Search Results (273)

Climate extremes threaten the resilience of Eucalyptus plantations, yet hybridization with drought-tolerant species may enhance stress tolerance. This study analyzed xylem anatomical and functional drought responses in commercial Eucalyptus grandis (GG) clones and hybrids: E. grandis × camaldulensis (GC), E. grandis × tereticornis (GT), and E. grandis × urophylla (GU1, GU2). We evaluated vessel traits (water transport), fibers (mechanical support), and wood density (D) in stems and branches. Theoretical stem hydraulic conductivity (k_Stheo), vessel lumen fraction (F), vessel composition (S), and associations with previous hydraulic and growth data were assessed. While general drought responses occurred, GC had the most distinct xylem profile. This may explain it having the highest performance in different irrigation conditions. Red gum hybrids (GC, GT) maintained k_Stheo under drought, with stable F and a narrower vessel size, especially in branches. Conversely, GG and GU2 reduced F and S; and stem k_Stheo declined for a similar F in these clones, indicating vascular reconfiguration aligning the stem with the branch xylem. Almost all clones increased D under drought in any organ, with the highest increase in red gum hybrids. These results reveal diverse anatomical adjustments to drought among clones, partially explaining their growth responses. Full article

This study investigates the potential of Eucalyptus benthamii wood from planted forests in southern Brazil for the production of cross-laminated timber (CLT) panels. The performance of E. benthamii CLT panels is compared to that of Pinus spp. panels and European commercial panels (KLH^®), using the finite element method applied to a two-story building model. Class 2 of the Brazilian standard ABNT NBR 7190-2 was adopted as the reference for the physical and mechanical properties of Pinus spp., while the European commercial specifications from KLH^® were used to represent European reference panels. The results indicate that E. benthamii wood exhibits superior mechanical properties, enabling reductions of 12.5% to 27.3% in panel thickness and a 20.7% decrease in wood volume when compared to Pinus spp., without compromising structural safety. Relative to the KLH^® and ETA 06/0138 standards, E. benthamii wood demonstrates higher stiffness (modulus of elasticity of 15,325 MPa vs. 12,000 MPa) and greater flexural strength (109.11 MPa vs. 24 MPa), allowing for the use of thinner panels. Stress and displacement analyses confirm that E. benthamii CLT slabs can withstand critical loads (wind and vertical) within normative limits, with maximum displacements of 18.5 mm. The reduction in material volume (22.8 m³ versus 28.7 m³ for Pinus spp.) suggests potential benefits in terms of environmental impact and logistical efficiency. It can be concluded that E. benthamii represents a sustainable and efficient alternative for CLT panels, combining high structural performance with resource optimization and contributing to the decarbonization of the construction industry. Full article

Occupational exposure to commercial formic and acetic acids through dermal contact and inhalation during rubber sheet processing poses significant health risks to workers. Additionally, the use of these acids contributes to environmental pollution by contaminating water sources and soil. This study investigates the potential of three types of wood vinegar—derived from para-rubber wood, bamboo, and eucalyptus—obtained through biomass pyrolysis under anaerobic conditions, as sustainable alternatives to formic and acetic acids in the production of ribbed smoked sheets (RSSs). The organic constituents of each wood vinegar were characterized using gas chromatography and subsequently mixed with fresh natural latex to produce coagulated rubber sheets. The physical and chemical properties, equilibrium moisture content, and drying kinetics of the resulting sheets were then evaluated. The results indicated that wood vinegar derived from para-rubber wood contained a higher concentration of acetic acid compared to that obtained from bamboo and eucalyptus. As a result, rubber sheets coagulated with para-rubber wood and bamboo vinegars exhibited moisture sorption isotherms comparable to those of sheets coagulated with acetic acid, best described by the modified Henderson model. In contrast, sheets coagulated with eucalyptus-derived vinegar and formic acid followed the Oswin model. In terms of physical and chemical properties, extended drying times led to improved tensile strength in all samples. No statistically significant differences in tensile strength were observed between the experimental and reference samples. The concentration of acid was found to influence Mooney viscosity, the plasticity retention index (PRI), the thermogravimetric curve, and the overall coagulation process more significantly than the acid type. The drying kinetics of all five rubber sheet samples displayed similar trends, with the drying time decreasing in response to increases in drying temperature and airflow velocity. Full article

