with results similar to previous studies. The methanol, formaldehyde, and total volatile organic emissions were reported according to the Environmental Protection Agency OTM-26 method, “Interim VOC Measurement Protocol for the Wood Products Industry.” The results were slightly higher than the NCASI VOC results because of more accurate quantification of methanol.
Flakeboard Bonded with Polymeric Diphenylmethane Diisocyanate/Bio-Oil Adhesive Systems
Authors: Mao An , Shi Sheldon Q. , Steele Philip
Published: October 2013

The objective of this study was to investigate the feasibility of using the bio-oil generated from the Mississippi State University's (MSU's) fast pyrolysis process as part of a polymeric diphenylmethane diisocyanate (pMDI) binder system for flakeboard production. The bio-oil was obtained from the pyrolysis process of pine wood (Pinus spp.) at the MSU bio-oil laboratory. The effect of the resin content and the pMDI to bio-oil ratio on the physical and mechanical properties of the flakeboards was examined. The properties include internal bond, modulus of rupture, modulus of elasticity, thickness swelling, and water absorption. The effect of adding acetone into the pMDI/bio-oil resin on the properties of flakeboards was also investigated. The results showed that the incorporation of acetone reduced the viscosity of the adhesive by up to 67 percent, from which the efficiency for resin spraying on the flakes was improved. The higher the bio-oil content, the lower the mechanical strength of flakeboard obtained. However, the pMDI resin with a bio-oil content of 25 percent showed comparable bonding properties to those of pure pMDI resin.
Analysis of Chain Saw Selective Felling Operations on Damage Rate of Residual Trees during Winter Time in a Mixed Conifer–Broad-Leaved Forest in China
Authors: Wang Lihai , Wang Na , You Xiangfei , Meng Chun
Published: October 2013

Decreasing the damage rate of residual trees during selective cutting operations is quite important for forest landowners to reduce wood production waste and to use forest resources sustainably. In this article we analyze the impacts of chain saw selective felling operations on the damage rate of residual trees during winter in a mixed conifer–broad-leaved forest. A case study was conducted in Dongfanghong Forest Farm located in northeast China. After theoretical analysis, the influencing factors were identified, and a mathematical model that considers the relationships among damage rate of residual trees, harvesting intensity, initial stand density, and single stem volume to be harvested was established. The theoretical model was verified using the data collected from harvesting sites. Results show that the residual trees' damage rate increases linearly with an increase in stand density and in the volume per stem of felled trees. The damage rate of residual trees increases initially then decreases as the selective cutting intensity increases. In theory, the damage rate is at its highest value when the selective cutting intensity reaches 50 percent. The damage rate is significantly reduced by controlling the falling direction of felled trees, which shifts the maximum damage rate such that the highest rate occurs when the selective cutting intensity is 39 percent. The following recommendations for loggers are proposed to reduce damage rate: (1) effectively control the falling direction of trees being felled, (2) conduct cutting operation in nonfrozen seasons, and (3) design the cutting intensity (E) to be either E > 20 percent or E < 60 percent.
Fully Mechanized Harvesting in Aged Oak Coppice Stands
Authors: Suchomel Christian , Becker Gero , Pyttel Patrick
Published: October 2013

Coppice is a traditional forest management system used all over the world. It takes advantage of fast early growth and the vegetative reproduction of the respective trees. Coppice forests provide firewood and many other products and services, especially to rural communities. In Central Europe, regular periodic cutting and management of coppice forests was abandoned due to socioeconomic changes in recent decades, resulting in aged stands that have gradually lost their coppice characteristics. Today, coppice forests are recognized again not only for their growth potential but also for their benefits for biodiversity and nature conservation. Together with the rising demand for energy wood, this recognition could result in a renaissance of the traditional coppice management system. Several stands grow on relatively easily accessible terrain where fully mechanized systems (harvester, forwarder) could be used. However, there is no current information regarding the technical feasibility and productivity of modern harvester technology used in coppice forests.

