Forests

Spodoptera frugiperda (J.E. Smith) is a highly significant agricultural pest that poses a threat to crop production worldwide. It is polyphagous, has a strong migratory ability, and is difficult to control, which makes it a threat not only to crops but also to woody plants. However, research on its adaptability to woody plants is limited. This study compares the feeding adaptations (survival rate, pupation time, pupation rate, weight, length, and daily food consumption), protective enzyme activities, and feeding preferences of S. frugiperda on leaves of six economically important tree species (Areca catechu L., Aquilaria sinensis (Lour.) Spreng, Cocos nucifera L., Camellia oleifera Abel, Dalbergia odorifera T. Chen, and Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg.), with Zea mays L. used as a control treatment. The results indicate that S. frugiperda did not survive when fed with A. catechu, C. oleifera, and D. odorifera. A. catechu had similar survival rates (83.33%), pupation (86.67%), weight, and length data compared to the maize control. C. nucifera had lower survival rates (46.67%) but no significant differences in pupation (76.67%), weight, and length data of S. frugiperda. H. brasiliensis exhibited significantly lower survival (50.00%) and pupation rates (46.67%) compared to maize. However, there was no significant difference in weight and length data, and its preference index was higher among the six tree species treatments. Therefore, A. sinensis is a vulnerable tree with a high risk, while H. brasiliensis and C. nucifera showed varying degrees of susceptibility. A. catechu, C. oleifera, and D. odorifera were found to be unsuitable hosts for S. frugiperda. In conclusion, this study extensively explores the feeding effects of S. frugiperda on six economically important tree species. It provides insights into the feeding preferences of the pest, thereby informing the potential threat posed by S. frugiperda to economically important trees. It helps to prevent further damage from S. frugiperda and provides a reference for agriculture and forestry to develop effective joint prevention and control measures. Full article

Examining the Saihanba Mechanical Forest Farm, this study utilized Landsat remote sensing data from 1987, 1997, 2001, 2013, and 2020 to interpret land use from the Support Vector Machine (SVM) method, and to decipher evolving land use patterns over the last four decades. Grounded in landscape ecology theory, an innovative evaluation index for landscape ecological risk was introduced, leading to the delineation of 382 ecological risk evaluation units. Employing landscape pattern indices and a method of spatial autocorrelation, we analyzed the spatial and temporal distribution characteristics and spatial correlation patterns of landscape ecological risk across five distinct periods. Geostatistical approaches were used to explore the driving factors of landscape risk. The results indicate that since 1987, there have been significant changes in land use types, especially in forest landscapes, their proportion increasing from 23.19% to 74.55%. In 1987, the proportion of high-risk areas was 72.30%, but in 2020, high-risk areas had significantly decreased and clustered in specific locations. The landscape ecological risks in each period of the study area showed a positive spatial correlation and tended to gather in space. After comprehensive exploration using a geographic detector, we found that landscape type, temperature, and vegetation coverage are the main risk factors. Among them, landscape type has the greatest impact on the landscape and works together with slope, aspect, and precipitation. In forest farm management, only the adaptation and adjustment of single factors are often paid attention to, while the compound effects of multiple factors are ignored. The results of this study bring important reference value to the operation and development of forest farms. Full article

Leaves facing different directions (north, south, east, and west) receive differing levels of illumination, resulting in spatial differences in photosynthesis P_N in the crowns of mature trees. We measured diurnal trends in P_N for a semi-solitary European ash (Fraxinus excelsior) over spring, summer, and autumn and compared these data with leaf biometric traits and leaf area distribution. The highest light-saturated P_N (P_Nmax) was to the south and west, and the lowest to the north. Likewise, intrinsic water use efficiency, defined as the ratio (P_N/g_S) of photosynthetic rate (P_N) and stomatal conductance (g_S), was also lowest to the north. The thickest leaves were found on the northern face and the thinnest in the south, suggesting differences in leaf anatomy may have contributed to differences in P_N. The greatest leaf area was recorded in the southern crown quadrant, which contributed more than 50% of the tree’s accumulated P_N. Our research emphasises the importance of choosing representative leaves for gas exchange measurements. In-depth studies into the spatial distribution of leaves and their traits will be necessary for accurate upscaling of leaf-level photosynthesis to whole tree and canopy levels. Full article

