bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Eco-Label Knowledge on Chinese Consumer Preferences for Certified Wood Flooring: A Case Study in Chongqing City
Authors: Tan Qin , Imamura Kohei , Nagasaka Kenji , Inoue Masafumi
Published: August 2021

Expanding the use of eco-labeled wood flooring in China is an important step in achieving the country's sustainable development goals. For a deep understanding of the relationship between the knowledge of the eco-label and consumer preferences for certified wood flooring in China, this study assessed consumers' purchase intention (PI) and price premium (PP) for Forest Stewardship Council (FSC)- and China Environmental Labeling (CEL)-labeled wood flooring versus nonlabeled wood flooring. A total of 367 face-to-face interviews were conducted at building material markets in Chongqing City with visitors planning to purchase wood flooring in March 2018. The results showed, first, that 21 percent of respondents knew the FSC label, and 65 percent of respondents intended to buy FSC-labeled wood flooring with a PP of 41 CNY/m2. Second, 46 percent of respondents knew the CEL label, and 81 percent of respondents intended to buy CEL-labeled wood flooring with a PP of 48 CNY/m2. Third, the knowledge of the FSC label positively affected consumers' PI and PP, but the knowledge of the CEL label only influenced PI for certified wood flooring. This study showed that the eco-label knowledge played a main role in consumer preferences for certified wood products and suggested that different strategies should be considered in promoting FSC- and CEL-labeled wood products in the Chongqing market.
Current Practices in Log Yard Design and Operations in the Province of Quebec, Canada
Authors: Trzcianowska Marta , Beaudoin Daniel , LeBel Luc
Published: August 2021

Log yards play an important role in the forest supply chain by connecting raw material supply to manufacturing processes. Log yard design and operations have not been thoroughly represented in the scientific literature, though research in other industrial sectors has demonstrated the strategic operational importance of warehouses. This article investigates the log yard design and operations in current industrial practices.

An analysis of existing log yards was conducted in Quebec. Detailed information about throughput, equipment, personnel, inventory management, and design considerations was gathered by means of questionnaires, on-site visits, and meetings with yard managers.

The survey of current practices (design, management, and operations) confirms that most existing yards have been designed without a systematic method. Crucial performance inhibitors included log yard shape, in-flow management, and poor surface material. Results point toward a potential gain in competitiveness by improving log yard practices, optimizing log yard shape and layout, better coordinating the forest–mill operations, and enhancing surface material.
Forestry's Economic Contribution in the United States, 2016
Authors: Pelkki Matthew , Sherman Gabrielle
Published: August 2021

Economic contributions of an industry sector are often vital information in the policy-making process. IMPLAN data and software were used to determine the economic contribution of forest industries to all 50 states plus Washington, D.C. Rankings of the states' contributions to employment, employee compensation, and value added were determined. National forest inventory data, rural population, and industrial energy costs were examined for correlation with total forestry contributions to each state's economies. Rankings were based on absolute contributions as well as contributions as a percentage of a state's total economy. Percentage rankings present the relative importance of forestry to a state's economy, and can differ considerably from absolute value rankings. Regional and national contributions were also calculated to model interstate and regional contribution “leakages,” or trade effects. Differences in both interstate and interregional trade flows are substantial. Industrial energy costs, rural population, and timber removals were significantly correlated with total economic contributions.
Financial Assessment of Future Stand Conditions Required to Recover the Opportunity Costs of a North Louisiana Streamside Management Zone
Authors: McConnell T. Eric , Crosby Michael K. , Holderieath Jason J. , VanderSchaaf Curtis L.
Published: August 2021

Understanding the costs that residual habitat spaces carry into future rotations can provide managers more complete information when financially assessing timber management options that often extend for many decades. This case study assessed a streamside management zone's (SMZ) opportunity costs for a timber harvest site in north Louisiana. Timber removal occurred in summer 2018 by clearcut. A wooded buffer extending 50 feet on each side of a streambank and totaling 7.52 acres was retained; partial harvesting of pine timber was allowed. A timber inventory revealed that 99.6 tons per acre of standing hardwoods resided within the SMZ. Excluding noncommercial species placed its current present value (opportunity cost) at $1,803. Two future active management scenarios, “controlled” and “intensive,” were modeled over the next rotation at a 4 percent real discount rate, where price changes occurred at 0, 1, 2, 3, and 4 percent annually. Both management strategies consistently produced positive land expectation values (LEV) when SMZ opportunity costs were not included in the assessment. However, inclusion of SMZ protection under “controlled” management required timber price changes of 4 percent annually, while the “intensive” management option required timber price changes of at least 3 percent annually to return positive LEVs.
Carbon Sequestration Due to Commercial Forestry: An Equilibrium Analysis
Authors: Loehle Craig
Published: August 2021

