Forests doi: 10.3390/f15111883
Authors: Feiyi Huang Jiaxin Wang
Mitogen-activated protein kinase kinase kinases (MAPKKKs) are the upstream components of MAPK cascades and are involved in mediating stress responses and developmental processes. Although MAPKKK genes have been investigated in many plants, the identification and characterization of MAPKKKs in moso bamboo were still limited. Here, 134 MAPKKKs were identified as unevenly distributed on 23 chromosomes (except for chromosome 1) of moso bamboo and divided into three subfamilies by phylogenetic analysis. The gene structure and conserved motif of PeMAPKKKs were investigated. The expansions of PeMAPKKKs were driven by whole-genome duplication (WGD) or segmental duplication events. The duplicated gene pairs were under purifying selection based on the Ka/Ks ratios, suggesting they underwent functional conservation. Most PeMAPKKKs contained cis-elements related to development, hormones, and stress responses. Tissue expression patterns showed that PeMAPKKKs had multiple expression patterns. The qPCR analysis showed distinct expression patterns of PeMAPKKKs under drought, salt, and cold stress conditions. Taken together, this study provides a solid foundation for future functional characterizations of MAPKKKs and identifies candidate stress-responsive genes for further study in moso bamboo.
]]>Forests doi: 10.3390/f15111882
Authors: Tomáš Mikita Marian Rybansky Dominika Krausková Filip Dohnal Ondřej Vystavěl Sabina Hollmannová
This study aims to evaluate the feasibility of using non-contact data collection methods—specifically, UAV (unmanned aerial vehicle)-based and terrestrial laser scanning technologies—to assess forest stand passability, which is crucial for military operations. The research was conducted in a mixed forest stand in the Březina military training area, where the position of trees and their DBHs (Diameter Breast Heights) were recorded. The study compared the effectiveness of different methods, including UAV RGB imaging, UAV-LiDAR, and handheld mobile laser scanning (HMLS), in detecting tree positions and estimating DBH. The results indicate that HMLS data provided the highest number of detected trees and the most accurate positioning relative to the reference measurements. UAV-LiDAR showed better tree detection compared to UAV RGB imaging, though both aerial methods struggled with canopy penetration in densely structured forests. The study also found significant variability in DBH estimation, especially in complex forest stands, highlighting the challenges of accurate tree detection in diverse environments. The findings suggest that while current non-contact methods show promise, further refinement and integration of data sources are necessary to improve their applicability for assessing forest passability in military or rescue contexts.
]]>Forests doi: 10.3390/f15111881
Authors: Kyeongnam Kwon Seong-kyun Im Sung Yong Kim Ye-eun Lee Chun Geun Kwon
A probabilistic estimation model for forest biomass using unmanned aerial vehicle (UAV) photography was developed. We utilized a machine-learning-based object detection algorithm, a mask region-based convolutional neural network (Mask R-CNN), to detect trees in aerial photographs. Subsequently, Bayesian regression was used to calibrate the model based on an allometric model using the estimated crown diameter (CD) obtained from aerial photographs and analyzed the diameter at breast height (DBH) data acquired through terrestrial laser scanning. The F1 score of the Mask R-CNN for individual tree detection was 0.927. Moreover, CD estimation using the Mask R-CNN was acceptable (rRMSE = 10.17%). Accordingly, the probabilistic DBH estimation model was successfully calibrated using Bayesian regression. A predictive distribution accurately predicted the validation data, with 98.6% and 56.7% of the data being within the 95% and 50% prediction intervals, respectively. Furthermore, the estimated uncertainty of the probabilistic model was more practical and reliable compared to traditional ordinary least squares (OLS). Our model can be applied to estimate forest biomass at the individual tree level. Particularly, the probabilistic approach of this study provides a benefit for risk assessments. Additionally, since the workflow is not interfered by the tree canopy, it can effectively estimate forest biomass in dense canopy conditions.