In this study, a machine learning-based method to assess and predict the cracking degree (CD) on wood fiber bundles (WFB) was developed, which is crucial for enhancing the quality control and refining the production process of wood scrimber (WS). By roller-cracking poplar wood one to three times, three distinct CD levels were established, and 361 WFB specimens were analyzed, using their water absorption rate (WAR) as the foundation for CD prediction. Through crack image analysis, four key quantitative parameters were identified—cracking density, coherence degree, crack count, and average width—and this study found through discriminant analysis that the discrimination accuracy on the CD levels by cracking density or coherence degree over 90%, emphasizing their significance in evaluation. Cluster analysis grouped the specimens into three clusters based on four key quantitative parameters, aligning with the CD levels. This study developed specialized prediction models for each CD level, integrating principal component analysis for dimensionality reduction with polynomial fitting, achieving mean squared error (MSE) of 0.0132, 0.0498, and 0.0204 for levels 1, 2, and 3, respectively. An integrated model, with an accuracy of 94.3% and predictions within a 20% error margin, was created, demonstrating the effectiveness of using surface crack image features to predict WAR of WFB. This research establishes a methodological framework for assessing CDs on WFB, contributing to enhancing WS product quality and helping to better understand wood cracking and water absorption mechanisms. Full article

The AP2/ERF gene family, referring to an exclusive class of transcription factors unique to plants, is involved in various biological processes, including plant growth and responses to environmental stresses like high salt and drought. In this study, the AP2/ERF gene in M. notabilis was comprehensively identified and bioinformatically analyzed based on the genomic data of M. notabilis. 106 members in the MnAP2/ERF gene family were identified in the M. notabilis genome and were categorized into five subfamilies: ERF, AP2, DREB, RAV, and Soloist, with the ERF subfamily representing 80.19% of the total. The MnAP2/ERF gene family was observed to be distributed on six chromosomes of M. notabilis. Members in the MnAP2/ERF gene family exhibited obvious differences in amino acid number, molecular weight, isoelectric point, and other properties. Approximately 68.87% of the MnAP2/ERF proteins were acidic, all exhibiting hydrophilic characteristics. Differences in conserved sequences and arrangement of AP2 domains were observed among distinct subfamilies, with genes in the same subfamily sharing similar conserved domain compositions. There were 47 genes without untranslated regions and 44 genes with two untranslated regions. The upstream functions of promoters were concentrated on light reactions and plant hormones. Evolutionarily, significant structural differences were identified, and 28 MnAP2/ERF gene family proteins could interact with each other. Moreover, 35 family genes were involved in 22 fragment repeat events, and 55 MnAP2/ERF and 84 AtAP2/ERF genes showed collinearity. The expression of the MnAP2/ERF gene family was significantly different in different parts, indicating that these gene family members were involved in different physiological activities. These results established a theoretical foundation for investigating the functional and evolutionary aspects of AP2/ERF gene family genes in M. notabilis, as well as exploring the root morphogenesis of M. notabilis. Additionally, this study contributes to a basis for the improvement of cultivar stress resistance of M. notabilis. Full article