In this study, an HSM 405H 6WD harvester with an CTL 40HW processor head was investigated with time studies to determine technical feasibility and time consumption of harvesting aged oak coppice. The results show high productivity for harvesting hardwood. The multiple stem structure that is typical for coppice forests does not result in technical problems or significantly higher time consumption for the harvester, even though it is slightly more time-consuming to grab and fell multi-stem trees than a single tree. Compared with a forest worker with a chainsaw, the harvester left significantly (5 cm) higher stools.
Characteristics of Wood Fuel Pellet Manufacturers and Markets in the United States, 2010
Authors: Lu Ning , Rice Robert W.
Published: October 2013

The wood fuel pellet industry has been growing rapidly in recent years. The survey results reported here are focused on the annual production, raw material, production cost rankings, market radius, barriers to market expansion, and other data that give an overview of the industry during a very difficult economic period. Eighty-four mills across the United States were contacted and 53 responded. The average volume of production was over 59,000 tons per year. Raw materials for pelletizing and labor were the principal costs of production according to respondents. Market demand and capital costs were cited as the chief barriers to expansion.

The industry is clearly subject to market forces that influence the cost and availability of raw materials as well as the cost of heating fuel alternatives such as oil. Despite the economic difficulties, demand continues to grow for pellet fuels both in the United States and in Europe.
Size, Moisture Content, and British Thermal Unit Value of Processed In-Woods Residues: Five Case Studies
Authors: Patterson David W. , Hartley Jonathan I. , Pelkki Matthew H.
Published: October 2013

With the increased emphasis in the utilization of biomass for energy, the interest in wood as an energy resource has moved from just mill residues to include in-woods residues. This study looked at five examples of in-woods biomass collection: two chipping operations and three grinding operations. Samples were taken from three truckloads at each operation and analyzed for particle size distribution, moisture content, British thermal unit value per ovendry pound, and ash content. The average characteristics of the processed residue were 87 percent moisture content, 7,945 Btu/lb oven dried, and 3.1 percent ash content.
Effects of Water Extraction Temperatures on the Yield, Molecular Weight, and Antioxidant Activity of Proanthocyanidins Extracted from Pinus radiata Bark
Authors: Ku Chang Sub , Mun Sung Phil , Jang Jeong Phil
Published: October 2013

Pinus radiata bark is a rich source of proanthocyanidins (PAs), a potent and valuable plant antioxidant. This study was performed to evaluate PA extraction conditions with water at various temperatures ranging from 25°C to 120°C. The properties of the water extract (WE) obtained at each temperature were investigated in terms of PA content, molecular weight (MW) distribution, and antioxidant activity. The WE yield was significantly dependent on temperature. The PA yield and the absorbance at 280 nm (an indicator of PA concentration) of WE reached maximum values at 80°C, implying increased extraction of monomeric polyphenols. Gel permeation chromatography results suggested that water extraction above 100°C caused depolymerization of extracted PAs, thereby noticeably reducing MW. It was found that more monomeric polyphenols can be extracted by increasing temperature. The WE antioxidant activity was maximized at 80°C and was dependent to some extent on the degree of polymerization.
Purchase Decision: Sustainability of Mountain Pine Beetle Wood Concrete Products
Authors: Choi Sungchul , Ng Alex , Park Sang-June
Published: October 2013

In British Columbia, many communities are dependent on the forest industry and are consequently concerned about uses for the millions of hectares of pine forests killed by the mountain pine beetle. The wood fiber from those dead trees is normally useless for traditional manufacturing of dimensional lumber due to its fragility and poor quality, but wood concrete provides an alternative use. This was a market research study on mountain pine beetle wood concrete product (MPBWCP), an innovative wood product that is a blend of pine beetle–killed wood and concrete. Three building product applications were investigated, including countertops, floor tiles, and garden blocks. We assessed the relative importance that consumers place on the product attributes of wood chip size, color, price, location of production, and green certification. Qualified consumer participants from cities on the West Coast of Canada and the United States were invited to evaluate physical samples of MPBWCP on site. The results of the conjoint analysis revealed that the consumers placed high importance on attributes pertaining to two forms of sustainability, economic and environmental. Indeed, economic sustainability of local communities was the most important attribute. Moreover, sustainability and aesthetic attributes were more important compared with the relative price attribute. Cluster analyses revealed that consumers could be divided into five different segments for all product types. Moreover, one consumer segment highly valued both attributes of sustainability (economic and environmental) more than any other segment. As for demographic insights, the most price-sensitive consumer segment had significantly higher education levels. Overall, consumers showed a desire for sustainable building products in their acceptance of MPBWCP. This is consistent with the importance they placed on both sustainability attributes versus the traditional product attributes of aesthetics and price. By examining a broader concept of sustainability that incorporates economic and environmental dimensions, this study extends the literature on wood products and environmental friendliness.
Effects of Outdoor Weathering and Wood Properties on Liquid Water Absorption in Uncoated Norway Spruce Cladding
Authors: Vestøl Geir I. , Sivertsen Mari Sand
Published: October 2013

