Search Results (1,294)

We studied the effects of stand age on the allocation of biomass and allometric relationships among component biomass in five stands ages (1, 3, 5, 7, and 8 years old) of two eucalypts hybrids, including Eucalyptus urophylla × E. grandis and E. urophylla × E. tereticornis, in the Leizhou Peninsula, China. The stem, bark, branch, leaf, and root biomass from 60 destructively harvested trees were quantified. Allometric models were applied to examine the relationship between the tree component biomass and predictor variable (diameter at breast height, D, and height, H). Stand age was introduced into the allometric models to explore the effect of stand age on biomass estimation. The results showed the following: (1) Stand age significantly affected the distribution of biomass in each component. The proportion of stem biomass to total tree biomass increased with stand age, the proportions of bark, branch, and leaf biomass to total tree biomass decreased with stand age, and the proportion of root biomass to total tree biomass first decreased and then increased with stand age. (2) There were close allometric relationships between biomass (i.e., the components biomass, aboveground biomass, and total biomass per tree) and diameter at breast height (D), height (H), the product of diameter at breast height and tree height (DH), and the product of the square of the diameter at breast height and tree height (D²H). The allometric relationship between biomass and measurement parameters (D, H, DH, D²H) could be applied to the biomass assessment of eucalypts plantation. (3) Allometric equations that included stand age as a complementary variable significantly improved the fit and enhanced the accuracy of biomass estimates. The optimal independent variable for the biomass prediction model varied according to each organ. These results indicate that stand age has an important influence on biomass allocation. Allometric equations considering stand age could improve the accuracy of carbon sequestration estimates in plantations. Full article

Mixed-species plantations involving Eucalyptus and Acacia trees are an effective alternative for managing sustainable plantations. In this study, we evaluated the growth, productivity, nutrient return, and soil properties of a mixed Eucalyptus hybrid (Eucalyptus camaldulensis Dehnh. × E. urophylla S.T. Blake; E) and Acacia auriculiformis A. Cunn. ex Benth. plantation (A) and Eucalyptus hybrid and A. auriculiformis plantations. The mixed Eucalyptus hybrid and A. auriculiformis plantation included three ratios at E33:A67, E50:A50, and E67:A33, while the Eucalyptus (E100) and A. auriculiformis (A100) plantations were established on degraded lands in the Had Wanakorn Forestry Research and Student Training Station, Prachuap Khiri Khan province, Thailand. Three replications within a plot size of 20 × 20 m² were designed to plant Eucalyptus hybrid and A. auriculiformis seedlings at a spacing of 2 × 3 m². The diameters at breast height (DBH) and height (H) of the Eucalyptus hybrid and A. auriculiformis were measured and monitored after planting for five years. The aboveground biomass of the five-year-old mixed and monoculture plantations was then estimated. Litterfall production and nutrient return from the mixed and monoculture plantations were measured for three years. In addition, soil samples at depths of 0–5, 5–10, and 10–20 cm were collected to analyze the soil’s chemical properties. Differences in growth, aboveground biomass, litterfall production, nutrient return, and soil properties were analyzed and tested using Tukey’s HSD. The results indicated that both the DBH and H of the Eucalyptus hybrid in the mixed and monoculture plantations were not significantly different (p > 0.05). Similarly, the DBH and H of A. auriculiformis in each treatment were also not significantly different (p > 0.05). However, the DBH and H of the Eucalyptus hybrid were higher than those of A. auriculiformis. The aboveground biomass for the mixed plantation ratios E50:A50, E100, E67:A33, and E33:A67 was not significantly different, while the stem biomass was the highest in E100. Litterfall production was influenced by the proportion of the Eucalyptus hybrid relative to A. auriculiformis, but the monoculture A100 plantation had the highest litter production. The nitrogen return estimated for the mixed plantation was between A100 and E100. Similarly, the total nitrogen in the topsoil (0–5 cm) of the mixed plantation was higher than that in the monoculture E100 plantation. These results indicate that mixing A. auriculiformis with Eucalyptus can improve soil nutrients and nutrient cycling and increase nutrient returns, suggesting that mixed plantations are an effective option for sustainable plantation management and can mitigate the negative environmental impacts of Eucalyptus monocultures. Full article

