Timber construction is gaining popularity in Germany due to its sustainability, versatility, and aesthetic appeal, but, as a biological material, it can develop issues when exposed to moisture. Wood-destroying fungi can significantly reduce durability and structural integrity. Adequate moisture protection during construction is crucial for the longevity and performance of timber structures. This paper examines moisture protection practices on German construction sites and emphasizes the importance of proper on-site moisture management for sustainable timber construction. Visits to sites using timber construction revealed the status of moisture mitigation practices in conjunction with timber construction in Germany. A mixed-methods approach included photo documentation and protocol completion, yielding data for analysis to understand the depth and effectiveness of moisture protection strategies. The findings reveal a gap between problem awareness in the scientific community and practical handling on construction sites. Many sites exhibited disorganized structures and deficiencies in moisture protection strategies. While self-adhesive weathering membranes were used in nearly half the sites visited, less than one-third of the sites demonstrated sufficient moisture mitigation practices that protected the construction throughout the entire assembly process. This underlines the need to step up efforts in this area to ensure durable and high-quality timber construction that will be less reliant on the experience of designers or craftsmen.
Concerns about the safety of preserved wood as a garden box frame material persist in the public stemming from fears about chemical contamination of homegrown food. This study describes the third and fourth years of a long-term study to measure copper migration from copper azole-treated garden bed frames into garden soil and vegetable biomass (Presley and Konkler 2024). Garden bed frames made of Douglas-fir lumber untreated or pressured treated with copper azole were planted with common garden vegetables over two growing seasons. Vegetables and soil samples were collected and analyzed for copper concentration. Average copper levels in vegetables collected from treated or untreated beds were not distinguishable, except for radish roots grown in year 4 which contained higher copper levels (7.5 PPM) when grown in untreated wood beds compared to those grown in treated wood beds (3.7 PPM; p < 0.05 Tukey's HSD). At the end of each growing season, average copper concentrations in soil were significantly elevated in soil in direct contact (0-25 mm) with the treated wood (77.8-101 PPM) over copper levels found at equivalent locations in untreated wood beds (21.1-33.2 PPM) (p < 0.05, Tukey's HSD). No differences in average copper concentrations were observed in soils taken from any other sampling location, indicating that measurable copper accumulation was limited to within 25 mm of the bed edge. This study shows that the use of treated wood as a bed frame material has no impact on vegetable copper content and the impacts of copper migration are small and spatially limited.
This study investigated the in-situ biomineralization of metal phytate in wood to improve the antifungal and flame-retardant properties. Pine and aspen wood were impregnated with phytic acid and metal chlorides (copper, aluminum, and iron) via two treatment pathways. Path-1 involved treating wood with metal chlorides followed by phytic acid, while Path-2 involved the reverse order. Mass gain and accelerated leaching tests were performed to assess the treatment retention, followed by soil-block decay testing against four wood-decaying fungi and fire-related assessments on aspen via thermogravimetric analysis (TGA) and mass loss calorimeter (MLC) test. Path-2 resulted in significantly higher initial mass gain than Path-1, but experienced more substantial mass loss during leaching, indicating weaker fixation of PA-derived components. Before leaching, most treated samples exhibited improved decay resistance, with mass loss values below 10%. However, decay resistance decreased after leaching, indicating the importance of fixation stability for long-term durability. TGA showed that treated samples before leaching exhibited earlier thermal degradation and higher residual char yield than controls, while MLC measurements revealed reduced peak heat release rate, total heat release, and fire growth index, as well as higher char residue. Importantly, these flame-retardant properties were largely retained even after leaching. Overall, these results indicate that in situ metal-phytate formation can provide measurable improvements in fire performance, while fungal protection remains dependent on treatment retention. Further optimization of fixation chemistry is recommended to achieve more durable, bio-based wood protection.
This study investigated the feasibility of manufacturing eco-friendly flakeboard from olive tree pruning residues using three concentrations of a tannin-formaldehyde adhesive, where the condensed tannin was extracted from pomegranate peels. The research evaluated the effects of adhesive concentration (11%, 12%, and 13%) on the physical and mechanical properties of panels to verify their compliance with European standards. Panels were tested for moisture content, density, water absorption, thickness swelling, modulus of rupture (MOR), internal bond (IB) strength, and screw withdrawal resistance. While moisture content and density were not significantly affected by adhesive ratio, water absorption and thickness swelling after 24 h decreased significantly with higher resin content. Mechanically, the 13% adhesive sample exhibited superior performance, achieving the highest values for MOR (18.8 MPa), IB strength (0.61 MPa), and screw withdrawal resistance (680 N), representing improvements of 7%-10%, 16%, and 10%, respectively, over panels with the lower resin content. All produced panels met the relevant European standard specifications. The results showed that olive tree pruning waste can be successfully valorized to produce sustainable oriented strand board (OSB) panels using a bio-based tannin-formaldehyde adhesive. The panels, which also feature an attractive natural appearance, are suitable for applications in furniture manufacturing, interior cladding, and structural uses, offering a promising solution to reduce reliance on synthetic adhesives and minimizing agricultural waste.