Microtubules, polymerized from α-tubulin (TUA) and β-tubulin (TUB) monomers, play a pivotal role in shaping plant morphogenesis according to developmental and environmental cues. Salix psammophila C. Wang & C. Y. Yang is an important shrub plant in sand-fixing afforestation in arid regions, with three significantly distinct plant types shaped under various environments, namely, upright, intermediate, and scattered types. However, how tubulin genes respond to the developmental and environmental signs in S. psammophila has been far less studied. Here, based on RNA-seq, Sanger sequencing, and real-time PCR (RT-PCR) data, we analyzed the phylogeny of tubulins and their expression profiles in S. psammophila among the three plant types. Furthermore, we analyzed the genetic structure and expression pattern of SpsTUB10 in S. psammophila under various abiotic stress treatments. In total, we identified 26 SpsTubulin genes in S. psammophila. The homologous alignment and phylogenetic analysis revealed that these SpsTubulin genes can be classified into two groups, corresponding to the TUA and TUB genes. The expression profiles of these SpsTubulin genes in various organs showed that most SpsTubulin genes were mainly expressed in the root. SpsTUB10 is a member of the TUB IIa group, consisting of two intros and three exons. The SpsTUB10 protein contains a typical GTPase domain and a C-terminal domain, with α-helix and random coil dominant in the secondary and tertiary structures. The RT-PCR results of SpsTUB10 showed an extremely significant difference in expression levels among the root and stem-developing organs between the upright and scattered types, and the transcript level of SpsTUB10 had a significantly negative correlation with the crown-height ratio. Under different treatments, we found that cold, osmotic stress, and short daylight could significantly increase SpsTUB10 expression levels compared to those in the controls, thereby supporting the positive role of SpsTUB10 in stress-induced responses. These results will provide evidence for the SpsTubulin genes’ response to the developmental and environmental cues in S. psammophila. Full article

While using sap-flow sensor measurements is a well-established technique for quantifying leaf water transpiration in tree species, installing and maintaining a large number of sensors and data loggers in large-scale plantations to obtain accurate measurements is both costly and time-consuming. We developed a copula-based approach to predict sap flows based on readily available vapor pressure deficits (VPDs) and found that the Normal copula was the best among five commonly used copulas. The Normal-copula approach was validated using our field-measured eastern cottonwood (Populus deltoides (Bartr. ex Marsh.)) sap flow data, yielding solid statistical measures, including Mann–Kendall’s τ = 0.59, R² = 0.81, and p-value < 0.01. The approach was applied to predict sap flows of eastern cottonwood during the growing period from 1 March to 31 October 2015 as well as the 5-year growing period from 2019 to 2023. It successfully replicated the characteristic diurnal sap flow pattern, with rates increasing during the day and decreasing at night, as well as the typical seasonal pattern, with rates rising from winter to summer and decreasing from summer to next winter. Our study suggests that the copula-based approach is a reliable tool for estimating sap flows based on VPD data. Full article

The incorporation of sustainability into the design of transport vehicles has become increasingly important in recent years. A low carbon footprint makes wood-based structures attractive to replace other lightweight materials such as aluminum or fiber-reinforced plastics. This paper investigates and compares the static and dynamic impact behavior of thin Beech wood veneer laminates in standardized mechanical tests. The results obtained from Quasi-Static Indentation (QSI) and dynamic Low-Velocity Impact (LVI) tests reveal similarities and differences with regard to load vs. displacement behavior, damage mechanisms, permanent deformation, and energy absorption. While yield strength and damage modes are comparable in both test cases, it is found that the bending stiffness is strain-rate sensitive. Plastic deformation in compression is identified as the governing mechanism for energy absorption. These results can guide the design of sustainable wood-based structures for future transport applications where a thorough understanding of impact and crashworthiness is important. Full article

Permafrost is widely degraded in the context of global warming. The spatial distribution of soil microbes in these cold habitats has received a lot of attention. However, knowledge on the changes in permafrost microbial communities following permafrost thaw is still limited. We used permafrost soil from a taiga forest for indoor experiments using pristine soil as a control (CK, −2 °C), simulating warming for 15 days at temperatures of 0 °C (T₁), 2 °C (T₂), and 4 °C (T₃). Amplicons of the hypervariable V4 region of the bacterial 16S rRNA gene were sequenced to identify bacterial communities present in the soils of pristine and warming treatments. Warming increased the average relative abundance of Proteobacteria (5.71%) and decreased that of Actinobacteriota (7.82%). The Beta diversity changed (p = 0.001) and significantly correlated with the pH, microbial biomass carbon (MBC), and available potassium (AK) of the soil (p < 0.05). Warming further increased the Alpha diversity (Simpson index), changing the functional pathways of the bacterial communities, whereby secondary functional pathways produced significant correlations with bacterial phyla (p < 0.05). Combined, the results indicated that short-term warming altered the Beta diversity of soil bacteria in a taiga forest’s permafrost soil by decreasing the abundance of Actinobacteria and increasing that of Ascomycetes, while pH, MBC, and AK were identified as the soil factors influencing the structure and diversity of the bacterial communities. Full article

