Transparent and credible environmental labeling of products is vital for a sustainable future. Ecolabeling shows information on the environmental performance of products, processes, and services. This article focuses on one type of ecolabeling referred to as environmental product declarations (EPDs) that provide environmental impact information based on life cycle assessment (LCA) data. Businesses and consumers who are not familiar with life cycle analysis can use LCA-based EPDs for comparison between competing products, much like using nutritional labels. In addition, this article describes the process of developing EPDs from LCA data in conjunction with product category rules and the status and future needs of EPDs in the U.S. forest products industry.
This research investigated an economic component of harvesting operations not previously studied for steep-slope thinning harvests in Douglas-fir (Pseudotsuga menziesii) stands in the Pacific Northwest. Of interest was the influence of allowable log lengths and the effect on revenues with a bucking-to-value strategy. Resulting log lengths influence revenues and logging costs important to forest managers, logging contractors, and mill managers. Here, a reduced set of log lengths was evaluated that approaches computer-generated optimal values and creates the potential for development of a bucking decision tool having the form of a bucking pattern cutting card. The reduced set of five log lengths (two mill-length logs and three woods-length logs resulting from combinations of the mill-length logs) was also compared with the full set of allowable lengths for value recovery and fiber utilization. Resulting values were 96 and 98 percent of full-set optimal values for 45- and 65-year-old stands, respectively. Value recovery exceeds that with current unaided bucking practices. The resulting bucking patterns can be easily incorporated into a cutting card based on length to merchantable top. This approach reduces the number of logs handled, increases mill-preferred long logs, decreases pattern count, and increases recovered value. Potential value gains of $4.09 to $8.80 per 100 cubic feet for the two stands are discussed with respect to mill constraints. Use of a combinatorial heuristic is suggested for matching produced logs to mill purchase orders. The board foot–to–cubic foot ratios used for the cubic foot–based analysis are also discussed.
John Deere's biomass bundler unit is an effective machine for harvesting forest residues, which can be used as a source of fuelwood and/or a feedstock for biofuel production. This project explored an avenue that could supply a promising source of readily available energy in southeastern forested lands. Typical southern harvesting operations consist of whole-tree harvesting in which trees are felled and then skidded to a landing. Limbs and tops are usually either deposited over the landscape or piled in windrows. The biomass bundler captures the otherwise nonmerchantable material and maximizes the marketability of the entire tree. In order to reduce costs, maximize efficiency, and implement the bundler in a tree-length harvesting operation, this project tested a prototype harvesting system. This venture (1) adapted the John Deere B380 bundler unit to a motorized trailer, (2) designed an optimum landing configuration, and (3) conducted a productivity study of the bundler unit. The unit produced 13.2 tonnes per productive machine hour (PMH; 14.6 tons/PMH) of 250-cm bundles and 14.9 tonnes/PMH (16.4 tons/PMH) of 350-cm bundles, assuming minor delays at a cost of $12.50 to $14.20/tonne ($11.25 to $12.85/ton).
A total of 230 logs from two species, red oak (Quercus rubra) and yellow poplar (Liriodendron tulipifera), were measured in five typical hardwood sawmills across West Virginia to evaluate log sawing practices and lumber recovery. Log characteristics such as length, diameter, sweep, taper, and ellipticality were measured in sawmills, while log scale and grade were determined by using the US Department of Agriculture Forest Service grading rules. The characteristics of sawing equipment, such as headrig type, headrig kerf width, and sawing thickness variation, were recorded during the measurement process. A general linear model was used to statistically analyze the relationship between lumber recovery and characteristics of logs and sawing practices. Results indicated that factors such as log grade, log diameter, species, log sweep, log length, and some two-factor interactions significantly affected lumber value and volume recovery.
With the monetary exchange for hardwood trees and logs changing from log-scale board feet to tons, it is important that bulk density values (also called scaling factors) be developed to aid in determining the value of standing trees and logs. This study included 14 species of hardwoods and a total of 325 trees. Ten species were oak, which were divided into a red oak group (seven species) and a white oak group (three species). The red oak group had an average bulk density of 80.7 lb/ft3, and the white oak group had an average bulk density of 79.2 lb/ft3. A significant difference was found between the groups, as were significant differences between species within each group. Southern red oak (Quercus falcate) had the highest value (83.0 lb/ft3), and white oak (Quercus alba) had the lowest (77.0 lb/ft3). Three hickory types had an average bulk density of 79.4 lb/ft3. Sweetgum (Liquidambar styraciflua) had a bulk density of 78.3 lb/ft3.
