The objective of this study was to explore the effect of selected gluing parameters such as different wood surface temperature and equilibrium moisture content (EMC), the use of primer, and pressing pressure and duration, on the bondline quality of Norway spruce (Picea abies). Eight various combinations were evaluated for gluing spruce samples using commercial 1-component polyurethane adhesives and compared with control boards that were bonded at standard conditions of 12% EMC, 20 degrees C surface temperature, 0.6 MPa pressing pressure and 75 min pressing duration. Tensile shear strength tests were conducted in accordance with the EN 302-1:2023 standard and revealed a negligible effect of EMC on the bonding strength, while highlighting the pronounced role of pressing pressure. The presence of primer offset the lower surface temperature by providing comparable tensile shear strength to that of the control samples. The microscopic observation of the bondline showed that at lower pressing pressure, adhesive penetration into the wood was limited, leading to low interfacial bonding and formation of voids in the bondline. However, increasing the duration of applied pressure or the application of primer under non-standard bonding conditions resulted in better bondline formation and adhesive penetration, as reflected by the comparable bonding strength to the control samples.

Wood modification with bio-based chemicals such as sorbitol–citric acid (SorCA) system is a low-cost and effective approach, while the low pH of the modifying agent reduces the mechanical properties of modified wood. Thus, this study was conducted to find alternative polycarboxylic acids with comparable functional groups, reactivity, and processing conditions. Silver beech wood (Betula pendula Roth.) was modified through in situ esterification approach using sorbitol in combination with citric acid (CA), tartaric acid (TA) or malic acid (MA). Wood samples were modified at 20% w/w of sorbitol–CA, –TA, and –MA at 1:3 molar ratio and cured at 140°C for 24 h. The SorCA modified samples showed the highest leaching resistance followed by SorMA and SorTA. The samples modified with SorTA and SorMA illustrated superior dimensional stability compared with SorCA. The modulus of elasticity (MOE) was slightly improved in all modified samples in comparison with unmodified birch. However, the modulus of rupture (MOR) was marginally decreased, particularly in the samples modified with SorCA and SorTA.

This study unravelled the intricacy of bio-based hydrophobic formulae as a substitute for the conventional emulsified paraffin wax (hydrowax), a hydrophobic additive currently utilised in high-density fibreboard (HDF) fabrication. Utilisation of hydrowax is not a sustainable practice due to the potential depletion of its fossil-based sources. The industrial acceptability of a renewable hydrophobic additive depends on several stages of trials. Therefore, through a pilot-scale trial, this study explored the substitution effect of bio-based tall oil distillation product (TODP) in the HDF panels, establishing its mechanical and water-related properties. While the mechanical properties of the panels were not primarily influenced by the TODP-based formula, the water-related properties of the HDF panels produced with 1% TODP were significantly better than the control panels. Additionally, the TODP exhibits superior mechanical and hydrophobic properties compared to the panels made with hydrowax. The ANOVA results further corroborate that TODP 1 at a 1% inclusion rate is the most significant formula. The types and concentrations of TODP are key factors influencing the performance of bio-based hydrophobic additives in HDF panels. Therefore, the present research supports the development of a sustainable hydrophobic bio-additive by determining the water-resistance and mechanical properties of TODP in HDF production.

Non-isocyanate polyurethanes (NIPUs) have been identified as a bio-based alternative to hazardous isocyanatebased polyurethanes. NIPU exhibits outstanding performance in polymer bonding, but its application in the plywood industry is questioned due to its relatively high curing temperature, typically above  180 degrees C. This study explored a unique method for producing NIPU adhesives through amination of lignin (LA), followed by quinone formation via disruption of condensed tannins with sodium periodate, and then methoxycarbonylation with dimethyl carbonate (TOC). LA and TOC were mixed in an alkaline medium to produce LT-NIPU adhesives (control sample) via urethane linkage formation, followed by reinforcement with microcrystalline cellulose (MCC), which effectively engaged the vacant -OH groups and densified the adhesive polymer network (MLTNIPU). The synergistic interactions between the prepolymers and MCC remarkably enhanced the MLT-NIPU adhesive chemistry. Consequently, MLT-NIPU adhesives at 30% MCC loading exhibited low curing temperatures of 130 degrees C, outstanding viscoelastic, shear-thinning behavior, and achieved dry and wet shear strength of 1.89 and 0.85 MPa, respectively. Therefore, this study presents a simple yet innovative strategy for constructing low-curing-temperature NIPU adhesives, enhancing bonding integrity, and establishing an alternative pathway for exploring bio-based feedstocks in adhesive development.