Honeydew honey is less studied than nectar honey, although it is characterized by peculiar nutritional properties. This is mainly due to its challenging production, which leads to easy counterfeiting and difficult valorization. This contribution aims to provide a comprehensive characterization of the physico-chemical, palynological, functional, and food safety properties of a large sampling of honeydew honeys collected throughout Italy. The honeydew elements, conductivity, color, antioxidant properties, total polyphenol content, hydroxymethylfurfural, major and trace elements, toxic and rare earth elements, and pesticide residues were measured in 59 samples of honeydew honey from forest, eucalyptus, fir, oak, and citrus sources. Physico-chemical and antioxidant properties were unable to differentiate the botanical origin of Italian honeydew honeys. Similarly, the mineral composition did not vary significantly, whereas rare earth elements appeared to be promising markers for classifying their origin. Multivariate analysis allowed discriminating fir honeydews from the other varieties. Concerning safety aspects, pesticide residues were detected in 90% of the samples, with fir honeydews exhibiting the lowest contamination levels, probably due to its production in less industrialized areas. Acetamiprid and imidacloprid were the most prevalent pesticide residues, but their concentrations were below the limit indicated by the EFSA. These findings suggest the need for a continuous monitoring program for contaminants to ensure safety and to assess risk. Full article

The medicinal potential of plant extracts, especially their antimicrobial, antioxidant, antiviral and cytotoxic properties, has gained significant attention in recent years. This study examined the in vitro bioactivities of several selected Greek medicinal plants, like Eucalyptus globulus L., Thymus vulgaris L., Salvia rosmarinus L. and Ocimum basilicum L., are well-known for their traditional therapeutic use. Minimum inhibitory concentration (MIC) assays were used to evaluate the antimicrobial activity of the extracts against pathogenic bacteria. The antioxidant activity was carried out using the DPPH method, while the cytotoxicity of the plants was determined using the Alamar Blue method. In addition, the antiviral efficacy of the samples was tested against DENV in different cell lines. The majority of medicinal herbs demonstrated significant antimicrobial action (MIC = 30–3000 μg∙mL⁻¹). The extracts showed great antioxidant activity, while the Salvia rosmarinus L. extract turned out to be the most effective (IC₅₀ = 12.89 ± 0.11 μg∙mL⁻¹). In contrast, the extract of Eucalyptus globulus L. had the lowest antioxidant action (IC₅₀ = 71.02 ± 0.42 μg∙mL⁻¹). The results of the Alamar Blue method were presented with CC₅₀ values, and it was shown that Eucalyptus globulus L. extract exhibited the highest cytotoxicity (CC₅₀ = 5.94% v/v ± 0.04). Similarly, the results of the antiviral potential of extracts were expressed as EC₅₀ values, and Eucalyptus globulus L. was characterized as the most effective sample against dengue virus infection, with EC₅₀ values estimated at 2.37% v/v ± 0.6 (HuhD-2 cells infected with DENV-2) and 0.36% v/v ± 0.004 (Huh7.5 cells infected with DVR2A). These findings provide a foundation for further studies in order to combat infectious diseases and promote human health. Full article

The genus Eucalyptus L’Hér., is native to Australia with 61 introduced taxa in Cyprus, including E. torquata Luehm., which has a wide distribution on the island. The aim of this study was to investigate the possible seasonal variations in the chemical composition of the essential oils of juvenile and mature leaves collected from Nicosia, Cyprus, by using multivariate statistical analysis. The leaves of 12 monthly collections were separately hydrodistilled, and GC-FID and GC/MS analyses were conducted. In general, the results revealed 1,8-cineole (mature: 3.6–27.8%; juvenile: 12.7–21.5%) and torquatone (mature: 27.6–48.8%; juvenile: 28.8–41.5%) as major compounds as well as an inverse relation between 1,8-cineole and torquatone content. Other important compounds found were α-pinene, β-eudesmol and α-eudesmol for all samples. The data support the existence of three major clusters, distinguished by the concentration of torquatone and miniatone. Minor compounds were also temporally relevant. The present study is among the first of its kind, analyzing the essential oils for a one-year period in Cyprus as well as conducting statistical analysis on E. torquata to reveal possible temporal variations between heterophyllous leaves, and also performing Hierarchical Cluster Analysis, determining the primary components of variability. Full article