]]>Forests doi: 10.3390/f15111880
Authors: Xiao Chen Zilong Li Zhenyu Wang Jiayu Li Yihua Zhou
Trees positively improve the annual thermal comfort of the built environment in tropical areas, where climate change is slight throughout the year. However, for areas with high changes in climate all year, the current studies have only explored the summer cooling performance of trees without the impact of different types of trees on annual thermal comfort, especially in cold seasons. Therefore, to quantify the impacts and scientifically guide the optimization of green space layout in hot summer and cold winter areas, this study selected Changsha City as the study area and analyzed how the annual thermal comfort is affected by evergreen trees and deciduous trees, which are two common types of trees in hot summer and cold winter areas. The analytical results indicated that the difference in the effect of deciduous and evergreen trees on outdoor thermal comfort was insignificant in summer, where the difference in the monthly mean PET for the three summer months was slight, being 0.28 °C, 0.14 °C, and 0.29 °C, respectively. However, evergreen trees greatly exacerbated winter cold compared to deciduous trees, with a monthly mean PET decrease by nearly 1.0 °C and an hourly PET reduced by up to 3.57 °C. The difference is mainly attributed to the absorption and reflection of solar radiation by the tree canopy, as well as the cooling and humidifying effect of the tree leaf. In hot summer and cold winter areas, outdoor thermal comfort is still in the “comfortable” and “slightly warm” acceptable stage despite the warming effect of deciduous trees in the spring and autumn seasons. Planting evergreen trees is an inevitable thermal mitigation choice for tropical areas. However, for the areas with high annual climate change, such as hot summer and cold winter areas in China, a change in empirical tree planting patterns and selecting deciduous trees where appropriate will improve year-round outdoor thermal comfort.
]]>Forests doi: 10.3390/f15111879
Authors: Dong Hyun Kim Byeong Il Ahn Gyuhun Shim
This study analyzes the impact of the EU′s policy to prohibit the import of illegally harvested timber on the trade of tropical timber and sawnwood. The analysis uses a difference-in-differences approach based on gravity models, with panel data from over 193 countries that trade tropical timber and sawnwood. The result of the analysis shows that the European Union Timber Regulation (EUTR) reduces the trade of illegally harvested timber. It further suggests that the EUTR caused a relatively larger reduction in tropical sawnwood (−0.21%) than that of tropical timber (0.07%). In addition, the Voluntary Partnership Agreement (VPA) appeared to cause a significant reduction in tropical sawnwood (−0.07~−0.05%), whereas tropical timber did not appear to have been significantly impacted. In particular, the reduction in timber exports in countries that have signed the VPA, which aims to encourage exports of legally produced timber, has significant implications for both the EU and timber exporters preparing for the VPA, as both parties strive to expand the VPA. The results of this study suggest that the EU needs to make additional efforts to address the decline in exports from countries that signed the VPA.
]]>Forests doi: 10.3390/f15111878
Authors: Ahmed Elsherif Magdalena Smigaj Rachel Gaulton Jean-Philippe Gastellu-Etchegorry Alexander Shenkin
Leaf chlorophyll content is a major indicator of plant health and productivity. Optical remote sensing estimation of chlorophyll limits its retrievals to two-dimensional (2D) estimates, not allowing examination of its distribution within the canopy, although it exhibits large variation across the vertical profile. Multispectral and hyperspectral Terrestrial Laser Scanning (TLS) instruments can produce three-dimensional (3D) chlorophyll estimates but are not widely available. Thus, in this study, 14 chlorophyll vegetation indices were developed using six wavelengths employed in commercial TLS instruments (532 nm, 670 nm, 808 nm, 785 nm, 1064 nm, and 1550 nm). For this, 200 simulations were carried out using the novel bidirectional mode in the Discrete Anisotropic Radiative Transfer (DART) model and a realistic forest stand. The results showed that the Green Normalized Difference Vegetation Index (GNDVI) of the 532 nm and either the 808 nm or the 785 nm wavelengths were highly correlated to the chlorophyll content (R2 = 0.74). The Chlorophyll Index (CI) and Green Simple Ratio (GSR) of the same wavelengths also displayed good correlation (R2 = 0.73). This study was a step towards canopy 3D chlorophyll retrieval using commercial TLS instruments, but methods to couple the data from the different instruments still need to be developed.