This study focused on a novel approach to combine humin, derived from fructose-based biorefinery processes, with two-dimensional graphene nanoparticles and glyoxal, a bio-based crosslinker, to formulate functional bioadhesives for manufacturing particleboards. Five different single-layer 8 mm particleboard panels were prepared using the developed humin-based adhesive formulas with and without graphene and tested by means of their mechanical properties and thickness swelling in accordance with the EN 310 and EN 319standards. The results were compared with panels bonded with commercial melamine-urea-formaldehyde (MUF), showing that the mechanical properties of particleboards bonded with humin reinforced with graphene nanoparticles were almost comparable to those of the control panels. Additionally, the humin-graphene adhesive exhibited significantly lower thickness swelling than the MUF bonded boards. By addressing the limitations of synthetic adhesives, this approach supports the growing demand for environmentally friendly alternatives in the forest products industry.

Archeological wood is a vital organic archive, yet its degraded state challenges traditional methods for species identification, provenance resolution, and decay assessment. This review synthesizes state-of-the-art advances-integrating artificial intelligence, isotopic systems, and molecular biology-and proposes a four-tier hierarchical diagnostic framework that moves the field from qualitative description to quantitative, high-resolution analysis. Landmark case studies demonstrate how multi-scalar data fusion provides mechanistic understanding of structural decay inaccessible through conventional approaches.

The global requirement to mitigate environmental challenges demands a paradigm shift towards sustainable materials. Forest-based products, primarily derived from wood, present a promising path due to their abundance and renewability. However, enhancing their properties to meet modern demands remains a challenge. This review article, the first of its kind, explores the transformative potential of incorporating graphene and graphene-based nanomaterials into forest-based products to overcome the challenges associated with mass-scale applications. Graphene, a two-dimensional carbon nanomaterial, has emerged as a multifunctional additive with exceptional mechanical, electrical, and thermal properties. Functionalization of graphene through covalent or non-covalent modifications has emerged as a key strategy to tune its characteristics and expand its utility across different domains. Recent studies highlight its promising role in forest-derived products, including coatings, composites, adhesives, and lignocellulosic substrates. Graphene and its derivatives, such as graphene oxide, reduced graphene oxide, and graphene nanoplatelets, have been shown to enhance barrier properties, mechanical strength, fire retardancy, and environmental resistance, while also reducing volatile organic compound emissions through formaldehyde scavenging. Moreover, graphene-coated forest-derived substrates demonstrate potential for applications in energy storage, smart sensors, and multifunctional green devices. This review compiles recent advances in integrating graphene with wood and lignocellulosic materials to address the urgency and potential of this innovative approach towards a more sustainable future. It also discusses the practical challenges in applying graphene, thereby providing a comprehensive perspective for its future research and industrial applications.

The increasing interest in sustainable and bio-based wood modification strategies has led to growing attention toward improving the performance of low-durability wood species for exterior applications. Sorbitol-citric acid(SorCA) modification has previously been reported as an effective approach for improving wood properties. However, despite these studies, the biological durability of SorCA-modified silver birch (Betula pendula), particularly its resistance to mold and fungal decay, has not been systematically investigated. Moreover, its performance under natural outdoor exposure conditions remains largely unexplored. Thus, this study evaluates the decay and outdoor weathering resistance of birch wood modified with a SorCA system. Birch wood samples were vacuum-pressure impregnated with aqueous solutions of SorCA at 20% and 40% w/w and cured at 140 °C. The distribution of the modifying agent within the wood structure was examined using X-raymicrotomography, which confirmed effective penetration with partial or complete filling of the wood lumina by the in-situ formed polyester network. The modified samples were subjected to ten months of natural weathering, mold exposure under high humidity conditions, and also to white-rot fungi (Trametes versicolor). Outdoor weathering results indicated improved resistance to surface deterioration in modified wood, although increased color change (ΔE) was observed due to the formation of chromophoric groups during curing and subsequent photodegradation. Under the conditions investigated, SorCA modification enhanced biological durability and weathering resistance, especially at higher concentrations. In general, SorCA modification showed great potential to improve the durability of birch wood with enhancing biological durability and weathering resistance.