Cryptococcosis is a fungal disease in humans and animals, caused by the Cryptococcus neoformans and Cryptococcus gattii species complexes. Clinical cryptococcosis primarily manifests as upper respiratory tract disease; however, dissemination to other organs, particularly the brain, can occur. Nasal colonisation and subclinical cryptococcosis are common in koalas (Phascolarctos cinereus) due to their shared environmental niche with Cryptococcus: Eucalyptus trees. However, for reasons that remain unclear, the prevalence of clinical disease is low in koalas. Interactions between respiratory pathogens and the nasal mycobiome are thought to play a role in the development and progression of numerous respiratory diseases. As such, this study aimed to characterise the mycobiome of the nasal vestibule in koalas with and without evidence of cryptococcal colonisation and subclinical disease via the next-generation sequencing (NGS) of the ITS1 region of the fungal internal transcribed spacer (ITS) gene. Samples were collected from 47 koalas from a population of free-ranging koalas in the Liverpool Plains, NSW, Australia, with a known history of Cryptococcus exposure and nasal colonisation. Of the 47 animals tested, 6.4% were culture-positive only, 4.3% were seropositive only, and 2.1% were culture- and seropositive. C. gattii was detected in four samples via NGS. C. neoformans was not detected via NGS. There were no significant differences in the nasal mycobiomes of Cryptococcus-positive and -negative animals; thus, we could not establish a definitive association between the mycobiome and infection outcomes. We identified a number of fungal genera that were significantly more abundant in samples from Cryptococcus-positive animals, but there was no apparent relationship between these genera and the development of cryptococcosis. This study represents the first investigation of the nasal mycobiota of wild koalas. Further studies involving koalas with clinical disease are necessary to determine the role of the nasal mycobiota in the development of cryptococcosis. Full article

This study investigates the biorefinery approach to extracting blood–brain barrier (BBB)-permeable compounds from Eucalyptus globulus Labill. and Salvia officinalis L. for neuroprotective purposes. A sequential extraction process was applied, starting with supercritical CO₂ extraction (SC-CO₂) to obtain non-polar terpenoids, followed by pressurized natural deep eutectic solvent extraction (PLE-NaDES) to recover phenolic compounds from the SC-CO₂ residue. PLE-NaDES extracts exhibited higher antioxidant and anticholinergic capacities than SC-CO₂ extracts for both plants, with S. officinalis extracts being more bioactive than E. globulus extracts. A total of 21 terpenoids were identified using gas chromatography–mass spectrometry from E. globulus while 24 were detected from S. officinalis SC-CO₂ extracts. In addition, 25 different phenolic compounds were identified in both plants using high-performance liquid chromatography coupled with mass spectrometry from PLE-NaDES extracts. The study of the permeability across the BBB showed limited permeability for non-polar compounds obtained by SC-CO₂ from both plants; however, the more polar compounds obtained by PLE-NaDES showed high permeability, particularly for flavonoids in E. globulus and rosmarinic acid in S. officinalis. This study revealed, for the first time, the antioxidant and neuroprotective potential of S. officinalis and E. globulus extracts obtained using SC-CO₂ followed by PLE-NaDES, as well as the high permeability of PLE-NaDES extracts when crossing the BBB to exert their protective effects. This research opens a new pathway for exploring alternatives to current drugs used in treating neurodegenerative diseases. Full article