Alkaline treatment is well suited for extracting high-molecular-weight hemicelluloses, specifically hardwoods xylans, which, due to their polymer structure and chemical characteristics, enable the production of films with desirable mechanical, barrier, and optical properties for packaging applications. Despite its relevance, the optimization of antisolvent addition has received little attention in the literature. This study explores the use of eucalyptus industrial residue as feedstock, utilizing a statistical design to determine the optimal extraction conditions for hemicelluloses while minimizing the lignin content in the recovered liquor. The process uses alkali loads that are compatible with those in conventional Kraft pulp mills. Optimal extraction conditions involve a temperature of 105 °C, 16.7% NaOH charge, and 45 min at maximum temperature. The resulting liquor was subjected to ethanol precipitation under varying pH conditions (initial pH, 9, 7, 5, and 2) and different ethanol-to-liquor ratios (1:1 to 4:1). The acidification was performed using hydrochloric, sulfuric, and acetic acids. Ethanol served as the main antisolvent, while isopropyl alcohol and dioxane were tested for comparison. Results show that 2.3 ± 0.2% of xylans (based on oven-dry biomass) could be extracted, minimizing lignin content in the liquor. This value corresponds to the extraction of 15.6% of the xylans present in the raw material. The highest xylan precipitation yield (78%) was obtained at pH 7, using hydrochloric acid for pH adjustment and an ethanol-to-liquor ratio of 1:1. These findings provide valuable insight into optimizing hemicellulose recovery through antisolvent precipitation, contributing to more efficient biomass valorization strategies within lignocellulosic biorefineries. Full article

The Brazilian forestry sector comprises 9.94 million hectares of plantations, with eucalyptus dominating 75% of this area for pulp production. Technological advances have enhanced machinery performance, with the cut-to-length system being the primary method for pulpwood production. This study aimed to optimize the operational cycle of the log loader by evaluating productivity, operational cycles, and loading costs. Data were collected in Bahia, northeastern Brazil, from a forestry company operating under varying productivity scenarios and forest rotations. Time and motion studies were conducted to assess the log loader’s cycles, while productivity and cost analyses were performed. The results indicated that predictive models effectively explained productivity variations. The log loader’s productivity increased with the average volume per tree (AVT) and decreased with the number of movements, which consumed 68% of the cycle time due to wood adjustment and stack organization. Stages such as personal breaks, truck movements, crane adjustments, and cleaning of fallen material showed no significant statistical differences. Loading costs rose by up to 154% with increased movements and decreased with a higher AVT. Additionally, loading tri-train trucks significantly influenced transportation efficiency, emphasizing the importance of optimizing the log loader’s cycle to balance costs and enhance transportation operations. Full article

5-Hydroxymethylfurfural (HMF) is a versatile carbohydrate-derived platform chemical that has been used for the synthesis of a number of commercially valuable compounds. In this study, several chromium (Cr)-doped, biomass-derived hydrochar catalysts were synthesized via the one-pot method using starch, eucalyptus wood, and bagasse as carbon sources. Then, the performance of these synthesized materials for the catalytic conversion of glucose into HMF was evaluated by, primarily, the yield of HMF. The synergistic interactions between the Cr salt and the different biomass components were investigated, along with their effects on the catalytic efficiency. The differences in the catalytic activity of the synthesized materials were analyzed through structural characterization, as well as assessments of the acid density and strength. Among the catalysts, Cr₅BHC₁₈₀ derived from bagasse presented the highest activity, achieving an HMF yield of 64.5% in an aqueous solvent system of dimethyl sulfoxide (DMSO) and saturated sodium chloride (NaCl) at 170 °C after 5 h. After four cycles, the HMF yield of Cr₅BHC₁₈₀ decreased to 38.7%. Characterization techniques such as N₂ adsorption–desorption and Py-FTIR suggested that such a decline in the HMF yield is due to pore blockage and acid site coverage by humic by-products, as demonstrated by the fact that regeneration by calcination at 300 °C restored the HMF yield to 50.5%. Full article