Wood is preferred as a building material due to its high strength, low weight, and ability to retain many of its properties even at moderately high temperatures. However, numerous wood adhesives lose strength as the temperature increases, especially around 200 degrees C. This study examined bond strength at temperatures above that required for initiation of wood degradation for bonds of wood-to-wood and wood-to-aluminum using two oil-based adhesives (resole phenolics and epoxies) and two bio-based adhesives (soy protein isolate and ovalbumin from egg whites). The phenolics not only gave the best strength in the wood-to-wood bonding, but also in the wood-to-aluminum bonding. The second best were the protein adhesives, and the epoxies were the weakest. This research reinforces the use of phenolic adhesives for wood exposed to high temperatures.
Hinoki (Chamaecyparis obtusa) and Sugi (Cryptomeria japonica) are two promising softwood species gaining attention beyond their traditional use in Japanese residential construction. Following the establishment of design values through in-grade testing and their inclusion in the American Wood Council (AWC) National Design Specification (NDS) Supplement, further evaluation of their connection performance is essential to increase the information about the two species of wood and support broader adoption, particularly in the U.S. construction market. This study characterized the connection performance of these species through a series of standardized tests: withdrawal resistance, lateral resistance, and dowel bearing strength. The objectives were to characterize the yield behavior, withdrawal capacity, and bearing strength of fasteners embedded in the species, and to evaluate the relevance of the predictive equations provided in the NDS for wood construction within the context of the experimental findings. The experimental results demonstrated species-specific differences in withdrawal and lateral resistance performance, with both species exhibiting consistent failure modes in agreement with NDS yield mode predictions, primarily modes IIIs and IV. Dowel bearing strength showed a similar trend to withdrawal behavior, with the species generally exhibiting higher bearing strength values that those predicted by current design equations. While the results were conservative, they indicate that designers can safely employ the current equations for connections in both Hinoki and Sugi. These findings contribute essential connection performance data to support the structural application of Hinoki and Sugi in mainstream construction.
Society of Wood Science and Technology (SWST) accreditation plays a crucial role in ensuring that wood science and technology programs remain relevant, industry-aligned, and future-ready. As the forest products sector evolves with shifting global markets and growing sustainability demands, the need for highly skilled professionals in areas like bio-based materials and advanced manufacturing is critical. SWST accreditation establishes rigorous standards, equipping graduates with the technical and professional skills necessary to thrive in the industry. However, awareness of accreditation's full potential remains limited, and many programs could better leverage it to enhance curriculum, strengthen industry connections, and boost global recognition. This paper provides an overview of SWST accreditation and its role in shaping the future of wood science and technology education by maintaining program quality, fostering interdisciplinary approaches, and supporting the development of a workforce that drives innovation and competitiveness within the forest products industry.
Wood-processing industries contribute to economic and social development by producing a variety of wood products, yet limited information exists on their competitiveness and cost structures in Ethiopia. In this study we examined their competitiveness by using diamond model and cost structures of chipboard, plywood, and sawn wood industries using a survey of 29 large and medium firms and detailed cost analysis of three case studies. We used both qualitative and quantitative data to ensure a comprehensive analysis; quantitative data were examined using descriptive statistics including frequencies, means, and percentages to identify measurable patterns and trends, while qualitative data provided contextual depth and insights into the operational and strategic challenges faced by respondents. Findings revealed that limited support from government was a key constraint to competitiveness, while growing demand for wood products had a positive effect. Cost structures varied by industry type: raw materials were the largest expense for chipboard (43%) and plywood (51%) producers, while overhead costs dominated (76%) for the sawn wood (sawmill) respondent from 2019 to 2024. Profitability improved across all products: chipboard margins rose from 6.9% to 7.1%, plywood from 9.6% to 22.8%, and sawn woods from 3.8% to 13.3%. Enhancing the competitiveness of Ethiopia's wood-processing sector requires addressing industry-specific challenges and costs.
The primary objective of this study was to determine whether in-house-developed flame-retardant-treated cedar could serve as an exterior material, not only by meeting the fire-resistance criteria of the cone calorimetry test, but also by demonstrating dependable performance under realistic fire conditions. The results of the cone calorimetry test indicated that the material met the established criteria for total heat release and peak heat release rate, validating its classification as a quasi-noncombustible material. Furthermore, the ASTM E84 Steiner tunnel test was conducted to evaluate the performance of the flame-retardant cedar siding under conditions that simulated real fire scenarios more closely. Flame propagation exhibited a delayed onset and progressed gradually from 2.5 ft to 5 ft over 10 min, indicating restrained flame spread. Concurrently, smoke development remained negligible throughout the test, which is critical for maintaining visibility and minimizing exposure to toxic combustion byproducts. Post-test examination revealed minimal structural degradation, with no evidence of cracking or penetration beyond superficial charring, suggesting that the material retained its physical integrity even under elevated thermal stress. Collectively, these findings confirm that the flame-retardant cedar siding meets the requirements for an ASTM E84 Class A rating and functions as a reliable exterior cladding material capable of enhancing occupant safety in fire scenarios.