Carbon sequestration is one of the tools being used to respond to climate change risks. It is known that carbon stored in wood products is a type of sequestration. However, time frames for evaluating wood use can affect conclusions about sequestration benefits; a long-term perspective and large spatial scale may help clarify these issues. Therefore, I undertook an equilibrium analysis of ongoing commercial forestry operations, relative to carbon sequestration, at the landscape scale. I found that for simple exponential decay functions for wood remaining in use over time, the total sequestered wood at equilibrium is simply the integral of the decay function multiplied by wood product produced. I show that this simple multiplier is a linear function of half-life. For a 50-year wood half-life, this equilibrium multiplier is 72.1. The half-life depends on the specific wood product (lumber, etc.). For waste wood used for energy at mills, typical values yielded a 100-year sequestration (avoided emissions) value of 12H where H is tons of carbon in logs delivered to the mill. This exercise demonstrates that commercial forestry is a significant provider of carbon sequestration through wood products, in addition to other sequestration benefits. The simple multipliers developed here are intuitive and can be easily used with operational wood product data at any scale.
Nano–Titanium Dioxide Coating of Chinese Fir Treated by High-Temperature Steam to Improve the Anticorrosion and Surface Hydrophobicity
Authors: Cui Hao , Li Qingde
Published: August 2021

The organic material of wood treated with inorganic nanoparticles has gained significant improvements in its stability against ultraviolet (UV) light and moisture degradation. Here, a new method was proposed to modify Chinese fir (Cunninghamia lancellata), which was treated by high-temperature steam and coated with titanium dioxide (TiO2) nanoparticles. Due to the synergistic effect, the treated Chinese fir can obtain the properties of surface hydrophobicity and photoaging resistance that can prevent the invasion of moisture and the damage of UV light from sunlight. Scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction were used to characterize the morphology, structure, chemical composition, hydrophobicity, and light-aging resistance of the treated Chinese fir. By means of comparative experiments, the Chinese fir was treated with 5 percent nano-TiO2 solution and annealed at 300°C. The surface water contact angle reached to about 130°, indicating the strong hydrophobicity. In addition, the total color difference (ΔE*) after accelerated light aging for 120 hours was only 45 percent of the control sample.
Addition of Polyurethane Foam Waste to Polymeric Diphenyl Methane Diisocyanate to Improve Plywood Binder Performance
Authors: Li Qi , Pang Yanfang , Liu Xiaosheng , Xi Enhua , Mao An , Wan Hui
Published: August 2021

The objective of this study was to investigate the feasibility of using polyurethane (PU) foam waste obtained from automobile shredder residue (ASR) in plywood production. The PU foam waste from ASR was cleaned by water and acetone, ground into powder, dried, and mixed with polymeric diphenyl methane diisocyanate (pMDI) resin at various ratios (2.5%, 5%, 7.5%, and 10%, based on the weight of pMDI). The mixed adhesives were examined with Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric (TG) analysis, and evaluated as plywood binders (measured in accordance with Chinese National Standard GB/T 17657-2013). The results indicated that the addition of PU powder into pMDI resin increased adhesive viscosity and efficiency, and also helped solve the problem of deficiency of pMDI on the veneer surface. FTIR results showed various reactions between pMDI and PU powder. This potential cross-linking might contribute to the cohesive strength of the cured adhesive. TG analysis results showed the possible increased thermal stability of the cured mixed adhesive at a temperature range of 150°C to 300°C. The best PU addition ratio was 7.5 percent of the pMDI weight, considering both the bond strength and production practice of plywood. Plywood testing showed that both the dry and wet bond strength reached the peak value at the optimal mixing ratio. The use of PU powder in plywood manufacturing provided a possible way of recycling PU foam waste while improving or maintaining the performance of plywood.
Statistical Process Control and Related Methods for Improvement of the Treated-Wood Industries
Authors: Young Timothy M. , Lebow Patricia K. , Lebow Stan , Taylor Adam
Published: August 2021

An approach for implementing statistical process control and other statistical methods as a cost-savings measure in the treated-wood industries is outlined. The purpose of the study is to use industry data to improve understanding of the application of continuous improvement methods. Variation in wood treatment is a cost when higher-than-necessary chemical retention targets are required to meet specifications. The data for this study were obtained in confidence from the American Lumber Standard Committee and were paired, normalized assay retentions for charges inspected by both the treating facility and auditing agencies. Capability analyses were developed from this data for three use categories established by the American Wood Protection Association (AWPA), including UC3B (above ground, exterior), UC4A (ground contact, freshwater, general use), and UC4B (ground contact, freshwater, critical structures, or high decay hazard zones). Agency and industry data indicate that between 4.45 and 9.82 percent of the charges were below the lower confidence limit of the passing standard (LCLAWPA), depending on use category. A Taguchi loss function (TLF), which is quadratic based and decomposes the monetary loss into shift and variation components, was developed to estimate the additional cost due to process variation. For example, if a treatment input cost of $1.00/ft3 is assumed for UC3B, reducing the variation in total retention allows lowering treatment targets, e.g., 1.45 to 1.38, reducing costs to $0.76/ft3. The study provides some important continuous improvement tools for this industry such as control charts, Cpk, Cpm capability indices, and the one-sided TLF.
Morphological Characterization of Wax and Surfactant–Encapsulated Microcrystalline Cellulose for Better Dispersion
Authors: Cheng Qingzheng , Zhou Chengfeng , Pan Yuanfeng , Via Brian
Published: August 2021

