Search Results (81)

The purpose of this study was to establish the relationship between the chilling resistance of rubber trees and the bark-bleeding characteristics caused by chilling stress, considering physiological indicators in rubber tree bark, cell wall chemical components, fiber morphologies, and tensile properties. This offered a unique perspective for examining the underlying mechanisms of latex bleeding and chilling stress in Hevea brasiliensis. One-year-old seedlings and two-year-old twig segments in five- and twenty-one-year-old rubber trees (5YB and 21YB) were used to compare the age-mediation differences in their various parameters. Meanwhile, the LT₅₀ values were calculated with Logistic regression analysis of relative electrical conductivity (REC) data under gradient low temperatures. Subsequently, changes in corresponding parameters of 1-year-old seedling stem bark at different ages were determined, and the bark-bleeding characteristics of seedlings and twig segments were analyzed under artificially simulated chilling stress, respectively. A correlation analysis between semi-lethal temperature (LT₅₀) values, relative water content (RWC) values, bark-bleeding characteristics, cell-wall chemical component contents, fiber dimensions, and tensile property parameters was implemented to estimate interrelationships among them. The LT₅₀ values ranged from −2.0387 °C to −0.8695 °C. The results showed that the chilling resistance order of rubber trees at different ages was as follows: 21YB (2-year-old twig bark from 21-year-old rubber trees) > 5YB (2-year-old twig bark from 5-year-old rubber trees) > SLB (semi-lignification bark in 1-year-old seedlings) > GB (green bark in 1-year-old seedlings). The chilling resistance of seedlings and twig segments in rubber trees was highly positively (p < 0.001) related to fiber morphologies. Chilling-induced bark-bleeding characteristics were significantly correlated (p < 0.001) with fiber morphologies, bark tensile properties, and cell-wall components. The analysis data in this study contribute towards building a comprehensive understanding of the mechanisms of chilling-induced bark bleeding needed not only in rubber tree cultivation but also in sustainable rubber production. Full article

Chile is among the leading global exporters of pulp and paper, supported by extensive plantations of Pinus radiata and Eucalyptus spp. This review synthesizes recent progress in the valorization of forestry biomass in Chile, including both established practices and emerging bio-based applications. It highlights advances in lignin utilization, nanocellulose production, hemicellulose processing, and tannin extraction, as well as developments in thermochemical conversion technologies, including torrefaction, pyrolysis, and gasification. Special attention is given to non-timber forest products and essential oils due to their potential bioactivity. Sustainability perspectives, including Life Cycle Assessments, national policy instruments such as the Circular Economy Roadmap and Extended Producer Responsibility (REP) Law, are integrated to provide context. Barriers to technology transfer and industrial implementation are also discussed. This work contributes to understanding how forestry biomass can support Chile’s transition toward a circular bioeconomy. Full article

Caragana korshinskii, a protein-rich feed plant in arid regions, lacks comprehensive nutrient analysis. This study compared the chemical composition of its five parts (leaves, bark, twigs, branches, and stems) and evaluated protein quality through amino acid profiling and enzymatic digestion. Results showed that leaves and bark contained higher crude protein (16.6–18.6%) than stems (6.8%), with fiber components (NDF > 81% and ADF > 65%) contributing to structural rigidity. Aspartic acid dominated caragana proteins, while bark and twigs exhibited elevated proline levels. CNCPS analysis revealed leaves contained 53.3% intermediately degradable protein (PB₂) versus 11.6% non-protein nitrogen (PA), whereas bark and twigs had 38.8% and 45.8% PA, respectively. Despite higher PA content, bark and twigs demonstrated superior in vitro protein digestibility (73.2% and 67.4%) compared to leaves (61.2%). The findings established baseline nutritional data, highlighting part-specific variations in protein characteristics critical for optimizing caragana’s application in animal feed technology within resource-limited ecosystems. Full article