]]>Forests doi: 10.3390/f15111877
Authors: Mujib Rahman Ahmadzai Mohd Hasmadi Ismail Pakhriazad Hassan Zaki Mohd. Maulana Magiman Paiman Bawon
Agroforestry practices evolve with the development of basic and advanced facilities, changes in natural and artificial factors of land, and land use trade-offs. This study aims to examine the farmers’ socioeconomic characteristics and perception of land use changes that define optimal agroforestry practices in Khost Province, Afghanistan. Data were collected from 662 farmers and analyzed using univariate Analysis of Variance (ANOVA) and Multivariate Analysis of Variance (MANOVA). The results found that forest and vegetable products, including fruits, berries, herbs, mushrooms, wild animals, oils, wood, honey, okra, eggplant, carrot, cucumber, pine nuts, pepper, and timber, have different impacts in terms of satisfaction with basic and advanced facilities, knowledge of land use changes, satisfaction with natural and artificial resources of land, and barriers to and economic benefits of land use. The limitations of this study included an absence of exogenous factors in the model such as climate change, financial conditions, market fluctuations, regulatory system, the area in which this study is selected, research design, and current condition of endogenous factors. Overall, this study defined a set of optimal agroforestry practices (expressed as crops and products) based on the farmers’ perception of land use changes in Khost Province, Afghanistan. This study provided useful insights for policymakers and development practitioners to promote agroforestry practice adoption and improve the socioeconomic development of agroforestry-dependent communities. Future works could explore the implications of agroforestry practices on the socioeconomic development of other dependent communities in Afghanistan.
]]>Forests doi: 10.3390/f15111876
Authors: Ruidong Wang Yanlong Han Zhongju Meng Yong Gao Zhenliang Wu
The Bulianta Coal Mine is among the problematic coal mining areas in China that is still creating environmental damage, especially associated with soil destruction. Therefore, a scientific investigation was conducted to establish a scientific basis for evaluating the impact of planted forest on soil physical and chemical properties, as well as the ecological benefits following 15 years of vegetation restoration in the area. The soil physicochemical characteristics and distribution of organic carbon storage in the 0–80 cm layer soils of Pinus sylvestris forests, Prunus sibirica forests, and Hippophae rhamnoides forests restored after 5, 10, and 15 years were investigated. The immersion method was used to determine soil porosity and density followed by the determination of soil indicators, and a statistical ANOVA test was applied to examine the differential effects of different vegetation types and restoration years on soil properties. The results clearly demonstrated the following: (1) The recovery of vegetation was achieved after a period of 15 years, with the average bulk density of the 0–80 cm soil layer as follows: P. sylvestris forest (1.513 g·cm−3) > P. sibirica forest (1.272 g·cm−3) > H. rhamnoides forest (1.224 g·cm−3), and the differences among different forest types were statistically significant (p < 0.05). (2) In planted forests, soil nutrients were predominantly concentrated in the 0–20 cm layer, while soil carbon storage exhibited a decline with an increasing soil depth. (3) The soil carbon storage across the three forest types was as follows: P. sylvestris forest (45.42 t·hm−2) > P. sibirica forest (44.56 t·hm−2) > H. rhamnoides forest (41.87 t·hm−2). In summary, during the ecological vegetation restoration process in the Bulianta Core Mine, both P. sylvestris forest and P. sibirica forest exhibit superior carbon storage capacities compared to H. rhamnoides forest, as well as more effective soil improvement outcomes.
]]>Forests doi: 10.3390/f15111875
Authors: Juhu Li Xuejing Zhao Xue Li Mengwei Ju Feng Yang
Wood-boring pests are difficult to monitor due to their concealed lifestyle. To effectively control these wood-boring pests, it is first necessary to efficiently and accurately detect their presence and identify their species, which requires addressing the limitations of traditional monitoring methods. This paper proposes a deep learning-based model called BorerNet, which incorporates an attention mechanism to accurately identify wood-boring pests using the limited vibration signals generated by feeding larvae. Acoustic sensors can be used to collect boring vibration signals from the larvae of the emerald ash borer (EAB), Agrilus planipennis Fairmaire, 1888 (Coleoptera: Buprestidae), and the small carpenter moth (SCM), Streltzoviella insularis Staudinger, 1892 (Lepidoptera: Cossidae). After preprocessing steps such as clipping and segmentation, Mel-frequency cepstral coefficients (MFCCs) are extracted as inputs for the BorerNet model, with noisy signals from real environments used as the test set. BorerNet learns from the input features and outputs identification results. The research findings demonstrate that BorerNet achieves an identification accuracy of 96.67% and exhibits strong robustness and generalization capabilities. Compared to traditional methods, this approach offers significant advantages in terms of automation, recognition efficiency, and cost-effectiveness. It enables the early detection and treatment of pest infestations and allows for the development of targeted control strategies for different pests. This introduces innovative technology into the field of tree health monitoring, enhancing the ability to detect wood-boring pests early and making a substantial contribution to forestry-related research and practical applications.