The main objective of energy balance analysis is to guide farmers in making informed decisions that promote the efficient management of natural resources, optimise the use of agricultural inputs, and improve the overall economic performance of their farms. In addition, it supports the adoption of sustainable agricultural practices, such as crop diversification, the use of renewable energy sources, and the recycling of agricultural by-products and residues into natural energy sources or fertilisers. This paper analyses the variation in energy efficiency between 2019 and 2022 of the main crops in Angola: maize, soybean, and rice, and the forest production of eucalyptus biomass in agroforestry farms. The research was based on the responses to interviews conducted with the managers of the farms regarding the machinery used, fuels and lubricants, labour, seeds, phytopharmaceuticals, and fertilisers. The quantities are gathered by converting data into Megajoules (MJ). The results show variations in efficiency and energy balance. In corn, efficiency fluctuated between 1.32 MJ in 2019 and 1.41 MJ in 2020, falling to 0.94 MJ in 2021 due to the COVID-19 pandemic before rising to 1.31 MJ in 2022. For soybeans, the energy balance went from a deficit of −8223.48 MJ in 2019 to a positive 11,974.62 MJ in 2022, indicating better use of resources. Rice stood out for its high efficiency, reaching 81,541.33 MJ in 2021, while wood production showed negative balances, evidencing the need for more effective strategies. This research concludes that understanding the energy balance of agricultural operations in Angola is essential not only to achieve greater sustainability and profitability but also to strengthen the resilience of agricultural systems against external factors such as climate change, fluctuations in input prices, and economic crises. A comprehensive understanding of the energy balance allows farmers to assess the true cost-effectiveness of their operations, identify energy inefficiencies, and implement more effective strategies to maximise productivity while minimising environmental impacts. Full article

The present study aims to evaluate the mechanical properties, colorimetric characteristics, and decay resistance of Pinus elliottii woods treated with oxides synthesized via green chemistry. For this purpose, an aqueous extract from Eucalyptus dunnii leaves was used to synthesize particles based on copper- and zinc-based oxides, as well as a binary oxide system (CuO/ZnO). Sodium polyacrylate was employed as a dispersant, impregnating the oxides into the wood through a horizontal autoclave using a modified Bethell process, assisted by a compressor, applying a pressure of 0.8 MPa for 30 min. The exposure to weathering aging did not significantly alter the mechanical properties of the samples, but it caused the leaching of particles from the treated wood surface, as shown by colorimetric results. Regarding the decay resistance, the copper-based oxide proved to be the most effective treatment against Trametes versicolor (a white-rot fungus), reducing mass loss down to 1.2%. The CuO/ZnO formulation reduced the mass loss caused by Gloeophyllum trabeum to 1.1%, while the zinc oxide showed minimal efficacy. Thus, oxides synthesized via green chemistry using aqueous leaf extracts and mild thermal conditions for synthesis and calcination proved effective in enhancing the wood resistance against biotic deterioration agents. Full article

Eucalyptus wood particleboard (EPB), commonly used in indoor decoration, releases volatile organic compounds (VOCs) that can adversely affect indoor air quality and human health. This study systematically examined the VOC emission characteristics of EPB using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography mass spectrometry (GC-MS). A total of 65 VOCs were identified, with medium-volatility organic compounds (MVOCs) accounting for 28 compounds, low-volatility organic compounds (LVOCs) for 26, and high-volatility organic compounds (HVOCs) for 11. Terpenoids dominated the VOCs, comprising 78.46%, followed by aldehydes (10.77%) and alkanes (7.69%). Key odorant compounds (KOCs) were identified using the relative odor activity value (ROAV), with hexanal (ROAV = 100) and o-cymene (ROAV = 76.90) emerging as the most significant contributors to the overall odor profile. Thermal post-treatment at temperatures of 50–60 °C for durations of 6–12 h was found to be an effective method for reducing the residual VOCs and KOCs in the EPB, leading to a marked decrease in the peak areas of key odorants. The findings suggest several strategies for minimizing VOC emissions and eliminating residual odor, including reducing the use of miscellaneous wood materials, controlling the production of o-cymene, and employing thermal post-treatment at moderate temperatures. These measures provide a promising approach to reducing VOC and odor emissions from EPB and similar composite wood products, thereby enhancing their suitability for indoor applications. This study innovatively establishes an evaluation system for VOC emission characteristics in wood-based panels based on the ROAV. It elucidates the contribution mechanisms of key odor-active substances (e.g., hexanal and pentanal) and presents a thermal post-treatment process for source control, achieving simultaneous VOCs and odor elimination. A ROAV-guided hierarchical management strategy is proposed, providing scientific guidelines for the industrial production of high-quality particleboards with ultralow emissions (TVOC < 50 μg/m³) and minimal odor intensity (OI < Grade 3). Full article