Paper-based packaging materials have gained attention from academia and industry for their outstanding environmental sustainability advantages. However, they still encounter major challenges, such as low mechanical strength and inadequate functionality, hindering the replacement of unsustainable packaging materials. Inspired by the remarkable strength of trees provided by cellulose fibers and the water and heat protection of trees provided by bark, this study developed a new biomass-based packaging material (SNC-C) that combines strength, thermal insulation, and water resistance. The material was created by simply blending straw nanocellulose (SNC) with oak bark (i.e., cork), which naturally provides water-resistant, thermal insulation, and unique regenerative properties. The dense layered structure formed entirely by SNC generates a tensile strength reaching up to 60.93 MPa. With the cork cavity structure, the heat transfer rate of the obtained material is reduced to 2.90–3.01 °C/(cm·min). The combining of the closed-cell structure and the suberin component of the cork results in a low water vapor transmission rate (WVTR) of the material of 400.30 g/(m²·24 h). This all-biomass material with excellent performance and low environmental footprint offers a promising solution for the development of sustainable multifunctional packaging materials. Full article

The continuous rise in global demand for wood products has led to an increase in prices and a surge in research into alternative resources. As a byproduct of the timber industry, bark has emerged as a promising supplement in particleboard (PB) production. However, its anatomical structure, the presence of extractives, and its inferior mechanical properties complicate the production process, which have not yet been fully overcome at a commercial scale. This study proposes a paradigm shift, advocating for separate and specialized bark constituent processing in a wet state. Three bark-based raw materials—namely, outer bark particles, bark fiber clumps, and bark fibers—were investigated under varying wood content scenarios. PBs with a target density of 0.7 g/cm³ and a thickness of 16 mm were produced using mixtures of these bark-based materials and wood particles in different ratios bonded with a urea–formaldehyde adhesive. The results demonstrated that these bark constituents exhibit distinct properties that can be optimized through tailored processing techniques. Compared to bark fibers, outer bark particles displayed about 40% lower water absorption and thickness swelling. However, bark fibers improved the internal bond by about 50% due to their favorable morphology compared to outer bark. These findings highlight the potential of bark as a valuable resource for particleboard production and pave the way for its efficient utilization through specialized processing strategies. Full article

In this study, the feasibility of using bamboo bark fibers as modifiers to enhance asphalt mortar performance was investigated. Bamboo bark fibers were modified with NaOH, KH570 silane coupling agent, and nano-SiO₂, and their preparation methods were established. The modified fibers were assessed for their oil absorption, thermal stability, and hydrophobicity. The asphalt mortar was evaluated for three key indicators: rutting resistance, deformation resistance, and durability at high temperatures. The microscopic morphology and modification mechanisms of the fibers were also studied. The results showed that modification with NaOH increased fiber porosity and surface roughness, while KH570 and its hydrolysis products enabled nano-SiO₂ grafting onto the fibers, improving their adsorption to asphalt. The NaOH-KH570-nano-SiO₂ ternary-composite-modified bamboo bark fiber (NKSBF) demonstrated superior hydrophobicity, oil absorption, and thermal stability at the asphalt mixing temperature. Among the modified fibers, asphalt mortar containing 3% NKSBF showed the best performance based on three key indicators, increased the shear strength by 96.4% and the softening point by 7.1% compared to the base asphalt, and increased the ductility by 1% compared to lignin fiber asphalt mortar. The incorporation of 3% bamboo bark fibers improved the rutting resistance, deformation resistance, and durability of short-term-aged asphalt mortar, with NKSBF showing the most significant improvement. Full article

Traditional thermal insulation panels consume large amounts of energy during production and emits pollutants into the environment. To mitigate this impact, the development of bio-based materials is an attractive alternative. In this context, the characteristics of the Eucalyptus fiber bark (EGFB) make it a candidate for insulation applications. However, more knowledge about the manufacturing process and in-service performance is needed. The present study characterized the properties that determine the in-service behavior of the EGFB insulation panel. The assessment involved two different manufacturing processes. The results indicated that the hot plates and the saturated steam injection manufacturing system can produce panels with similar target and bulk density. The thermal conductivity fluctuated between 0.064 and 0.077 W/m·K, which indicated good insulation, and the values obtained for thermal diffusivity (0.10–0.37 m mm²/s) and water vapor permeability (0.032–0.055 m kg/GN s) are comparable with other commercially available panels. To guarantee a good in-service performance, the panels need to be treated with flame retardant and antifungal additive. The good performance of the panel is relevant because bio-based Eucalyptus bark panels generate less CO₂ eq and require less energy consumption compared to traditional alternatives, contributing to the sustainability of the forestry and the construction industry. Full article