Enhancing the total factor productivity in forestry is an important part of deepening the reform of the collective forest rights system. Based on the survey data of 295 forest plots in 12 towns of Liuyang City, Hunan Province, China, the study utilized a three-stage DEA model to assess the total factor productivity of forestry at the plot level. The empirical study employs Tobit and fractional regression models to investigate the effects and differences of forestry subsidies and forestry regulatory policies on the heterogeneous total factor productivity of different types of forests. The study found that: (1) the mean value of plot-scale forestry total factor productivity is 0.127, and there are obvious differences in total factor productivity among timber forests, economic forests, and mixed forests; and (2) afforestation subsidies and nurturing subsidies significantly positively influence high-level TFP. Ecological benefit compensation positively affects high-level TFP, but is not significant at any level of TFP. Forestry regulatory policies negatively impact high-level TFP, but are not significant at any level of TFP. This paper puts forward countermeasure suggestions to improve forestry subsidy policies, optimize forestry regulatory policies, and improve forestry total factor productivity from the perspective of heterogeneous forest types. Full article

Pine wilt disease (PWD) poses a significant threat to global pine resources because of its rapid spread and management challenges. This study uses high-resolution helicopter imagery and the deep learning model You Only Look Once version 7 (YOLO v7) to detect symptomatic trees in forests. Attention mechanism technology from artificial intelligence is integrated into the model to enhance accuracy. Comparative analysis indicates that the YOLO v7-SE model exhibited the best performance, with a precision rate of 0.9281, a recall rate of 0.8958, and an F1 score of 0.9117. This study demonstrates efficient and precise automatic detection of symptomatic trees in forest areas, providing reliable support for prevention and control efforts, and emphasizes the importance of attention mechanisms in improving detection performance. Full article

Pheromones play an important role in mate choice in insects, and pheromone synthesis pathways are potential targets for the control of harmful insects, among which desaturation is of great significance in pheromone structural diversity. However, little is known about the desaturase genes regulating pheromone synthesis in Coleoptera. In this study, taking the internationally significant pest Anoplophora glabripennis as a research object, we identified 6 AglaFAD genes, all of which were mapped to the endoplasmic reticulum and shared a highly similar distribution of conserved domains. A phylogenetic analysis showed that AglaFAD1–2 and AglaFAD3–6 exerted desaturation at different positions of the acyl chain, respectively. In regard to the expression levels of these six AglaFADs in both sexes, six tissues and three developmental stages were analyzed by qPCR. Combined with the chemical composition of the female pheromones that have been identified, two candidate genes, AglaFAD2 and AglaFAD5, which are specifically expressed in females, were screened, showing higher expression levels before mating and significantly decreasing after mating. It is speculated that they may be involved in the biosynthesis of contact pheromones in females. These results provide a basis for detailed functional studies of candidate genes in insect pheromone synthesis. Full article

The drastic increase of forest fire occurrence, which in recent years has posed severe threat and damage worldwide to the natural environment and human society, necessitates smoke detection of the early forest fire. First, a semantic segmentation method based on multiple color spaces feature fusion is put forward for forest fire smoke detection. Considering that smoke images in different color spaces may contain varied and distinctive smoke features which are beneficial for improving the detection ability of a model, the proposed model integrates the function of multi-scale and multi-type self-adaptive weighted feature fusion with attention augmentation to extract the enriched and complementary fused features of smoke, utilizing smoke images from multi-color spaces as inputs. Second, the model is trained and evaluated on part of the FIgLib dataset containing high-quality smoke images from watchtowers in the forests, incorporating various smoke types and complex background conditions, with a satisfactory smoke segmentation result for forest fire detection. Finally, the optimal color space combination and the fusion strategy for the model is determined through elaborate and extensive experiments with a superior segmentation result of 86.14 IoU of smoke obtained. Full article