A comparison of liquid water absorption in uncoated Norway spruce (Picea abies L.) claddings before and after 1 year of outdoor weathering was performed. The study was based on 150 specimens from two sites with high-productive forest and two sites with low-productive forest in southern Norway. The specimens included inner and outer boards; density, annual ring width, and proportion of heartwood were recorded. Water absorption increased after weathering. The relative change of short-term absorption was larger for outer boards than for inner boards, whereas it did not vary between origins. The outer boards also had more cracks than the inner boards after weathering. The differences between inner and outer boards were explained by different heartwood proportion and different annual ring orientation. The variability of short-term absorption increased after weathering since the sample groups with the highest initial absorption also had the largest increase after weathering. The change of long-term absorption did not vary between inner and outer boards or between origins.
Effects of Changes in Impact Analysis for Planning Model Industry Sector Data on the Economic Impacts of the Logging Industry in Mississippi
Authors: Santos Xiana T. , Grado Stephen C. , Grace Laura A. , Stuart William B.
Published: October 2013

Effects of changes on industry sector data for the Mississippi logging industry were examined to determine importance to and economic impact in that state's economy. Quantification, evaluation, and improvements upon current methodology of data and data collection for use in the Impact Analysis for Planning (IMPLAN) software model to more accurately reflect and support IMPLAN inputs and outputs were also determined. Economic impact estimates derived from model default data were compared with estimates derived from survey-based expenditure data collected within the state. The top 20 output sectors in the state economy resulting from logging expenditures were determined. In turn, new data were acquired to replace 4 of the top 20 sectors and new economic impact estimates derived. Economic impact assessment results on the model default data showed total economic impacts of $2.309 billion and $2.489 billion in industry output in 2006 and 2009 dollars, respectively. Total economic impacts generated using survey-based data from a sample of 33 loggers were $129.310 million and $131.747 million in 2006 and 2009 dollars, respectively. Total economic impacts generated by replacing 4 of the top 20 sectors from 33 loggers were $109.979 million in 2009 dollars. While this study was limited by a small sample size in regard to making statewide estimates, results indicated that limitations within the IMPLAN model further manifest themselves when implementing economic impact assessments. Rather than just relying on the default model data, more localized data should be collected when doing studies of this type.
Development of an Optimal Three-Dimensional Visualization System for Rough Lumber Edging and Trimming in Central Appalachia
Authors: Lin Wenshu , Wang Jingxin , Sharma Benktesh
Published: October 2013

An optimal three-dimensional visualization system was developed for edging and trimming of rough lumber in central Appalachia. ActiveX Data Objects were implemented via MS Visual C++/Open Graphics Library to manipulate board data at the backend supported by a relational data model with four data entity types: Board, Shape, Defect, and Defect Type. Exhaustive search procedures and a dynamic programming algorithm were used to achieve the optimal edging and trimming solution. A lumber grading module was also developed to grade hardwood lumber based on National Hardwood Lumber Association grading rules. The system was validated through comparing the total lumber values generated by the system with those generated by six local sawmills. A total of 360 boards were measured for board dimensions, defects, shape, wane, and the results of edging and trimming. Results indicated that the lumber value and surface measure gained in these six sawmills could be increased, on average, by 21.37 and 6.1 percent, respectively, using the optimal edging and trimming system. The optimal edging and trimming system not only can be used as a training tool but also can be installed on a field PC to aid the edging and trimming process.
Using Value Stream Mapping to Analyze an Upholstery Furniture Engineering Process
Authors: Wang Chao , Quesada-Pineda Henry , Kline D. Earl , Buehlmann Urs
Published: October 2013

