Abstract

Utilization of hardwoods in the manufacture of cross-laminated timber (CLT) faces many challenges, one of which is the selection of raw material that is both technically and economically feasible. From an economic perspective, it would make sense to choose species and grades that are both readily available and relatively competitive with softwood species currently used in CLT manufacturing. For the purposes of this study, lower grades (2A Common, 2B Common, 3A Common, and 3B Common) of red oak and soft maple were deemed appropriate in fitting this profile.

All lumber was visually graded according to both National Hardwood Lumber Association (NHLA) and Northeastern Lumber Manufacturers Association (NeLMA) grading rules, as well as nondestructively tested through flatwise bending to determine modulus of elasticity (MOE). The yield distribution of each species and NHLA grade, by visual structural grade, were analyzed. The mechanical testing of each species was analyzed based on the minimum allowable MOE of 1.2 x 10⁶ psi as required by ANSI/PRG-320. Mechanical testing resulted in much higher yields of acceptable CLT material than visual grading, for both species.

A total net worth analysis was conducted to evaluate the value of NHLA graded lumber being processed into structurally graded lumber for both species and both grading methods. Finally, a procurement analysis was conducted to determine the volume of lumber required for both species, in order to achieve a fixed volume of CLT-ready lumber.

Abstract

Global trade of wood forest products is a complex system, and its flow between trading countries forms a trade network of wood forest products. The transmission efficiency of the trade network largely depends on its network structure. The commonly used method in recent years to analyze the network structure is complex network analysis. Therefore, this study used the complex network method, through using kernel density curves every 5 years to show distribution changes of complex network indictors to study the evolution of the trade network of global trade of wood forest products, based on trade data from 1995 to 2020. The results show that the trade relationship between countries is deepening. Compared with resource-based wood forest products, the trade of deeply processed wood forest products is larger in scale, more complex in structure, and more closely linked. The core countries in global wood forest products trade mainly comprise North American and European countries, while several developing countries in Asia with abundant forest and labor endowments are gradually joining the core tier and jointly control the trade market. We also revealed the intervention of world forestry development goals and national forestry policies on changes to trade structure and trade groups.

Abstract

The effect of biodeterioration on the structural connection performance of timber for conventional framing and mass timber has been investigated recently, but there is a need for additional data as well as for the development of analytical models to utilize these data. An empirical material model (seismic analysis of wood frame shear walls) was fitted to cyclic connection test data of four species of cross-laminated timber at different levels of biodeterioration by two brown-rot fungi. These model inputs were then analyzed to account for trends between wood species and fungal species. Weak trends were most prominent for initial stiffness, intercept load, and displacement at peak force. Correlations were poor with postyield and postpeak stiffness modifiers. These relationships were consistent both as a function of time and as a function of mass loss, but additional data are needed to more accurately predict the effects. The limited relationships likely reflect the variations in fungal decay across the test members.

Abstract

Solid-state surface attenuated total reflectance Fourier transform infrared spectroscopy (SATR-FTIR) and solid-state nuclear magnetic resonance spectroscopy (SSNMR) were used to characterize the physiochemical changes in solid soy-flour adhesives upon exposure to water. Comparisons were made between adhesives that were prepared with and without the crosslinking chemical polyamideamine-epichlorohydrin (PAE). Comparisons were also made between neat monolithic adhesive films, and adhesives that were laminated to yellow poplar (Liriodendron tulipifera). FTIR data revealed that the relative surface concentration of water-soluble components on neat monolithic adhesives was higher prior to water-exposure as compared with the adhesive laminated to wood. Moreover, the chemical composition of the water-soluble extract was affected by PAE. After soaking in water, the water-soluble components were observed to dissolve and disappear from the surfaces of the adhesives, as well as from the surfaces of water-soaked wood-laminate specimens. Similarly, SSNMR results corroborated with the dissolution and disappearance of the water-soluble components from the neat monolithic adhesives after water soaking. Moreover, it was discovered that the water-soluble components have a plasticization effect when PAE is used as a crosslinker. The implications of these findings as they pertain to the mechanism of adhesion will be discussed.

Abstract

Reclaimed wood is a repurposed building material salvaged from old or abandoned buildings that offers a sustainable approach to using wood in communities. Although there have been some studies on reclaimed wood, there has been a limited amount linking reclaimed wood to consumerism. In August 2021, an online survey was conducted to gauge adult consumers’ knowledge of the wood products industry and their attitudes on reclaimed wood practices. Adult consumers are defined as individuals residing in the United States who are 18 years of age or older. Study results indicate that many respondents have little to no knowledge of reclaimed wood. Of the 1,516 respondents, only 44% have any knowledge of reclaimed wood. Most respondents are not aware that reclaimed wood is a separate sector in the industry. Caucasian men were the most knowledgeable of all respondents. Respondents believe that reclaimed wood is environmentally friendly, durable, and aesthetically pleasing and that there should be better marketing practices for reclaimed wood. Respondents’ top three reasons for purchasing reclaimed wood was to promote sustainability, for the aesthetics, and because there was a need. Respondents also acknowledge the importance of knowing where their wood products come from and believe that the reclaimed wood sector is very important.

