Wood and Fiber Science

On site moisture protection: An unnoticed but essential basis for sustainable timber construction

Kai Schubert — 2026-04-04

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.

High heat resistance of adhesive bonds to wood and aluminum

Linda Lorenz — 2026-04-04

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°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.

Manufacturing of oriented strand board from olive tree pruning residues

Antypas Imad Rezakalla — 2026-04-04

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.

Copper migration from treated wood garden boxes into soil and vegetable biomass Part II: The third and fourth growing seasons after installation

G. N. Presley — 2026-04-04

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.

SWST accreditation: Shaping the future of wood science and technology education and its role in the forest products industry

Judith Gisip — 2026-04-04

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.

Experimental characterization of basic connection properties of Hinoki and Sugi

Arijit Sinha — 2026-04-04

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.

In situ biomineralization of metal phytates in wood for improved bio-durability and flame retardancy

Aynun Nishat Farhabi — 2026-04-04

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.