Search Results (10)

Canadian sawmills commonly use chipper-canters to process softwood logs into squared lumber and wood chips for pulp mills. However, the declining demand for newsprint and print paper has led to an oversupply of wood chips, resulting in economic losses and environmental concerns. To address this issue, a strander-canter capable of producing both softwood cants and strands for oriented strand board (OSB) presents a promising alternative. This study evaluates the feasibility of using jack pine strands generated by a novel strander-canter equipped with a cutterhead for OSB strand production. Strands were generated from frozen and unfrozen logs under varying cutting parameters and incorporated in the core layer of the panels. Industrial aspen strands were used for the surface layers. OSB panels were assessed for mechanical and physical properties following the CSA O325:21 standard. Strand size distribution and vertical density profiles were also analyzed. The results indicated that panels made from jack pine strands demonstrated bending and internal bond properties that were either comparable to or superior to those of the control panels. However, including jack pine strands in the core layer increased the thickness swelling of the panels. Full article

The relationship between silvicultural strategies, manifested in the thinning method and rotation age on sites with different water supply, and the mechanical properties of engineered wood products plywood and laminated veneer lumber has been analyzed. Sample logs from five German sites of Norway spruce (Picea abies (L.) Karst.) and Douglas fir (Pseudotsuga menziesii (M.) Franco) have been rotary-peeled and processed into boards with a phenol–resorcinol–formaldehyde adhesive to evaluate their performance under flexural, tensile, and compressive loads. Satisfactory coefficients of determination were reached for Norway spruce in regard to the silvicultural framework and the tree characteristics of slenderness and crown base height. Douglas fir products did not achieve comparable determination due to high variance within boards and stands but did achieve significantly better mechanical properties. Norway spruce was observed to be more responsive to thinning measures, while the effect of different thinning regimes was not evident for Douglas fir. The on-site evaluation of Douglas fir stands for veneer product quality based on silvicultural parameters and tree characteristics was shown to be inconclusive, with its naturally higher wood density being the decisive constant. Full article

The strength properties of softwood components with bonded joints reinforced with fasteners were investigated and compared. Initial tests of the strength of the glue joints were carried out, with a change in the type of adhesive used. The application method significantly influenced the shear strength of the joint. With the adhesive and pre-bonding systems used, the shear strength of the adhesive joint of pine wood (Pinus silvestris L.) with PUR and PVAC resin was determined. The industrial results were 31% lower than in the shear test of the wooden joint bonded with PVAC glue. In terms of transverse shear force with staples, the joint has a transverse holding force that is higher than components connected with screws or nails. As the number of glue sticks increased, the shear strength of the pine wood increased. The strengths of the joined components in the glue roller method had an intermediate value. They did not differ significantly between the two-row gluing systems used. An increase in the force required to shear the bonded joint was observed for the different adhesive systems, the fasteners used, and their density. Full article

Engineered wood products (EWPs) have evolved over time to become a popular and sustainable alternative to traditional lumber by offering design flexibility, increased strength, and improved quality control. This work analyzes the potential of Portuguese eucalyptus wood (Eucalyptus globulus) to produce glued-laminated timber (glulam) for structural applications. Currently, this hardwood is used for less noble applications in Portugal’s construction industry. To promote the use of this species of timber in construction, an experimental campaign was conducted to characterize its compression parallel to the grain and bending strength. The results demonstrated that this hardwood presents a compression parallel to the grain strength of 73 N/mm² and a bending strength of 151 N/mm² with a global value of elastic modulus equal to 24,180 N/mm². Based on those strength values obtained from the glulam produced with eucalyptus, one can conclude that the test results presented here are higher than the ones declared by the current glulam made of softwoods; thus, additional studies are encouraged. Full article

The COVID-19 pandemic led to unprecedented changes in the U.S. price of softwood lumber by more than 300% between 2020 and 2022. The increased volatility of lumber prices after the COVID-19 outbreak remains unexplained. In this paper, we examine how a calibrated random walk can induce similar price volatility through the development of a stochastic process. As a preferred approach, we employ an event model to estimate the impact of COVID-19 and other key events on the price of softwood lumber. The econometric model serves to provide evidence that the price volatility of softwood lumber is not completely random, and we can instead attribute part of the variation to recent regional and global events. We found that, while COVID-19 did result in a price jump, it was smaller than a rainfall event that restricted imports from Canada, while import duties and other trade actions had no discernible impact on U.S. lumber prices. Full article