]]>Forests doi: 10.3390/f15111874
Authors: André Luis Christoforo
The recent Special Issue (SI) of Forests on “Wood Quality and Mechanical Properties” offers an in-depth exploration of the complex relationship between the quality of wood and its mechanical properties, in addition to describing innovations in the field [...]
]]>Forests doi: 10.3390/f15111873
Authors: Juan C. Castro Stalin J. Vasquez-Guizado Bianca E. Vigil Francisco Ascue Naysha Rojas-Villa Jae D. Paredes Marianela Cobos Carlos G. Castro Daniel E. Motta Pedro M. Adrianzén Sixto A. Imán J. Dylan Maddox
The Amazonian shrub Myrciaria dubia (camu-camu) produces vitamin C-rich fruits of growing commercial interest. However, sustainable utilization requires assessment and protection of the genetic diversity of the available germplasm. This study aimed to develop and apply microsatellite markers to assess genetic diversity and construct a core collection of M. dubia germplasm from the Peruvian Amazon. Sixteen polymorphic microsatellite loci were developed using an enrichment approach. The evaluation of 336 genotypes from 43 accessions of the germplasm bank, originating from eight river basins, was conducted using these newly developed markers. Genetic diversity parameters, including observed and expected heterozygosity, were calculated. Analysis of molecular variance (AMOVA) was performed to assess the distribution of genetic variation within and among accessions and river basins. Bayesian clustering analysis was employed to infer population structure. A core collection was constructed to maximize allelic richness. High genetic diversity was observed, with heterozygosity values ranging from 0.468 to 0.644 (observed) and 0.684 to 0.817 (expected) at the river basin level. AMOVA indicated significant genetic variation within (73–86%) compared to among (14–27%) accessions and river basins. Bayesian clustering detected ten genetic clusters, with several degrees of admixture among river basins, except for the genetically homogeneous Putumayo River basin. A core collection comprising 84 plant genotypes (25% of the full collection) was established, representing 90.82% of the overall allelic diversity. These results have important implications for M. dubia conservation strategies and breeding programs, in demonstrating a need for genetic connectivity between populations but preserving unique genetic resources in isolated basins. These results validate the expected levels of diversity and population subdivision in a crop and stress the need to secure genetically diverse germplasms, underscoring the importance of thorough genetic characterization for ex situ germplasm management.
]]>Forests doi: 10.3390/f15111872
Authors: Yuan Liu Chengyuan Wang Yuwen Liu Tiantian Feng Enheng Wang Liwei Yang Qian Niu Xuegang Mao
As the largest terrestrial ecosystem covering extensive expanses of the Earth’s surface, forests offer crucial health benefits to humans, both directly and indirectly. Presently, health services derived from forest resources have presented significant opportunities for enhancing human well-being. Nonetheless, the absence of a comprehensive understanding regarding the mechanisms by which forests impact human health jeopardizes the potential gains in health. Regrettably, there remains a dearth of scholarly work elucidating these pathways. This paper aims to furnish a thorough examination of how forests influence human health. We initiate by formulating a conceptual framework upon which we delineate the various pathways through which forests impact human health. These encompass the provisioning of resources, preventive services, and forest therapies. Concurrently, we outline the moderating influence of social, economic, and individual characteristics as mediators within this pathway. These characteristics are classified into two overarching dimensions: accessibility and behavioral choices, which notably affect marginalized demographics such as those with lower socioeconomic status, women, the elderly, individuals with disabilities, and children in developing nations. Consequently, we build upon these foundational insights to propose six strategies aimed at perpetuating the positive impact of forests on human health in the foreseeable future. In the future, the development of forest management policies, the assessment of long-term health benefits, social practices, and international cooperation must be considered holistically to attain the dual objective of sustainable forest management and the advancement of human well-being.
