A buffered amine oxide carrier has shown promise to deeply penetrate dry lumber with insecticides for termite control without using pressure treatment. Pine sapwood from trees attacked by mountain pine beetle (MPB) has increased permeability. In this study, short lengths of heavily blue stained, post-MPB lodgepole pine lumber (Pinus contorta) were treated with the buffered amine oxide carrier to borate levels less than the retentions recommended for protection against attack by the Formosan subterranean termite (average, 0.5% mass/mass boric acid equivalent ), with and without the addition of organic insecticides. Additional samples were pressure treated with alkaline copper quaternary type D carbonate (ACQ-D) and disodium octaborate tetrahydrate (DOT). The boards were installed in field tests in Hawaii and Japan at sites with confirmed populations of Formosan subterranean termites. They were inspected after 2 and 5 years. Dip plus kiln-conditioning treatment with imidacloprid, permethrin plus imidacloprid, and permethrin provided good protection to post-MPB lodgepole pine lumber against termite attack over 5 years in Hawaii and Japan. Dip plus kiln-conditioning treatment with the buffered amine oxide alone provided no protection because of the low loading of borate used as the buffer. Samples that were DOT pressure treated to below the retention required for Formosan termites in American Wood Protection Association standards did not perform as well, possibly as a result of poor heartwood penetration as well as below-standard retentions. Addition of permethrin to DOT pressure treatment improved performance. ACQ pressure-treated samples did not perform as well, with two failures in Hawaii. This was also likely associated with poor penetration in the heartwood because this material was not incised.Abstract
Essential oils from forestry by-products, such as pine needles, have antimicrobial effects against pathogenic bacteria. Pine needle essential oils inhibit growth of Staphylococcus aureus, which is the causative agent for numerous human infections, ranging from superficial skin infections to deep abscesses and infections that are more serious. Crude essential oils from pine needles were proposed as a topical antimicrobial agent against both susceptible and methicillin-resistant strains of S. aureus. A Clevenger apparatus was used to extract essential oil from needles from a single clone of young loblolly pine (Pinus taeda L.). By gas chromatography–mass spectrometry analysis, it was determined that the major components of the oil were α-pinene (0.52 to 1.02 mg g−1), β-pinene (0.04 to 0.67 mg g−1), limonene (0.00 to 0.06 mg g−1), terpineol (0.01 to 0.18 mg g−1), and (−)-caryophyllene (0.02 to 0.52 mg g−1), with quantities depending on sampling dates. Results demonstrated that the essential oils had antimicrobial activity against four S. aureus strains.Abstract
Researchers, governing agencies, and other stakeholders frequently use the term “urban wood waste” to describe either waste from wood products, municipal trees, or some combination. The materials that actually make up the waste may come from very different sources. For example, those utilizing recovered building materials and municipal waste describe urban wood waste as construction and demolition debris. Arborists and other urban tree stakeholder groups define urban wood waste as material from pruning or tree removal operations that would otherwise be discarded in a landfill. In addition to diverse definitions among stakeholder groups, the term “wood waste” has evolved over time due to advances in processing and technologies. The objective of this article is to review the current usage of the terminology regarding urban wood waste and to develop a clear definition that can be accepted across stakeholder groups. It was determined that a universal definition does not exist and may not be appropriate.Abstract
The study determined the performance of industrial firewood processing operations under the typical work conditions of Southern Europe. In particular, we surveyed five commercial operations processing 1-m-long oak logs from coppice forests. Mean log volume was very small, in the range of 0.01 to 0.02 m3 solid. Machine utilization was quite high, ranging from 70 to 80 percent. Mechanical availability was excellent, always exceeding 90 percent of the total worksite time. Productivity varied between 1.4 and 4.9 m3 per scheduled machine hour (SMH), inclusive of all delays. Processing cost ranged from 26 to 44 €/m3. The largest machine in the group offered significant productivity and cost benefits over all the others. Owing to their multiple log handling capacity, firewood processors designed for Southern Europe may be less sensitive to log volume, compared with Nordic machines. The energy balance was always very favorable. The ratio between output and input was never smaller than 220 and peaked at 327. That was much higher than recorded for small-scale firewood processors, and it may depend on the use of more efficient electric motors compared with diesel engines. However, the main advantage of industrial firewood processors is production capacity and operator comfort and safety. This allows business growth, in the face of a very large market and a decreasing availability of skilled labor. Cost reduction is a secondary advantage, which becomes dramatic only when adopting machines at the higher end of the range.Abstract