The emission levels of hazardous air pollutants (HAPs) from wood kilns are needed to comply with the Clean Air Act. Softwood lumber, including southern pine (Pinus taeda, Pinus palustris, Pinus echinata, and Pinus elliottii), is considered kiln dry when the wood moisture content reaches below 19 percent, but it is sometimes overdried or dried to 8 percent moisture content for export or interior applications. To study HAP emissions when drying to 8 percent moisture content, green lumber was obtained from a local mill, and 12 charges were kiln dried using three schedules: a 99°C elevated schedule and 116°C and 127°C high-temperature schedules. Methanol and formaldehyde were collected and analyzed using the National Council for Air and Stream Improvement (NCASI) 98.01 method, “Chilled Impinger Method for Use at Wood Products Mills to Measure Formaldehyde, Methanol, and Phenol,” where formaldehyde was analyzed via spectrophotometry using acetylacetone and methanol was analyzed via gas chromatography with a flame ionization detector. The high-temperature schedules had significantly greater HAP emissions than the elevated schedule. When drying from 19 to 8 percent moisture content, methanol and formaldehyde emissions increased by an average of 48 and 52 percent, respectively. Volatile organic compounds (VOCs) were also measured using a flame ionization detector by the NCASI VOC method with results similar to previous studies. The methanol, formaldehyde, and total volatile organic emissions were reported according to the Environmental Protection Agency OTM-26 method, “Interim VOC Measurement Protocol for the Wood Products Industry.” The results were slightly higher than the NCASI VOC results because of more accurate quantification of methanol.
Conversion of lignocellulosic materials, including wood, to fuel is currently cost prohibitive due to the expenses involved and the lack of value addition, even though small-diameter hardwoods are readily available. Alternative processes therefore need to be investigated. Partially hydrolyzing wood may offer an opportunity to add value to the conversion process by producing a modified woody by-product that can be used as a wood composite raw material. Experiments were conducted on the effects of a partial hydrolysis on the mass loss, specific modulus, and surface free energy of modified southern hardwoods, and this article reports the changes in holocellulose content of water-saturated yellow-poplar (Liriodendron tulipifera L.), sweetgum (Liquidambar styraciflua L.), and red oak (Quercus spp.) heated at 150°C for 30 minutes in three solutions: 1 percent sulfuric acid, deionized water, and 1 percent sodium hydroxide. The treated woods were compared with untreated controls. The previously tested wood samples were ground to a size 20 mesh, and holocellulose content was analyzed gravimetrically. Properties of the modified wood were then regressed on holocellulose content following partial hydrolysis. All three treatments significantly reduced the holocellulose content in each species, with the greatest reduction obtained in the acid treatment, followed by the alkaline solution treatment and the deionized water treatment, respectively. The changes in holocellulose explained a majority of the variation in mass loss due to treatment and specific modulus, whereas surface free energy was poorly explained by changes in the wood structure. Implications for wood composites manufacturing are discussed.
The objective of this study was to investigate the feasibility of using the bio-oil generated from the Mississippi State University's (MSU's) fast pyrolysis process as part of a polymeric diphenylmethane diisocyanate (pMDI) binder system for flakeboard production. The bio-oil was obtained from the pyrolysis process of pine wood (Pinus spp.) at the MSU bio-oil laboratory. The effect of the resin content and the pMDI to bio-oil ratio on the physical and mechanical properties of the flakeboards was examined. The properties include internal bond, modulus of rupture, modulus of elasticity, thickness swelling, and water absorption. The effect of adding acetone into the pMDI/bio-oil resin on the properties of flakeboards was also investigated. The results showed that the incorporation of acetone reduced the viscosity of the adhesive by up to 67 percent, from which the efficiency for resin spraying on the flakes was improved. The higher the bio-oil content, the lower the mechanical strength of flakeboard obtained. However, the pMDI resin with a bio-oil content of 25 percent showed comparable bonding properties to those of pure pMDI resin.