Encapsulation of cellulose with wax and surfactant is a physical way to restrict cellulose-to-cellulose attraction. Because wax is often used in the wood composite process, industrial manufacturers would not have to upgrade or add expensive equipment to handle cellulose addition. The encapsulated cellulose particles could easily be transported to composite and polymer facilities and blended in a homogeneous fashion for a multitude of products and composites. It was the objective of this study to utilize differential interference contrast (DIC) microscopy to characterize the wax and surfactant coverage and encapsulation morphology of the wax–surfactant–cellulose composite. The lengths and widths of the cellulose particles were significantly changed after encapsulation. DIC microscopy found that we could fine-tune wax coverage to control homogeneity and reduce fiber bundling during dispersion. It was found that surfactants were not necessary to enhance coverage if a 1:4 ratio of wax to microcrystalline cellulose was used. However, if more wax is desired, then surfactants may be necessary to suppress fiber bundles during dispersion.
Wood Density, Anatomical Characteristics, and Chemical Components of Alnus sibirica Used for Industrial Applications
Authors: Zhao Xiping , Guo Pingping , Zhang Zhaolin , Yang Yongqiang , Zhao Penghui
Published: August 2021

In this study, wood density, anatomical characteristics, and major chemical components were investigated on branchwood, trunkwood, and rootwood of three Alnus sibirica trees grown in Maoershan Mountain, Northeast China. The anatomical structure and composition of xylem within a tree were spatially heterogeneous. At the alpha = 0.05 level, the differences among branchwood, rootwood, and trunkwood were significant in wood density, cell dimensions, extractives, and ash content. The trunkwood was desired as papermaking raw material and structural timber because of its high-quality fibers, cellulose content, and medium density value. Because of its similar density to trunkwood, large-sized branchwood could be used as a substitute for structural materials. The rootwood with low densities and large vessel dimensions was suitable for producing short fiber biocomposite.
Effects of Sanding Process on Adhesion of Waterborne Paint Film on a Polypropylene Membrane Surface
Authors: Peng Xiaorui , Zhang Zhankuan , Zhang Ran
Published: August 2021

In this article, the surfaces of 2D and 3D polypropylene (PP) membranes were sanded with different brush-type sanding belts and a waterborne primer and topcoat were applied; the effect of the sanding process on the adhesion of the waterborne paint film on a PP decorative membrane surface was tested. A contact angle meter was used to determine the effect of the sanding process on the hydrophilicity of a PP decorative membrane surface. A scanning electron microscope and a roughness tester were used separately to observe the changes in the surface microfeatures and the roughness on PP decorative membranes before and after the sanding process. A 3D profilometer was used to test the changes in the surface roughness and 3D microtopography on PP decorative membranes before and after the sanding process, and a crosscut tester was used to test the changes in the surface adhesion of waterborne paint film on PP decorative membranes before and after the sanding process so as to research the effects of different sanding parameters on the adhesion of waterborne paint films on PP decorative membrane surfaces. The research results showed that the surface sanding process could be used to decrease the surface contact angle, increase the roughness, and improve the wettability of PP decorative membranes. In general, under experimental conditions, a 400-grit sanding belt and two sanding passes were the suitable parameters for 2D PP decorative membranes, and a 320-grit sanding belt and two sanding passes were suitable for 3D PP decorative membranes.
Can Efficiency Gains in the Wood Processing Industry Conserve Forests in Developing Countries? The Case of Andhra Pradesh
Authors: Schons Stella Z. , Gudimenda Haripriya , Amacher Gregory S. , Cobourn Kelly M. , Wynne Randolph H. , Thomas Valerie A.
Published: August 2021

Growing world demand for processed goods made from wood and a large supply of native timber in tropical regions combined with development incentives from national governments have driven rapid growth in the forest products industry in many developing countries. Contract farming schemes have emerged as an important mechanism to ensure an adequate supply of raw timber for processing. These contracts also encourage secondary forest establishment, which is argued to reduce harvesting pressure on ecologically valuable native forests. We explore whether there exists a potential for efficiency gains within the forest products industry given the current installed capacity in the state of Andhra Pradesh, India. We estimate a stochastic production frontier function for this industry based on Annual Survey of Industries data from 2010 to 2013. We present evidence that there is space for efficiency gains and that the marginal value product of wood as a raw input is high enough to justify the engagement of companies and farmers in wood supply agreements as a means to reduce pressure on native forests.
Development of a Renewable Hybrid Resin System by Blending Isocyanate with Novolac Phenolic Resins
Authors: Li Qi , Liu Xiaosheng , Su Huidong , Mao An , Wan Hui
Published: August 2021