Abstract

The aim of this study is to evaluate the possibility of re-establishment of the Paulownia tomentosa (Thunb.) Steud. forestry and wood industry for sustainable wood production in Japan. Bending properties were preliminarily investigated for dimension lumber (2 by 4, 38 by 89 mm in transverse section) and small-clear specimens of this species. The severe slope of grain in lumber reduced the modulus of rupture (MOR) and disturbed the relationship between the modulus of elasticity (MOE) and MOR. Preliminary studies determined a 5 percent lower tolerance limit with a 75 percent confidence level in MOR of lumber was 12.1 MPa. The value exceeded the characteristic value of MOR of 2 by 4 lumber in structural grade Western redcedar (Thuja plicata).

Abstract

Timber-framed architecture has a long history in both China and Japan. As an eco-friendly construction material, it is universally acknowledged that the use of timber can be conducive to the achievement of sustainable development for architecture. During the past decades, the development of timber-framed buildings in China and Japan appeared significantly different. Consumers’ cognition about timber as a construction material has been widely researched by European academics, while there are few such kinds of studies in China, especially the comparative study between China and Japan. To fill this gap, this study aims to figure out consumers’ acceptance and attitudes toward timber used as a construction material in China and Japan. By adopting a structured questionnaire method, this study analyzed consumers’ thoughts, knowledge, and awareness of modern timber-framed architecture from the consumer level. The results indicate that Chinese and Japanese consumers have the same prejudices regarding the deficiency of timber-frame houses, in terms of fire resistance, acoustic insulation, and durability, while having positive attitudes regarding health and nature, and doubts about environmentally friendly performance. Moreover, the background developing driving forces and developing obstacles have also been analyzed. These results help to provide a better understanding of the challenges and difficulties that the timber-framed house market is facing in China and Japan. Thus, some suggestions were proposed to policymakers, developers, and timber companies for the future development of timber-structure architecture.

Abstract

Global use of renewable energy has risen over the past few decades because of international energy policy changes, new legislation, and an effort to create a more sustainable energy source for a rapidly growing global population. One of these renewable energy sources is biofuels, specifically in the form of wood pellets created from wood chips. Wood pellet manufacturers in the southeastern United States must adhere to rigid quality-control standards of the European markets where their pellets are shipped and consumed. Thus, there is a need to improve our understanding of the factors that influence the quality of the source materials. Higher heating value (HHV), moisture content (MC), ash content, elemental composition, and size stratification are all important quality factors to consider when analyzing wood chips. Variations in these quality factors can cause longer drying times, blockages in feed systems, excess waste, and fluctuations in energy output. The objective of this study was to quantify these quality factors across multiple sources of wood chips. Softwood and hardwood in-woods chip samples as well as softwood mill residual chips were collected from thinnings and clear-cuts across the southeastern United States. Softwoods had a greater HHV and MC than hardwood chips, with 18,949 kJ/kg and 18,242 kJ/kg, respectively. Softwood thinnings had the highest HHV and lowest ash content. However, only 4 of the 60 samples analyzed were from softwood thinnings. This study provides an overview of the variation in wood chip quality across the southeastern United States.

Abstract

In order to be utilized in the design of a wood building, the lumber must pass grade. Machine-vision inspection grading offers higher efficiency and accuracy than traditional manual visual grading. In this paper, a fast and accurate method for identifying defects in large-size structural lumber based on machine vision of Fujian Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) constructional lumber (FCF CL) is proposed. Specifically, the grey matrix of the captured images on the surface of the sawn timber is initially scanned and the pixel weights on the edges of the image greyness variables are calculated. A matrix-valued torus was formed by fitting the knot edge profile and analyzing changes in the gradient values at the knot's edge, as well as calculating the directional derivative's rate of change. The knot three-dimensional mapping curves were projected onto the plane to form horizontal rise contours. Observe from the contour map of the whole large-size sawn timber, and extract the positional information of the knot where there is a trough (groove).

The test results show that the rRMSE (Relative Root Mean Square Error) measured at the x axis position of knots is within 0.49 percent; the rRMSE measured at the y axis is 0.35 percent, which has high detection accuracy and meets the production requirements. We also investigated the effect of knots in different positions on the modulus of elasticity and the bending strength of FCF CL, with a view to establishing a link between machine-vision knot detection and mechanical properties of sawn timber in our next work.

Abstract

The goals of Chile’s forest policy regarding the use of wood in construction are far from being achieved. Chile is the ninth-largest global producer of sawn softwood and has an industry with numerous sawmills; however, structural sawn wood (SSW) represents less than 1 percent of the industry’s total production, which is insufficient to address large-scale construction programs with wood. Therefore, policy instruments are needed to lead to an increase in the volume of SSW production. This research aimed to design a typology of sawmills that facilitates the definition and implementation of these policy instruments to ensure attainment of the 2035 goal of the forest policy. Multiple linear regression and multiple logistic regression were used to assess the impact of various variables on SSW production; variable selection was done using stepwise regression. The number of clusters was determined using the gap method, and sawmill clusters were determined using k means. The result is a typology with five categories of sawmills based on their propensity to produce SSW. The most significant variable was the quality of the supply, so it is suggested to prioritize the management of Pinus radiata plantations. With this result, a map for the application of policy instruments was created, proposing an intervention pathway. The proposed typology will stimulate decisions to provide direct support to the sawmill industry, thereby increasing SSW production.