Search Results (923)

Individual tree modeling (ITM) is an effective system for thinned stands, especially in teak (Tectona grandis Linn F.) plantations, allowing the estimation of individual-tree-specific variables. Heartwood diameter and volume have high added value and can be estimated in living trees. Therefore, we developed an ITM system for clonal teak stands capable of projecting technical intervention ages and quantifying heartwood production throughout the rotation in the Eastern Brazilian Amazon. The system included equations for total tree height, site index, and taper of both stem and heartwood, with volumes obtained by integrating the respective taper equations. Future diameters and heights were projected using models based on the algebraic difference approach (ADA) and the generalized algebraic difference approach (GADA). Ages of technical intervention were defined by the maximum mean annual increment in volume with bark. The Lundqvist-Korf-ADA base model was the most accurate in estimating future trees’ diameters and heights. The inclusion of the number of trees as a covariate to represent thinning had a significant and positive impact on variable projections. Optimal technical rotations ranged from 17.1 to 21.3 years, considering volume with bark. An increase in the proportion of heartwood was observed, reaching 78% of the diameter and 53% of the volume at rotation ages. The modeling system developed in the present study enables the estimation of technical rotation ages and the quantification of heartwood production throughout the rotation, which provides reliable information for silvicultural planning and decision-making in the management of clonal teak stands. Full article

The by-products of the wood-processing industry are still predominantly used for energy generation, despite being a rich source of high-value phenolic compounds. This review focuses on the valorization of bark from economically crucial European tree species. Based on an extensive literature survey, three deciduous species (Fagus sylvatica, Quercus robur/petraea, Carpinus betulus) and three coniferous species (Pinus sylvestris, Picea abies, Abies alba) were selected on the basis of their distribution in the European Union, their industrial relevance, and the composition and bioactivity of their extractive phenolic fractions. Conventional and nonconventional extraction techniques are briefly compared, with particular emphasis on deep eutectic solvents (DESs) as emerging green media for the selective isolation of phenolics from bark and other lignocellulosic residues. DESs are typically renewable, nontoxic, biodegradable, and nonflammable, and their tunable composition allows them to be tailored to specific target compounds. The literature data demonstrate that DES-based extractions can provide phenolic-rich extracts with high antioxidant and antimicrobial activities and, in some cases, can outperform conventional solvents. Finally, the potential applications of bark-derived phenolic extracts in the pharmaceutical, agricultural, food, polymer processing, and cultural heritage sectors are outlined. The review also identifies knowledge gaps in DES selection, extract purification, and solvent recovery, highlighting future research needs for integrating DESs into sustainable wood-biomass biorefineries. Full article

This study aimed to develop and compare prognostic models (logistic regression, Cox proportional hazards, and random forest) to assess delayed mortality in pine (Pinus densiflora) following fires in Korea. Data from a 72-month monitoring of 734 trees across four fire areas were used, accounting for 19 variables: tree size, fire severity, multispectral indices, topography, and bioclimatic variables. Key predictors of mortality included diameter at breast height (DBH), bark scorch index (BSI), delta normalized burn ratio (dNBR), slope, topographic wetness index (TWI), precipitation of the warmest quarter, temperature seasonality and isothermality. The key results indicate that the random forest model was the most effective (AUC = 0.924; sensitivity = 0.892) in identifying trees at high risk of mortality. These results suggest that nonlinear approaches are effective for predicting delayed mortality in fire-damaged pines and can support rapid decision-making in post-fire forest management and restoration under increasing wildfire risk. Full article

