Search Results (47)

The aim of the work is to analyze the survival strategy of Taxus baccata L., one of the promising plants for landscaping and the creation of woodlands, in the changing ecological conditions of the steppe zone of the Donetsk ridge. In order to achieve this goal, we used biomechanics methods, which help to understand the relationship between the physical and mechanical properties of living tissues and the overall stability of trees during interactions with environmental factors such as temperature, snow and ice storms, cyclic freeze–thaw processes, wind loads, and others. The work was based both on experimental studies on the estimation of the tissue elasticity modulus in response to temperature changes, the mechanical stability of plants, the field collection of materials, and studies on the modeling of forest stand conditions of English yew. As a result of the conducted experiments, it was established for the first time that at the absolute wood moisture content of 77 ± 5.1%, the density of wood tissues in the conditions of Donetsk is 907 ± 43 kg m⁻³. The modulus of elasticity of living tissues depending on the temperature factor varied in the following range: 8.8 ± 0.31 GN m⁻² (T = 288 K), 11.5 ± 0.55 GN m⁻² (T = 255 K) and 6.9 ± 0.47 GN m⁻² (t = 308 K). It was revealed that during the local thawing of skeletal branches and tables, the mechanical resistance of T. baccata is reduced by 20–22% and this critically affects the overall plant resistance. It was established for the first time that T. baccata in the conditions of the steppe zone has an adaptive strategy of preserving the integrity of the organism under the action of environmental factors with limited loads. The secret lies in the formation of the shape memory effect, under the influence of critical loads. The plant, thus, chooses not migration, not death, but adaptation to changes in environmental conditions, which can become a serious factor in the use of T. baccata in the landscaping of urban areas and the creation of artificial forests. Full article

This article analyses the main effect and interaction of thermal modification, wood moisture content, frequency, and vibration direction on the damping of spruce wood. Samples were thermally modified at three different temperatures (180 °C, 200 °C, and 230 °C) and then equilibrated at four different relative humidities (RHs) (20%, 44%, 76%, and 88%). The specimens were then freely supported and excited with a hammer to vibrate freely. Damping at the frequencies of the first three bending vibration modes for vibrations in the radial (LR plane) and tangential (LT plane) directions was determined using the wavelet transform method, which enables a decoupling of the vibration modes and thus a precise and accurate determination of the damping values. Damping increases with the wood moisture content for different modification levels, whereby the damping in the LR vibration direction plane differs from the damping in the LT vibration direction plane. For an unmodified sample and at frequency at the first vibration mode, damping in the radial plane is greater than in the tangential plane, but the relationships change with RHs, modification levels, and vibration direction planes. The dependence of damping on various factors has a strong influence on the calculation of various acoustic indicators, where damping of the wood is considered for the calculation, since damping for the same sample differs depending on the direction of vibration and the frequencies at different vibration modes. Full article

Due to increasing environmental concerns and the scarcity of high-quality hardwood resources, enhancing wood properties—such as strength, surface smoothness, and impact resistance—has become essential, especially for veneer-based products. Wood densification is a promising method for such improvements, typically involving mechanical, thermo-mechanical, or hygrothermal-mechanical processes. However, most prior studies examined only one densification parameter at a time. This study systematically investigates the combined effects of equilibrium moisture content (EMC), pressing temperature, and pressure on birch veneer densification. Birch veneers were densified radially using four temperatures (90–210 °C), three pressures (1.8–5.4 MPa), and three EMC levels (5%–20%) for a fixed pressing time of 8 min, resulting in 36 unique combinations. Results showed that higher pressing pressure and higher initial EMC consistently led to greater veneer densification. Optimal outcomes were achieved under two distinct conditions: (1) 90 °C with high EMC and high pressure, and (2) 210 °C with the same high EMC and high pressure. Intermediate temperatures (130–170 °C) were less effective. Temperatures above 200 °C were found critical due to lignin softening beyond its glass transition temperature. These findings highlight the interactive role of key parameters and provide practical guidance for upgrading low-quality veneers into high-performance engineered wood products in a sustainable and resource-efficient manner. Full article

