Search Results (390)

The NAC transcription factor superfamily is one of the most prominent plant-specific regulatory gene families, extensively participating in multiple metabolic processes that govern plant growth, tissue development and stress adaptation. Masson pine (Pinus massoniana Lamb.) is a native dominant conifer widely cultivated across South China, whose timber resources possess great exploitation potential in pulp manufacturing and the paper industry. In this study, a total of 98 non-redundant NAC family members were mined at the genome-wide level. Functional validation revealed that PmNAC82, a member belonging to the VND evolutionary subgroup, acts as a core regulatory factor controlling wood formation. Subcellular localization tests confirmed PmNAC82 exclusively resides in the cell nucleus. Heterologous genetic transformation in poplar demonstrated that this gene positively regulates the accumulation of lignin and cellulose. Furthermore, through RT-qPCR, yeast one-hybrid assays, and EMSA, we confirmed that PmNAC82 can bind to the promoters of PtrMYB3, PtrMYB21 and PmCesA7. These findings provide a solid foundation for further investigation into the molecular functions of NAC genes in Masson pine as well as their potential application towards molecular breeding strategies aimed at improving wood quality. Full article

The efficient utilization of hardwood lignocellulosic biomass has attracted increasing attention as a sustainable strategy for the high-value conversion of renewable resources. Chemical-mechanical pulping (CMP) is a promising route for hardwood utilization; however, its performance is strongly influenced by species-dependent differences in chemical composition, macromolecular structure, and physical accessibility. In this study, four representative hardwood species (poplar, sycamore, eucalyptus, and acacia) were selected as model feedstocks to investigate the relationships between structural characteristics and CMP performance in alkali-assisted systems. The chemical composition and structural features of cellulose, hemicellulose, lignin, and lignin-carbohydrate complexes were characterized, together with key physical parameters including density, porosity, and fiber morphology. The effects of alkali charge on fiber softening, fibrillation development, and paper properties were then evaluated. The results revealed pronounced species-dependent differences in alkali response, which were closely correlated with variations in cellulose supramolecular organization, hemicellulose substitution characteristics, lignin structural features, lignin-carbohydrate associations, and wood microstructure. This study provides a comprehensive qualitative comparative analysis of the relationships between wood structural features and CMP performance. Hardwoods with lower density and higher porosity exhibited more efficient alkali penetration and superior performance under mild conditions, whereas denser species such as sycamore and eucalyptus required higher alkali charge. This work provides important insights into the structure-performance relationships governing alkali-assisted CMP behavior, and offers useful guidance for the efficient utilization of lignocellulosic biomass in pulp and paper applications. Full article

Wood is a sustainable material, but hygroscopicity can affect dimensional stability and mechanical durability. Recent research has increasingly focused on combining citric acid with various polyols as eco-friendly crosslinking systems to improve wood properties. Herein, a solvent-free and catalyst-free method was used to synthesize bio-based polyesters from citric acid and mannitol. In situ curing was carried out after vacuum-pressure impregnation of fast-growing poplar wood (Populus deltoides Marshall). Morphological characterization showed that the polyester filled the cell lumen and penetrated the cell wall structure. It was confirmed by Fourier Transform Infrared (FTIR) and cross-polarization/magic angle spinning (CP/MAS) ¹³C nuclear magnetic resonance (NMR) analysis that the polyester formed covalent ester bonds with wood hydroxyl groups, which indicated successful chemical grafting. The dimensional stability and mechanical properties of the modified wood were greatly improved. The parallel compressive strength of the grain reached 41.5 MPa, which was 41.7% higher than that of the untreated wood. This research adopted a citric acid–mannitol polyester, providing a sustainable, economical, and scalable approach for the development of high-performance, degradable wood composites for construction/furniture applications. Full article