Tree bark is a relatively stable visual feature for tree species detection because it remains visible throughout the year and is less affected by seasonal changes than leaves or flowers. However, bark-texture-based tree species detection in natural scenes remains challenging because of limited dedicated datasets, subtle inter-class texture differences, complex backgrounds, and scale variation. This work evaluated whether task-oriented multi-scale feature fusion and attention-based feature enhancement can improve YOLOv8s for bark-texture-based tree species detection. To this end, the Tree_bark dataset was constructed, containing 134 annotated classes and 8216 valid images, and YOLOv8s was used as the baseline detector. Three multi-scale enhancement strategies, three lightweight attention mechanisms, and their fused configuration were systematically compared under the same data split and evaluation setting. On the validation set, the baseline YOLOv8s achieved a mAP@0.5 of 0.443, a mAP@0.5:0.95 of 0.339, and a Recall of 0.400. The final fused D1 model, combining WeightedConcat_B1 and EMA, showed the highest overall performance among the compared settings under the current experimental setting, with a mAP@0.5 of 0.485, a mAP@0.5:0.95 of 0.365, and a Recall of 0.435. Compared with the baseline, D1 improved mAP@0.5 by 0.042, mAP@0.5:0.95 by 0.026, and Recall by 0.035. These results indicate that moderate adaptive multi-scale fusion and lightweight attention enhancement can improve bark-texture-based tree species detection in complex natural scenes. The proposed framework provides a useful reference for fine-grained tree species detection based on bark texture, although further validation across broader regions and more complex field conditions is still needed. Full article

White pine blister rust disease (WPBR), caused by Cronartium ribicola, ranks among the most destructive pathogens of five-needle pines. We developed a hydroxynaphthol blue (HNB)-based Loop-mediated isothermal amplification (LAMP) assay enabling rapid, visual detection of C. ribicola directly following DNA extraction. LAMP primers targeting the internal transcribed spacer (ITS) region were designed and validated through in silico comparison with related Cronartium species and in vitro testing against sympatric forest fungi. The optimized 25 μL reaction contained 8.0 mM Mg²⁺, 1.0 mM dNTPs, and an inner-to-outer primer ratio of 8:1, with amplification conducted at 62 °C for 40 min. Positive amplification produced a distinctive color transition from purple to sky blue, enabling visual interpretation without instrumentation. Under the tested conditions, the assay achieved a detection limit of 460 ± 3.2 fg/μL genomic DNA—a 10-fold improvement over conventional PCR in concentration-based sensitivity. Assay applicability was evaluated using 211 field-collected Pinus armandii samples sourced from China. Detection efficiency varied significantly across tissue types. Symptomatic bark exhibited a substantially higher positive detection rate (68.97%, 95% CI: 49.2–84.7%) compared to needles from symptomatic trees (18.75%, 95% CI: 4.1–45.7%). Among asymptomatic samples, 3.75% of bark samples tested positive for C. ribicola DNA, whereas all needle samples were negative. Geographically, positive detections clustered at several discrete sampling sites in southwestern China, predominantly at elevated elevations. The established LAMP-HNB assay provides a rapid, visually interpretable diagnostic tool for early detection and quarantine monitoring of WPBR following DNA extraction. Beyond its practical utility, this assay establishes valuable baseline data for targeted disease surveillance in the context of evolving climate conditions. Full article

Testing harvested logs is a critical step in the wood products supply chain. Non-destructive evaluation (NDE) methods are essential for grading and sorting logs, especially given variations associated with tree age. In this study, plantation-grown Eucalyptus nitens from two age groups were sourced from two Tasmanian harvesting sites for NDE and comparison with destructive stiffness testing. The key finding is that the correlation between dynamic modulus of elasticity (DMOE) and static modulus of elasticity (MOE) weakens with increasing age, particularly at the whole-log level. For further analysis, the radial location of recovered small clear samples (from pith to bark) was examined. Core samples (near the pith) showed the strongest correlation between DMOE and static MOE (R² = 0.51), followed by middle (R² = 0.46) and outer samples (R² = 0.25). This study demonstrates that considering the radial location of recovered samples is a more effective approach for improving grading accuracy. Age is a key factor for initial segregation of logs before applying NDE for property analysis of both logs and recovered samples. Full article

