The identification of the tree species and the extent of material deterioration in the wooden components of the walkway of the first courtyard of the ancient Yangjia Courtyard were analyzed in this study using bright-field microscopy, polarized light, fluorescence, and Fourier-transform infrared (FTIR) spectroscopy methods. The results are as follows: (1) samples No. 1 and No. 2, and No. 4, No. 3, and No. 5 taken from the roots of the wooden pillars were identified as lace-bark pine wood (Pinus bungeana), poplar woods (Populus spp.), large-fruited elm wood (Ulmus macrocarpa), and spruce wood (Picea sp.), respectively on the basis of observation of anatomical structural characteristics and analysis of selection principle of “local selection” in ancient buildings. (2) The observation of polarization and fluorescence and the analysis of FTIR spectra showed that the brightness of crystalline cellulose birefringence reduced severely, and analysis of FTIR spectra showed that the absorption peaks representing cellulose and hemicellulose in the lace-bark pine and spruce wooden components disappeared or decreased. However, the polarization and fluorescence and the FTIR spectra of the poplar and elm wooden components showed that the brightness of the crystalline cellulose birefringence and the absorption peaks remained constant, as the controls did. (3) According to the results of the effects of the polarization and fluorescence effects and the FTIR spectra, we concluded that the lace-bark pine and spruce wooden components were severely attacked by brown rot fungi; in contrast, the wooden components of poplar and elm were not attacked by wood decay fungus, but were attacked by insects. These results provide scientific guidance for subsequent preventive conservation such as preservative treatment and insect prevention.Abstract
The balance among forest industry development, forest operators' well-being, and environmental conservation has been noted as an emerging concern in forest sustainability strategy. In this study, we innovatively adopted a multidimensional assessment method that integrates economic, environmental, and social dimensions to compare the comprehensive sustainability of roundwood, bamboo, tea products, and fruit industries, which are representative subtypes of the timber industry and the nontimber forest products (NTFP) industry. Additionally, our study examined whether a relationship exists between the forest industry's comprehensive sustainability and operators' proactiveness. We collected data on selected types of forest operators involved in productive loans from 115 villages in southern China between 2008 and 2020. Empirical results indicate that an increase in the comprehensive sustainability rank of the subtype forest industry led to growth in forest operators' financing amount. Specifically, the NTFP industry motivated operators' proactiveness more than did the timber industry, the effect of which was considerably greater in company group than in household group. Our findings reveal the necessity of policy interventions in developing countries to encourage the transition to optimizing forest industrial structure and sustainable forestry operations, which could initiate the socio-economic goal of sustained forest resource use and growth in forest sector output through the natural promotion effect posed by the sustainability advantages.Abstract
Low-grade yellow-poplar (Liriodendron tulipifera) graded No. 2 Common, and No. 3 Common (National Hardwood Lumber Association - NHLA rules) is mainly used by the industry to produce wood pallets. Cross-laminated timber (CLT) panels are options to diversify the usage and increase the value of this material. Therefore, the objective of this study was to produce CLT panels from a population of NHLA graded No. 2A, No. 2B, No. 3A, and No. 3B lumber and to evaluate whether the panel properties meet the bending criteria (major strength direction) and adhesive bond requirements listed for “V” type CLT in ANSI/APA PRG 320-2019 (2020) using Northeastern Lumber Association Manufacturers No. 2 and No. 3 in longitudinal and transverse layers, respectively. Ten panels were produced to evaluate the bond quality and mechanical properties. The bond test results showed average delamination under 5 percent and were more frequent in the central areas of the panel than in the outer panel areas. The results from testing showed that the calculated allowable stress-design bending-strength (major direction) value for the yellow-poplar CLT panels was 1,718 psi (11.84 MPa), which corresponds to a value 90 percent higher than V1 (900 psi, 6.20 MPa) layups. Modulus of elasticity (MOE; major direction) was comparable to V2 and V3, with an average MOE of 1.39 by 106 psi (9,584 MPa). Based on these findings, the study indicated the potential for using low-grade yellow-poplar lumber to produce CLT panels. However, more research is needed to evaluate other mechanical properties in both the major and minor axis.Abstract
To recalibrate the connection between participation in global value chains (GVCs) and carbon embodied in trade is of great importance because it provides significant insights about how China's forest products industry should integrate into GVCs and promotes the reduction of carbon embodied in trade. This paper obtains panel data related to the GVC participation of, and carbon embodied in, the trade between China and 43 of its trading partners from 2000 to 2018, and uses fixed effects and quantile regressions to explore the impact of China's participation in the value chains of its trading partners on the carbon embodied in the trade of forest products from the perspective of bilateral trade. It is found that (1) China's participation in the value chains of its trading partners significantly reduces the carbon embodied in forest product trade, especially that of pollution-intensive products (e.g., paper and its products); (2) China's participation in the value chains of high-income countries reduces the carbon embodied in forest product trade; (3) foreign direct investment (FDI) in trading partners weakly suppresses the carbon embodied in the trade of Chinese forest products; (4) the effect on the carbon embodied in the trade of Chinese forest products is only suppressive when China's degree of participation in the value chain is higher; and (5) China's forward participation in the forest product value chains of its trading partners reduces its overall carbon embodied in trade, while the backward participation has the opposite effect.Abstract
