Search Results (65)

Acorns represent an underutilized source of forest biomass with potential for producing edible oils and bioactive compounds. This research compared lipid fractions from pedunculate oak (Quercus robur L.) and northern red oak (Quercus rubra L.) collected in Poland, examining how different extraction methods influence oil yield and quality. Oils were extracted using Soxhlet with hexane, cold hexane extraction for both species, and mechanical pressing for Q. rubra. Fatty acid profiles analyzed by GC-FID facilitated calculation of lipid quality indices. Oxidative stability was assessed through isothermal PDSC, and total phenolics, flavonoids, and antioxidant activity (DPPH, ABTS) were measured in acorn extracts. Q. rubra produced more oil than Q. robur regardless of extraction method, but Q. robur oils exhibited significantly higher PDSC oxidation times (τ_on, τ_max). Pressed Q. rubra oil showed higher acid and peroxide values compared to solvent-extracted oils. Fatty acid composition was predominantly influenced by species rather than by extraction method, as confirmed by multivariate analysis, which indicated species as the main driver of variability. Overall, these results highlight a trade-off between oil yield and oxidative stability, suggesting acorns as a promising, species-dependent oil resource. Full article

Urban forests serve as representations of nature within city landscapes. Green Forest, spanning 5,198,412 square meters, has been incorporated into the Municipality of Timișoara’s public domain and designated as a forest park. This fact increased green space per capita and enriched biodiversity within Timișoara’s landscape architecture. This study explores the diversity of Green Forest trees and highlights their contribution to the urban landscape. Statistical methods, including comparative and linear relationships analyses, were employed to assess significant variations in the dendrometric parameters of the analyzed tree species: mean tree height, mean trunk diameter at breast height (DBH), tree age, and stand density. Principal Component Analysis (PCA) and cluster analysis were applied to uncover underlying patterns in the data. Using ArchiCAD and Lumion, high-quality 3D visual representations were developed for an ecological education area, an active recreation region, and a passive recreation area within Green Forest. Due to their morphological characteristics and phenotypic traits, the predominant tree species include Quercus robur, Quercus cerris, Quercus rubra, Fraxinus excelsior, Acer platanoides, Acer pseudoplatanus, Ulmus campestris, and Robinia pseudoacacia, which contribute to Timișoara’s urban aesthetic. Moreover, the results of the dendrometric analysis provide a foundation for further research in urban ecology. A key practical application of this study is landscape design renderings, which provide detailed and realistic visualizations to effectively communicate the design and functionality of Green Forest’s spaces. If implemented, these developments will encourage public engagement with nature, promoting mental and physical well-being within the community. Full article

This study aimed to systematically characterize the pyrolysis characteristics and combustibility of six typical tree species across different altitude gradients in southwestern Yunnan, providing references for fuel management and selection of potential fire-resistant species in this region. Thermogravimetric analysis (heating rate: 20 °C·min⁻¹, air atmosphere) was employed to obtain TG-DTG curves of bark, branches, and leaves. The Coats–Redfern integral method was applied to calculate kinetic parameters, and principal component analysis was conducted for comprehensive combustibility evaluation. The results demonstrated the following: (1) The pyrolysis process of all species underwent the following four distinct stages: moisture evaporation, holocellulose decomposition, lignin decomposition, and ash formation. Among these, holo-cellulose decomposition constituted the primary mass loss stage. Significant differences in pyrolysis characteristics were observed among different plant parts, with leaves and bark exhibiting lower initial pyrolysis temperatures; (2) The activation energy ranged from 56.05 to 86.41 kJ·mol⁻¹ across different components, with branches requiring the highest energy for pyrolysis; (3) Principal component analysis based on multiple indicators yielded the following comprehensive combustibility ranking: Pinus yunnanensis > Betula alnoides > Lithocarpus henryi > Quercus acutissima > Cunninghamia lanceolata > Myrica rubra; and (4) The combustibility assessment results integrating multiple variables (total mass loss rate, stage-specific mass loss, activation energy, and ash content) showed significant differences from the analysis based solely on activation energy, verifying the necessity of a multi-dimensional comprehensive evaluation. Full article