Currently, workers in the ribbed smoked sheet (RSS) rubber production industry face increasing health risks, primarily due to their direct involvement in converting fresh latex into raw rubber sheets. This process involves the manual addition of appropriately diluted commercial formic acid and acetic acid to induce coagulation, resulting in a tofu-like consistency, which is subsequently processed into rubber sheets. Previous studies have indicated that the use of commercial formic and acetic acids poses significant health hazards to workers and contributes to environmental pollution. Therefore, this study explores the feasibility of replacing commercial formic and acetic acids with wood vinegar derived from para-rubber wood, bamboo, and eucalyptus in the RSS production process. Wood vinegar samples from the three biomass sources were analyzed for their organic compound compositions using gas chromatography and subsequently used as coagulants in the preparation of raw rubber sheets. The drying kinetics and antifungal properties of the resulting sheets were then evaluated. The results revealed that wood vinegar derived from para-rubber wood contained the highest concentration of acetic acid (41.34%), followed by bamboo (38.19%) and eucalyptus (31.25%). Rubber sheets coagulated with wood vinegar from para-rubber wood and bamboo exhibited drying kinetics comparable to those obtained using acetic acid, with the two-term exponential model providing the best fit. Conversely, rubber sheets coagulated with eucalyptus-derived wood vinegar, which had a relatively high concentration of phenolic derivatives (22.08%), followed drying behavior consistent with the Midilli et al. model, similar to sheets treated with formic acid. In terms of antifungal properties, five fungal genera—Aspergillus, Penicillium, Fusarium, Trichoderma, and Paecilomyces—were identified on the rubber sheets. Fungal growth was most pronounced in the control samples (untreated with wood vinegar), whereas samples treated with wood vinegar exhibited significantly reduced fungal colonization. These findings indicate that wood vinegar is effective in inhibiting fungal growth on the surface of rubber sheets and may serve as a safer and more environmentally friendly alternative to commercial acid coagulants. Full article

Forest wood biomass is a key renewable resource for advancing energy transition and mitigating climate change. This review analyzes the physicochemical properties of forest biomass from major European tree species to assess their suitability for bioenergy applications. This study encompasses key parameters, such as moisture content, ash content, volatile matter, fixed carbon, elemental composition, bulk density, and energy content (HHV and LHV). This review analyzed data from 43 publications and extracted 140 records concerning the physicochemical properties of the most common European forest species used for bioenergy. The most commonly represented species were Quercus robur, Eucalyptus spp., and Fagus sylvatica. Moisture content, referring to fresh matter, ranged from 5% to 65%; ash content, referring to a dry basis, ranged from 0.2% to 3.5%; and higher heating value (HHV), referring to dry matter, ranged from 17 to 21 MJ kg⁻¹. This study highlights variability among species and underscores the importance of standardizing biomass characterization methods and the scarcity of data on bulk density and other key logistical parameters. These findings emphasize the need for consistent methodologies and species-specific selection strategies to optimize sustainability and efficiency in forest biomass utilization for bioenergy. Full article