The objective of this study was to develop a performance-competitive bio-based hybrid resin system composed of methylene diphenyl diisocyanate (MDI) resin and novolac phenol-formaldehyde (PF) resin for engineered wood panel manufacturing. A novolac PF resin and a bio-oil–modified PF resin were blended with MDI at weight ratios of PF to MDI of 85:15, 75:25, 50:50, and 25:75, respectively. The obtained hybrid resins were examined with Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA), and evaluated as plywood binders. The results indicated that the gel times and viscosities of hybrid resins were closely related to the weight ratio of PF resin to MDI. At a ratio lower than 75:25, the viscosities of hybrid resins were appropriate for plywood application. FTIR results showed some reactions between the novolac PF resin and MDI. TGA results showed that reacting novolac PF resin with MDI resin possibly increased the thermal stabilities of hybrid resins in the temperature range of 150°C to 300°C. Panel performance tests showed that blending novolac PF resin with MDI increased both the dry and the wet bonding strength of panels at the optimal ratio of 50:50. Replacing phenol with bio-oil of the hybrid resin had the trend of reducing the hybrid resin gel time and increasing panel dry and wet bonding strength.
Properties of Aging Pentachlorophenol-Treated Douglas-Fir Crossarms
Authors: Schauwecker Christoph , Clauson Milo , Konkler Matthew J. , Sinha Arijit , Morrell Jeffrey J.
Published: August 2021

Wooden crossarms play a major role in supporting electric distribution lines in North America, but relatively few data exist on their condition as they age. The residual capacity of Douglas-fir crossarms in service in western Oregon for 45 to 60 years was investigated. Arms were sampled for residual preservative retention, the presence of visible decay fungi, and residual flexural properties; these results were then compared with three nondestructive tools. A majority of the arms tested had preservative levels well below those required for new arms, but only one decay fungus was isolated, and only five arms removed and dissected had any evidence of visible internal decay. Moduli of rupture for the arms were generally below the minimum levels required by national standards, but most still retained at least 67 percent of this value. Nondestructive evaluation tools were generally poorly correlated with flexural properties, possibly because of the heavily weathered and checked exterior condition.
Improving Performance of Phenol-Formaldehyde Resins Modified/Blended with Phenol-Rich Pyrolysis Bio-Oil
Authors: Li Qi , Liu Xiaosheng , Su Huidong , Mao An , Wan Hui
Published: August 2021

In this study, we compare the panel performance of plywood made with phenol-formaldehyde (PF) resins modified and blended with phenol-rich bio-oil produced from pyrolysis of biomass. The modified PF resins were synthesized with phenol-rich bio-oil at phenol substitutions of 10, 25, 50, and 75 percent. The blended PF resins were prepared by blending control PF resin with phenol-rich bio-oil at 4, 13, 23, and 38 percent by weight. These resins were examined with Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) and evaluated as plywood binders. The results indicated that the apparent viscosities of modified PF resins were similar to those of control PF resin, while the apparent viscosities of blended PF resins increased with the addition of phenol-rich bio-oil. As the amount of phenol-rich bio-oil increased, the gel times of both modified and blended PF resins decreased first and then increased. FTIR results showed that modified PF resins with up to 25 percent substitution had FTIR spectra similar to those of control PF resin, while blended PF resins with a higher amount of added bio-oil had spectra more like those of bio-oil. TGA results showed that at temperatures of 25°C to 400°C, both modified and blended PF resins with high bio-oil content had better thermal stability than the control PF resin. Panel tests showed that modifying or synthesizing PF resin with phenol-rich bio-oil up to 50 percent increased both dry and wet bond strength. Blending PF resin with phenol-rich bio-oil up to 13 percent increased both dry and wet bond strength compared with control PF resin.
Lateral Load Performance of Panelized Wood I-Joist Floor Systems
Authors: Zhang Sigong , Chui Ying Hei , Joo David
Published: August 2021

Panelized light wood frame construction is becoming more popular due to the faster construction time and shortage of onsite skilled labor. To use light wood frame panels effectively in panelized floor systems, panel-to-panel joints must be fastened adequately to allow load transfer between panels. They must also possess in-plane shear strength and stiffness comparable to stick-built, staggered-sheathed assemblies. This study was designed to develop efficient and effective panel-to-panel joints for connecting adjacent floor panels built with wood I-joists and evaluate the efficiency of the joints in achieving diaphragm action. At first, a number of these panel-to-panel joints were tested in the laboratory using a small-scale diaphragm test setup to determine their efficiency in transferring in-plane forces between panels. Test results showed that a small decrease in in-plane stiffness was expected for the most effective joints, but their strengths were significantly higher than at the same location in a conventional site-built floor diaphragm. The presence of blockings and use of two-row nailing were found to considerably improve stiffness and strength. These features can be used to mitigate the potential reduction in mechanical performance of panelized floor construction, in comparison with the site-built wood I-joist floor.
A Comparison between Architects' and Residents' Perceived Living Quality in Wooden Multifamily Houses in Sweden
Authors: Lindblad Fredrik , Gustavsson Åsa
Published: August 2021

There is currently great interest in the production of wooden multifamily houses in Sweden, due to increased environmental concern combined with a demand for modern building solutions. The focus in industry and academia alike has been dominated by new innovative building solutions along with increased industrialization of the building process, aiming to improve the overall building quality and the profitability for the involved actors. However, little attention has been paid to what the residents perceive as living quality. Understanding residents' perceived living quality—compared with architects' perceptions—allows the possibility of adjusting the modern building solution of wooden multifamily houses in order to meet residents' actual expectations and, in the long term, to increase the wood-building industries' market share.