The effects of continuous Eucalyptus cropping on soil properties and microbial characteristics and the specific factors influencing tree species growth remain elusive. In this study, three Eucalyptus stands of three different ages were selected, and soil nutrients, microbial biomass, enzyme activity, microbial community composition, and diversity were quantified for each. The findings indicated a significant decline in soil pH, soil cation exchange, soil organic matter, and available phosphorus content with the plantation age. Simultaneously, there was an observed increase in soil alkaline hydrolyzed nitrogen content. In addition, urease and acid phosphatase activities did not show a significant difference with age. In spite of this, catalase activity exhibited a decline corresponding to the advancement in plantation age. The carbon and nitrogen content of the soil microbial biomass increased with the progression of Eucalyptus planting time. The high-throughput sequencing data demonstrated a reduction in microbial diversity in Eucalyptus soils as the planting age increased. Interestingly, the microbial community structure exhibited minimal alterations, and did not exhibit a predominantly oligotrophic state overall. In conclusion, the study results showed that short-term successive Eucalyptus cropping exerts a significant negative impact on the soil system. Full article

The physical and mechanical properties of heat-treated wood are essential factors in assessing its appropriateness for different applications. While back-propagation (BP) neural networks are widely used for predicting wood properties, their accuracy often falls short of expectations. This paper introduces an improved Beluga Whale Optimisation (IBWO)-BP model as a solution to this challenge. We improved the standard Beluga Whale Optimisation (BWO) algorithm in three ways: (1) use Bernoulli chaos mapping to explore the entire search space during population initialization; (2) incorporate the position update formula of the Firefly Algorithm (FA) to improve the position update strategy and convergence speed; (3) apply the opposition-based learning based on the lens imaging (lensOBL) mechanism to the optimal individual, which prevents the algorithm from getting stuck in local optima during each iteration. Subsequently, we adjusted the weights and thresholds of the BP model, deploying the IBWO approach. Ultimately, we employ the IBWO-BP model to predict the swelling and shrinkage ratio of air-dry volume, as well as the modulus of elasticity (MOE) and bending strength (MOR) of heat-treated wood. The benefit of IBWO is demonstrated through comparison with other meta-heuristic algorithms (MHAs). When compared to earlier prediction models, the results revealed that the mean square error (MSE) decreased by 39.7%, the root mean square error (RMSE) by 22.4%, the mean absolute percentage error (MAPE) by 9.8%, the mean absolute error (MAE) by 31.5%, and the standard deviation (STD) by 18.9%. Therefore, this model has excellent generalisation ability and relatively good prediction accuracy. Full article

In order to explore the effects of enhanced UV-B radiation on the decomposition and nutrient cycling characteristics of Cunninghamia lanceolata (Lamb.) Hook litter, we collected material from C. lanceolata in a middle-aged forest (16 years) and over-mature forest (49 years). Four different UV-B radiation enhancement gradient treatments of CK, CK + 30 uw/cm² (T1), CK + 45 uw/cm² (T2), and CK + 60 uw/cm² (T3), with natural light (CK) as the baseline, were conducted to determine the impact of UV-B radiation indoor simulation enhancement on the litter decomposition and nutrient release of C. lanceolata at various developmental stages. The results indicate that UV-B radiation increases the dry weight decomposition rate and the nutrient decomposition rate of C. lanceolata litter, and the decomposition rate of C. lanceolata litter in an over-mature forest is always greater than that in a middle-aged forest litter, with observable influences on its chemical composition. Such changes significantly alter the nutrient release pattern of N, P, and K in litter in middle-aged forests and N in litter from over-mature forests, and promote the release of C, which may affect the nutrient cycle and carbon sink function of C. lanceolata plantations. Full article