To address the issue of the deformation recovery in teakwood bending components when they undergo moisture absorption, the potential for superheated steam technology to improve the dimensional stability of the material and the means of optimizing this improvement were systematically analyzed. After setting a medium temperature, treatment time, and initial moisture content, we performed a 120 h water immersion test and dynamic thermo-mechanical analysis (DMA), which revealed the multi-scale mechanism by which superheated steam technology inhibits deformation recovery. It was shown that under the optimized conditions of 130 °C, a 2 h treatment time, and a 30% initial moisture content, the deformation recovery of water-immersed teakwood bending components could be reduced to 2.02–5.13%. The water-absorption resilience was decreased by 41.05% compared with the conventional drying and shaping, which was attributed to the synergistic effect of the degradation of hemicellulose and the cross-linking of lignin, which released residual stresses efficiently. Our investigation of the chemical–mechanical coupling revealed a significant positive correlation between the water-absorption resilience and the hemicellulose content (R² = 0.912), and the interaction of the chemical constituents resulted in a directional evolution of the energy storage modulus and loss modulus, which enhanced the stiffness of the material and effectively inhibited water-absorption resilience. This study provides a theoretical basis and process guidance for the efficient industrialization of solid wood bending components, which has important guiding value for the innovation of manufacturing technology for bending wood furniture. Full article

In multi-layered wood materials, varying rates of dimensional changes can easily lead to cracking, which can have a negative impact on their structure and functionality. This study focuses on cracking issues of decorated blockboard caused by moisture content changes. First, surface cracks on the decorated blockboard were observed and classified using optical microscopy and scanning electron microscopy (SEM). Second, from modeling perspectives, the critical tensile strength of the surface of the decorated blockboard was predicted to be 16.93 MPa, providing guidance for crack-resistant modification. Subsequently, halloysite nanotubes (HNTs) were incorporated into MF-resin-impregnated paper, achieving a Grade 5 crack resistance for decorated blockboard. The interaction between HNTs and MF resin forms a multiscale stress–dispersion system, as confirmed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), indicating hydrogen and covalent bonding between HNTs and the MF resin. With a 5% HNTs addition, the tensile strength and strain break of the MF-resin-impregnated paper reached 36.60 MPa and 1.12%, respectively, representing increases of 97.39% and 60.00%, respectively, effectively preventing surface cracking. This has significant implications for improving the durability and performance of decorated blockboard in practical applications. Full article

The growing environmental concerns associated with petrochemical-based adhesives have driven interest in sustainable alternatives. This study investigates the use of bio-oil, derived from municipal sewage sludge (MSS) through hydrothermal liquefaction (HTL), as a reactive filler in polymeric methylene diphenyl diisocyanate (pMDI) wood adhesives. The bio-oil, rich in hydroxyl and carbonyl functional groups, was characterized using FTIR (Fourier transform infrared spectroscopy), elemental analysis, and NMR (nuclear magnetic resonance). These functional groups interact with the isocyanate groups of pMDI, enabling crosslinking and enhancing adhesive performance. Various MSS bio-oil and pMDI formulations were evaluated for tensile shear strength on Southern yellow pine veneers under dry and wet conditions. The formulation with a 1:4 bio-oil to pMDI weight ratio exhibited the best performance, achieving tensile shear strengths of 1.96 MPa (dry) and 1.66 MPa (wet). Higher bio-oil content led to decreased adhesive strength, attributed to reduced crosslinking and increased moisture sensitivity. This study demonstrates the potential of MSS-derived bio-oil as a sustainable additive in pMDI adhesives, offering environmental benefits without significantly compromising adhesive performance and marking a step toward greener wood adhesive solutions. Full article