In this study, we developed three forest management scenarios for Simcoe County Forest in Southern Ontario, Canada, using the Physiological Principles Predicting Growth (3-PG) model to simulate future forest growth and carbon dynamics. The focus was on four main species: Red pine (Pinus resinosa), White pine (Pinus strobus), Sugar maple (Acer saccharum), and Red oak (Quercus rubra). We parameterized, calibrated, and validated parameters of the 3-PG model for these four species and applied the model to evaluate the performance of management scenarios incorporating timber and carbon values in Simcoe County Forest. The first scenario, “business as usual,” maintained the existing management plan for the forest, ensuring stable timber income (531.2 CAD/hectare) and moderate carbon sequestration. The second scenario aimed to optimize management for the highest timber Net Present Value (NPV), with half of the trees harvested before 2030, followed by gradual thinning over 15 years. This approach yielded the highest financial returns (1634.1 CAD/hectare) but the lowest carbon sequestration potential. The third scenario integrated carbon certification, emphasizing the retention of sugar maple stands over the next 20 years. This scenario produced financial returns (580.2 CAD/hectare) higher than the “business as usual” scenario, while saving 49.33 tons of biomass per hectare. Overall, this study provides a reference for the implementation of carbon sequestration projects. Full article

Acute Oak Decline (AOD) is a progressive disease affecting oaks across Europe and is increasingly recognised as a threat to the health of forests and urban trees. While the occurrence of this disease has been documented in forest ecosystems, its presence in urban landscapes is still poorly understood. In this study, the occurrence of AOD-associated bacteria (Brenneria goodwinii, Gibbsiella quercinecans, Rahnella victoriana, Lonsdalea quercina) was investigated in Quercus robur and Q. rubra growing in urban areas of Wrocław, Poland. Multiplex real-time PCR analyses confirmed the pathogens in 11 trees, with B. goodwinii being the most common species. Importantly, we provide the first confirmed detection of B. goodwinii in Q. rubra under urban conditions, possibly the first such detection in Europe. The results show the occurrence of AOD-associated pathogens in urban environments, suggesting that such habitats may provide favourable conditions for their occurrence. However, further investigations, including epidemiological and spatial analyses, are needed to clarify whether urban areas contribute to the persistence or spread of these pathogens. Beyond local documentation, our results emphasise the need to include urban ecosystems in AOD surveillance and highlight potential pathways for pathogen adaptation and spread in cities. This work provides new insights into the ecology of AOD in anthropogenically modified habitats and has direct implications for urban tree health monitoring, biodiversity conservation, and the development of integrated management strategies. Full article

The increasing interest in fibre-enriched and functional bakery products has led to the exploration of novel plant-based ingredients with both technological functionality and consumer acceptance. This study evaluates the effects of incorporating flours derived from apple (Malus domestica cv. Oberländer Himbeerapfel), sweet chestnut (Castanea sativa), horse chestnut (Aesculus hippocastanum), and red, sessile, and pedunculate oak (Quercus rubra, Q. petraea, and Q. robur) into wheat bread at 5%, 10%, and 15% substitution levels. The impact on crumb structure, crust colour, textural parameters (hardness, adhesiveness, springiness), and sensory attributes was assessed. The inclusion of apple and sweet chestnut flours resulted in a softer crumb, lower adhesiveness, and higher sensory scores related to flavour, aroma, and crust appearance. In contrast, higher levels of oak- and horse-chestnut-derived flours increased crumb hardness and reduced overall acceptability due to bitterness or excessive density. Apple flour preserved crumb brightness and contributed to warm tones, while oak flours caused more intense crust darkening. These findings suggest that selected non-traditional flours, especially apple and sweet chestnut, can enhance the sensory and physical properties of wheat bread, supporting the development of fibre-rich, clean-label formulations aligned with consumer trends in sustainable and functional baking. Full article