Mowing significantly influences nutrient cycling and stimulates metabolic adjustments in plants to promote regrowth. Plant growth-promoting rhizobacteria (PGPR) are crucial for enhancing plant growth, nutrient absorption, and stress resilience; however, whether inoculation with PGPR after mowing can enhance plant regrowth capacity further, as well as its specific regulatory mechanisms, remains unexplored. In this study, PGPR Pantoea eucalyptus (B13) was inoculated into mowed Leymus chinensis to evaluate its effects on phenotypic traits, root nutrient contents, and hormone levels during the regrowth process and to further explore its role in the regrowth of L. chinensis after mowing. The results showed that after mowing, root nutrient and sugar contents decreased significantly, while the signal pathways related to stress hormones were activated. This indicates that after mowing, root resources tend to sacrifice a part of growth and prioritize defense. After mowing, B13 inoculation regulated the plant’s internal hormone balance by reducing the levels and signal of JA, SA, and ABA and upregulated the signal transduction of growth hormones in the root, thus optimizing growth and defense in a mowing environment. Transcriptomic and metabolomic analyses indicated that B13 promoted nutrient uptake and transport in L. chinensis root, maintained hormone homeostasis, enhanced metabolic pathways related to carbohydrates, energy, and amino acid metabolism to cope with mowing stress, and promoted root growth and regeneration of shoot. This study reveals the regenerative strategy regulated by B13 in perennial forage grasses, helping optimize resource utilization, increase yield, and enhance grassland stability and resilience. Full article

The supercritical water gasification (SCWG) and carbon dioxide gasification of agro-industrial and urban waste residues—Coffee Husk, Eucalyptus Biochar, Energy Sugarcane, and Refuse-Derived Fuel (RDF)—were studied using TeS^® v.2 software, which employs a non-stoichiometric thermodynamic model to minimize Gibbs free energy and predict equilibrium compositions. The effects of temperature (873.15–1273.15 K), pressure (220–260 bar), biomass feed (18–69%), and gasifying agents on hydrogen and methane formation were analyzed. Higher temperatures and biomass feed percentages favored hydrogen production, while lower temperatures increased methane formation. At 1273.15 K, RDF showed the highest hydrogen yield in SCWG, rising from 0.43 to 1.42 mol, followed by Energy Sugarcane (0.39 to 1.23 mol), Coffee Husk (0.34 to 0.74 mol), and Eucalyptus Biochar (0.33 to 0.62 mol). In CO₂ gasification, hydrogen yields were lower but followed a similar trend. At 873.15 K, RDF also exhibited the highest methane increase in SCWG, from 0.14 to 0.91 mol, followed by Energy Sugarcane (0.12 to 0.65 mol), Coffee Husk (0.11 to 0.36 mol), and Eucalyptus Biochar (0.11 to 0.29 mol). Methane formation in CO₂ gasification was significantly lower, with RDF increasing from 0.0035 to 0.35 mol, followed by Energy Sugarcane (0.0024 to 0.24 mol), Coffee Husk (0.0002 to 0.058 mol), and Eucalyptus Biochar (0.0002 to 0.028 mol). On the other hand, a slight increase in hydrogen formation was observed as pressure decreased, while the opposite effect was observed for methane formation, with a small increase in its production as pressure increased. The impact of pressure change on the equilibrium compositions was not as significant as the effect observed by varying temperature; this behavior was observed in both gasification processes studied. Additionally, the behavior of the H₂/CO molar ratio for each biomass in the studied gasification processes was analyzed to assess the potential uses of the produced syngas. It was observed that the SCWG resulted in significantly higher H₂/CO molar ratios compared to CO₂ gasification. Full article