In the fire-prone tropical savanna landscapes of northern South America, forest edge effects significantly shape tree structural integrity and functional traits, with implications for ecosystem resilience, carbon storage, and biodiversity. This study examines how the edge effect, intensified by fire, affects species dominance, forest structure, and functional trait distributions in this region. Using non-metric multidimensional scaling (NMDS) and generalized additive mixed models (GAMMs), we analyzed changes in species abundance and structural variables (biomass, basal area, tree height, and wood density), as well as leaf (leaf thickness, leaf moisture, leaf dry matter content (LDMC), and specific leaf area (SLA)) and stem (bark and stem thickness and stem-specific density) traits across edge-to-interior gradients. The key findings indicate significant reductions in tree height (F = 19.27, p < 0.01), basal area (F = 6.52, p < 0.01), and biomass (F = 5.44, p < 0.01) near the edges. Leaf moisture (F = 11.8, p < 0.01) and specific leaf area (SLA, F = 7.02, p < 0.01) increased at the edges, reflecting microenvironmental gradients, with heightened fire sensitivity seen in traits like bark thickness (F = 11.88, p < 0.01). Fire-affected areas displayed intensified adaptive trait shifts, suggesting a compounded resilience but potential functional convergence, limiting adaptive capacity under climate stressors. These findings emphasize the ecological significance of edge–fire interactions, advocating conservation strategies to enhance structural and trait diversity for ecosystem stability. Our study underscores the need for targeted management to bolster resilience and biodiversity within these dynamic landscapes as climate pressures intensify. Full article

Dehydration is the principal conservation process for waterlogged archaeological wood (WAW), with the aim of preventing shrinkage and cracking. For well-preserved WAW, shrinkage mainly takes place when the moisture content is below the fiber saturation point. Here, we conduct a new trial using ionic liquid as a dimensional stabilizer to maintain a stable swollen state of WAW. Molecular dynamics simulation (MD), shrinkage measurement, Fourier transform infrared spectroscopy (FTIR), and dynamic vapor sorption (DVS) were adopted to investigate the interactions and effects of 1-Butyl-3-methylimidazolium chloride ([Bmim][Cl]) on WAW (Dipterocarpaceae Dipterocarpus sp. with a maximum moisture content of 80.3%) in comparison with the conventional material polyethylene glycol (PEG). The results show that [Bmim][Cl] and its water mixtures have a comparable or slightly greater ability to swell amorphous cellulose than does water at room temperature, while crystalline cellulose is left intact. The samples treated with [Bmim][Cl] show less shrinkage than the PEG 300- and PEG 2000-treated samples at all tested concentrations after air-drying. The best dimension control was achieved by 40 wt% [Bmim][Cl], with volumetric shrinkage reduced from 5.03% to 0.47%. DVS analysis reveals that [Bmim][Cl] reduces moisture contents at moderate and low relative humidity (<80%) when the concentration is at or below 20 wt%, which suggests that good dimensional stability was not achieved by simply preserving the moisture content but possibly through the interaction of the ionic liquid with the wood polymers. Full article

Sustainable biomasses are vital to ensure preservation of the Amazon biome within the Mato Grosso State whilst enabling energy generation for the region and its population. Here, the potential of the elephant grass cultivar BRS Capiaçu as an alternative to replace native forest wood as biomass for energy generation is investigated, considering the whole process from plant cultivation to biomass characterisation in terms of productivity of green and dry mass per hectare; density, moisture, ash, volatile and fixed carbon content, as well as higher heating value (HHV). MANOVA indicates that the effects of plant parts and age on density and proximate analysis parameters are influenced by the plant parts and age interaction, whereas HHV can be considered similar between them. The cultivar BRS Capiaçu showed suitable energetic values (17,922 < HHV < 18,918 kJ.kg⁻¹) compared to that of native Amazon wood. Energetic results combined with cultivation outputs of high productivity (dry mass production of 44.1 tonnes.ha⁻¹ at 180 days) with a short cutting interval (3 months), adaptation to the region’s climate and soil, and the possibility of cultivation in areas currently consolidated for agriculture demonstrate the potential of BRS Capiaçu as biomass to reduce native wood usage and deforestation rates. Full article