In the context of global sustainable development, using natural fibers as reinforcement for composites have become increasingly attractive due to their lightweight, abundant availability, renewability, and comparable specific properties to conventional fibers. This paper investigates the tensile properties of a sycamore bark fiber-reinforced composite. The tensile tests using digital image correlation showed that, by adding 18% by volume of sycamore bark for the polyester matrix, the tensile modulus achieves 4788.4 ± 940.1 MPa. Moreover, the tensile strength of the polyester resin increased by approximately 90% when reinforced with sycamore bark fiber, achieving a tensile strength of 64.5 ± 13.4 MPa. These mechanical properties are determined by the way loads are transferred between the polyester matrix and fibers and by the strength of the bond between the fiber-matrix interfaces. Since it is difficult and time consuming to characterize the mechanical properties of natural fibers, an alternative approach was proposed in this study. The method consists of the identification of the fiber elastic modulus using a finite element analysis approach, based on tensile tests conducted on the sycamore bark fiber-reinforced composites. The model correctly describes the overall composite behavior, a good agreement is found between the experimental, and the finite element predicted stress–strain curves. The identified sycamore bark fiber elastic modulus is 17,763 ± 6051 MPa. These results show that sycamore bark fibers can be used as reinforcements to produce composite materials. Full article

The anticoccidial monensin (MON) is a high-concern emerging pollutant. This research focused on six low-cost bio-adsorbents (alfa, cactus, and palm fibers, and acacia, eucalyptus, and zean oak barks), assessing their potential for MON removal. Batch adsorption/desorption tests were carried out, and the results were fitted to the Freundlich, Langmuir, Linear, Sips, and Temkin models. The concentrations adsorbed by the six materials were very similar when low doses of antibiotic were added, while they differed when adding MON concentrations higher than 20 µmol L⁻¹ (adsorption ranging 256.98–1123.98 μmol kg⁻¹). The highest adsorption corresponded to the sorbents with the most acidic pH (<5.5) and the highest organic matter and effective cation exchange capacity values (eucalyptus bark and acacia bark, reaching 92.3% and 87.8%), whereas cactus and palm fibers showed the lowest values (18.3% and 10.17%). MON desorption was below 8.5%, except for cactus and palm fibers. Temkin was the model showing the best adjustment to the experimental data, followed by the Langmuir and the Sips models. The overall results indicate that eucalyptus bark, alfa fiber, and acacia bark are efficient bio-adsorbents with potential for MON removal, retaining it when spread in environmental compartments, reducing related risks for human and environmental health. Full article

The forest industry produces several low-value by-products, such as bark, sawdust, limbs, and leaves, that are not ultimately disposed of and remain in the forests and sawmill facilities. Among these by-products are leaves, which contain not only cellulose fibers and lignin but also essential oils such as terpenes. These are biosynthesized in a similar way as cis-1,4-polyisoprene. In this context, this work evaluates the use of screened and unscreened dried Eucalyptus nitens leaves in natural rubber. Among the most relevant results of this work is a significant increase in mechanical properties, such as tensile strength and elongation at break, reaching values of 9.45 MPa and 649% of tensile strength and elongation at break, respectively, for a sample of natural rubber containing sieved dried leaves of Eucalyptus nitens. In addition, it is observed that the content of this vegetable filler allows for inhibiting the antibacterial effect of vulcanized rubber against several bacteria, such as Bacillus subtilis, Staphylococcus aureus, Escherichia coli K 12, Escherichia coli FT 17 and Pseudomonas fluorescens. These results are promising because they not only add value to a by-product of the forestry industry, improving the mechanical properties of natural rubber from a sustainable approach but also increase the affinity of rubber with bacterial microorganisms that may play a role in certain ecosystems. Full article