In the realm of hydrological engineering, integrating extensive geospatial raster data from remote sensing (Big Data) with sparse field measurements offers a promising approach to improve prediction accuracy in groundwater studies. In this study, we integrated multisource data by applying the LMC to model the spatial relationships of variables and then utilized block support regularization with collocated block cokriging (CBCK) to enhance our predictions. A critical engineering challenge addressed in this study is support homogenization, where we adjusted punctual variances to block variances and ensure consistency in spatial predictions. Our case study focused on mapping groundwater table depth to improve water management and planning in a mixed land use area in Southeast Brazil that is occupied by sugarcane crops, silviculture (Eucalyptus), regenerating fields, and natural vegetation. We utilized the 90 m resolution TanDEM-X digital surface model and STEEP (Seasonal Tropical Ecosystem Energy Partitioning) data with a 500 m resolution to support the spatial interpolation of groundwater table depth measurements collected from 56 locations during the hydrological year 2015–16. Ordinary block kriging (OBK) and CBCK methods were employed. The CBCK method provided more reliable and accurate spatial predictions of groundwater depth levels (RMSE = 0.49 m), outperforming the OBK method (RMSE = 2.89 m). An OBK-based map concentrated deeper measurements near their wells and gave shallow depths for most of the points during estimation. The CBCK-based map shows more deeper predicted points due to its relationship with the covariates. Using covariates improved the groundwater table depth mapping by detecting the interconnection of varied land uses, supporting the water management for agronomic planning connected with ecosystem sustainability. Full article

This study explores the conversion of lignocellulosic biomass from softwood, hardwood, and grasses into humic acid via a mild hydrothermal process and its application in Pb²⁺ adsorption. The investigation focused on adsorption isotherms, kinetics, thermodynamics, and the intraparticle diffusion model to evaluate the adsorption performance of humic acids from different sources. The results indicate that the humic acid of broad-leaved wood (Eucalyptus-HA) possesses the optimal adsorption capacity and removal efficiency of Pb²⁺. When the initial concentration of Pb²⁺ is 100 mg/L, the adsorption capacity and removal efficiency of Eucalyptus-HA reach 49.75 mg/g and 25.57%, respectively, which are far higher than the adsorption capacity (26.82 mg/g) and removal efficiency (13.71%) of commercial humic acid (Commercial-HA). The pore structure of humic acid plays a critical role in its Pb²⁺ adsorption capacity. High Pb²⁺ concentrations and a low pH negatively impact adsorption efficiency, and instability in the humic acid pore structure affects reproducibility. Adsorption isotherm fitting showed that Pb²⁺ adsorption conforms most closely to the Langmuir model. While commercial humic acid exhibited faster adsorption rates, its capacity was constrained by thermodynamic limitations and lower specific surface areas. The intraparticle diffusion model revealed that Pb²⁺ diffusion proceeded more efficiently in hydrothermal humic acids than in commercial ones due to lower diffusion resistance. This study highlights the potential of feedstock source regulation to enhance humic acid’s heavy metal adsorption capabilities, expanding its application across various fields. Full article

Standard carbon accounting methods and metrics undermine the potential of fast-growing biogenic materials to decarbonize buildings because they ignore the timing of carbon uptake. The consequence is that analyses can indicate that a building material is carbon-neutral when it is not climate-neutral. Here, we investigated the time-dependent effect of using fast-growing fibers in durable construction materials. This study estimated the material stock and flow and associated cradle-to-gate emissions for four residential framing systems in the US: concrete masonry units, light-frame dimensional timber, and two framing systems that incorporate fast-growing fibers (bamboo and Eucalyptus). The carbon flows for these four framing systems were scaled across four adoption scenarios, Business as Usual, Early-Fast, Late-Slow, and Highly Optimistic, ranging from no adoption to the full adoption of fast-growing materials in new construction within 10 years. Dynamic life cycle assessment modeling was used to project the radiative forcing and global temperature change potential. The results show that the adoption of fast-growing biogenic construction materials can significantly reduce the climate impact of new US residential buildings. However, this study also reveals that highly aggressive, immediate adoption is the only way to achieve net climate cooling from residential framing within this century, highlighting the urgent need to change the methods and metrics decision makers use to evaluate building materials. Full article