This study presents a systematic approach of streamlining an upholstery furniture engineering process based on a case study in one of the largest export-oriented furniture manufacturers in China. The approach encompasses an analysis of the current state of the engineering process and the proposal of a lean future state value stream map (VSM). The current state analysis includes the definition of the product family, analysis of current customer demands, and the definition of the process metrics of the engineering process. Data were collected during a half-month visit to the furniture plant in China. Results from the current state VSM show that the value-added ratio of the current engineering process is 26.0 percent. Many engineering steps present deficiencies, such as the processes of creating drawings, compiling mass production documents, checking and signing off on engineering documents, creating CNC programs, and generating packaging files. After the current state VSM, it is found that unpredictable process cycle time and expediting engineering change orders are two major problems in the current engineering process. Based on current state VSM, the research focuses on countermeasures to solve the root causes of the major problems and proposes the best practices for the future VSM.
Measuring the Moisture Content of Green Wood Using Time Domain Reflectometry
Authors: Schimleck Laurence , Love-Myers Kim , Sanders Joe , Raybon Heath , Daniels Richard , Mahon Jerry , Andrews Edward , Schilling Erik
Published: October 2013

The responsible usage of water by facilities that rely on wet log storage in the southern United States has become an issue of great importance as restrictions on water usage have grown in recent years. In order to learn about the dynamics of moisture content in wet-stored logs over time, it is necessary to conduct continuous monitoring of log piles. Time domain reflectometry (TDR) is a method that current research has shown to have potential for use in this area. In this study, TDR probes of three lengths (75, 100, and 125 mm) were systematically inserted into 39 saturated bolts of Pinus taeda L., and both TDR and moisture content measurements were taken nine times over a period of 16 days as the bolts air dried. The samples were then oven dried, and measurements were taken three more times during that process. TDR readings from the 125-mm probes had the strongest relationship (R2 = 0.9426) with moisture content measurements. This result indicates TDR readings are sufficiently correlated with moisture content to accurately predict moisture variation over time and can be used to learn how water application and other factors affect the moisture content of wet-stored logs.
Impact of Wood Variability on the Drying Rate at Different Moisture Content Levels
Authors: Berberović Adin , Milota Michael R.
Published: October 2013

The impacts on drying behavior of basic density, initial moisture content, percentage and position of heartwood, ring count, rings from the pith, growth ring angle, and earlywood and latewood coverage on board faces were investigated for western hemlock (Tsuga heterophylla) lumber. Mathematical relations for the effects of wood properties and board geometric features related to position within its parental log were developed to predict the drying rate at four moisture content levels for drying temperatures of 80°C and 115°C. These relations were used for simulating wood drying as well as for predicting drying times of individual boards, which were used as a criterion for sorting green boards prior to entering their properties in the drying simulation.

Drying rate was affected by basic density, initial moisture content, percent heartwood, and growth ring angle at 80°C and only initial moisture content at 115°C. Presorting into two groups based on these wood properties reduced the standard deviation of the final moisture content distribution by 40 percent.
A Field-Tested Log Traceability System
Authors: Möller Björn , Wikander Jan , Hellgren Mikael
Published: October 2013

Today, an information gap exists between log measurements performed in the forest and at the sawmill. By applying a code in the forest during harvesting and then reading it at the sawmill, this information gap would vanish. A log applicator, which applies two-dimensional log codes through the saw bar, and a corresponding detection system based on vision technology have been developed. Key features of this technology are the very low cost of each mark and the zero-time-loss characteristic of both marking and detection.

A field test utilizing this equipment was performed on 210 logs in northern Sweden in December 2009. For logs harvested during real harvesting conditions and automatically detected at the log sorting station of a running sawmill, a detection rate of 40 percent was achieved. A comparison between parameters (length and diameter) measured in the forest and at the sawmill is presented, as are a number of suggested improvements to increase the detection rate substantially.
The Utilization of Chips from Comminuted Wood Waste as a Substitute for Flakes in the Oriented Strand Board Core
Authors: Mirski Radosław , Dziurka Dorota
Published: October 2013

This study evaluated the applicability of substituting flakes in the core layer of oriented strand board (OSB) with chips from comminuted and unrefined particle boards and wood waste. Results from the analyses show that the applied modification of the core, even at a relatively high proportion of chips (amounting to 75%) makes it possible to manufacture OSB with good mechanical properties, meeting the requirements of the standard EN 300. In contrast, the use of melamine–urea–phenol–formaldehyde resin does not guarantee the requirements (in terms of moisture resistance) will be met.
Factors Affecting Customer Loyalty in the Taiwanese Imported Lumber Market
Authors: Lee Jun-yen , Hsieh Tse-Wen
Published: October 2013