Degumming is a critical process in the purification of natural fibers, essential for enhancing their quality and usability across various applications. Traditional degumming methods employed for natural fibers encounter inherent limitations, encompassing prolonged procedures, excessive energy consumption, adverse environmental impact, and subpar efficiency. To address these challenges, a groundbreaking wave of degumming technique has emerged, transcending these constraints and heralding a new era of efficiency, sustainability, and eco-friendly techniques. This study represents the Firmiana simplex bark (FSB) fiber’s delignification by using deep eutectic solvents (DESs). The study explores the application of deep eutectic solvents, by synthesizing different types of DES using a hydrogen bond acceptor (HBA) and four representative hydrogen bond donors (HBDs) for FSB fiber degumming. This study investigates the morphologies, chemical compositions, crystallinities, and physical properties of Firmiana simplex bark fibers before and after the treatment. Furthermore, the effects and mechanisms of different DESs on dispersing FSB fibers were examined. The experimental results showed that choline chloride-urea (CU)-based DES initiates the degumming process by effectively disrupting the hydrogen bond interaction within FSB fibers, primarily by outcompeting chloride ions. Following this initial step, the DES acts by deprotonating phenolic hydroxyl groups and cleaving β-O-4 bonds present in diverse lignin units, thereby facilitating the efficient removal of lignin from the fibers. This innovative approach resulted in significantly higher degumming efficiency and ecofriendly as compared to traditional methods. Additionally, the results revealed that CU-based DES exhibits the utmost effectiveness in degumming FSB fibers. The optimal degumming conditions involve a precise processing temperature of 160 °C and a carefully controlled reaction time of 2 h yielding the most favorable outcomes. The present study presents a novel straightforward and environmentally friendly degumming method for Firmiana simplex bark, offering a substantial potential for enhancing the overall quality and usability of the resulting fibers. Our findings open new pathways for sustainable fiber-processing technologies. Full article

Detailed anatomical features of bark are used and interpreted in plant taxonomy, phylogenetics, and other areas of plant science. However, the delicate nature of bark cells, combined with the difficulty of obtaining high-quality sections and reliable data, limits the potential for utilizing and processing bark. In this study, the anatomical structure of the bark of 10 Quercus species growing in Yunnan Province, China, was characterized in detail. The results indicate that the anatomical features of the barks of 10 Quercus spp. show a certain degree of consistency. Specifically, sieve tubes are distributed in solitary elements or in small groups, mostly as compound sieve plates containing 2–8 sieve areas, suggesting that Quercus spp. may occupy a conservative evolutionary position. Additionally, for the first time, this study reports the presence of simple sieve plates in the sieve tube elements of Quercus phloem. Each sieve tube element has a companion cell on one side. The companion cell strands contain 2–7 cells. Axial parenchyma is diffuse, with parenchyma strands typically consisting of 4–7 cells; druses are present within chambered crystalliferous cells. Phloem rays are of two distinct sizes and often exhibit dilatation and sclerification, and the ray composition consists of procumbent cells. Sclerenchyma is composed of fibers and sclereids, both of which contain prismatic crystals. Most of the fibers are gelatinous fibers, which are distributed in discontinuous tangential bands of about five cells in width. Sclereids appear in clusters. The presence of sclerenchyma provides mechanical support to the bark, reducing the collapse of the phloem. Periderm usually consists of around 10–30 layers of phellem, and Quercus acutissima and Q. variabilis can reach dozens or hundreds layers. The phelloderm typically consists of from two to five layers, with Q. variabilis having up to ten or more layers. The filling tissue of lenticels in all Quercus species is nonstratified (homogeneous) and largely nonsuberized. Overall, this study enriches our comprehension of Quercus bark anatomy, elucidating evolutionary patterns, functional adaptations, and ecological ramifications within this significant botanical genus. Full article

Ramie is one of the most important fiber crops in China, with fibers extracted from stem barks having been used as textile materials for thousands of years. DNA methylation is an important epigenetic modification involved in plant growth and development. However, the role of methylation in ramie fiber growth remains poorly understood. In the present study, we investigated the DNA methylation landscape of the nuclear genome in bark sections taken from the top (TPS) and the middle (MPS) of the stems of ramie plants, which represent different stages of fiber growth, using whole-genome bisulfite sequencing. We detected 7,709,555 and 8,508,326 5-methylcytosines in the TPS and MPS genomes, respectively. The distribution of methylation across three sequence contexts, CG, CHG, and CHH, varied greatly among gene elements, with methylation at CHH being the most prevalent. Comparison of methylation levels between the TPS and MPS genomes revealed 23.162 Mb of differentially methylated genomic regions, encompassing 9485 genes. Among these differentially methylated genes, 841 exhibited altered expression in the MPS genome. Notably, an SND2 ortholog Bni05G006779 showed a negative correlation between its expression and methylation levels. Overexpression of Bni05G006779 in Arabidopsis dramatically increased the number of xylem fibers and the secondary wall thickness of the fibers in the stems of transgenic plants. These findings provide important insights into the involvement of DNA methylation in regulating ramie fiber growth. Full article