Accurate tree species identification through bark characteristics is essential for effective forest management, but traditionally requires extensive expertise. This study leverages artificial intelligence (AI), specifically the EfficientNet-B3 convolutional neural network, to enhance AI-based tree bark identification, focusing on northern red oak (Quercus rubra), hackberry (Celtis occidentalis), and bitternut hickory (Carya cordiformis) using the CentralBark dataset. We investigated three environmental variables—time of day (lighting conditions), bark moisture content (wet or dry), and cardinal direction of observation—to identify sources of classification inaccuracies. Results revealed that bark moisture significantly reduced accuracy by 8.19% in wet conditions (89.32% dry vs. 81.13% wet). In comparison, the time of day had a significant impact on hackberry (95.56% evening) and northern red oak (80.80% afternoon), with notable chi-squared associations (p < 0.05). Cardinal direction had minimal effect (4.72% variation). Bitternut hickory detection consistently underperformed (26.76%), highlighting morphological challenges. These findings underscore the need for targeted dataset augmentation with wet and afternoon images, alongside preprocessing techniques like illumination normalization, to improve model robustness. Enhanced AI tools will streamline forest inventories, support biodiversity monitoring, and bolster conservation in dynamic forest ecosystems. Full article

The presence of heavy metals in groundwater and wastewater has been a concern for health organizations. This study investigated the effectiveness of activated carbon derived from various natural precursors, including acorns from red oak trees (Quercus rubra), date seeds, and peach seeds, employing the thermal activation method for the removal of heavy metals from aqueous solutions. Batch adsorption tests investigated the effects of sorbent quantity, pH levels, disinfectant presence, and dissolved organic matter (DOM) on the removal efficiency of Pb and Cu. Characterization of the prepared activated carbon was conducted using scanning electron microscopy (SEM). Lead removal efficiency diminished at pH 7 relative to pH 3 and 5, but copper exhibited superior removal efficiencies at pH 7 compared to pH 5. The addition of monochloramine at 4 parts per million (ppm) effectively eliminated lead from the solution. A rise in free chlorine concentration from 2 to 4 mg/L led to a reduction in metal removal from water by 20 to 60%. DOM at concentrations of 1 and 6 mg/L reduced metal removal efficacy relative to DOM at 3 mg/L. Date seed-activated carbons underscore their distinctive potential, offering useful insights for the enhancement of water and wastewater treatment systems. Full article

Old growth forests are increasingly rare but important carbon sinks which harbour rich biodiversity. Chronic browsing by the white-tailed deer (Odocoileus virginianus) is a threat to the sustainability of the services provided by these forests, particularly in northern temperate forests where deer numbers have increased in recent decades (driven by stricter hunting rules and reduced predation) and necessitating local monitoring of vegetation responses. The objective of this study was to determine the effects of deer exclusion on tree regeneration dynamics and soil nutrients in an old growth Carolinian forest. This was performed using exclusion fencing and tip-up mounds at McMaster Forest Nature Preserve and the Sheelah Dunn Dooley Nature Sanctuary in Hamilton Ontario. Tree regeneration was surveyed from thirty 1 m × 1 m quadrats within exclusion plots and another thirty quadrats from deer-browsed areas adjacent to the exclusion plots. Soil samples were taken from each quadrat to analyze browsing impacts on nitrate, phosphate and soil organic matter. Red oak (Quercus rubra) was planted at the top and base of tip-up mounds of varying heights and widths and monitored for deer access and browsing activity. Results show a significantly higher density of woody plants within exclosures compared to non-exclosures (p = 0.0089) and twice more abundance of highly palatable species within the exclosures. However, species richness (p > 0.05) and diversity (p > 0.05) were minimally impacted by deer browsing, showing a resilient old growth forest. Soil nitrate was consistently higher in the non-exclosures, while phosphate was consistently higher within deer exclosures. Finally, more seedlings survived at the top of mounds than the bases, showing the potential of tip-up mounds to be a natural method of deer exclusion and a critical avenue for restoring over-browsed forests. Full article