This study utilized molecular dynamics simulation to investigate the adhesion process between wood tar-rejuvenated asphalt and acid/alkaline aggregate. Initially, various indicators including the contact area, cohesion coefficient, and interaction energy were employed to assess the adhesion effect under dry conditions. This revealed the action mechanism of the wood tar-rejuvenator in enhancing the adhesion performance between aged asphalt and aggregate. Subsequently, an asphalt–water–aggregate interface model was developed to simulate the water damage process of the asphalt mixture. This aimed to unveil the damage mechanism of water intrusion on the adhesion performance of the asphalt–aggregate interface and evaluate the water damage resistance of wood tar-rejuvenated asphalt through adhesion energy, stripping work, and the energy ratio. The findings indicate that wood tar-rejuvenated asphalt exhibits favorable adhesion properties with both acid and alkaline aggregates. The addition of wood tar-rejuvenated asphalt increased the interaction energy between aged asphalt and acid and alkali aggregates by 67.75 kJ/mol and 97.3 kJ/mol, respectively. The addition of a wood tar rejuvenator enhances the interaction energy between aged asphalt and aggregate, thereby increasing mutual attraction and enlarging the contact area. The adhesion between asphalt and aggregates hinges on the interaction between asphaltene and aggregates, and the wood tar rejuvenator reduces the diffusion ability of asphaltene in the attractive state of the aggregate, resulting in stable aggregation. Moisture intrusion increased the aggregation distance between asphaltene and aggregate by 14.1% and decreased the degree of aggregation by 24.0%, thereby reducing the interaction energy. The extent of damage caused by water intrusion is linked to the aggregation distance, with greater distances leading to deeper damage. Under wet conditions, the interaction energy of wood tar-rejuvenated asphalt increased by 78.2% in the acidic aggregate system and 98.1% in the basic aggregate system compared with aged asphalt. Meanwhile, wood tar-based rejuvenated asphalt improves the adhesion between aged asphalt and aggregate and reduces the stripping function of asphalt affected by water replacement, which results in the ER value of wood tar-rejuvenated asphalt being higher than that of the original asphalt by 0.12 and 0.22 in the acidic and alkaline environments, respectively, thus showing excellent resistance to water damage. This study provides new criteria for the selection of rejuvenators for waste asphalt, which will help in the future selection of superior rejuvenators for aged asphalt and reduce the possibility of choosing the wrong rejuvenator. Full article

Materials used to replace peat in growing media include wood fibre (WF), often used in combination with composted bark (BC), coir (CR), green compost (GC), and anaerobic digestate fibre (AD). The physical and chemical properties of these materials are relatively well characterised; however, biological properties are less well understood. Biological stability of growing media is an important factor in plant performance. The aim of this research was to identify whether dynamic respirometry methods are suitable for measuring growing media stability and to assess the effect of blending two raw materials in a mix. Raw materials were run for 42 days in aerated conditions at 35 °C. Except for AD, individually run samples were considered stable, with CO₂ production over 7 days ranked BC < CR < WF < GC << AD in the early stages of the test. The AD was run at two moisture levels, with greater biological activity at lower moisture content. In the most active mixture, AD and WF, there was an increase of activity when nutrients were added at 28 days, indicating major elements were limiting microbial activity. There were interaction effects in sample mixtures, with the CO₂ production of WF + GC, WF + CR greater than the sum of the CO₂ production from the separate components. Full article