The purpose of this article is to compare how residents and architects perceive living quality and whether these stakeholders' perceptions differ regarding building type and material choice (i.e., multifamily wooden or concrete buildings). A survey was sent out to 485 respondents in Sweden to gain insight into living quality perceptions. The results revealed discrepancies in what is perceived to be important in new housing development, although neither group was willing to pay more to live in a wooden building compared with a concrete building.
Analysis of Forklift and Pallet Jack Injuries in Wood-Related Industries
Authors: Michael Judd , Gorucu Serap
Published: August 2021

Many wood-based businesses rely on forklifts and pallet jacks to load, unload, or move product around facilities. The use of forklifts or other powered industrial trucks (PITs) to facilitate movement and storage of goods is expected to grow steadily over the next 10 years. Unfortunately, forklifts are known to be a common source of occupational injuries and fatalities. The purpose of this article is to examine severe injuries related to the use of forklifts and pallet movers in various segments of the wood-related industries. We used data from an Occupational Safety and Health Administration (OSHA) database to investigate all severe injuries related to forklifts or pallet jacks in the 5 years from 2015 to 2019. Our focus was on various wood products and paper manufacturers, as well as wood building material dealers and wholesalers; this provides a broad overview of the hazards associated with forklifts and pallet trucks across the spectrum of wood-related businesses. Results show there were 17 fatalities and 211 severe injuries during the 5-year period. Building material dealers saw the highest number of injuries, followed by a wood manufacturing segment. Fractures were the most prevalent type of injury, with the lower extremities being the most vulnerable to serious injury. The most prevalent injury event type was pedestrians hit by a forklift or other PIT. Improper use of PITs is a regular source of OSHA fines for wood-based businesses. Implications are drawn for businesses that use forklifts and pallet jacks to reduce the likelihood of injuries from this type of equipment.
Design of a Total Revenue Forecasting Tool to Estimate the Economic Output of Hardwood Logs
Authors: González Juan J. , Quesada Henry , Adhikari Sailesh , Bond Brian , Grushecky Shawn
Published: August 2021

This article introduces a total revenue forecasting tool designed for calculating the economic output of visually graded hardwood lumber. The tool integrates Monte Carlo simulation from previous studies' data, providing a pseudoestimation of total board-feet based on log grades. The lumber output from different log groups is modeled using probability distributions for each lumber grade. The estimated volume output is multiplied by the respective price for each grade, leading to an expected amount of economic output for given log-grades. The tool was implemented using Microsoft Excel 2016 and Visual Basic. This work provides hardwood lumber producers with a valuable and simple tool to determine different scenarios of total income from each log, as established by the user with a statistical perspective. This total revenue forecasting tool provides the industry with a way to reduce waste and estimate their potential revenue by maximizing the interaction between the log yield's variables and providing the economic output of log, leading to an improvement of the economy of the hardwood market.
Differential Expression of a Putative Copper Homeostasis CutC Gene in Fibroporia radiculosa During Initial Decay of Copper-Treated Wood
Authors: Ohno Katie M. , Bishell Amy B. , Stanosz Glen R.
Published: August 2021

Living organisms require copper for several cellular processes. Yet intracellular concentrations of copper must be regulated to avoid toxicity. Not much is known about mechanisms of copper regulation in wood decay fungi. However, one putative annotation for a copper homeostasis CutC gene (FIBRA_00129), found in other brown-rot wood decay fungi, has been annotated in Fibroporia radiculosa. The aim of this study was to evaluate wood mass loss and differential expression of FIBRA_00129 during initial decay of untreated and copper-treated wood by two copper-tolerant F. radiculosa isolates (FP-90848-T and L-9414-SP) compared with copper-sensitive Gloeophyllum trabeum. Untreated southern pine (Pinus spp.) and ammoniacal copper citrate treated southern pine at three concentrations (0.6%, 1.2%, and 2.4%) were used in a 4-week-long standard decay test. Results showed G. trabeum was unable to decay copper-treated wood while both F. radiculosa isolates successfully decayed southern pine at all copper concentrations. G. trabeum and F. radiculosa L-9414-SP showed no detectable FIBRA_00129 expression over the course of this study. F. radiculosa FP-90848-T showed greater FIBRA_00129 downregulation on copper-treated wood than on untreated wood (P = 0.003). Additionally, there was greater FIBRA_00129 downregulation in F. radiculosa FP-90848-T at week 3 compared with other weeks (P = 0.015). Future studies are needed to further evaluate FIBRA_00129 during the decay process to determine its potential role in copper-tolerance.
A Study on the Coupling Coordination between Forestry Production Efficiency and Regional Economic Development in China
Authors: Gao Dandan , Li Shunlong
Published: August 2021