This study examines the effect of surfactant-enhanced enzymatic hydrolysis on eucalyptus Kraft pulps produced under high (CPHA) and mild (CPMA) alkali conditions to optimize saccharification and sugar yield. Compositional analysis revealed an increase in glucan content, from 40% in untreated eucalyptus to 70.1% in CPHA. Both pulps were hydrolyzed using Cellic^® CTec3 HS enzyme (Novozymes). A 2² factorial design revealed maximum sugar conversion (~100%) with enzyme loading of 10 FPU/g carbohydrate and 10% (w/v) solids. Tween 20 significantly boosted hydrolysis in CPMA, increasing reducing sugars from 42 g/L to 65 g/L and efficiency from 59.6% to 92.2% within 6 h. By contrast, Tween 80 and PEG 400 showed limited effects on CPMA. Surfactants mitigated lignin–enzyme interactions, especially in CPMA, as higher lignin content restricted hydrolysis efficiency. Phenolic content in the hydrolysates revealed that Tween 80 increased the release of inhibitory compounds, while Tween 20 kept phenolic levels lower. Overall, Tween 20 improved sugar yields and hydrolysis efficiency even with moderate lignin removal during kraft pretreatment, highlighting its potential to reduce enzyme loading and costs in industrial biorefineries. This study underscores the importance of optimizing surfactant selection based on biomass composition for effective enzymatic hydrolysis for cellulosic sugar recovery. Full article

Light serves as the unique driving force of photosynthesis in plants, yet its intensity varies over time and space, leading to corresponding changes in the photosynthetic rate. Here, the photosynthetic induction response under constant and fluctuating light was examined in naturally occurring saplings of four sun-demanding woody species, Eucalyptus. Ficus macrocarpa L., Hibiscus syriacus L. and Ficus carica L. We aimed to find out the relations among gas exchange parameter adaptions among different species during photosynthetic induction. The net photosynthetic rates (A) versus time course curves were sigmoidal or hyperbolic after the dark-adapted leaves were irradiated by continuous saturated light. Compared with other species, Ficus carica L. have the largest net photosynthesis rate, stomatal conductance to CO₂ (g_sc), and the maximum carboxylation rate (V_cmax) at both the initial and steady photosynthetic state. The initial g_sc (g_sci) was as much as sixfold higher compared to the other shrub, Hibiscus syriacus L. The time required to reach 90% of A (t_A90) was 7–30 min; t_A90 of Ficus carica L. and Ficus macrocarpa L. were lower than that of the other two species. The time required to reach 90% of g_sc (t_gsc90) significantly lagged behind t_A90 among species. Biochemical induction was fast in leaves of Ficus carica L., as about 4 min were needed to reach 90% of V_cmax, while the other species needed 7–18 min. Correlation analysis showed that the t_gsc90 was the main factor in limiting t_A90, especially for Eucalyptus spp. and Hibiscus syriacus L.; g_sci was negatively correlated with t_gsc90 among species. Moreover, time-integrated limitation analysis revealed that g_sc still accounted for the largest limitation in constraining A of Eucalyptus spp. and Hibiscus syriacus L. and Ficus macrocarpa L. Overall, the findings suggest that to enhance the carbon gain by woody species under naturally dynamic light environments, attention should be focused on improving the rate of stomatal opening or initial stomatal conductance. Full article

This study comprehensively analyzes the mineral and heavy metal profiles of seven honey types, focusing on the contents of potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), cadmium (Cd), and lead (Pb), with particular emphasis on honey produced in eastern Morocco. Multifloral honey was found to have the highest total mineral content (661 mg/kg), while rosemary honey had the lowest (201.31 mg/kg), revealing the strong influence of floral and botanical origin. Darker honey, such as multifloral and jujube, were richer in minerals, with potassium consistently being the most abundant, followed by calcium, magnesium, and iron, while cadmium and lead remained within safe, trace-level concentrations. Additionally, sugar profiling showed that all samples contained fructose, glucose, maltose, turanose, erlose, sucrose, and palatinose, with particularly high fructose and glucose contents in multifloral honey. Principal component analysis (PCA) accounted for 75% of the variation and identified three distinct groups of honey based on mineral content multifloral, eucalyptus, and rosemary. Multifloral and eucalyptus honey had higher concentrations of iron, magnesium, and calcium, whereas rosemary honey was richer in zinc and copper. The findings underscore the potential of honey as a marker of environmental quality and suggest that eastern Morocco honey possesses favorable characteristics for national and international commercialization. Full article