Taxol is an anticancer drug that is widely used in cancer treatment worldwide. Since the source of the drug is a plant, the increase in its production is one of the concerns of researchers. One way to increase the production of Taxol is to use stimulants for secondary metabolite production. Therefore, in this study, methyl jasmonate was used as a bioelicitor, and its effect on Taxol production was evaluated. For this purpose, Taxus baccata was elicited for 48 and 72 hours with concentrations at 0, 100, 250, and 500 μM methyl jasmonate, and the quantities of Taxol in the leaf and stem explants were measured by high-performance liquid chromatography (HPLC). The results showed that among the leaf and stem explants, a tremendous amount of Taxol production is related to the leaf, which is a great advantage in reducing the number of trees cut down to obtain Taxol. In addition, the 48-hour elicitation time demonstrated the best result in the production of Taxol. The optimal concentration of methyl jasmonate was also estimated at 500 μM and 0.326 mg/g of dried leaf biomass. The results of this experiment showed that methyl jasmonate has the potential to be used as a biological elicitor to produce considerable amounts of Taxol in Taxus baccata.Abstract
Near-infrared reflectance (NIR) spectroscopy was used to determine correlations between acoustic velocity and stiffness properties of downed pine trees in the southern coastal plains of the United States. Three acoustic measurement methods (longitudinal, transverse, and offset) were used. From the measurement of the acoustics, the time of flight (TOF) was determined from the downed trees. Increment core samples were obtained from each thirty downed pine trees in the study. NIR spectra were obtained using a fiber probe on the radial surface of each core to rapidly correlate the speed of sound, estimate the strength properties of the downed trees, and the TOF acoustic assessments. The NIR prediction was very good for the transverse and offset methods. The predictability diagnostic was above an R2 of 0.70 for both offset measurements for the transverse methods for the acoustic velocity and dynamic modulus of elasticity (MOE). The longitudinal measurement exhibited the weakest model (R2 < 0.65) for both the acoustic velocity and the MOE with the highest standard error of prediction between 3.0 (ELVLSWV) and 0.31 (VLSWV) for the three measurement types. All the standard errors of calibration were below 1% except in ELVOSWV, which was ∼2%. The dry density measured from the increment cores had a moderate correlation (R2 ∼ 60%), compared with the lower correlation (R2 ∼ 50%) by the green density in the multiple linear regression output. The results of the acoustic model indicated that NIR spectroscopy has the potential to predict the acoustic velocity and corresponding stiffness of downed trees.Abstract
Fourteen 1,220 by 2,440 by 11.1-mm commercial Oriented Strandboard (OSB) panels were X-ray scanned to obtain horizontal density matrices. Localized densities around the concentrated static load (CSL) testing points of the panels were calculated prior to the CSL test. A linear regression analysis was conducted to assess the impact of the localized density on CSL performance. The results indicated that both deflection and ultimate load were highly correlated with the local density. Deflection and ultimate load were somewhat correlated (R2 = 0.52). The CSL deflection decreased and ultimate load increased significantly with increasing local density. The impact of local density on ultimate load was greater than on deflection. Horizontal density variation is inherent in OSB manufacturing processes, especially in the mat forming process. A number of factors, including evenness of strands in the metering bin, condition of picker rolls and dissolving rolls, and strand and fines surging, can affect horizontal density distribution. OSB panels with a high degree of variation in horizontal panel density may cause low density spots that increase the chance of failure in CSL test. It is therefore crucial to minimize the occurrence of very low density areas in order to reduce the odds of ultimate load failure. Reducing density variability allows OSB companies to increase the CSL properties of their products, which would otherwise need to be done by making the panel denser. Improving horizontal density uniformity allows for lowering of the average panel density, which reduces the manufacturing cost and helps improve the company's bottom line.Abstract
Considering the high demand for housing and the ongoing environmental issues our society faces, it's crucial to opt for more ecofriendly materials for building purposes. In that scenario, engineered wood products play an important role as they are not only based on a sustainable material but also can reduce the carbon footprint from construction. Cross-laminated timber (CLT) is one of the products that could expand wood products use while keeping up with low and mid-rise building needs. Although CLT use has been expanding in the United States for the last few years, there is still a high necessity for understanding this composite behavior. One of those needs is assessing the effect of notching on the panels and measuring strength reduction as well as possible reinforcement methods. The goal of this project was to evaluate the performance of CLT panels focusing on strength and stiffness properties. Mechanical bending testing of three-ply southern pine CLT samples was performed to evaluate the influence of notches and stitching reinforcement on panels. The strength reduction caused by notching was successfully measured. Control samples supported significantly higher loads than notched samples. However, it was found that the deeper the notch, the more effective the stitching can be regarding strength. Control samples presented cross-grain tension and splintering tension failure modes, whereas notched samples presented simple tension failure mode. The findings of this work are of great value toward updating manufacturing, design, and use criteria for notched CLT panels and can be potentially used in future building codes.Abstract