Housing industrialization and modularization have gained traction as responses to two pressing challenges in the construction sector: the chronic shortage of affordable housing and the substantial environmental footprint of conventional building methods. Yet prevailing modular housing models in Europe remain constrained by dependence on global supply chains, production concentrated in large industrial operators, and insufficient adaptation to local material and territorial conditions. This article presents a state-of-the-art review of modular timber housing in Europe, examining technological typologies, market structures, and national regulatory frameworks. The methodology integrates a systematic literature and market review, a comparative country analysis, and an embedded case study. Findings indicate that the viability of modular timber housing depends not only on material performance but on its embeddedness in coherent industrial systems, business strategies, and regulatory contexts. Against this backdrop, the VICHO project is introduced as a case study exploring an open, proximity-based industrialization model that valorizes local poplar timber in southern Europe, in alignment with circular bioeconomy principles and the New European Bauhaus. Full article

Oxidative catalytic fractionation (OCF) under the lignin-first strategy has emerged as a critical technological approach for biomass refining. To address the inevitable carbohydrate degradation and lignin condensation in conventional OCF, this study designed a cobalt-doped layered double hydroxide oxide (Co-LDO) catalyst compatible with non-alkaline (without Brønsted bases) organic systems, which exhibits excellent performance in poplar biomass OCF. With a straightforward preparation process, the Co-LDO catalyst yields high-content oxidized lignin oligomers while efficiently retaining carbohydrates, providing feedstock rich in carbohydrates (cellulose and hemicellulose) for the subsequent production of bioenergy and biomass-based chemicals. Under optimized conditions screened via systematic reaction condition investigation and metal-doped LDO catalyst evaluation, the process achieved a 94.01 wt% delignification rate, with 72.19 wt% of lignin converted into lignin oligomer oil, supported by detailed product composition and structural characterization. Meanwhile, 74.14 wt% hemicellulose and 98.23 wt% cellulose were recovered in solid residues, with structurally intact hemicellulose retention being 2.3 times higher than in traditional OCF. Mass balance calculation confirmed a total poplar refining yield of 81.58 wt%. In summary, this Co-LDO-catalyzed OCF strategy provides a high-activity non-precious metal system, effectively suppressing lignin condensation while preserving high-yield carbohydrates, realizing the efficient full-component refining of poplar biomass. Full article

This study investigated the surface characteristics and wettability behaviour of grey poplar (Populus × canescens) compared with spruce (Picea abies) in order to evaluate its potential as an alternative raw material for bonded structural wood products. Surface roughness was analysed on freshly planed radial surfaces using amplitude and functional roughness parameters, complemented by multivariate factor analysis and dynamic contact angle measurements. The results showed that grey poplar sapwood exhibited roughness values comparable to spruce (R_a ≈ 6–7 μm; R_z ≈ 35–40 μm). Grey poplar heartwood showed slightly higher roughness and greater variability, which can be attributed to its heterogeneous anatomical structure characterised by larger vessel elements and higher extractive content. Hybrid roughness parameters indicated favourable bonding-related surface characteristics in sapwood due to lower R_pk values, suggesting fewer protruding fibres, while higher R_vk values reflected the diffuse-porous anatomical structure of poplar. Static contact angle measurements revealed higher initial values for grey poplar (37.9° for heartwood and 41.9° for sapwood) compared with spruce (31.7°), indicating lower initial wettability with polar liquids. However, dynamic measurements demonstrated faster early-stage spreading in grey poplar heartwood (Δθ = 26.1° within the first second) compared with sapwood (16.8°) and spruce (17.5°), suggesting that vessel-driven capillary uptake may facilitate liquid penetration once wetting begins. Overall, the results indicate that grey poplar—particularly its sapwood fraction—exhibits surface characteristics comparable to spruce after planing. Despite slightly lower initial wettability, its spreading behaviour and surface morphology indicate favourable conditions for adhesive interaction. These findings support the potential use of grey poplar as an alternative raw material for laminated structural products such as glulam or bonded panels, provided that adhesive application parameters are properly adjusted. Full article