Fallen leaves in cities are often treated as waste; therefore, they are collected, transported outside urban areas, and composted, which contributes to greenhouse gas (GHG) emissions. Instead of this conventional management approach, fallen leaves could be utilized as a feedstock in biogas production, helping to reduce GHG emissions, increase renewable energy generation, and provide fertilizer. The aim of this study was to compare the mono-digestion of fallen leaves from three tree species commonly found in parks and along streets—northern red oak (Quercus rubra L.), small-leaved lime (Tilia cordata Mill.), and Norway maple (Acer platanoides L.)—in both wet and dry anaerobic digestion (AD) systems. A biochemical methane potential (BMP) test was conducted in batch assays for each of the three substrates in both AD technologies at a temperature of 38 ± 1 °C. The highest specific methane yield (SMY) was obtained from Quercus leaves in wet AD technology, with a methane yield of 115.69 ± 4.11 NL kg_VS⁻¹. The lowest SMY (55.23 ± 3.36 NL kg_VS⁻¹) was observed during the dry AD of Tilia leaves. The type of technology had no significant impact on the SMY of Acer and Tilia leaves; however, the methane yield from Quercus leaves in wet AD was significantly higher (p < 0.05) than that from dry AD. Studies on the use of fallen leaves from Tilia cordata, Quercus rubra, and Acer platanoides as substrates in mono-digestion technology have shown their limited suitability for biogas production. Nevertheless, this feedstock may be more effectively used as a co-substrate, mainly due to the low concentrations of ammonia (NH₃) and hydrogen sulfide (H₂S) in the biogas produced from these leaves, both of which are considered inhibitors of the AD process. Full article

Soil fungal communities are critical for forest ecosystem functions in the Central Hardwood Region (CHR) of the USA. This evaluation, which took place in 2022–2023, investigates the influence of Juglans nigra (BW, black walnut) and Quercus rubra (NRO, Northern red oak) on soil properties and fungal community structures across three CHR sites. The objectives of this study are to investigate how the fungal communities identified beneath J. nigra and Q. rubra serve to influence biodiversity and soil health within hardwood plantations. Soils from two locations in Indiana and one in Michigan were examined and assessed for variations in fungal composition and diversity. Soil fungal communities were characterized using Illumina high-throughput sequencing while multivariate analysis was applied to analyze patterns in these fungal communities. These data provided insights into how environment, location, and tree species affect fungal community structure. Results indicate that J. nigra soils exhibited higher carbon (0.36%, 1.02%, 0.72%), nitrogen (25%, 29%, 56%), and pH (0.46, 1.08, 1.54) levels than Q. rubra soils across all three sites and foster greater fungal diversity. Specifically, J. nigra was associated with increased Ascomycota diversity, whereas Q. rubra supported a higher prevalence of Basidiomycota. Basidiomycota were negatively correlated with carbon and pH, while Ascomycota showed positive correlations with these variables. These findings highlight how crucial it is to understand how different tree species influence fungal communities and, consequently, how they influence forest soil health. Our findings serve to improve forest management practices by emphasizing the importance of fungal communities in maintaining the function and resilience of an ecosystem. Our study underscores that grasping these specific interactions is essential for effective forest management, especially when considering how to use fungal communities to boost plant growth. This work focuses on hardwood plantations rather than either agricultural ecosystems, monocultures, or native forests, thus filling a gap in the current literature where many studies are limited to specific fungal groups such as mycorrhizae. In future research, it is important to examine a wider range of tree species. This will deepen our understanding of fungal community dynamics and their impact on maintaining healthy forest ecosystems. Our hardwood plantation focus also notes the potential for adaptive forest management as environmental conditions change. Full article

Estimation of tree volume typically focuses on excurrent forms, with less attention given to decurrent forms. Species with a decurrent form, particularly hardwoods, lack a dominant stem and have large diameter branches that can be included in the merchantable wood volume. We developed a preliminary two-equation system comprising a taper equation and a merchantable whole-tree volume (stem and branches) equation for Quercus rubra L. growing in Navarra (Northern Spain). The equation system includes the diameter at breast height and total tree height as independent variables, along with merchantable height—the height up to which the stem maintains a well-defined excurrent form—as an additional variable. After estimating the stem volume, the branch volume is estimated by subtracting the stem volume from the merchantable whole-tree volume. A second order continuous autoregressive error structure was used to correct for autocorrelation between residuals from the fitted taper equation. The equations explained 90% of the observed variability in diameter and 86% of the observed variability in merchantable whole-tree volume. Both equations have been implemented in the Cubica Navarra 3.0 software for use as a system of equations. These equations are considered preliminary and will be refitted or validated as additional data becomes available from new locations. Full article