]]>Forests doi: 10.3390/f15111871
Authors: Jiaman Zheng Mengyuan Wang Mingyue Liang Yuyang Gao Mou Leong Tan Mengyun Liu Xiaoping Wang
Leaf Area Index (LAI), as a pivotal parameter in characterizing the structural properties of vegetation ecosystems, holds significant importance in assessing the carbon sink function. Given the availability of multiple long-term LAI products, validating these LAI products with consideration of topographic factors is a prerequisite for enhancing the quality of LAI products in mountainous areas. Therefore, this study aims to evaluate the performance of MODIS LAI and GLASS LAI products from 2001 to 2021 by comparing and validating them with ground-measured LAI data, focusing on the spatio-temporal and topographic aspects in the Qinling Mountains. The results show that the GLASS LAI product is a better choice for estimating LAI in the Qinling Mountains. The GLASS LAI product has better completeness and generally higher values compared to the MODIS LAI product. The time-series curve of the GLASS LAI product is more continuous and smoother than the MODIS LAI product. Both products, however, face challenges in quantifying LAI values of evergreen vegetation during winter. The MODIS and GLASS LAI products exhibit differences between sunny and shady slopes, with mean LAI values peaking on sunny slopes and reaching their lowest on shady slopes. When the slope ranges from 0 to 10°, the mean values of GLASS LAI product show a higher increasing trend compared to the MODIS LAI product. At elevations between 1450 and 2450 m, the mean LAI values of the GLASS LAI product are higher than the MODIS LAI product, primarily in the southern Qinling Mountains. Compared to ground-measured LAI data, the GLASS LAI product (R² = 0.33, RMSE = 1.62, MAE = 0.61) shows a stronger correlation and higher accuracy than the MODIS LAI product (R² = 0.24, RMSE = 1.61, MAE = 0.68).
]]>Forests doi: 10.3390/f15111870
Authors: Quangang Liu Wenying Li Xin Zhao Hongrui Zhang Jianhua Chen Qingbai Liu Tianlai Li Shengjun Dong
Siberian apricot (Prunus sibirica) is an important ecological and commercial woody plant that is negatively affected by spring frosts. However, the mechanisms that control gene expression in adaptation to freezing remain largely unknown. In this work, we investigated the physiological, molecular, and phenotypic characteristics of pistils of two P. sibirica clones that differ in their ability to withstand freezing stress. A total of 14,717 unigenes categorized into 38 functional groups were identified. Additionally, the two P. sibirica clones included 3931 up-regulated and 2070 down-regulated differentially expressed genes (DEGs). Many DEGs are related to Ca2+ and MAPK signaling, carbohydrate biosynthesis and metabolism, plant hormone signal transduction, biosynthesis of amino acids, and photosynthesis. The metabolism of carbohydrates, amino acids, lipids, secondary metabolites, plant hormone signal transduction, and terpenoid metabolism were the transcriptome modifications most significantly altered by freezing stress. Real-time quantitative PCR (RT-qPCR) was used to verify the precision of the RNA-seq data. PsbHLH18, PsMYB4, PsMYB44, PsPOD1, and PsCDPK5 may play important roles in the freezing tolerance of the P. sibirica floral organ. This study provides a foundation for further studies on the complex mechanisms of freezing stress response in P. sibirica.
]]>Forests doi: 10.3390/f15111869
Authors: J. Julio Camarero Cristina Valeriano José Antonio Sánchez-Sancho Chabier de Jaime Loren
Pollarding has historically been used in broadleaf tree species across European woodlands. However, despite pollarding enhances vigor growth in the short term, it is still unclear how long this effect lasts and whether it can alleviate drought stress in seasonally dry regions. We compared the radial growth and wood δ13C (13C/12C), a proxy of intrinsic water-use efficiency (iWUE), of trees pollarded 10 and 20 years ago in two black poplar (Populus nigra L.) riparian stands located in North Eastern Spain and subjected to different ecohydrological conditions. We also assessed if pollarded trees showed different leaf phenology as compared with uncut trees of coexisting white poplar (Populus alba L.) trees. The relationships between growth, climate variables, drought severity and river flow were quantified. Pollarded and uncut trees showed a similar leaf phenology with a trend towards earlier leaf unfolding as springs become warmer. Pollarding increased growth rates by 54% (ratio between trees pollarded 10 and 20 years ago, respectively), but this enhancement was transitory and lasted ca. 10 years, whereas wood δ13C decreased −5%. The growth of black poplar increased in response to high precipitation in the previous winter, cool wet conditions, and a higher river flow in summer. Pollarding improves growth and relieves drought stress.