Establishing long-term relationships with Taiwanese lumber buyers generates profits and lowers costs. Marketing efforts, trust, and brand equity may be factors that strengthen relationships in this market. In this study, we assessed the relationships among these constructs using the structural equation model and data collected from a questionnaire sent to Taiwanese lumber importers. Path parameters are found to be statistically significant except for the link between brand equity and trust. Some factors must exist between these two constructs, and further exploration may be necessary in the future. The mediating effects of brand equity and trust are discovered between marketing efforts and customer loyalty. It suggests that lumber suppliers should focus marketing efforts on brand equity and customer trust in order to create customer loyalty.
Effects of Vertical Density Profiles on Bending Properties of Fiberboard with a “Bowl-Shaped” Vertical Density Profile
Authors: Zhang Yang , Yu Zhiming
Published: October 2013

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.
An Assessment of the Downturn in the Forest Products Sector in the Northern Region of the United States
Authors: Woodall C.W. , Piva R.J. , Luppold W.G. , Skog K.E. , Ince P.J.
Published: October 2013

The forest industry within the northern region of the U.S. has declined notably in employment, mill numbers, wood consumption, and forest harvests since 2000...a downturn exacerbated by the recession of 2007 to 2009. Longer term industrial decline (since 2000) has been evidenced by reductions in secondary products (e.g., furniture) and print paper manufacturing which can be attributed, respectively, to the lack of global competitiveness due to high U.S. wages and ascent of electronic media. In contrast, shorter term (since 2008), yet sharper declines occurred in industries such as composite panel production that serve the housing industry. Despite a decade of decline, there are future opportunities for this region's forest industry. The region's forests are predominantly within private ownership and represent tremendous volumes of some of the world's most valuable sawtimber (e.g., select hardwoods). Coupled with this natural resource is a present, but underutilized industry with excess capacity and a skilled work force. As evidenced by recent trends in positive trade balances, the decline of the northern region's forest industry may be mitigated with a focus on new markets (e.g., wood energy) and balancing increased export of unfinished products (e.g., logs) with increased use of the region's skilled secondary product workforce (e.g., increasing international competiveness of U.S. production).
Impact Assessment of the 2008 to 2010 Economic Downturn Period on Appalachian Hardwood Sawmill Operations
Authors: Lin Wenshu , Wang Jingxin , DeVallance David , Summerfield David
Published: October 2013

A mail survey was conducted in the fall of 2010 to investigate the impacts of the 2008 economic downturn on sawmill production, employment, and marketing in the Appalachian region. The mail survey was sent to 776 hardwood sawmills in the region and 58 valid responses were used in the study. It was determined that the average number of employees per mill had decreased from 42 to 30, a reduction of 29 percent during the period. At the same time, annual operating hours decreased 9 percent and weekly lumber production fell by 26 percent. Additional information collected with the survey indicated that the average log inventory reported by the responding mills was sufficient to allow production for 6 weeks. Weekly chip and sawdust production was reported as 139 and 81 tons, respectively. Sixty-seven percent of the reporting mills indicated they had changed their marketing strategies as a result of the downturn. Forty-six percent of the respondents reported they were exporting production to overseas markets.
Productivity and Cost of Integrated Harvesting for Fuel Reduction Thinning in Mixed-Conifer Forest
Authors: Vitorelo Brian , Han Han-Sup , Elliot William
Published: October 2013

Removing submerchantable size trees and forest residues as well as sawlogs is preferred in fuel reduction thinning because it improves treatment effectiveness and avoids slash burning. Fuel reduction thinning was investigated to describe integrated harvesting machine processes and productivity and to characterize stump-to-truck costs for sawlogs and biomass for energy production. This system was studied in mixed-conifer forest on land owned by the US Forest Service in northern California and southern Oregon. Detailed time-study methods were paired with standard machine rate calculation methods to evaluate productivity and costs for the system. Sensitivity analysis and a standardized comparison were performed to evaluate costs and productivity under varying operation parameters. Treatment costs (stump-to-truck; without mobilization, overhead, or profit) were US$0.42/ft3 for sawlogs and US$52.41 per bone dry ton (BDT) for biomass. Standardized unit production costs for sawlog skidding varied little, but the smaller skidder was clearly preferable for biomass tree skidding when external skidding distances exceeded 200 feet. The grinder had the highest hourly cost of any machine in the system and its unit production cost (US$/BDT) was sensitive to changes in utilization rate. Evaluations on system balance showed that improved utilization of the grinder could be accomplished as the grinder and loader often waited for a chip van. Integrated harvesting was a cost-effective way of implementing fuel reduction thinning method because of the potential for sawlog revenues to offset some of the biomass extraction cost.
Improved Plywood Strength and Lowered Emissions from Soybean Meal/Melamine Urea-Formaldehyde Adhesives
Authors: Gao Qiang , Shi Sheldon , Zhang Shifeng , Li Jianzhang , Liang Kaiwen
Published: October 2013