Creosote is used as a wood preservative in a variety of terrestrial and aquatic environments, and some of its components can be detrimental to ecosystem function at high enough concentrations. Therefore, it is important to quantify chemical migration from creosote-treated commodities to better understand their impact. This work measures the migration of 16 polycyclic aromatic hydrocarbons (PAHs) from creosote-treated southern pine and Douglas-fir roundwood posts set in soil contact in barrels under controlled laboratory conditions. Experiments were carried out in soils with both low and high organic matter (OM) content. PAH content was measured in soil over a 32-month period at two distances from the post surface (76 and 152 mm) and at three different depths from the surface (0-15 cm, 15-30 cm, and 30-46 cm). PAH concentration varied widely among the 16 different compounds measured, but generally PAHs with four or fewer rings were more abundant and more frequently found than larger five-ringed PAHs across sample types. It was difficult to identify clear patterns in PAH migration by distance from wood and depth from soil surface because levels were generally low (below 0.4 PPM), and the data was highly variable, which eliminated the possibility of differentiating means statistically in most cases. In many cases, PAH levels found in controls that contained untreated wood were similar to levels found in control soil that contained treated wood, indicating some PAHs found could originate from the soil or surrounding environment. The clearest trend found was that high OM soils much more frequently contained measurable levels of the different PAHs, which is likely due to the known affinity PAHs have for OM. This work provides some methodological insight into studying PAH migration in soils that can help explain PAH migration patterns in soils with different proportions of OM. It also shows that without wetting with liquid water or other physical disturbances faced by wood in service, PAH migration from creosote-treated wood into soil is minimal.
Heartwood formation influences timber quality and utilization, yet the factors driving its variation remain poorly understood. Understanding these variations can guide management strategies to influence heartwood development and enhance timber value through adapted silvicultural practices. This study examined the relationships between heartwood area and various tree characteristics in Douglas-fir plantations aged 25-34 years, across four sites within their native range in the southern interior of British Columbia, Canada. Stem analysis was used to quantify heartwood area and its relationships with tree-level variables, including sapwood area, tree height, root infection, and competition. To account for vertical variation along the stem, discs were categorized into three height classes based on relative stem height: lower (0-30%), middle (31%-60%), and upper (61%-100%). Heartwood area was primarily influenced by sapwood area, with the strongest effect at the middle stem, followed by the upper and lower positions. Tree height showed a position-dependent effect: positive in the lower stem and negative in the middle and upper sections. Root infection significantly increased heartwood area in the lower stem, with its effect weakening at higher positions. Competition had statistically significant but minimal effects, ranging from slightly negative in the lower stem to slightly positive in the upper stem. Our findings suggest that promoting sapwood development, particularly in the mid-stem, can enhance heartwood formation. While practices like thinning may contribute to this, the positive association between competition and heartwood in the middle stem indicates that maintaining moderate stand density may be more beneficial than aggressive spacing. Although root infection may locally stimulate heartwood near the base, its longer-term effects can disrupt the sapwood-heartwood balance and reduce tree vigor. Therefore, silvicultural strategies should aim to promote heartwood primarily through stand density management while limiting reliance on root stressors, integrating disease control measures to sustain overall tree health.
This study determined the Hankinson's formula coefficient n for red pine (Pinus densiflora) using the indirect elastic wave transmission test under varying moisture contents (12%, 15%, and 18%). Hankinson's formula is a mathematical relationship used to predict the mechanical properties of wood at any angle relative to the grain. With information on the elastic wave transmission speed parallel (P, 0 degrees) and perpendicular (Q, 90 degrees) to the fiber direction, the wave transmission speed at intermediate angles can be predicted using Hankinson's formula. A visually defect-free 81-to 90-year red pine board (400 & times; 400 & times; 50 mm) was selected as the test specimen. The moisture content of specimens was adjusted to 12%, 15%, and 18%. Coefficient n of Hankinson's formula, was calculated by taking measurements were taken at grain angles of 0 degrees, 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, and 90 degrees using both ultrasonic and stress waves by the indirect transmission method. The coefficients (n) obtained from ultrasonic wave measurements were 2.0, 1.9, and 1.9 at 12%, 15%, and 18% moisture contents, respectively. The values determined from stress wave measurements were 1.7, 1.7, and 1.6 at the same moisture contents, respectively. These results indicate that the transmission path of elastic waves in red pine can be effectively modeled using the coefficient n from Hankinson's formula, which varies with moisture content. This suggests the potential applicability of the formula in evaluating internal defects or decay in wood through quantitative wave-based analysis.
