Abstract

Brazil has regions where the potential for wood supply is substantial and the lack of knowledge about forest species becomes a possible barrier to its acceptance, as is the case of the wood from the Caatinga biome. This research aims to identify the highlights attributes of wood from this biome in the perception of producers of small wooden objects as a premise for market studies. For this purpose, nine species of this biome were used as study objects for exploratory research with semistructured interviews and use of word cloud and similarity analyses with the IRAMUTEQ software. As a result, it was found that, in the perception of the producers, Caatinga biome species have peculiarities with the “color” aspect of the wood, which is the attribute considered important in adding value to products and, moreover, making it possible to group the woods according to their subjective peculiarities. It was found that a more effective participation of little-known species and an increase in demand due to greater acceptance in the market could enable the use in association with and/or as a replacement for traditional woods. In addition, the analysis of qualitative data with IRAMUTEQ is still incipient in the scientific forestry area; the present research contributes methodologically, demonstrating that its use increases the rigor of the investigation and the identification of prominent attributes of wood species, specifically those of the Caatinga studied, as alternatives for the market beyond firewood and charcoal.

Abstract

Face layer density is widely known to be important for increasing bending strength (i.e., modulus of rupture [MOR]), whereas outer core layer density is not regarded as such. This study reports the importance of the outer core layer density for commercial particleboards. The core and face layers were manufactured with coarse and fine particles, respectively. The coarse particles increased MOR because of the long wood fibers retained in the particle, whereas fine particles did not increase MOR because of the absence of long wood fibers. Long wood fibers in the outer core layer, as opposed to face layers, increase MOR. Moreover, the sampling position of the density profile specimen was important for the MOR. The MOR was influenced with the density profile specimens obtained near the center of the MOR specimen; thus, the low-density part near the center of the MOR specimen exerted a large influence by significantly decreasing the MOR.

Abstract

Circular saw blades have many states, before and during the sawing process, depending on the different residual stresses and flatness of the circular saw blades. Based on the different states of circular saw blades, the effect of rotating centrifugal stress on the dynamic stability of circular saw blades is different, mainly reflected in flattening and stiffening effects. In this article, three representative states of circular saw blades were chosen and studied. The finite element method was chosen to simulate the deformation behavior of circular saw blades in the three states. The flattening and stiffening effects of centrifugal stress on circular saw blades in the three states were systematically studied. The axial stiffness of the outer edge of circular saw blades is increased with rotating speed. The rotating speed has a flattening effect on the circular saw blade, as a result of a centrifugal stress field. When the circular saw blade is in a different state, there are some differences in the flattening and stiffening effect of centrifugal stress.

Abstract

The International Standard of Phytosanitary Measures No. 15 (ISPM-15) requires signatory countries of the International Plant Protection Convention to use approved treatment methods on wood packaging materials used in international trade to significantly reduce the risk of spreading alien species. One of the approved methods utilizes dielectric heating (DH) to raise the temperature in the wood to 60°C through the profile of the workload for 1 minute to eradicate pests. To improve the uniform distribution of heat within a wood workload using radio frequency, a form of DH, we tested the use of a wool blanket as a thermal insulation material for wood pallet components. Three species commonly used in the pallet industry—yellow poplar (Liriodendron tulipifera L.), northern red oak (Quercus rubra L.), and eastern white pine (Pinus strobus L.)—of low moisture content were used to generate matched sets of stringer samples. Internal wood temperatures were monitored continuously during treatment to comply with the ISPM-15 schedule. Applying a wool (keratin) insulation blanket increased the rate of heating, improved heating uniformity throughout the workload, and reduced moisture loss compared to uninsulated controls for some wood species, but not all. These findings were most significant for pallet materials with higher moisture content and more permeability (white pine and yellow poplar). By reducing treatment time, power consumption costs can be reduced using wool insulation when implementing the ISPM-15 DH treatment schedule.

Abstract

Korean wood preservation standards require deep penetration, which precludes the use of many refractory species. However, such treatments of refractory species have been shown to be effective in other parts of the world. A field test was therefore initiated to evaluate the performance of western hemlock, a moderately refractory species, and white spruce, a highly refractory species, pressure treated with either copper azole or alkaline copper quaternary under Korean field conditions that included both decay and termite hazards. After 10 years of exposure in a ground proximity and field stake test in Jinju, Korea, the treated materials remained largely sound, while untreated controls failed much earlier, largely due to termite attack. These data suggest that material that does not meet current Korean penetration requirements could still provide effective protection against biodegradation under Korean conditions. Decay was more advanced in matched treated stakes exposed at a test site in Canada than at the site in Korea.