Cynometra iripa Kostel. is a Fabaceae species of mangrove used in traditional Ayurvedic medicine for treating inflammatory conditions. The present study aims to establish monographic botanical and chemical quality criteria for C. iripa leaf and bark as herbal substances and to evaluate their in vitro antioxidant potential. Macroscopic and microscopic qualitative and quantitative analyses, chemical LC-UV/DAD-ESI/MS profiling, and the quantification of key chemical classes were performed. Antioxidant activity was evaluated by DPPH and FRAP assays. Macroscopically, the leaf is asymmetrical with an emarginated apex and cuneate base. Microscopically, it shows features such as two-layered adaxial palisade parenchyma, vascular bundles surrounded by 3–6 layers of sclerenchyma, prismatic calcium oxalate crystals (5.89 ± 1.32 μm) along the fibers, paracytic stomata only on the abaxial epidermis (stomatal index–20.15), and non-glandular trichomes only on petiolules. The microscopic features of the bark include a broad cortex with large lignified sclereids, prismatic calcium oxalate crystals (8.24 ± 1.57 μm), and secondary phloem with distinct 2–5 seriated medullary rays without crystals. Chemical profile analysis revealed that phenolic derivatives, mainly condensed tannins and flavonoids, are the main classes identified. A total of 22 marker compounds were tentatively identified in both plant parts. The major compounds identified in the leaf were quercetin-3-O-glucoside and taxifolin pentoside and in the bark were B-type dimeric proanthocyanidins and taxifolin 3-O-rhamnoside. The total phenolics content was higher in the leaf (1521 ± 4.71 mg GAE/g dry weight), while the total flavonoids and condensed tannins content were higher in the bark (82 ± 0.58 mg CE/g and 1021 ± 5.51 mg CCE/g dry weight, respectively). A total of 70% of the hydroethanolic extracts of leaf and bark showed higher antioxidant activity than the ascorbic acid and concentration-dependent scavenging activity in the DPPH assay (IC₅₀ 23.95 ± 0.93 and 23.63 ± 1.37 µg/mL, respectively). A positive and statistically significant (p < 0.05) correlation between the phenol content and antioxidant activity was found. The results obtained will provide important clues for the quality control criteria of C. iripa leaf and bark, as well as for the knowledge of their pharmacological potential as possible anti-inflammatory agents with antioxidant activity. Full article

To explore the radial variation in wood properties of slash pine (Pinus elliottii Engelm.) during its growth process and to achieve the early prediction of these properties, our study was carried out in three slash pine harvest-age plantations in Ganzhou, Jian, and Jingdezhen, Jiangxi province of South China. Wood core samples were collected from 360 sample trees from the three plantations. SilviScan technology was utilized to acquire wood property parameters, such as tangential fiber widths (TFWs), radial fiber widths (RFWs), fiber wall thickness (FWT), fiber coarseness (FC), microfibril angle (MFA), modulus of elasticity (MOE), wood density (WD) and ring width (RD). Subsequent systematic analysis focused on the phenotypic and radial variation patterns of wood properties, aiming to establish a clear boundary between juvenile and mature wood. Based on determining the boundary between juvenile and mature wood, a regression equation was used to establish the relationship between the properties of juvenile wood and the ring ages. This relationship was then extended to the mature wood section to predict the properties of mature wood. Our results indicated significant differences in wood properties across different locations. The coefficients of variation for RD and MOE were higher than other properties, suggesting a significant potential for selective breeding. Distinct radial variation patterns in wood properties from the pith to the bark were observed. The boundary between juvenile and mature wood was reached at the age of 22. The prediction models developed for each wood property showed high accuracy, with determination coefficients exceeding 0.87. Additionally, the relative and standard errors between the measured and predicted values were kept below 10.15%, indicating robust predictability. Mature wood exhibited greater strength compared to juvenile wood. The approach of using juvenile wood properties to predict those of mature wood is validated. This method provides a feasible avenue for the early prediction of wood properties in slash pine. Full article