This study investigated the feasibility of using wood flour (WF) as a partial substitute in polymeric methylene diphenyl diisocyanate (pMDI) resin and compared its performance with soy flour (SF) substituted in pMDI resin. The physical and mechanical properties of experimental particleboards made with WF and SF substituted in pMDI resin at different substitution percentages were evaluated. The viscosity for the WF at different substitution ratios (5%, 10%, 20%, and 30%) ranged from 314.7 to 6,256.3 cP, whereas SF-substituted resin ranged from 249.7 to 1,291.8 cP. During the production of the boards, it was observed that because of the high viscosity of WF substituted in pMDI resin above 10 percent, it was exceedingly difficult to apply it through spraying and brushing, either to wood particles or veneers. Dimensional stability test results established that the incorporation of SF assisted in mitigating board thickness swelling. The results from the study showed that panels made with SF substituted in pMDI resin at 5 and 10 percent exhibited the overall best performance in all the properties considered compared with panels made with WF substituted in pMDI resin.Abstract
The US wood pellet exports—mostly to Europe, Japan, and South Korea—comprised 85 percent of its wood pellet production in the past 20+ years. In this article, we estimate the regional excess supply of wood pellets in the United States using annual data from 1996 to 2021.We use Seemingly Unrelated Regression (SUR) analysis in a profit maximization framework for the South, North, and West regions of the United States. We also include some clean energy policies of the European Union (EU) to examine their potential impact on US wood pellet export volume. Our results show that after application of the low-carbon energy target in the EU, the export volume of the United States has increased, especially in the South region. Elasticity of excess wood pellet supply from the United States was approximately 0.15 in all three regions, and interest rates and energy costs have negative impacts on regional excess supply. Therefore, the recent increase in interest rates and energy costs could slow down the growth of excess supply of wood pellets in the United States.Abstract
In the current study, three-ply bolt-laminated southern pine (Pinus sp.) 244 by 427 cm (8 by 14 ft) mats were evaluated. Mats were destructively tested in ⅓-point bending on a universal testing machine according to ASTM International standards. Twenty-eight unique specimens were destructively tested, and mean modulus of rupture (MOR) and modulus of elasticity (MOE) were calculated. According to the results both MOR and MOE values for the specimens were highly uniform. The mean MOR was 11.74 MPa (1,704 psi) and the mean MOE was 1,144 MPa (0.166 × 106 psi). Additionally, the values of parametric and nonparametric Fb (design fiber stress in bending values ) were reported as 4.05 MPa and 4.54 MPa (588 psi and 659 psi), respectively. The mechanical properties of these three-ply pine mats were also compared with other studies of mats from other species groups and design architectures.Abstract
In this work, we used the conventional wet papermaking process and the solution casting procedure to make paper sheets and optimized the relative content of eucalyptus and Simao pine pulps using the mechanical properties of the paper sheet as the evaluation index. The chemical composition, water retention value, zeta potential, carboxyl content, and drainage behavior of the pulp created using the optimal mass ratio for each method were measured, and the resulting paper sheets were characterized via Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and nitrogen adsorption/desorption isotherms. We found that for a ratio of eucalyptus to Simao pine pulps of 94:6 using the wet papermaking process, the mechanical properties of sheets took their optimal values, and the tear, tensile, and burst indexes and the folding endurance were equal to 4.43 mN·m2·g−1, 27.47 N·m·g−1, 1.13 kPa·m2·g−1, and 11.38 times, respectively, whereas the ratio leading to the best possible mechanical performance in the solution casting process was 88:12, and the corresponding paper sheets had tear, tensile, and burst indexes and the folding endurance of 11.73 mN·m2·g−1, 23.03 N·m·g−1, 0.68 kPa·m2·g−1, and 25.50 times, respectively. The cellulose, hemicellulose, and lignin contents of the pulp treated by the solution casting method were lower by 1.88, 3.11, and 2.67 percent, respectively, compared to that obtained via the wet papermaking process. However, the water retention value, zeta potential, and carboxyl content of the pulp obtained via solution casting were higher by 50.31, 123.41, and 50.15, percent, respectively, compared to that obtained via the wet papermaking process. The drainage time obtained via the solution casting method was one-fifth of that obtained via the wet forming process. The paper sheet prepared via the solution casting method was found to exhibit weaker hydrogen bonding, a decreased level of crystallinity (26.64% lower), and an increased compactness and N2 gas adsorption capacity (19.55% and 66.7% higher, respectively) compared to the sheet obtained via the wet papermaking process. This work shows that the physical properties of the paper prepared via the two processes considered here, using their respective optimal weight ratios of the different types of pulp, have their own advantages.Abstract