Abstract

Wood composite panels (WCP) are well known for their environmentally friendly attributes of being sustainable, renewable, biodegradable, and predominantly made from wood residues generated during lumber and plywood production. This paper focuses on the ability of WCPs to store carbon for long periods of time in nonstructural applications such as cabinets, furniture, and flooring. WCPs, include particleboard, medium density fiberboard (MDF), and hardboard–engineered wood siding and trim (EWST). These panels are anticipated to have an average service life of 25–30 years. In 2019, there was an estimated 291 million cubic meters (m³) of WCPs in use in North America that corresponds to a carbon pool of 354 million metric tons of carbon dioxide equivalents. This WCP carbon pool is enough to offset 24 years of cradle-to-gate cumulative carbon emissions (fossil and biogenic sources) emitted during production of these panels. In other words, producing and using WCPs stores carbon for long periods because the amount of carbon emitted during the production of the panels is far less than what the panels themselves are capable of storing over their lifetime of product use.

Abstract

Japanese larch (Larix kaempferi) boxed-heart timbers with the dimension of 100 × 100 × 1,000 mm were dried after being steamed at 100°C and 0°C wet-bulb depression for 5 hours, and then dried at 120°C and 30°C wet-bulb depression for 8, 12, and 16 hours, respectively. The radial permeability of the surface layers of the timbers during drying was measured to discover the moisture movement mechanism in the transverse direction. The radial permeability in the surface layers of pretreated timbers decreased and tended to decrease as pretreating time increased. The decreased permeability can be attributed to the reduced distance between microfibrils inside the surface layers of pretreated timbers attributable to the pretreatment. This reduced distance decreases the moving rates of the bound water and water vapor from the inner part to surface layers of pretreated timbers during drying. Therefore, the average drying rate of pretreated timbers was decreased.

Abstract

Batch log studies are frequently used by sawmills to provide insight into lumber grade yields and overrun for a given log grade. This information is then used to determine log pricing. These batches often contain logs with a wide range of diameters and clear faces. Little research has been done to determine the reliability of a batch log study for use in determining log break-even pricing.

A series of 16 batch log studies were conducted at a hardwood sawmill to gain insight into the accuracy and reliability of the batch log study method. Batch compositions were found to be statistically different in four of five log grades. These statistically different batches led to statistical differences in lumber grade yields and overrun.

The batch log study method does not provide accurate insights into lumber grade yields and overrun. As a result, these data are not reliable for mill management decisions such as the calculation of log prices. Several changes could be made to improve the batch log study method, but the individual log study method would be of much more use to mill managers.

Abstract

The chemical composition of wood determines the color development when applying chemical stains to the surface of wood. However, different species and individuals from the same species can show variations in the chemical composition, resulting in the risk of nonuniform color development in industrial staining processes between different batches of wood. In the present study, near-infrared (NIR) models were developed to predict wood specimen color development after applying three different concentrations of the chemical stains iron acetate and sodium bicarbonate. The modeling dataset included the NIR spectra of the untreated wood, stain treatment, concentration, and the International Commission on Illumination (CIE) L*a*b* color value before stain application for 210 specimens from five commercial wood species, including red oak (Quercus rubra), white oak (Quercus alba), yellow poplar (Liriodendron tulipifera), southern yellow pine (Pinus spp.), and western red cedar (Thuja plicata). The models were developed by partial least squares regression (PLSR), using 13 different mathematical transformations on the NIR spectra as well as the raw spectral data. Models with single stains and global-species/stain models were developed and compared. The models for iron acetate showed promising results in predicting the color development with the coefficient of determination for cross-validation ( ≥ 0.92), while the models for sodium bicarbonate showed acceptable results with of 0.71 to 0.89. However, a global model including both stains resulted in an unsatisfying prediction of the CIE L*a*b* color values, with of 0.46 to 0.76. The NIR models can be useful for online predictions of color development in industrial staining processes of wood with chemical stains.