The differences of physical and mechanical properties of different laminations, such as softwood, hardwood or other structural composite lumber, in hybrid cross-laminated timber (HCLT), lead to their dimensional stability and bonding performance more complex than generic cross-laminated timber (CLT). In this paper, the spruce-pine-fir (SPF) dimension lumber and construction oriented strand board (COSB) were employed to fabricate HCLT. The effects of four configurations and three adhesives on the dimensional stability and bonding performance of CLT and HCLT were evaluated in term of the water absorption (WA), thickness swelling (TS), block shear strength (BSS), wood failure percentage (WFP) and rate of delamination (RD). The results showed that with the increase of the COSB laminations, the WA of HCLT specimens decreased, and the values of TS, BBS and WFP increased. The configuration had a significant influence on the dimensional stability, BBS and WFP of the specimen. The adhesive had a significant influence on the dimensional stability and some bonding performances of the specimen. The phenol resorcinol formaldehyde (PRF) specimens had the lowest average RD value compared with the one-component polyurethane (PUR) and emulsion polymer isocyanate (EPI) specimens. Failures were prone to occur in the middle of the thickness of COSB lamination during block shear and delamination tests. The outcome of this paper could help the engineering application of HLCT. Full article

This study aims to investigate the feasibility of producing OSB from softwood species used in the Eastern Canadian softwood lumber industry in the context of the overcapacity of softwood chips traditionally produced for the pulp and paper industry. Balsam fir, black spruce, and jack pine logs were used to make 15 mm thick OSB panels with a target density of 600 kg/m³. The panels were manufactured at a temperature of 210 °C during a pressing cycle of 300 s. Strands with different thicknesses were used to obtain a constant specific surface of 6.7 m²/kg for the three species. The bending modulus of the rupture and modulus of elasticity, internal bond, and thickness swelling of the OSB panels were determined and compared to the CSA standard requirements. The species significantly affected the physical and mechanical properties of OSB. The bending properties of OSB decreased with an increase in the species wood density. The internal bond strength of OSB increased with the increase in species wood density. The panels made from softwood species showed physical and mechanical properties exceeding the standard requirements, except for high thickness swelling. The combination of softwood and aspen strands significantly improved the thickness swelling of softwood-based OSB. The reduction in the surface layer density could also be explored to reduce the thickness swelling of the OSB made from the softwoods considered in this study. Full article

Mass timber products are growing in popularity as a substitute for steel and concrete, reducing embodied carbon in the built environment. This trend has raised questions about the sustainability of the U.S. timber supply. Our research addresses concerns that rising demand for mass timber products may result in unsustainable levels of harvesting in coniferous forests in the United States. Using U.S. Department of Agriculture U.S. Forest Service Forest Inventory and Analysis (FIA) data, incremental U.S. softwood (coniferous) timber harvests were projected to supply a high-volume estimate of mass timber and dimensional lumber consumption in 2035. Growth in reserve forests and riparian zones was excluded, and low confidence intervals were used for timber growth estimates, compared with high confidence intervals for harvest and consumption estimates. Results were considered for the U.S. in total and by three geographic regions (North, South, and West). In total, forest inventory growth in America exceeds timber harvests including incremental mass timber volumes. Even the most optimistic projections of mass timber growth will not exceed the lowest expected annual increases in the nation’s harvestable coniferous timber inventory. Full article

This study evaluated the effects on forest resources and forest product markets of three contrasting mass timber demand scenarios (Conservative, Optimistic, and Extreme), up to 2060, in twelve selected countries in Asia, Europe, North America, and South America. Analyses were carried out by utilizing the FOrest Resource Outlook Model, a partial market equilibrium model of the global forest sector. The findings suggest increases in global softwood lumber production of 8, 23, and 53 million m³ per year by 2060, under the Conservative, Optimistic, and Extreme scenarios, respectively, leading to world price increases of 2%, 7%, and 23%, respectively. This projected price increase is relative to the projected price in the reference scenario, altering prices, production, consumption, trade of forest products, timber harvest, forest growth, and forest stock in individual countries. An increase in softwood lumber prices due to increased mass timber demand would lead to the reduced consumption of softwood lumber for traditional end-use (e.g., light-frame construction), suggesting a likely strong market competition for softwood lumber between the mass timber and traditional construction industries. In contrast, the projected effect on global forest stock was relatively small based on the relatively fast projected biomass growth in stands assumed to be regenerated after harvest. Full article

The transition of our current economic system towards a bioeconomy that is based on renewable materials and energy can be an important contribution but at the same time a threat to mitigate the challenges of the 21st century, such as global warming and resource depletion. To assess societal, economic, and environmental impacts associated with this transition, we propose an approach for a sustainability assessment as an integral part of a future bioeconomy monitoring concept. The assessment approach is based on material flow analyses of the bioeconomy and their core products. As a proof of applicability, the proposed assessment approach is exemplified for the material flow of softwood lumber and its core product ‘EPAL 1 pallet’. To simulate a frequent monitoring, material flow analysis and assessment of six sustainability effects are applied for the years 2010 and 2015. Since a frequent bioeconomy monitoring requires regularly updated and quality assured data, official statistics should be the major source of information. Whereas cutoff thresholds, nondisclosure of data, and high level of aggregation are major limitations of official production statistics and for material flow analysis, lack of information regarding environmental effects is the major limitation for material flow related sustainability assessment. We make suggestions on how to overcome these limitations and put our approach in to context with other ongoing monitoring activities. Full article