This article examines the key factors influencing the aromatic profile of mead, which is increasingly popular in artisanal markets worldwide. Based on a bibliometric review of 44 scientific studies, the analysis highlights the significant role of honey type in shaping mead’s sensory characteristics. Acacia honey contributes subtle floral notes, while eucalyptus honey brings bolder, resinous aromas. The bibliometric analysis also emphasizes fermentation conditions, such as temperature and yeast selection, as crucial factors. Lower fermentation temperatures help preserve volatile compounds, enhancing fruity and floral aromas, while higher temperatures lead to increased concentrations of undesirable higher alcohols. Additionally, aging mead in oak barrels for 6 to 12 months adds complexity by introducing vanilla, coconut, and spice notes from the wood’s phenolic compounds. The maturation process, including its duration and storage conditions, also enables the flavors to blend and develop over time. Moreover, the addition of herbs and fruits during fermentation or maturation has been proven to introduce new layers of aroma and flavor, with ingredients like citrus, berries, and aromatic herbs enhancing the final product with fresh, lively notes. The potential of non-Saccharomyces yeasts is also explored as an alternative for enriching aromatic profiles, with the capacity to introduce unique sensory characteristics, including diverse flavor profiles and regional or terroir-based variations. Finally, the bibliometric review reinforces the importance of selecting appropriate ingredients and controlling fermentation processes to improve mead quality. It also suggests exploring microbiomes, exotic honey varieties, and the use of herbs and fruits for even more distinct aromatic profiles. Full article

This study explores a circular economy approach in charcoal production, utilizing combustion gases from the process itself to optimize efficiency and quality, minimizing waste and reducing emissions. The research investigates the pre-drying of Eucalyptus sp. wood with these gases before carbonization, through an innovative system that directs gases from the carbonizing furnace to a separate drying furnace. Wood samples were dried at 120 °C and 150 °C for 15, 22.5, and 30 h before carbonization. The analysis included the gravimetric yield of charcoal, semi-carbonized wood, and fines, in addition to evaluating key charcoal properties. Results demonstrated that drying with combustion gases at 150 °C increased the charcoal yield by 7%, regardless of drying time. Furthermore, this pre-drying improved charcoal quality, raising fixed carbon content from 74.68% to over 81% and reducing volatile matter from 24.40% to below 18%. These findings highlight that the utilization of combustion gases for wood drying not only significantly enhances the efficiency and quality of charcoal production but also contributes to the reduction in greenhouse gas emissions, promoting a more sustainable and environmentally friendly alternative compared to conventional methods. Full article

Integrating different ecosystem services (ES) to determine when to harvest a forest stand is still challenging. This is due to the difficulty of obtaining information, models, and methods to quantify those ES and achieving an adequate valuation of these services. In this study, we propose a methodology comprising two different models that could allow for different ES integration with the optimal silviculture to calculate the optimal economic rotation. We have applied both models to eucalyptus plantations in Brazil considering two ES: wood with four different assortments and carbon sequestration. For both models, we calculated a ranking with previously defined management alternatives, with decreasing trees-per-hectare compared to traditional plantations. For the first model, when the ES are measured in monetary units, the optimal rotation corresponds to fewer trees per hectare than the traditional plantations and greater associated profitability. The second model incorporates the ES in physical units through a multi-criteria decision-making model and results in a longer rotation with again fewer trees per hectare. This study suggests that optimum forest rotation analysis should consider ES other than timber production integrated with silvicultural alternatives, such as spacing. Full article

The diversity of commercial tree planting sites, with their distinct environmental conditions, directly influences tree growth and consequently impacts the wood properties in various ways. However, there is limited research evaluating the impact of these variations in nondestructive testing. Therefore, this study aimed to investigate whether edaphoclimatic variations affect parameters obtained through nondestructive tests conducted on standing trees. To this end, 30 specimens were selected from 3 Eucalyptus sp. clones, aged 1, 3, and 4 years, grown in 2 regions, totaling 540 trees. Tree development was monitored quarterly over 12 months. The tests included ultrasound propagation, drilling resistance, and penetration resistance, and the trees were measured for diameter at breast height (DBH) and height. Among the edaphoclimatic factors evaluated, only temperature and soil water storage differed statistically between the two study regions. The higher temperature and lower soil water storage in region 2 promoted tree growth, with these trees showing greater drilling resistance and higher longitudinal wave velocities. In addition, the influence of climatic factors was evidenced by the variation of wave propagation velocity throughout the year. Periods of lower water availability resulted in higher velocities, while periods of greater precipitation were associated with lower velocities. The research results showed that temperature and soil water storage had significant effects on tree growth (DBH and height), as well as ultrasound wave propagation velocity and drilling resistance. Full article