Addressing the challenges of multi-parameter interactions and unclear micro-mechanisms in poplar biomass panel manufacturing, this study employed a multi-scale approach integrating statistical optimization, microstructural characterization, and mechanism validation. A central composite design was used to investigate the effects of pressing time, pressure, and baking temperature (conditioning step) on modulus of rupture (MOR), modulus of elasticity (MOE), water absorption (WA), and thickness swelling (TS), establishing predictive models for multi-objective performance. Quantitative SEM analysis correlated macroscopic properties with microstructural parameters (porosity, pore size distribution, fiber–fiber contact ratio), elucidating how process conditions govern performance via interface quality and material densification. The optimized parameters yielded panels with MOR of 30.04 MPa, MOE of 10,716 MPa, WA of 4.98%, and TS of 1.75%. Modifier incorporation enhanced MOR and MOE by 23.10% and 26.38%, respectively, while reducing WA and TS by 50.59% and 29.89%. SEM confirmed an improvement in fiber–matrix interfacial bonding under optimized conditions. Environmental emission and combustion tests validated compliance with green development principles. This work establishes a cross-scale framework linking processing, microstructure, and performance, offering theoretical foundations for green manufacturing of high-performance biomass panels. Full article

In this study Laminated Veneer Lumber (LVL)—widely used in structural wood applications—was manufactured from seven poplar veneers bonded with polyurethane (PU) adhesive and reinforced with either one sheet of glass fiber or carbon fiber fabrics. In order to determine the effects of the fiber fabrics incorporated into the structure of the produced LVLs on their thermal and acoustic insulation performance in structural applications, the thermal conductivity coefficient (λ), thermal transmittance (U), sound absorption coefficient (α), and sound transmission loss (dB) values were determined. The experimental results indicated that the thermal conductivity coefficient of the glass fiber-reinforced LVL was lower than that of both the control group and the carbon fiber-reinforced LVL. The thermal transmittance coefficient, an important indicator of thermal insulation performance in buildings, followed a similar trend. Regarding the sound absorption coefficients, the fiber fabric-reinforced LVL samples demonstrated lower coefficients compared to the control group. For sound transmission loss, no significant differences were observed among the groups, and the sound transmission loss was found to increase with frequency. Results indicate that glass fiber-reinforced LVL composites can be used as replacement of other wood-based insulating materials in green buildings which exhibit worse sound insulation or thermal insulation and which are significantly more affected by changes in relative humidity of surrounding air. Full article

Thermo-hydro-mechanical (THM) densification is an effective method for improving the mechanical performance of low-density, fast-growing hardwoods such as poplar. This study examined the bending performance of THM-densified poplar wood at different compression ratios (CR = 0%, 50%, 60%, and 65%), with emphasis on the effects of ultrasonic pretreatment (US) and thermal modification posttreatment (TM), applied individually and in combination. A paired sampling design was used to reduce material variability, and modulus of rupture (MOR) and modulus of elasticity (MOE) were evaluated using linear mixed-effects models (LMM). Bending tests were performed in accordance with EN 310:1993. Increasing the compression ratio led to substantial increases in MOR and MOE; compared with non-densified specimens, MOR increased by approximately 240% and MOE by about 140% at CR = 65%, confirming densification as the dominant factor controlling bending performance. US did not affect non-densified wood but significantly enhanced MOR and MOE after densification, particularly at CR = 50%. In contrast, TM consistently reduced MOR and, to a lesser extent, MOE across all compression ratios. The results demonstrate that the bending performance of densified poplar wood is governed by both compression ratio and compression-dependent treatment effects. Full article