The objective of this study was to improve the wet shear strength and reduce the formaldehyde emissions for the soybean meal/melamine urea-formaldehyde (MUF) adhesive–bonded plywood by optimizing the hot pressing parameters in plywood manufacturing. An L(44) experimental design was used. A dynamic mechanical analyzer (DMA) was used to study the curing process of the adhesive during hot pressing. The DMA results showed that the storage modulus (E′) first decreased to a minimum at 72.9°C and then increased as the temperature increased to a maximum at 157.2°C. At temperatures higher than 157.2°C, the storage modulus decreased as the temperature increased. The hot press temperature had a significant effect on both the wet shear strength and the formaldehyde emissions from 120°C to 150°C, while no significant effect was found by varying the hot press time from 50 to 80 s/mm and changing the pressure from 0.8 to 1.2 MPa. The adhesive spread rate had a significant effect on the formaldehyde emissions. No significant effect was found on the wet shear strength of plywood by varying the adhesive spread rate from 145 to 205 g/m2. The optimum hot pressing parameters were found: 150°C hot press temperature, 70 s/mm in hot press time, 1.2 MPa in hot press pressure, and 165 g/m2 in adhesive spread rate. Under such optimum processing conditions, the wet shear strength of the plywood was improved by 24.2 percent from 0.95 to 1.18 MPa, while the formaldehyde emissions was reduced by 21.4 percent from 0.28 to 0.22 mg/liter, which met the type II plywood requirement for wet shear strength and the level E0 requirement for formaldehyde emissions described in the China National Standard GB/T 9846.3-2004.
Effects of End Plates on Reducing Checking of Pentachlorophenol-Treated Douglas-Fir Crossarms
Authors: Love Connie S , Morrell Jeffrey J.
Published: October 2013

The effect of metal end plates on reducing checking of pentachlorophenol-treated Douglas-fir crossarms was evaluated over 13 wet–dry cycles. Check development was variable over the first three to four cycles, and then steadily increased for both plated and nonplated ends of arms; however, both the number of checks and the maximum width of the checks were significantly lower on plated ends. The results suggest that end plating reduces the potential for deep check development in crossarms that could lead to early failure.
Veneer-Reinforced Particleboard for Exterior Structural Composition Board
Authors: Hse Chung Y. , Shupe Todd F. , Pan Hui , Feng Fu
Published: October 2013

Two experiments were performed to determine the physical and mechanical characteristics of panels consisting of a veneer face and a particleboard core composed of mixed wood particles/powdered-recycled polyethylene (PE) bag waste (MWP) using urea-formaldehyde (UF) resin as a binder. The addition of 25 percent powdered-recycled PE bag waste to the MWP panels did not adversely affect nonaged bonding strength but did result in substantial improvement in internal bond (IB) retention after a 24-hour water soak and improved dimensional stability. Average MWP panel IB retention was more than 300 percent higher than the IB retention of wood particle (WP) panels and MWP thickness swell and linear expansion were 70 and 44 percent lower, respectively, than the values for WP panels. For the veneer overlay composite, the mean modulus of rupture (MOR) parallel to the surface grain veneer (MOR||) was lowest (3,668.2 pounds per square inch [psi]) for panels with two veneers cross-laminated on each face over a WP core. Conversely, MOR|| was greatest (8,535.6 psi) for panels with single 1/8-inch veneers on each face over an MWP core. However, the large percentage of shear failure when stressed parallel to face veneer grain hindered an accurate determination of true MOR. As expected, all specimens tested in bending parallel to the surface grain of the veneers resulted in higher modulus of elasticity (MOE) than those tested perpendicular to the grain. For a single veneer overlay on each face, it is interesting to note that thinner veneers (i.e., 1/8 in.) resulted in higher MOE than thicker veneers (i.e., 3/16 in.).
Comparative Study of the Storage Stability between a Melamine-Urea-Formaldehyde and a Urea-Formaldehyde Resin
Authors: Lee Sang-Min , Park Jong-Young , Park Sang-Bum , Han Seung-Tak , Kang Eun-Chang
Published: October 2013