Forestry production is one of the fundamental industries of the national economy, and enhancing production efficiency can aid in balancing the contradiction between the economic growth of forestry and forest resource conservation. Therefore, studying the coupling coordination between forestry production efficiency and regional economic development is of great practical significance for obtaining the development philosophy of green and circular economies and implementing supply-side structural reform in forestry. In this study, the forestry production efficiencies and economic development levels of 31 provincial-level administrative regions of China during 2009 to 2018 are estimated using the super efficiency slacks-based measure model and the entropy weight method. Additionally, the coupling coordination and development trends of forestry production efficiencies and regional economic development levels are investigated by means of the coupling coordination model and GM (1,1) model. Research findings suggest that forestry production efficiencies and economic development levels of 31 provincial-level administrative regions in China maintained steadily growing trends during 2009 to 2018; however, there was middle to low-level coupling coordination between regions. Such coupling coordination remains to be improved because it indicated a spatial pattern of high in the east and south and low in the west and north. To conclude, some suggestions for promoting sound and coordinated interactions between forestry production efficiency and regional economic development are offered.
Comparison of Building Construction and Life-Cycle Cost for a High-Rise Mass Timber Building with its Concrete Alternative
Authors: Gu Hongmei , Liang Shaobo , Bergman Richard
Published: August 2021

Mass timber building materials such as cross-laminated timber (CLT) have captured attention in mid- to high-rise building designs because of their potential environmental benefits. The recently updated multistory building code also enables greater utilization of these wood building materials. The cost-effectiveness of mass timber buildings is also undergoing substantial analysis. Given the relatively new presence of CLT in United States, high front-end construction costs are expected. This study presents the life-cycle cost (LCC) for a 12-story, 8,360-m2 mass timber building to be built in Portland, Oregon. The goal was to assess its total life-cycle cost (TLCC) relative to a functionally equivalent reinforced-concrete building design using our in-house-developed LCC tool. Based on commercial construction cost data from the RSMeans database, a mass timber building design is estimated to have 26 percent higher front-end costs than its concrete alternative. Front-end construction costs dominated the TLCC for both buildings. However, a decrease of 2.4 percent TLCC relative to concrete building was observed because of the estimated longer lifespan and higher end-of-life salvage value for the mass timber building. The end-of-life savings from demolition cost or salvage values in mass timber building could offset some initial construction costs. There are minimal historical construction cost data and lack of operational cost data for mass timber buildings; therefore, more studies and data are needed to make the generalization of these results. However, a solid methodology for mass timber building LCC was developed and applied to demonstrate several cost scenarios for mass timber building benefits or disadvantages.
Effects of Drying Temperatures on the Occurrence of Sticker Stain in Japanese Cedar (Cryptomeria japonica D. Don)
Authors: Toba Keisuke , Kanbayashi Toru , Murano Tomoya
Published: August 2021

Sticker stain is a material defect that results from moisture migration during wood drying, often spoiling the appearance of the surface of wood products. The effect of drying temperatures on the occurrence of surface sticker stain was investigated using Japanese cedar (Cryptomeria japonica D. Don) and three types of stickers (air-dried Japanese cedar, aluminum, and stainless steel) under four drying temperatures (20°C, 50°C, 75°C, and 100°C). At lower drying temperatures, the air-dried wood sticker tended to suppress the occurrence of surface sticker stains, whereas higher temperature or metal stickers produced sticker stains with deep color. However, no definitive relation was shown between the initial moisture content and the extent of sticker stain with deep color regardless of drying temperatures. It was considered that the partial delay of drying happened around the contact area with stickers, especially in cases of metal stickers. It was also found that the use of metal stickers at higher drying temperatures induced depressions in Fourier transform infrared spectra related to the occurrence of hygrothermal conditions.
Hardwood Log Grading in the United States—Part III: An Assessment of the Current Status of Log Grading in the Hardwood Industry
Authors: Hassler Curt C. , Thompson Jordan R. , McNeel Joseph F.
Published: August 2021

This article documents how the hardwood industry, in the absence of a standardized, industry-wide log grading system, has gone about grading and scaling hardwood logs by surveying mills, primarily in the Appalachian region. In total, 135 surveys were completed by respondents and returned via mail, with only 110 of those surveys considered usable for further analysis, after a thorough review of the individual surveys. Survey responses were grouped around annual production level, with three defined levels; ≤2.5 million board feet (MMBF), >2.5 and ≤8.0 MMBF, and >8.0 MMBF. Responding mills used some variation of a log grading system based on the number of clear faces on the log and the small end diameter of the log. The most common log rule used by mills in this study was the Doyle log rule, with over 75 percent using Doyle for scaling logs. Nearly 90 percent of all mills sampled graded logs without rolling the log to examine all four sides/faces. Half of all the sawmills surveyed pay the same price per thousand board feet (MBF) for butt logs and uppers. When asked if they would support the development of a standard log grading system, about two-thirds of the respondents (66%) indicated they would indeed support a standardized system for Appalachian hardwoods. These findings can help guide the development of a set of log grading standards for buyers and sellers in the Appalachian region and other parts of the world where hardwood lumber is produced.
Span Rating of Solid-Sawn Deck Boards
Authors: Broers Madison A. , Bender Donald A.
Published: August 2021