Finding new wood resources is a permanent challenge nowadays, especially due to the fact that there is a crisis of these resources through the continuous degradation of forest areas that can be exploited. In this general context, the use of spruce (Picea abies L.) branches to create panels with a transverse texture becomes the main purpose of this research. Going beyond the current stage of research in the field, this research highlights the particularities of cutting panels with a transverse texture made from spruce branches, especially due to the cutting direction compared to the wood grain. In addition to the activities of collecting and sorting the branches, processing and joining, in order to obtain dimensionally stable panels, the workability of these panels with a transverse texture represents a new challenge in this field. The work methodology was based on the effective measurement of the cutting and advance power during cutting with a circular blade. The obtained results referred to the comparison of 10 working regimes from the point of view of the electrical power consumed, according to the two main parameters taken into account, which are the rotational speed of the circular blade and the advance speed. The final conclusion of the work highlighted the fact that the processing of panels with a transverse structure requires specific work regimes, namely an optimal regime of electric consumption of 2.2 kW, at a cutting speed of 79.2 m/s and an advance speed of 3.7 m/min. Full article

The notable absence of juvenile Pseudolarix amabilis trees in forest understories suggests their vulnerability to ecological niche competition, leading to limited survival prospects. This study examines the key factors limiting the growth of P. amabilis seedlings by investigating the effects of five ecological factors: light intensity, rainfall, groundwater level, soil type, and type of fertilization, on the growth of one-year-old P. amabilis seedlings. Our results demonstrate that increasing the light intensity promotes plant growth by augmenting the leaf count, leaf biomass, plant height, stem biomass, root biomass, and total biomass. Further analysis reveals that increased light intensity influences biomass allocation, reducing the specific leaf area and leaf–stem biomass ratio, and favoring root and stem growth over leaf investment. Rainfall, groundwater level, fertilization type, and rhizosphere soil type primarily influence root growth by impacting the soil’s physicochemical properties. Specifically, rising groundwater levels lower the soil temperature and increase the soil moisture, total potassium content, and soil pH, leading to reductions in root biomass, plant height, net height increment, leaf number, and total biomass. When groundwater levels reach 21 cm and 28 cm, submerging the surface soil layer, root biomass decreases by 1.6 g/plant (−51.6%) and 2.3 g/plant (−74.2%), respectively. Further analysis reveals a gradual decrease in the root–shoot ratio above the 14 cm groundwater level, while the specific leaf area and leaf–stem biomass ratio remains unaffected, indicating stronger belowground root stress compared to aboveground stem and leaf components. The results highlight light intensity as the key ecological factor determining the growth of P. amabilis seedlings. These findings underscore the importance of considering light intensity in the management of natural stands, the cultivation of artificial forests, and the nursery cultivation of endangered P. amabilis. Full article

Urban areas play a crucial role in carbon absorption, while also producing a considerable amount of carbon emissions. However, there has been a lack of research that has systematically examined the carbon storage and sequestration in green spaces located within urban environments, at a spatial scale. This study analyzes carbon storage and sequestration in Yurim Park, Daejeon, South Korea on a grid basis to fill the research gap. The research compares the variation in sequestration capacity across different grids and provides insights into the development of sustainable urban parks in urban planning. The classification of grids is based on specific site characteristics, such as land cover, tree distribution, type, and density. This results in a total of seven distinct types. The study employs a combination of the I-tree eco model, drone-based modeling, and on-site surveys to estimate carbon storage and sequestration in urban parks. The results show that the average carbon storage per unit area in the entire park was 15.3 tons of carbon per hectare, ranging from a minimum of 5.0 to a maximum of 21.4 tons per hectare. For the planted area, the average carbon storage was 8.6 tons per hectare. Grids with green areas dominated by broad-leaved trees and closed canopy cover had the highest carbon sequestration and storage values. The planting area ratio and the type of trees planted were found to directly influence the carbon sequestration capacity per unit area of urban parks. This study stands out from previous research by conducting a detailed area-based comparison and analysis of carbon sequestration capacity in urban parks using sophisticated measurement techniques. The findings offer direct insights into strategies and policies for securing future urban carbon sinks and can be of practical use in this regard. Full article