Amino resin wood adhesives used for medium-density fiberboard (MDF), a melamine-urea-formaldehyde (MUF) resin and a urea-formaldehyde (UF) resin, were each synthesized with an overall formaldehyde/urea molar ratio of 1.10. The storage stability of the resins was monitored by their gel times and viscosity changes, as well as by a multiple light scattering method. The storage stability tended to be affected by the temperature at which the resins were stored. MUF resin had a higher storage stability at a storage temperature above room temperature, whereas UF resin exhibited the best storage stability at 10°C with overall good stability at all tested temperatures from 10°C to 40°C.
Decorative Materials from Rice Straw and Cornstarch Adhesives
Authors: Liu Junjun , He Chunxia , Yu Min , Zhang Huan , Hou Renluan
Published: October 2013

The main goal of this work was to use rice straw fiber as a filler in the production of environmentally sound decorative materials using cornstarch adhesives as matrix. Treatments of rice straw with NaOH, oxalic acid, and hot water were undertaken to evaluate the effect of such treatments on the characteristics of rice straw and the performance of produced materials. The influence of temperature and shear rate on apparent viscosity of cornstarch adhesives was also investigated. Results showed that all treatments were efficient in partially modifying rice straw surface properties, as evidenced by Fourier transform infrared spectroscopy, and improving wettability of rice straw. Scanning electron microscopy suggested that NaOH and hot-water treatments resulted in a more significantly changed rice straw substrate than oxalic acid treatments. Apparent viscosity of the cornstarch adhesive decreased with increasing shear rate and increased and then decreased with increasing temperature, reaching a peak value at 10°C. The dependence of physical–mechanical properties of obtained materials on treatments performed on rice straw was also studied. Hot-water–treated straw materials displayed the best set of final mechanical properties. The materials exhibited poor waterproof performance but considerable moisture resistance and environmental friendliness, and such materials could be used for indoor decorative materials.
Determining Stocks and Flows of Structural Wood Products in Single Family Homes in the United States between 1950 and 2010
Authors: Sianchuk Robert A. , Ackom Emmanuel K. , McFarlane Paul N.
Published: October 2013

The stocks and flows of six major structural wood products (SWPs)—lumber, plywood, oriented strand board [OSB], glue laminated timber, I-joists, and laminated veneer lumber (LVL)—in US single family homes were modeled from 1950 to 2010. The consumption of these products in US single family homes and their emissions as construction and demolition wastes were estimated. The net consumption of SWPs decreased from 119 kg/m2 constructed in 1986 to 82 kg/m2 in 2010. Softwood lumber was consistently the predominant SWP, but its usage intensity decreased from 95 kg/m2 in 1986 to 52 kg/m2 in 2010. Since the 1980s, modern SWPs, such as I-joists, LVL, and OSB, have replaced lumber and plywood products. The needs of the US single family housing industry have been met by a smaller mass of SWPs per unit area constructed.

The mass of SWP present in construction wastes was influenced strongly by building cycles. Production of construction waste peaked in 2005, when 3.31 million tonnes of SWPs were produced by 1.72 million single family housing starts. It diminished to 0.874 million tonnes of SWPs as the housing starts fell to 445,000 in 2009. In contrast, the mass of demolition wastes produced was affected substantially by the number of houses in the stock and their half-lives. Approximately 4.5 million tonnes of SWP demolition waste were produced in 2010, and in the same year, the stock of SWPs in US single family homes reached 1,220 million tonnes.
Effect of Moisture Sorption State on Vibrational Properties of Wood
Authors: Lu Jianxiong , Jiang Jiali , Wu Yiqiang , Li Xianjun , Cai Zhiyong
Published: October 2013