Research Highlights: Environmental abiotic stressors generate secondary stresses in plants, such as osmotic and oxidative stresses, which negatively influence their normal growth, development, and metabolism. Research about other non-enzymatic components with antioxidant capacity has recently focused on polyphenols. However, their role as indicators of drought and shade tolerance in woody species leaves and roots has been poorly explored or was limited to leaves only. Background and Objectives: Under a scenario of increasing drought, understanding the seedling responses in terms of total polyphenols and their antioxidant activity, in particular at the fine root system level, may help to elucidate the native–alien species interaction. Materials and Methods: At the beginning of July, 5-month-old native Quercus robur and alien Quercus rubra seedlings were transferred indoors to the growth chamber and subjected to progressive soil drying for 21 days. Results: The decrease in soil water content was more pronounced for Q. robur (9%) than for Q. rubra (34% of field capacity). Leaf water potential significantly decreased over time in Q. robur but did not differ from the control in Q. rubra. The total polyphenol concentration in Q. robur was markedly lower in the leaves and significantly higher in the fine roots than in Q. rubra. For the leaves, both species showed markedly higher values if well-watered, and the values significantly decreased in response to drought only in Q. rubra. In contrast, the fine root values for both species were markedly higher if droughted and decreased significantly in time only in Q. robur. Differently from the polyphenol concentration, the antioxidant capacity of Q. rubra was always higher in both the leaves and fine roots. Conclusions: The higher antioxidant activity of the alien species Q. rubra revealed by this work, combined with its isohydric behaviour, could further shed some light on our understanding of its competitive performance at the seedling stage against the native Q. robur. Full article

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is crucial in plant metabolism and responses to various abiotic stresses. In the glycolysis pathway, glyceraldehyde-3-phosphate (G3P) is oxidized to 1,3-bisphosphate glycerate (1,3-BPG) through the catalytic action of GAPDH. However, the GAPDH gene family in Quercus rubra has been minimally researched. In this study, we identified 13 GAPDH-encoding genes in Q. rubra through a bioinformatics analysis of genomic data. Evolutionary studies suggest that these QrGAPDH genes are closely related to those in Glycine max and Triticum aestivum. We conducted a comprehensive whole-genome study, which included predictions of subcellular localization, gene structure analysis, protein motif identification, chromosomal placement, and analysis of cis-acting regions. We also examined the expression of GAPDH proteins and genes in various tissues of Q. rubra and under drought stress. The results indicated diverse expression patterns across different tissues and differential expression under drought conditions. Notably, the expression of Qurub.02G290300.1, Qurub.10G209800.1, and Qrub.M241600.1 significantly increased in the leaf, stem, and root tissues under drought stress. This study provides a systematic analysis of QrGAPDH genes, suggesting their pivotal roles in the drought stress response of trees. Full article

Torrefaction and combustion have been applied to naturally decomposed red oak logging residues. The results indicated that four-year natural decomposition would lower the energy density of red oak from 20.14 to 18.85 MJ/kg. Torrefaction reduced the O/C and H/C ratios but improved the energy yield values. Two combustion stages were observed for all samples, and no hemicellulose derivative thermogravimetric peak appeared for torrefied samples. The differential scanning calorimetry exothermic heat flow increased after torrefaction. In addition, the Kissinger–Akahira–Sunose average activation energy of untorrefied samples decreased in the first stage (from 157.77 to 149.52 KJ/mol), while it increased in the second stage (from 131.32 to 181.83 KJ/mol). The ∆H, ∆G, and ∆S values of all samples decreased in the first stage, while they increased when the conversion rate was greater than 0.5 for torrefied samples. These findings can aid in a better understanding of the fuel performance of torrefied and untorrefied naturally decomposed red oak logging residues. Full article