This study examined the bending performance of composite I-joist/oriented strand board (OSB) structural roof panels. The 1.22-m-wide panels were fabricated from commercially available I-joists with OSB sheathing bonded to the top and bottom I-joist flanges. To provide baseline bending performance, two sets of 10 bare I-joists were tested to failure in four-point quasistatic bending. The first consisted of 4.72-m-span, 241-mm-deep joists, and the second set consisted of 7.16-m-span, 356-mm-deep joists. Two sets of 10 I-joist/OSB panels fabricated with identical I-joists of the same spans were tested in four-point bending. Results of the bend tests showed strength gains of 59 to 124 percent and stiffness gains of 79 to 115 percent on a per-joist basis for the I-joist/OSB panels. While the bare I-joists primarily exhibited bending failures, the panels predominantly failed in shear. These strength and stiffness gains and the shift in failure mode indicate that the bonded OSB sheathing significantly improved panel bending strength. A transformed section analysis predicted panel stiffness reasonably well and indicated that shear failure was the most likely panel failure mode. Finally, four specimens were tested under sustained loading equal to 55 percent of the 5 percent parametric lower tolerance limit. Two of the specimens tested under sustained loading failed in creep rupture. Results of this study indicate that the roof panels show promise for practical application as long-span, pre-insulated structural members. However, creep deformation and creep rupture need further study, as does the durability of the I-joist–OSB bond line.
Tests were conducted to determine the withdrawal capacities of 10-mm (nominal ⅜-in.) and 15.9-mm (nominal ⅝-in.) through-bolts with Diameter Nominal (DN) 15-mm (nominal ½-in.) and DN 25-mm (nominal 1-in.) pipe-nut connectors intended for use in light-timber frame construction. The capacity of unreinforced 15.9-mm through-bolts with DN 25-mm pipe-nut connectors was approximately 31.1 kN; the capacity of comparable reinforced connectors was approximately 71.2 kN. Likewise, the withdrawal capacity of smaller unreinforced 10-mm through-bolts with DN 15-mm pipe-nut connectors was approximately 13.3 kN; comparable reinforced connectors had a capacity of 17.8 kN. Similar 10-mm through-bolts with DN 10-mm pipe couplings had a capacity of 26.7 kN. Overall, results indicate that high-capacity joints can be constructed with through-bolt and pipe-nut connectors.
Five-year performance ratings are presented for two types of untreated, uncoated wood joints (L and lap) in aboveground tests under shaded conditions. The effect of shading on moisture entrapment in pine and maple L and lap joints was evaluated in a moderate decay zone (Madison, Wisconsin). Variations were observed between wood species, visual ratings, joint type, moisture content readings, and fungal growth on the specimens. Representative fungal fruiting bodies were identified as members of the Peniophorella praetermissa species complex by microscopic and DNA analyses. After 5 years, the highest average rating (indicative of most severe deterioration) occurred in white pine L-joint specimens followed by maple lap joints and maple L joints. Pine and maple L-joint specimens demonstrated considerably lower rating variation between specimens compared with lap-joint specimens. White pine lap joints shaded with a tarp had lower average moisture content but showed similar average ratings to pine lap joints shaded by a tree. Regardless of the shading method, white pine lap joints had the lowest average decay rating. Under shaded conditions in a moderate decay zone, untreated and uncoated L-joint performance was notably more uniform from specimen to specimen than lap-joint performance following 5 years of outdoor exposure. A single-point moisture content taken at the time of inspection was not a reliable indicator of the degree or rate of decay for aboveground joint test assemblies evaluated in this study. Likewise, uniform specimen wetting or drying is not predictable under shaded conditions.
This study investigated the leaching of copper azole (CA-B) preservative, according to JIS K 1571 standard, from sundri (Heritiera fomes Buch.-Ham.) lumber treated by full-cell and passive-impregnation methods. Although the preservative retention was similar for both methods, penetration was higher with the passive-impregnation method (66%) than with the full-cell method (43%). Further, it was found that the leaching of preservative was significantly higher in wood treated by the full-cell method (1.18%) than by the passive-impregnation method (0.92%).