]]>Forests doi: 10.3390/f15111868
Authors: Lu Liu Xiao Yang Jingli Yan Wenwen Zhang Yunzheng Ke Tong Zhang Shan Yin
Urban soundscapes are valuable indicators of urban biodiversity and ecosystem health. This study investigated the spatial and temporal characteristics of soundscapes in megacity green spaces and their relationship with the urban environment. An acoustic index was formulated and calculated using long-term data from Shanghai’s urban green spaces. The results show a significant increase in the acoustic index during spring and summer, peaking during these periods, while a decrease was observed from December to February, dominated by abiotic sounds. Diurnal variations indicate a rapid increase in the acoustic index at sunrise, reflecting heightened avian activity during the dawn chorus. Human interference in the urban center limited acoustic activity, whereas the outer suburbs, with their more natural environments, supported greater acoustic richness.
]]>Forests doi: 10.3390/f15111867
Authors: Lang Huang Guangyu Zhu Guoqi Chen
Site and climate conditions are the key determinants controlling dominant height growth and forest productivity, both independently and interactively. Secondary natural oak forests are a typical forest type in China, especially in Hunan Province, but little is known about the site index of this forest under the complex site and climate variables in the subtropics. Based on survey data of dominant trees and site variables from 101 plots in Hunan oak natural secondary forests and climate data obtained using spatial interpolation, we used the random forest method, correlation analysis, and the analysis of variance to determine the main site and climate factors affecting oak forest dominant height and proposed a modeling method of an oak natural secondary forest site index based on the random effect of site–climate interaction type. Of the site variables, elevation affected stand dominant height the most, followed by slope direction and position. Winter precipitation and summer mean maximum temperature had the greatest impact on stand dominant height. To develop the modeling method, we created 10 popular base models but found low performance (R2 ranged from 0.1731 to 0.2030). The optimal base model was Mitscherlich form M3 (R2 = 0.1940) based on parameter significance tests. Since site and climate factors affect the site index curve, the dominant site and climate factors were combined into site types and climate types, respectively, and a nonlinear mixed-effects approach was used to simulate different site types, climate types, site–climate interaction types, and their combinations as random effects. Site–climate interaction type as a random factor enhanced model (M3.4) performance and prediction accuracy (R2 from 0.1940 to 0.8220) compared to the optimum base model. After clustering the 62 site–climate interaction types into three, five, and eight groups using hierarchical clustering, a mixed-effects model with the random effects of eight groups improved model performance (R2 = 0.8265) and applicability. The modeling method developed in this study could be used to assess a regional secondary natural oak forest site index under complex site and climate variables to evaluate the forest productivity.
]]>Forests doi: 10.3390/f15111866
Authors: Miaohang Zhou Xujun Han Jinghan Wang Xiangyu Ji Yuefei Zhou Meng Liu
Eucalyptus plantations are one of the primary artificial forests in southern China, experiencing rapid expansion in recent years due to their significant socio-economic benefits. This expansion has raised concerns about the ecological environment, necessitating accurate mapping of eucalyptus plantations. In this study, the phenological characteristics of eucalyptus plantations were utilized as the primary classification basis. Long-term time series Landsat and Sentinel-2 data from 2000 to 2022 were rigorously preprocessed pixel by pixel using the Google Earth Engine (GEE) platform to obtain high-quality observation data. The Continuous Change Detection and Classification (CCDC) algorithm was employed to fit the multi-year observation data with harmonic curves, utilizing parameters such as normalized intercept, slope, phase, and amplitude of the fitted curves to characterize the phenological features of vegetation. A total of 127 phenological indices were generated using the Normalized Burn Ratio (NBR), Normalized Difference Fractional Index (NDFI), and six spectral bands, with the top 20 contributing indices selected as input variables for the random forest algorithm to obtain preliminary classification results. Subsequently, eucalyptus plantation rotation features and the Simple Non-Iterative Clustering (SNIC) superpixel segmentation algorithm were employed to filter the results, enhancing the accuracy of the identification results. The producer’s accuracy, user’s accuracy, and overall accuracy of the eucalyptus plantation map for the year 2020 were found to be 96.67%, 89.23%, and 95.83%, respectively, with a total area accuracy of 94.39%. Accurate mapping of eucalyptus plantations provides essential information and evidence for ecological environment protection and the formulation of carbon-neutral strategies.