Drosophila suzukii is one of the most destructive pests of soft fruits worldwide due to its high reproductive capacity, wide host range, and great adaptability. In this context, Drimys winteri, a tree native to southern Chile and Argentina, is recognized as a source of bioactive compounds with insecticidal and repellent properties. This study evaluated the repellent and oviposition-deterrent activity of essential oils (EOs) from the bark and leaf of D. winteri on D. suzukii. Chemical analysis by GC/MS showed that both EOs were dominated by monoterpenes, with α-pinene, β-pinene, and D-limonene being the major compounds, while the leaf EO exhibited greater chemical diversity and a higher proportion of sesquiterpenes. In choice bioassays, all treatments generated significant avoidance responses, with a preference for the control. The leaf EO showed the greatest repellent effect, exceeding 85% at 12 h and remaining above 80% at 96 h. In oviposition assays, the leaf EO significantly reduced egg laying at all concentrations, with negative oviposition preference index values indicating a consistent deterrent effect. Overall, the leaf EO of D. winteri showed repellent and oviposition-deterrent effects against D. suzukii under laboratory conditions. Full article

The mountain pine beetle, Dendroctonus ponderosae, is a bark beetle that can cause extensive tree mortality of its hosts in western North America. Lodgepole pine, Pinus contorta, is one of its primary and most widely distributed hosts. The insect exhibits a one-year life cycle with a dispersal flight of emerging adults, referred to as brood adults, which attack new trees in the late spring–early summer. The larvae develop through the summer and overwinter. The following spring, development resumes, followed by pupation and emergence of a new generation of brood adults. Every year, a proportion of adults survive the winter, referred to as parent adults, re-emerge and attack new trees prior to brood adult emergence. These contribute little to population dynamics, but it is unknown whether these parent adults contribute to host finding by brood adults by initiating attacks that lead to clustering of attacks by brood adults. We tested this hypothesis by sequentially marking attacked trees from early spring to the fall in 2006, 2008, and 2015 in stands in northern Colorado. The sudden increase in the number of attacks indicates brood adult emergence. We tested for clustering of parent adult- and brood adult-attacked trees and of brood adult-attacked trees around parent adult-attacked trees using Ripley’s K-function. We found evidence of clustering of parent adult-attacked trees and brood adult-attacked trees, but there is no evidence of clustering of brood adult-attacked trees around parent adult-attacked trees. Full article

Logging causes damage on residual trees, with differing characteristics and severities. The causal agent, as well as the size and type of injury, is influenced by the type of machines, the harvesting technology adopted, and the machine operator. This study descriptively documents residual tree damage observed in two sledge-yarding operations conducted under contrasting stand and operational conditions: a beech stand managed with a full-tree system and a Scots pine stand managed with a cut-to-length system. Two stands were selected: the harvesting intensity was 50% in the coniferous stand (salvage logging) and 20% in the deciduous stand (thinning). In each stand, six 20 × 20 m plots (0.04 ha) were delineated to assess residual tree damage. In the two observed cases, the beech operation showed a higher proportion of damaged residual trees, 32.2%, than the Scots pine operation, 5.3%. In the deciduous stand, bark injuries were mainly slight wood exposure (75%), whereas in the coniferous stand, crushed bark (42.9%) was most frequent, followed by slight wood exposure (35.7%). No concerning damage to seedlings was detected. In general, the number of damaged trees and the severity of injuries were considerably lower than those typically observed when extracting with a cable skidder, and especially with an adapted farm tractor. To reduce mechanical damage to residual trees, protective devices can be deployed around trees at risk of root and stem injury. Another effective measure is to financially motivate workers to implement environmentally sound forest operations. Full article