In this study, we investigated the drying behavior of a waterborne wood coating (WWC) on pine wood using hot air drying. An analysis of variance of the experimental data revealed that both temperature and humidity exerted significant effects on the surface drying time. An analysis of the structure and wettability indicated a faster moisture migration rate through the cross section than through the tangential section of porous wood. We also determined that temperature, humidity and their interactions significantly affected the glossiness, while temperature had a greater effect on the wear resistance of the WWC films than humidity. The drying conditions had a minimal effect on the adhesion strength. By considering both the drying efficiency and the coating performance, the optimal drying conditions for the WWC on pine wood were determined to be 60 °C and 55% relative humidity. Our findings suggest that establishing a correlation between drying performance and substrate can ensure the quality of WWCs for practical applications in the wood coating industry. Full article

Wood, being a natural hygroscopic material, the interaction between wood and moisture plays a crucial role in wood processing and utilization. Moisture affects the physical and mechanical properties of wood, and is also one of the main external factors that cause wood deformation and cracking. Drying shrinkage is a common phenomenon during the processing and utilization of wood induced by moisture loss. Drying stress is the main cause of wood deformation and cracking. The shrinkage differential between tangential and radial direction and moisture content gradient of wood are two reasons induced the generation of drying stresses. In this review, the existing states of moisture in wood and the interaction between water molecules and wood components were systematically summarized. The current research progress and deficiencies in three aspects including the factors resulted in deformation and cracking in wood caused by moisture loss, the correlation between wood mechanical properties and moisture, as well as the development of deformation and cracking in wood under moisture loss were discussed. This review aims to facilitate further research on the deformation and cracking of wood under moisture loss by providing valuable insights and assistance, ultimately reducing the occurrence of wood deformation and cracking. And thus, it will enhance the overall utilization of wood resources, making wood better serve human life. Full article

The development and utilization of wood briquettes is one of the efforts to reduce dependence on fossil fuels, including to fulfill overseas market need. This study aimed to evaluate the properties of wood briquettes made of the branches of three mangrove species and to analyze the effect of different wood species of mangrove branches, and the types of starch adhesive, on the quality of wood briquettes. The wood briquettes made in this study were 3 cm × 4 cm in a cylindrical shape using three wood species of mangrove branches, namely mata buaya (Bruguiera sexangula), buta-buta (Excoecaria agallocha), and bakau minyak (Rhizophora apiculata), while the adhesives used were tapioca starch, maize starch, and potato starch. The results showed that the moisture, ash content, and calorific value of the wood briquettes mostly met the ISO 17225-3:2-2020 class A2 standard and the specification and quality standards of wood briquettes for Grade A2 issued by the Korea Forest Research Institute, except the density. Wood briquettes made of mata buaya by using the three types of starch adhesives generally had better properties than all other types of wood briquettes. The interaction of mangrove wood species and the types of starch adhesive had a significant effect on the properties of wood briquettes, except for volatile matter and calorific value for which they had no significant effect. The use of wood briquettes from mangrove wood branches contributes to sustainable forest management and maintains the ecological function of mangrove forests while providing environmentally friendly alternative energy for households as a source of fuel/energy. Furthermore, future research is needed, such as investigating the optimal pressing pressure needed to achieve higher density of the wood briquettes. Full article

This work presents a new all-inclusive mathematical model that combines both processes and an energy analysis of a semi-automated biomass-powered multipurpose dryer. A mathematical model was developed and a wood sample was used to simulate the model. Energy interaction between the system and sample was established. Most importantly, the incorporation of a sensor control system ensures that, once there is an increase in thermal energy from the combustion of the biomass, a signal is passed to the temperature sensor module that controls the system’s temperature and hence shuts down the heat supply at a predetermined temperature; in this case, at 67 °C. The results of the system’s modification show that the peak temperature of the drying space and the sample was 67 °C and 56 °C, respectively, and that the maximum temperature lag witnessed by the two regimes was 10 °C. The peak temperature removal rate of the sample was 0.0066 kg/h, while the sample attained 0.4 (40%) moisture concentration of its initial value; 90% mass content removal (10% remaining mass content) of the initial mass of the sample was achieved at the end, with a simulation time of 240 s. Full article