The cross-laminated timber (CLT) construction system has recently emerged as an excellent alternative for civil construction. The objective of this work is to analyze the structural performance of CLT panels using plantation lumber, especially eucalyptus (Eucalyptus grandis) heartwood and pine (Pinus taeda). After visual grading, all boards were mechanically graded through the ultrasonic nondestructive testing method. Boards were organized to compose four types of three-layered CLT panels: 1) exclusively eucalyptus heartwood (EEE), 2) eucalyptus in the outer layers and pine in the central layer (EPE), 3) exclusively pine (PPP), and 4) pine in the outer layers and eucalyptus in the central layer (PEP). Three panels with graded timber were manufactured for each type, and one more panel was made out of ungraded timber, so each group had four panels altogether. Panels containing eucalyptus in the outer layers (EEE and EPE) were stiffer than the ones with pine in outer layers (PPP and PEP). However, the first two groups presented lower bending strength than the second ones. Modulus of elasticity and modulus of rupture results were compared to values observed in the literature and to the international standard that regulates CLT (American National Standards Institute/American Plywood Association PRG 320). From the four types studied, only panels containing mostly eucalyptus (EEE and EPE) could meet the PRG 320 E2 class. Panels containing mostly pine (PPP and PEP) did not reach the thresholds of any class in terms of stiffness although their resistance was much higher than that specified in the standard.Abstract
X-ray computed tomography (CT) scanning of sawmill logs is associated with costly and complex machines. An alternative scanning solution was developed, but its data have not been evaluated regarding detection of internal features. In this exploratory study, a knot detection algorithm was applied to images of four logs to evaluate its performance in terms of knot position and size. The results were a detection rate of 67 percent, accurate position, and inaccurate size. Although the sample size was small, it was concluded that automatic knot detection in coarse resolution CT images of softwoods is feasible, albeit for knots of sufficient size.Abstract
Due to the multidimensional complexity and redundancy between wavelengths in the visible and near infrared (Vis-NIR) region, the speed and accuracy of data analysis can be affected. This study aims to investigate the feasibility of simplifying high dimensional data based on transformation of the spectra and local correlation maximization (LCM). These two methods will be applied to determine the prediction accuracy of air-dry density of Ulmus pumila wood. In this study, the reflectance spectra (Refl.) were subjected to the reciprocal (1/Refl.) and logarithm reflectance to improve the spectra signal for prediction. LCM was developed for selecting spectral sensitive regions that were important in the prediction of density. A local correlation coefficient (r) criterion was developed such that if the r ≥ 0.75 (between wavelength and density), then partial least squares and support vector machine (SVM) were employed as the prediction method. Likewise, 2D correlation spectroscopy plots were used to further reduce the data matrix by removing redundant wavelengths. The results showed that (1) although the sensitive region of density was different, the region of r ≥ 0.80 was mainly in the Vis and NIR spectral region. Additionally, the performance of models developed from the sensitive region was better than that of data used from the less-sensitive region. (2) The SVM model was optimized by a genetic algorithm based on the log (1/Refl.) of the sensitive region. In conclusion, it was found that the spectral transformation presented better density estimation results (Abstract
= 0.909, root mean square error of calibration = 0.014) than when less sensitive wavelengths were used in the data matrix.
Northwest Arkansas was identified as a region of interest for the production of wood-fueled electrical power due to its pervasive timber industry and need for cost-effective forest management. It is believed that by utilizing wood residuals produced from sawmill operations, a stable source of revenue could be provided to local wood processing businesses while simultaneously providing clean energy to the region. In order to evaluate the amount of available material available for energy production, all known mills were surveyed within the 16-county study region for their annual production of sawdust, slabs, and other residual products. Data on production of residuals were developed into supply curves and equations. Supply was found to be inelastic for both hardwood and softwood mill residuals in the region. Given that residual production is a secondary effect of timber processing, supply inelasticity is expected. Increasing the quantity of mill residuals in the region will likely be accompanied by greater-than-proportional price increases. We determined that 96,744 tons of ovendried material would be available annually for purchases at a delivered price of $38 per ton. With this quantity, the region could be expected to support a small combined heat and power energy facility with output between 5 and 10 MW.Abstract
The aim of this research is to show useful utilization of agricultural residues such as cotton stalks and branches of pistachio, pomegranate, and Haloxylon species with recycled plastic in manufacturing wood–plastic composite (WPC) panels. Wood–plastic panels were made from a combination of agricultural residues (as natural fiber) and recycled plastic (as resin) at 50 percent, and 60 percent by weight fiber loading. Density and dimensions of the panels were 0.61 g/cm3 and 350 by 350 by 14 mm, respectively. Physical and mechanical properties of the panels including thickness swelling, water absorption, static bending (modulus of rupture and modulus of elasticity ), and internal bond were investigated. Physical and mechanical properties of the WPC panels decreased with an increase in fiber content from 50 percent to 60 percent. Physical and mechanical properties of samples made with 50 percent plastic were higher than samples with 40 percent plastic. The best values of physical and mechanical properties of the WPC panels were found at 10 percent and 5 percent Haloxylon particle loading, respectively. The highest values of mechanical properties of WPC panels were found at 50 percent plastic and 5 percent Haloxylon particle loading.Abstract