]]>Forests doi: 10.3390/f15111865
Authors: Jozef Kúdela Richard Hrčka Ján Svocák Simona Molčanová
The objective of this study was to investigate the colour stability of spruce wood surfaces treated with coating systems (CS) and exposed to accelerated ageing. The tested CSs were transparent and three-layered; the top layer was modified with ultraviolet (UV) absorbers, while the base layer was modified with lignin stabiliser. Spruce wood surfaces treated with unmodified CSs were not colour-stable during the accelerated ageing process, with the surface exhibiting colour change after just 100 ageing hours. Adding specific UV absorbers into the top layer and lignin stabiliser into the base layer significantly improved the colour stability of the surface-treated wood. In all cases, however, the colour variation associated with ongoing ageing was significant. An additional study task was to determine whether the discolouration of surface-treated wood is caused by the discolouration of the wood substrate alone or also by the CS discolouration. Consequently, there was also the examination of discolouration of the individual coating materials or coating systems applied to glass slides. This testing proved that in the case of wood surface-treated with CS, without lignin stabiliser, the discolouration was the same as that of the substrate, and this was true throughout the whole ageing process. In the case of wood surface-treated with CS, but with lignin stabiliser, there were, in some cases, significant differences in discolouration between surface-treated wood and the wood substrate. These variations were especially evident during the initial 300 ageing hours.
]]>Forests doi: 10.3390/f15111863
Authors: Shen Shen Xueli Zhang Shengqi Jian
Heterobasidion, a significant forest pathogen affecting coniferous forests in the Northern Hemisphere, can infect 27 species of coniferous trees, leading to widespread forest mortality. It has already caused considerable damage to both natural and plantation forests in Europe. As essential components of the global ecosystem, forests are increasingly affected by ongoing environmental changes. The ability to accurately predict and effectively respond to pathogen outbreaks across different habitats is becoming increasingly critical. This study employs an optimized MaxEnt model in conjunction with six Global Climate Models (GCMs) to simulate and predict the potentially suitable distributions and changes of three Heterobasidion species in Europe (Heterobasidion abietinum, Heterobasidion annosum sensu stricto, Heterobasidion parviporum) under current conditions and four future climate scenarios (SSP126, SSP245, SSP370, and SSP585) for the period 2081–2100. The objective of this analysis is to assess the potential effects of climate change on the distribution of Heterobasidion species. The results indicate that the distributions of the three Heterobasidion species are influenced by factors such as temperature and precipitation. By 2081–2100, under most climate scenarios, except for the SSP585 scenario, the distribution areas of the three Heterobasidion species show an expansion trend. Notably, Heterobasidion abietinum showed the most significant expansion of its suitable habitat, while the expansion of low-suitability areas for Heterobasidion parviporum and Heterobasidion annosum sensu stricto was more pronounced. Heterobasidion abietinum is projected to shift southward due to factors such as precipitation, while Heterobasidion parviporum and Heterobasidion annosum sensu stricto are expected to migrate northward, influenced by factors such as temperature and host tree species.
]]>Forests doi: 10.3390/f15111864
Authors: Chengyao Liu Junwen Wu Jianyao Gu Huaijiao Duan
Pinus yunnanensis is an endemic tree species in southwest China that has high ecological and economic benefits. Nowadays, global climate change is remarkable, the frequency of drought is increasing day by day, the distribution of rainfall is unbalanced, and even the phenomenon of alternating drought and flood has appeared, which is unfavorable to the growth of P. yunnanensis. We set up four treatments, namely normal water (CK), light drought (LD), moderate drought (MD), and severe drought (SD), and water content was controlled by the weighing method. After continuous drought for 30 days, re-watering was performed for 7 days. The stoichiometric characteristics of non-structural carbohydrates (NSC), soluble sugars (SS), and starch (ST), as well as carbon (C), nitrogen (N), and phosphorus (P), in various organs of P. yunnanensis seedlings were measured. The results revealed significant effects of re-watering on NSC and its components in P. yunnanensis seedlings. The SS and NSC contents in the leaves of P. yunnanensis seedlings treated with SD were significantly higher than those of the control. The C content in the leaves and stems of P. yunnanensis seedlings recovered to the CK level after re-watering under different drought degrees. The contents of N in different organs and P in the fine roots of P. yunnanensis seedlings increased after re-watering with the LD, MD, and SD treatments, while the C/N ratio decreased. In summary, the recovery mechanism of P. yunnanensis seedlings to re-watering varied with the drought degree. The contents and ratios of NSC, C, N, and P in different organs of P. yunnanensis seedlings were significantly affected by re-watering. Combining the phenotypic plasticity index and PCA results, seedlings of P. yunnanensis adapted to drought re-watering by adjusting leaf NSC, leaf P, stem SS/ST, fine root ST, and fine root NSC.