Deck boards are key components in outdoor decks and balconies. The deck board market is shared primarily between solid-sawn and composite products. The focus of this article is solid-sawn wood deck boards, which are manufactured in North America as span-rated products following a policy promulgated by the American Lumber Standard Committee (ALSC). The latest revision of the ALSC span rating policy was approved in November 2020, and this article describes the technical basis for the changes. Distributed and concentrated design loads specified in the policy exceed building code minimum requirements. In addition, dynamic load amplification due to deck occupants is included in the new policy. Testing was performed to characterize the effects of partial fixity at joist supports caused by screw fasteners and was incorporated into the span rating methodology.
Regional Analysis of U.S. Lumber Exports for Important Hardwood Species from 1990 to 2020
Authors: Luppold William , Bumgardner Matthew
Published: August 2021

In 1990, Europe, North America, and the Asian democracies of Japan, Taiwan, and South Korea (JTK) were the major export markets for U.S. hardwood lumber and oak species accounted for 59 percent of total exports. In the 1990s, shipments to Europe and North America increased, while shipments to JTK declined. During the early 2000s, exports to China and Vietnam (CHV) increased. The worldwide recession of 2009 caused exports to decline in all regions, and oak species accounted for 37 percent of total shipments that year. Since 2010, CHV has become the most important export market for all species except maple. In 2020, oak species accounted for 43 percent of total export volume, and walnut ranked third in value of shipments. An examination of imputed prices found that exports tend to be composed of mid- to higher-quality hardwood lumber. Since 1997, real prices of exported lumber have declined for most species, and this decline occurred concurrently with increased U.S. sawtimber volume. In the 1990s, increased exports expanded the market for domestically produced hardwood lumber. Since the early 2000s, increased lumber exports have partially countered reduced domestic demand and have acted as a hedge against greater declines in overall demand for U.S. hardwood lumber.
Forest to Mill Timber Price Trends and Volatility for Mississippi Timber Products
Authors: McConnell T. Eric , da Silva Bruno Kanieski , Sun Changyou , Tanger Shaun M.
Published: August 2021

We examined timber price trends along the Mississippi roundwood supply chain. Quarterly statewide data from Timber Mart-South for pine sawtimber, pine pulpwood, mixed hardwood sawtimber, and pulpwood were obtained covering 1992 to 2018. Prices for stumpage, delivered logs, and timber conversion—measured as the difference between delivered wood and stumpage—were analyzed across products for the 27-year series, as well as three equally spaced 9-year periods (Period 1, 1992 to 2000; Period 2, 2001 to 2009; Period 3, 2010 to 2018). Flat delivered wood prices, increased rates for timber conversion, and declining pine sawtimber and pulpwood stumpage prices were revealed over the long term. Hardwood product prices, however, increased across their supply chains. Prices have generally become less volatile, particularly from Period 2 to Period 3, indicating an increasing degree of price homogeneity within each product's market. The exception to this was pine sawtimber, suggesting resource, locational, and/or market differences may have emerged for this product. The hardwood price trends supported, as appropriate, considering silvicultural options to allow this resource's continued growth. Declining price expectations for pine products call into question any strictly financial rationale for extending rotation length.
Flexibility and freedom for whom? Precarity, freedom and flexibility in on-demand food delivery
Authors: Cano Melissa Renau , Espelt Ricard , Morell Mayo Fuster
Published: August 2021

On-demand delivery platforms appropriate ‘freedom’ and ‘flexibility’ discourses with claims such as ‘be your own boss’ and ‘work as much as you want to’. During the COVID-19 pandemic, Deliveroo updated its courier platform application with a ‘free login system’ in Barcelona whereby platform couriers could connect to the platform whenever, wherever, and as often as they wanted to. In this paper, we ask why the introduction of a ‘free login’ system generated even more precarious forms of work, by comparing workforce management systems both before and during the COVID-19 period. We argue that the reason it becomes problematic is rooted in Deliveroo's business model, which is characterised by hiring on-demand, using a piece-rate payment and exercising hard workforce control through algorithmic management.
At a crossroads: Uber and the ambiguities of the COVID-19 emergency in Lisbon
Authors: Allegretti Giovanni , Holz Sheila , Rodrigues Nuno
Published: August 2021

The emergence of the COVID-19 pandemic has brought to the surface some problems and trends within digital platforms, including working conditions, while simultaneously transforming the relationship between platform capitalism and the pandemic complex. Through the case analysis of Uber in Lisbon, we were able to identify a situation where several ambiguities emerged, some of which are associated with the Portuguese singularity of intermediary platform capitalism. From this analysis, anchored to several interviews with Uber drivers/partners, we observed that the pandemic crisis has aggravated some inequalities and problems generally associated with platform capitalism, but also seen new trends and solutions emerge for a political and socio-economic reformulation of this sector.
Smart working is not so smart: Always-on lives and the dark side of platformisation
Authors: Risi Elisabetta , Pronzato Riccardo
Published: August 2021