The purpose of this study was to investigate the vibrational properties and corresponding anisotropicity in wood during different states of moisture sorption. Samples of maple (Acer spp.) and red oak (Quercus rubra Michx.f.) were moisture conditioned by the adsorption process from an ovendried state and by the desorption process from a water-saturated state. The dynamic modulus of elasticity (DMOE) and logarithmic decrement (δ) were examined as a function of grain orientation during moisture change processes and under constant moisture contents (MC). It was observed that regardless of species and grain direction, the DMOE and δ were lower and higher, respectively, during the moisture change process compared with those measured without a change in MC. The increase in δ value during adsorption was greater than that during desorption. These results suggest that wood in an unstable state shows lower elasticity and strength and higher damping properties than wood in an equilibrium state. Furthermore, results of this study demonstrate that a greater adsorption rate leads to greater destabilization during an adsorption process. The anisotropy in vibrational properties was found to vary between two species.
Examination of the Specimen Configuration and Analysis Method in the Flexural and Longitudinal Vibration Tests of Solid Wood and Wood-Based Materials
Authors: Yoshihara Hiroshi
Published: October 2013

The Young's modulus and shear modulus of solid wood (Sitka spruce, Picea sitchensis), medium-density fiberboard (MDF), and Lauan wood (Shorea sp.) with five-ply construction were determined by conducting flexural and longitudinal vibration tests with various specimen depth/length ratios and performing a subsequent finite element analysis (FEA). The values of Young's modulus and shear modulus were calculated by three analysis methods: (1) the method based on the rigorous solution of Timoshenko's differential equation (Phil. Mag. 41:744–746, 1921), (2) the iteration procedure proposed by Hearmon (Brit. J. Appl. Phys. 9:381–388, 1958), and (3) the method in which Young's modulus measured by the longitudinal vibration test is substituted into an approximated equation proposed by Goens (Ann. Physik. Ser. 7 11:649–678, 1931). The results obtained from the FEA suggested that the analysis method does not influence the values of Young's modulus or shear modulus. However, the results obtained indicated that the analysis method influenced the measured values of these moduli. Although Method 3 is simpler than Methods 1 and 2, the influence of depth/span ratio was more pronounced when using resonance frequencies lower than the second flexural vibration mode. When using the resonance frequency for flexural vibrations higher than the third mode, however, it is promising that the shear modulus can be measured while reducing the influence of the depth/length ratio.
Dynamic Mechanical Properties of Polymeric Diphenylmethane Diisocyanate/Bio-Oil Adhesive System
Authors: Mao An , Shi Sheldon Q.
Published: October 2013

Abstract

Bio-oil obtained from the pyrolysis of pine wood was mixed with polymeric diphenylmethane diisocyanate (pMDI) to form an adhesive binder system for flakeboard. Acetone was added for reducing the viscosity of the adhesive system. The thermal properties and curing behavior of five different adhesive mixes were examined using dynamic mechanical analysis (DMA). Temperature scans were performed in a range of 50°C to 200°C with a heating rate of 10°C/min, frequency of 1 Hz, and strain amplitude of 15 μm. Results indicated that less time was needed to reach the maximum storage modulus of the adhesive mix with an increase in bio-oil content. The adhesive with the pMDI/bio-oil ratio of 25/75 presented the fastest curing speed but the lowest modulus value at temperatures of approximately 100°C. The pMDI-acetone adhesive showed the best thermal mechanical properties among the five adhesive binder systems.
Effects of Melamine on the Properties of Medium-Density Fiberboard Fabricated with Urea-Based Resins
Authors: Lee Sang-Min , Park Jong-Young , Park Sang-Bum , Hwang Won-Joung
Published: October 2013

Urea-melamine-formaldehyde (UMF) resins were synthesized and used for manufacturing medium-density fiberboard (MDF). As melamine content was increased at the same formaldehyde/urea (F/U) molar ratio, the solids content of the resin increased. Physical properties and storage stability of the resins tended to improve slightly when the final pH of resin was 8.5 compared with 7.5 and 9.5. At the same F/U molar ratio, free formaldehyde content and gel time of the resins decreased as melamine content increased. Chemical structures of the resins were proposed from the results of 13C nuclear magnetic resonance and Fourier transform infrared analyses. Formaldehyde emissions of MDF prepared with UMF resins with the same F/U molar ratio decreased as melamine content of resin was increased. MDF fabricated with UMF resin showed slightly better resistance against decay fungi and termites compared with MDF fabricated with urea-formaldehyde (UF) resin. Other physical properties of MDF fabricated with UMF resin were comparable to those of MDF fabricated with a commercial UF resin. An optimum F/U molar ratio of 1.2 with melamine content of 15 percent, equivalent to an F/(U+M) molar ratio of 0.98, was found from the results.