Polyphenol chemical components extracted from merbau (Intsia spp.) wood exhibit a strong affinity for resorcinol and formaldehyde in alkaline conditions, forming a copolymer that could serve as an adhesive. A liquid extract of merbau wood (M) was allowed to copolymerize with resorcinol (R) and formaldehyde (F) under alkaline conditions, with an M:R:F weight ratio of 100:5:10. The course of the reaction and potential mechanisms of copolymerization were scrutinized using Fourier transform infrared spectroscopy, X-ray diffraction, and differential thermal analysis. The adhesive was used to manufacture three-ply composite flooring consisting of a back layer of rubberwood (Hevea brasiliensis), a core layer from sengon (Paraserianthes falcataria) wood, and a face layer with one of seven wood species, namely, sengon, sungkai (Peronema canescens), mangium (Acacia mangium), rubberwood, mahogany (Swietenia spp.), kempas (Koompassia malaccensis), and merbau. The adhesive was spread on the face and back layers of 170 g/m2 single glue line, which was followed by pressing at 11 kg/cm2 for 3 hours at room temperature. After conditioning for 10 days, the resulting composite flooring was examined to assess its physical and mechanical properties, shear strength, and formaldehyde emission. Results revealed that the bioadhesive exhibited crystallinity of 23.32 percent and a melting glass transition of 115.31°C. IV-meter intrinsic viscosity tools were used to determine the product's molecular weight of 49,658. Physical–mechanical properties and shear quality of the composite flooring were similar to products that use synthetic phenolic adhesive and belong to the exterior quality type with E0 or F**** types of low formaldehyde emission.Abstract
In order to better use the hemp shiv in manufacturing particleboard panels, tests for determining the mechanical and physical properties of this particleboard were performed according to the Chinese standard for wood-based paneling. The results showed the following. (1) The properties of the particleboard are optimal, with a 1:1 ratio of hemp shiv to wood particles; hemp shiv and wood particles actually strengthen each other when particleboard is made from a mixture of hemp shiv and wood particles. (2) The low density and the low mechanical properties of fiber cell walls were both advantages for the hemp shiv used to manufacture the particleboard panels.Abstract
The manufacturing of wood–polymer composites (WPCs) by compounding wood particles with plastic at temperatures above their melting point may cause thermal degradation of the wood, which can lead to undesirable properties, including odor, discoloration, and degradation of the mechanical properties of the panels. This study was conducted to investigate the effect of a particle pretreatment (cold-water soaking and hot-water extraction) on the performance and properties of WPC panels made of four lignocellulosic materials (LCMs) and polypropylene (PP), 50/50 by weight. Composites filled with pretreated and untreated particles of three wood species and date palm midrib fronds were manufactured using a melt blending technique followed by compression molding. The physical, mechanical, and dimensional stability properties of the WPC panels were evaluated. The results indicated that the four LCMs are significantly different in all chemical constituents. Pretreating the wood particles by either cold or hot water resulted in significant improvements in the compatibility of each wood species with PP, as was observed by an increase in the mechanical properties and by a decrease in the water uptake and thickness swelling of the composite panels. An enhancement in strand color and a decrease in smoke and excessive odor during the compounding process were also observed, which resulted in an enhancement in the performance of the produced panels, particularly for the date palm midrib fronds.Abstract
The moisture gradient in wood is a characteristic of major interest in lumber drying. Two methods, an ovendry slicing method and an X-ray scanning method, were used to examine moisture gradients in wood during the drying of Chinese fir (Cunninghamia lanceolata). The results of the comparison between these two methods confirmed that X-ray radiation can be used to monitor moisture distribution during the drying of Chinese fir. Compared with the moisture content (MC) values obtained by the ovendry slicing method, the X-ray scanning method is capable of determining MC to within ±12.9 percent. Using a control volume approach, a numeric model for estimating the moisture gradient in wood during drying was developed in this work. The validation tests indicated that the model can be used to estimate moisture gradients during the drying of Chinese fir and is capable of predicting moisture distribution to within ±12.6 percent.Abstract
This study looked at three properties of cottonwood trees: moisture content, specific gravity, and foliage as a percentage of limb weight. There was an irrigated plot and an unirrigated plot. The study included six southern clones and one hybrid from the northwestern United States. There was no significant difference in moisture content among the southern clones, but the hybrid moisture content was significantly higher in both plots. The specific gravity values of two clones were significantly higher than the hybrid in the irrigated plot, while in the unirrigated plot, the values of three clones were higher than the value of two clones, and the hybrid value was close to the lower clones. The percent foliage values were higher in the irrigated plot, and the hybrid values were significantly lower in both plots compared with the six clones.Abstract
Many believe the logging industry faces significant challenges in recruiting and maintaining a qualified workforce. The relationship between wage and productivity is a critical component of attracting quality workers while controlling labor cost. We attempted to examine the relationship between worker performance and wage with results from a mixed (mail, Internet, and interview) national survey targeting logging firm owners, corporate officers, and supervisors. Respondents (162 total) varied regionally (North, South, and West) with respect to harvest systems and firm size. Wage expectations were considerably higher with aerial harvest systems, which were confounded with the respondents from the West, larger firm size, and greater respondent experience. Wages for workers with higher skill levels were more related to firm and respondent attributes than were lower skill levels, and most of the relationships were logical. Respondents indicated that equipment operators perform adequately after 12 months on the job and supervisors after 24 months. For chainsaw operators, results appeared to vary by region from 6 to 36 months of experience. Changes in wage due to increased skill level were similar across regions when expressed as a percentage of the lower skill level. Once the worker was able to perform at an adequate level, it appears that wage changes due to performance were roughly equivalent to the expected increase in productivity.Abstract