In this study, poplar wood and a phenol-formaldehyde (PF) resin were used to produce a large-scale scrimber product by a combined cold pressing and heat curing method. The water resistance, mechanical properties, and formaldehyde emission of the scrimber boards prepared at different core temperatures (100°C, 110°C, 115°C, and 120°C) were investigated. The results showed that the peak core temperature had a significant effect on the scrimber performance. The thickness swelling rate and width swelling rate of the scrimber boards prepared at a core temperature of 100 °C were significantly higher than other samples. The formaldehyde emission from the surface layer of the scrimber boards prepared at a high core temperature (115°C and 120°C) was much lower than that at a core temperature of 100°C and 110°C. These results can be explained by the correlation between curing degree and temperature of the PF resin in the scrimber. With increasing core temperature, the modulus of rupture, compression strength, and horizontal shear strength of the scrimber boards first increased and then decreased, suggesting that core temperature during the heat curing process also played an important role in determining mechanical properties. The scrimber boards with the best mechanical properties were prepared at a core temperature of 115°C. The results of the study demonstrated that the optimal core temperature necessary to produce a low-cost and high-performance scrimber was 115°C.Abstract
The contribution of income from nontimber forest products (NTFPs) to rural livelihoods and household income has received global recognition. However, there are growing concerns of overexploitation of NTFPs driven by poverty and policy neglect that threaten the sustainability of the NTFP resource base in Kassena-Nankana West District (KNWD) of Ghana. The study investigated the contribution of income from NTFPs to household income and socioeconomic factors that influence the collection and marketing of NTFPs in KNWD. Using a multistage sampling technique, quantitative data were collected from 375 households through structured survey questionnaires. Qualitative data were gathered through focus group discussions, key informant interviews, and field observations. Results showed that income from NTFPs forms a significant part of household income with a contribution of 32.69 percent to household income. Regression analysis revealed sex of respondent (P = 0.057), household size (P = 0.046), agricultural land size (P = 0.000), NTFP retailers (P = 0.000), NTFP wholesalers (P = 0.000), and value-added NTFPs (P = 0.000) as significantly and positively correlated with income from NTFPs. Results further indicated that poor households depend primarily on NTFPs in order to achieve their subsistence and income needs compared to high-income households. This research recommends that stakeholders and policymakers consider the needs of forest-dependent communities in policy analysis on NTFP conservation measures. Also, the role of households, especially the low income (poor), in the management of forest resources should be spelled out since they depend primarily on NTFPs to meet their subsistence and income needs.Abstract
China is the world's largest furniture producer and exporter, but its furniture industry has always been at the bottom of the global value chain. Wooden furniture is the most important component of China's furniture industry. Its capacity and scale have been expanding; however, the industry's income and profit growth rate have declined. China's wooden furniture industry is in a period of transition, and industry regulators, participants, and even investors need to understand the future development trends of the industry. This study collected time series data for annual sales as well as the value of output, exports, and imports of the wooden furniture industry in China and used the autoregressive integrated moving average (ARIMA) model to predict future market supply and demand. The study found that each figure will continue to grow over the next 5 years. However, the industry as a whole will face the challenge of oversupply. In addition, the domestic market share on behalf of industrial competitiveness will decline year by year. Through a comprehensive and systematic analysis of the changing trend of China's wooden furniture production and its domestic and foreign markets, this study is the first to predict the supply and demand of research, filling the gap in the research field of wooden furniture, and its research ideas have some innovation. It can provide a reference for industry regulators, enterprise decision makers, and domestic and foreign investors.Abstract
This article analyzes the behavior of surface finish and pressing time in glued pieces of eucalyptus wood. The importance of the study lies in verifying the influence of two variables (surface finish and pressing time) on the gluing of wood pieces for the furniture industry over time. For this purpose, the quality of adhesion of Eucalyptus urograndis wood pieces with polyvinyl acetate adhesive and the behavior of the wood to shear in the glue line are evaluated. It was necessary to produce test specimens according to the ABNT-NBR 7190 standard; three different surface finishes were evaluated on the faces to be adhered and three different cold pressing times, a variable that has not been analyzed in previous studies. It was possible to determine the shear resistance in the glue line and also to observe the percentage of wood failure when performing the destructive test on the test specimen 1 year after being glued. The highest shear strength was obtained for test specimens without surface finish and with a pressing time of 24 hours. With the results obtained in this study, the optimal surface finish and pressing time to be used in the furniture industry is evidenced.Abstract