Perennial trees in temperate regions precisely coordinate the timing of seasonal growth cessation and dormancy with environmental cues, primarily photoperiod. While the roles of abscisic acid (ABA) in dormancy regulation are well-established, its function in growth cessation remains less defined. ABSCISIC ACID-INSENSITIVE 5 (ABI5) is a basic leucine zipper transcription factor that plays a central role in ABA-mediated development and abiotic stress responses, yet its roles in photoperiodic regulation of growth cessation and its coordination with radial stem growth remain unknown. Here, we demonstrate that in poplar (Populus tomentosa) trees, exogenous ABA application exacerbated short-day (SD)-induced growth inhibition, accelerated bud set, and strongly suppressed secondary xylem formation. We identified a Populus ABI5 homolog, PtoABI5, whose expression is induced by both ABA and SDs. Overexpression of PtoABI5 phenocopied and enhanced SD responses, leading to premature growth cessation and a pronounced inhibition of cambial division and wood formation under SDs. Conversely, PtoABI5 suppressed the expression of the GA biosynthesis gene, while it enhanced the expression of GA catabolic genes. Exogenous GA application partially rescued both the apical growth defects and the impaired secondary xylem development in PtoABI5-overexpressing plants. Our findings establish PtoABI5 as a central integrator, linking ABA and GA signaling pathways to coordinately arrest shoot apical growth and seasonal wood formation, thereby fine-tuning the seasonal growth cycle in perennial trees. Full article

The accurate and non-invasive measurement of moisture content in wood is essential for the preservation of historical and artistic artifacts. This study presents the calibration of a planar Microwave Planar Capacitive Coupled Ring Resonator (MPCCRR) designed to indirectly and non-destructively assess the water content in wood samples. The method relies on analyzing shifts in the resonant frequencies and variations in the transmission parameter |S21| resulting from changes in the material’s dielectric permittivity. After preliminary characterization via parametric simulations (εr = 1–10) and validation with low-permittivity reference materials, the sensor was tested on three wood species (poplar, fir, beech), including measurements at two sensor positions and with different grain orientations. The results demonstrate a monotonic, repeatable response to increasing moisture content with frequency shifts up to ≈220 MHz and normalized sensitivities ranging from 3 to 9 MHz/% water content, depending on species and measurement position. Position 2 showed the greatest sensitivity due to stronger field–sample interaction, while Position 1 provided a quasi-isotropic response with excellent repeatability. Linear regression analyses revealed good correlations between the frequency shifts and the gravimetric water content (R² ≥ 0.85). The MPCCRR sensor therefore proves to be a promising tool for the non-invasive monitoring of wood moisture, which is particularly suitable for the low-moisture range encountered in cultural heritage conservation, with an estimated moisture uncertainty of 0.12–0.35% under controlled laboratory conditions. Full article

The problem of urban surface runoff (USR) treatment is associated with the presence of high concentrations of specific pollutants. One of these pollutants is petroleum product (PP), whose concentration depends on the season and the location of the formation of snow masses, meltwater, and rainwater. For USR treatment, it is possible to use very environmentally friendly and inexpensive technologies. The article discusses natural sorbents based on wood materials, which effectively remove dissolved petroleum products from water. Pine sawdust and shredded branches of maple, birch, and poplar are used as raw materials, which are waste products from the city’s woodworking enterprise and utilities. These materials were pre-microwave (MW) treated to improve their sorption properties. As a result of the experiment, it turned out that modified pine sawdust and crushed maple pinwheels proved to be the most effective sorbents. The maximum sorption capacity values were 0.689 mg/g and 0.952 mg/g for pine and maple sorbents, respectively. This article proposes schemes for filtering devices that can be used in practice in an urban environment. Full article