This article investigates the lived experiences of remote workers during the Italian lockdown, and the role of digital platforms in their working and everyday life activities, as well as the consequences of home confinement measures on personal and working conditions. Drawing on 20 in-depth semi-structured interviews, the paper's findings suggest that, following a massive extension of transmedia work, remote workers experienced a ‘fractured’ and ‘always-on’ life. During the lockdown, the ever more pervasive role of digital media favoured the convergence of different spaces and times into the home, the erosion of the distinction between private and professional life and the exacerbation of previous social inequalities, especially inequalities in relation to gender and digital access. In this scenario, platform and surveillance capitalist logics were further reinforced, while ‘presence bleed’ in the experiences of workers increased.
Analysis of Mie resonances using the Debye series
Authors: Laven Philip
Published: August 2021

Scattering of light from homogeneous spherical particles can exhibit sharp resonances as functions of particle size, wavelength, or refractive index. Such resonances, usually known as morphology-dependent resonances or whispering gallery modes, have been exhaustively studied using Mie theory. This paper demonstrates that the Debye series expansion provides a succinct and easily understood representation of these resonances: For example, the Debye coefficient

R
n

121

determines (a) the exact conditions for resonance, (b) the number of terms required to replicate the Mie result, and (c) the

Q

-factor of the resonance.
Spectrally-tunable femtosecond single-molecule pump-probe spectroscopy
Authors: Moya Raymundo , Kondo Toru , Norris Audrey C. , Schlau-Cohen Gabriela S.
Published: August 2021

Single-molecule spectroscopy has been extensively used to investigate heterogeneity in static and dynamic behaviors on millisecond and second timescales. More recently, single-molecule pump-probe spectroscopy emerged as a method to access heterogeneity on the femtosecond and picosecond timescales. Here, we develop a single-molecule pump-probe apparatus that is easily tunable across the visible region and demonstrate its utility on the widely-used fluorescent dye, Atto647N. A spectrally-independent, bimodal distribution of energetic relaxation time constants is found, where one peak corresponds to electronic dephasing (∼ 100 fs) and the other to intravibrational relaxation (∼ 300 fs). The bimodal nature indicates that relaxation within each individual molecule is dominated by only one of these processes. Both peaks of the distribution are narrow, suggesting little heterogeneity is present for either process. As illustrated here, spectrally-tunable single-molecule pump-probe spectroscopy will enable investigation of the heterogeneity in a wide range of biological and material systems.
DSP-free remote antenna unit in a coherent radio over fiber mobile fronthaul for 5G mm-wave mobile communication
Authors: Song Haiping , Cheng Wen , Dai Longquan , Huang Chuanming , Yang Yu , Liu Ziqi , Xiong Xuan , Cheng Mengfan , Yang Qi , Liu Deming , Deng Lei
Published: August 2021

We propose a novel coherent analog radio over fiber (A-RoF) scheme to realize the generation, separation, and detection of four-independent mm-wave signals with the same carrier frequency on a single-wavelength for 5th generation (5G) mobile communication, and no digital signal processing (DSP) algorithms are required in remote antenna unit (RAU). In baseband unit (BBU), four-independent mm-wave signals are modulated on the two orthogonal polarization states of a single wavelength based on a dual-polarization IQ modulator using the dual single-sideband (SSB) modulation and polarization division multiplexing (PDM) technique. In RAU, a novel carrier polarization rotation module based on the self-polarization stabilization technique is proposed, and thus the four-independent mm-wave signals can be detected by self-coherent detection. Besides, the power fading effect induced by the chromatic dispersion could be overcome thanks to the optical SSB modulation, contributing to the increased coverage. By these means, no DSP algorithms are required in RAU, and the latency of signal processing could be significantly reduced. The experimental results show our proposed scheme could support 38.4 Gbps 16-ary quadrature amplitude modulation (16QAM) signals at 14 GHz over 30 km standard single-mode fiber (SSMF) transmission without DSP, satisfying 3rd Generation Partnership Project (3GPP) requirements. Besides, the measured error vector magnitude (EVM) value of 800 MBaud 16QAM signals at 28 GHz over 50 km SSMF transmission is 12.99%. This research provides a potential solution for the 5G mobile fronthaul.
Channel prediction for intelligent FSO transmission system
Authors: Song Song , Liu Yejun , Xu Tianming , Liao Shasha , Guo Lei
Published: August 2021

Free space optical (FSO) communication has attracted significant attention due to its high transmission rate and information security. Nevertheless, the FSO link is sensitive to various weather conditions which limit its application range. Thus, research on the FSO channel plays an important role for combatting channel fading. In the paper, we first establish a FSO transmission testbed to obtain received signal strength indication (RSSI) information of optical signal. Then we utilize an environmental chamber for indoor experiments to simulate weather changes in the real world. Finally, based on the true meteorological dataset from the official department and the RSSI dataset from the experiments, we employ expanded gated recurrent unit (GRU) neural networks to implement the FSO channel prediction. The results demonstrate that the proposed scheme can achieve the prediction of FSO channel fading with a high precision, where the absolute percentage error (APE) values lower than 6.9% account for up to ninety% of results.