Phoebe bournei is a rare and economically valuable tree species native to China that plays an important ecological role. In this study, we conducted a genome-wide identification of the SQUAMOSA promoter-binding protein (SBP) transcription factor family in Phoebe bournei and characterized 19 PbSBP genes distributed across 10 chromosomes. Phylogenetic analysis grouped these genes into five distinct subfamilies, each of which showed homology to SBP genes in Arabidopsis thaliana and Oryza sativa, indicating strong evolutionary conservation within the family. All identified PbSBP proteins contain the conserved SBP domain, and some members also harbor additional motifs such as the ANK domain, which may mediate protein–protein interactions. Tissue-specific expression profiling revealed that several PbSBP genes are predominantly expressed in root bark and leaves, suggesting their potential roles in defense responses and developmental regulation. Moreover, qPCR validation showed that PbSBP2, PbSBP9, and PbSBP16 were significantly upregulated under PEG-induced drought stress, implying their involvement in abiotic stress responses. This study provides a foundational understanding of the SBP gene family in P. bournei and highlights candidate genes for future genetic improvement and breeding for stress resistance. Full article

The occurrence of pear Valsa canker caused by Cytospora pyri poses a serious threat to the healthy and sustainable development of the Korla fragrant pear industry. To effectively control the disease, endophytic strains were isolated from the bark of Korla fragrant pear trees and screened for strong antagonistic activity against the pathogen. The selected strain was identified based on morphological characteristics and 16S rRNA phylogenetic analysis. Its biocontrol potential and functional traits were further evaluated, along with its growth-promoting ability assessed through in vitro tests and preliminary tomato pot experiments. Results showed that a total of 264 endophytic isolates were obtained from 200 pear tissue samples using dilution plating and tissue separation methods. Among them, strain FB-4 exhibited significant inhibition against C. pyri. Morphological observations and phylogenetic analysis identified the strain as Bacillus velezensis, named FB-4. The cell-free supernatant inhibited conidial germination and mycelial growth of the pathogen by 88.21% and 85.51%, respectively, and showed preventive and curative efficacies of 74.49% and 58.97% against pear Valsa canker. In vitro assays indicated that FB-4 could produce indole-3-acetic acid, protease, amylase, and cellulase, and demonstrated abilities to solubilize inorganic phosphate and synthesize siderophores. Inoculation with FB-4 bacterial suspension promoted the growth of tomato seedlings, with higher concentrations yielding more pronounced effects. In conclusion, strain FB-4 represents a dual-functional biocontrol agent with both antagonistic and plant-growth-promoting properties. Full article

This paper examines the energy potential of silver fir (Abies alba Mill) and Norway spruce (Picea abies (L.) Karst) trees across three tree crown defoliation degrees (TCDDs): healthy, severely defoliated (61–99%) and dead. The study was conducted in the area of the Forest Administration Delnice, Management Unit »Milanov vrh«, in the Republic of Croatia. Field measurements were conducted on 83 silver fir trees and 114 Norway spruce trees to determine the mass of live and dead branches per tree and to collect samples of wood, bark, main live and dead branches, and side live and dead branches (in total, 813) for further laboratory analyses. Further, differences in wood basic density, moisture content, ash content, net calorific value, and carbon, hydrogen, nitrogen, and sulfur content across TCDD classes were also determined. For both tree species, wood basic density across TCDDs decreased as follows: severely defoliated trees > healthy trees > dead trees. Regression analyses showed that the largest masses of branches occurred on healthy silver fir trees (R² = 0.48), followed by severely defoliated (R² = 0.41) and dead trees (R² = 0.46). The same trend in determined total branch mass per tree was observed for Norway spruce trees, where the coefficient of determination was highest for dead trees (R² = 0.72), followed by severely defoliated (R² = 0.69) and healthy (R² = 0.61) trees. A negative correlation between moisture content and TCDD class was observed for wood, bark, and live branches. The highest net calorific value was found for side live branches for both researched species, and only the net calorific value of side live branches of Norway spruce was statistically significantly different across TCDD classes. Overall, this study showed a negative impact of TCDD on the amount of available tree residues (branches) that could be utilized as a solid biofuel. Furthermore, the results of the laboratory analyses were ambiguous, increasing the complexity and heterogeneity of the wood material and underscoring the need for further investigation. Full article