Megaplatypus mutatus, a major poplar pest in South America, tunnels into the xylem, weakening trunks and reducing wood quality. Volatile organic compounds (VOCs) are key mediators of plant–insect interactions and may reflect genotype-specific defence strategies. This study analysed VOC profiles of young and adult Populus deltoides cv. Harvard and P. × canadensis cv. Conti 12 under natural M. mutatus infestation. Gas chromatography–mass spectrometry putatively annotated 31 VOCs, including green leaf volatiles (GLVs), pentyl leaf volatiles (PLVs), terpenes, alcohols, aromatics and phenolics, 12 of which, to our knowledge, have not been previously reported in Populus VOC profiles. Harvard trees showed ~14.5-fold higher total VOC abundance than Conti trees. In Conti, constitutive VOC emissions remained stable regardless of infestation status or age. In contrast, under infestation, Harvard trees emitted10-fold higher constitutive VOCs than non-infested Harvard trees and ~52-fold higher than Conti, a pattern consistent with increased defensive activity. GLVs and PLVs relatively dominated both genotypes, although Harvard showed higher emissions. Terpenes were not detected in young Conti trees under our analytical conditions but were abundant and diverse in infested Harvard trees, which may indicate a stronger terpene-associated response in this clone. Several compounds were detected only under specific genotype–condition combinations in our dataset and therefore represent candidate volatiles for future behavioural and functional studies. These results are consistent with differences in VOC emission patterns between genotypes and age classes, improve our understanding of putative chemical cues in the interaction between Populus and M. mutatus, and provide a basis for future work towards sustainable pest management strategies. Full article

As a fast-growing timber tree species with a wide cultivation area, poplar is facing the problem of declining economic benefits under long-term monoculture. Intercropping provides an effective solution. Using Illumina Miseq sequencing, we analyzed soil microbiomes under four patterns: poplar monoculture, and intercropping with amorpha fruticosa, black locust, or cassia seed. The results showed that the Alpha diversity index of intercropping area was significantly higher than that of single planting poplar area under intercropping and monoculture conditions. In the intercropping area, the highest species richness was the intercropping of poplar and black locust, and the lowest was the intercropping of poplar and amorpha fruticosa. The dominant microorganisms in the intercropping mode were Vicinamibacterales, and the fungi were Alternaia and Enterocarpus. In the single planting poplar area, a large number of bacteria gathered in the soil were Dongia and Alphaproteobacteria, and fungi were Fusarium and Mortierella. Functional prediction results showed that the biosynthetic function of ansamycin was the highest in the bacterial community. In the intercropping area, the functional abundance of methanol oxidation, sulfate respiration, sulfate compound respiration, nitrate denitrification, nitrite denitrification, and nitrous oxide denitrification was higher than that in the single planting poplar area. On the contrary, the abundance of methanotrophy function is lower than that of single planting poplar area. In the fungal community, the functional abundance of animal pathogens and the animal pathogen–dung saprotroph–endophyte–plant saprotroph–soil saprotroph–wood saprotroph group in the monoculture poplar area was higher than that in the three intercropping areas. In summary, the intercropping mode of poplar is better than the monoculture mode, and the species richness is the highest when poplar and black locust are intercropped. Therefore, the intercropping pattern of poplar and other tree species improved microbial community. This provides some theoretical guidance for the subsequent solution of continuous cropping obstacles in poplar. Full article

Specialized poplar plantations are relevant for wood-based panel production. In recent years, the Italian poplar sector has progressively moved towards more sustainable cultivation systems. Breeding programs developed new clones with fast growth and increased disease resistance. Agroforestry (AF) has emerged as a promising alternative to the conventional plantation (C), and its ecosystem services have been widely documented. This exploratory study compares the main physico-mechanical properties of solid wood from five new poplar clones cultivated in conventional and agroforestry plantation models. The peeling yields and the performances of plywood produced with their veneers are also investigated. Wood was obtained by harvesting seven-year-old trees in two experimental plantations located in the Veneto Region. All the clones were found to have a higher basic density than that of the ‘I-214’, the reference in the sector, and were suitable for veneers production. It was possible to obtain top-quality sheets from trees of both systems, with some differences between clones. However, the overall quality of the veneers depended on the type of clone and on the cultivation system, where conventional plantations provided better results. Higher mechanical performances were found in plywood produced from clones with higher density. The results provide knowledge to optimize agroforestry cultivation of poplar, also as a complementary source of timber supply for the concerned industrial sector. Full article