Tree bark, an abundant by-product of the timber industry, represents a promising feedstock for sustainable construction. This study investigates the thickness swelling, water absorption, hygroscopicity and mechanical (compressive strength) properties of insulation panels produced from hardwood bark (Tilia spp. and Robinia pseudoacacia) via hydromechanical treatment and a wet-forming process. The panels were produced without added adhesives, relying on the formation of hydrogen bonds during the drying phase to ensure structural integrity. Both bark-based insulation boards (thermal conductivity coefficient 0.055–0.057 W/m·K) showed similar hygroscopic behavior, reaching equilibrium moisture contents of max. 25% at 93.9% RH. Water absorption after 24 h immersion was highly material-dependent; Tilia-based panels showed 57.11 ± 5.81%, and Robinia-based panels 320.61 ± 11.34%. Thickness swelling remained low (max. 6% for Robinia), showing significant orthotropic anisotropy. At 10% compressive strain, the Tilia and Robinia bark-based panels showed compressive strengths of 188 ± 14.6 kPa and 298 ± 18.1 kPa, accordingly. These findings demonstrate that hardwood bark can be successfully valorized into high-performance, binderless insulation, supporting circular economic strategies. Full article

Phellodendron amurense Rupr. is a native tree species in China, well known for its significant medicinal value. Its pharmacological activity mainly derives from the abundant isoquinoline alkaloids in its bark. Berberine serves as the key compound underlying the multiple pharmacological effects of P. amurense and exhibits organ-specific accumulation. However, the genetic mechanisms governing this organ-specific accumulation remain unclear. Genes encoding O-methyltransferase (OMT) and cytochrome P450 (CYP) may play an important role in this regulatory process. In this study, by integrating transcriptomic and metabolomic data from the leaves and stems of P. amurense plantlets, we identified core candidate genes and transcription factors (TFs) that regulate the differential biosynthesis of berberine between these two organs. The results showed that 37 metabolites were significantly upregulated in stems, including main medicinal components such as berberine and jatrorrhizine, while 8497 genes were differentially expressed between leaves and stems. Among these, downstream genes in the berberine biosynthesis pathway, including OMTs and CYPs, were predominantly highly expressed in stems. A co-expression regulatory network identified some TFs such as PaBES1, PaWRKY12/13, PaNAC5, and PaMYB12 as the key nodes regulating the differential biosynthesis of berberine. Phylogenetic analysis classified the 97 PaOMTs into four subgroups. Core candidate genes such as PaOMT7 and PaOMT9 were contained in subgroup IV, potentially contributing to the specific modification of characteristic alkaloids in P. amurense. This study reveals the transcriptional regulatory networks underlying the organ-specific accumulation of berberine in P. amurense plantlets, providing key targets and theoretical support for the targeted improvement and development of elite medicinal varieties. Full article

Trypophloeus binodulus is a bark beetle present in mature poplar plantations that damages the bark of healthy trees and is currently expanding, posing a risk to these crops and impacting their economic profitability, since there is currently no early detection method or control strategy for this pest. This study was carried out in the province of León in three experimental plots affected by this pest, located in Villasabariego, Villoria de Órbigo, and Turcia to evaluate the effectiveness of different combinations of primary and secondary kairomonal compounds in different trap types. Moreover, the capture results obtained during 20 and 22 weeks in 2023 and 2024 years, respectively, of the field trial made it possible to determine that the most effective lure for monitoring and controlling T. binodulus is Ethanol + Salicylaldehyde, since its synergistic effect enhances its attractiveness. Also, the results confirmed that ESCOLITRAP^® traps are the most effective under field conditions. These results identify an effective method for monitoring the pest, which could be a promising candidate for adoption by poplar growers, enabling progress toward sustainable management through semiochemical compounds. Full article