]]>Forests doi: 10.3390/f15111862
Authors: Shun Zou Chumin Huang Tu Feng Yang Chen Xiaolong Bai Wangjun Li Bin He
Tea (Camellia sinensis (L.) Kuntze) plantations have been rapidly expanding in recent years in developing countries, but there is a lack of knowledge about the effects of woodland conversion to tea plantations and tea plantation aging on soil organic carbon (SOC) accumulation in subtropical regions, which may be a critical issue for accurately estimating the regional C balance in tea planting areas. Thus, in this study, we selected four tea plantations with ages ranging from 5 to 23 years, along with an adjacent mature pine forest (PF, more than 60 years of age), to investigate the effects of woodland conversion to tea plantations and stand age on SOC. Lignin phenols and amino sugars were used to distinguish the contributions of plant-derived C and microbial-derived C to SOC. The results showed that when PF is converted to a tea plantation, 54.12% of the SOC content in the topsoil is lost, with reductions of 84.77% in plant-derived C and 10.23% in microbial-derived C; however, there is a slight increase in microbial-derived C in the deep-layer soil. The tea planting age only has a negative effect on microbial-derived C in the topsoil. Additionally, the plant aboveground biomass, ratio of carbon to nitrogen, total nitrogen concentration, and clay–silt content are key environmental variables influencing SOC accrual, explaining 59.8% of the total variance. SOC and plant-derived C are thus implicated in the quick response to decreasing plant inputs with land conversion and do not accumulate with increasing tea plantation age under the current tea plantation management practices. Generally, more attention should be focused on SOC loss with woodland conversion to tea plantations at the regional scale, and more effective practices can be applied to enhance SOC accrual in subtropical tea plantations.
]]>Forests doi: 10.3390/f15111861
Authors: Lu Wang Yilin Ju Yongjie Ji Armando Marino Wangfei Zhang Qian Jing
Accurate estimation of forest above-ground biomass (AGB) is significant for understanding changes in global carbon storage and addressing climate change. This study focuses on 53 samples of natural forests at the Greater Khingan Ecological Station, exploring the potential of integrating Canopy Height Model (CHM) with multi-source remote sensing (RS) data—airborne LiDAR, Landsat 8 OLI, and hyperspectral data to estimate forest AGB. Firstly, RS features with strong horizontal and vertical correlation with the forests AGB are optimized by a partial least squares algorithm (PLSR). Then, multivariate linear stepwise regression (MLSR) and K-nearest neighbor with fast iterative features selection (KNN-FIFS) are applied to estimate forest AGB using seven different data combinations. Finally, the leave-one-out cross-validation method is selected for the validation of the estimation results. The results are as follows: (1) When forest AGB is estimated using a single data source, the inversion results of using LiDAR are better, with R2 = 0.76 and RMSE = 21.78 Mg/ha. (2) The estimation accuracy of two models showed obvious improvement after using fused CHM into RS information. The MLSR model showed the best performance, with R2 increased by 0.41 and RMSE decreased to 14.15 Mg/ha. (3) The estimation results based on the KNN-FIFS model using the combined data of LiDAR, CHM + Landsat 8 OLI, and CHM + Hyperspectral imaging were the best in this study, with R2 = 0.85 and RMSE = 18.17 Mg/ha. The results of the study show that fusing CHM into multi-spectral data and hyperspectral data can improve the estimation accuracy a lot; the forest AGB estimation accuracies of the multi-source RS data are better than the single data source. This study provides an effective method for estimating forest AGB using multi-source data integrated with CHM to improve estimation accuracy.
]]>Forests doi: 10.3390/f15111860
Authors: Lingnan Dai Zhao Chen Xiaoli Zhang Dianchang Wang Lishuo Huo
The three-dimensional reconstruction of forests is crucial in remote sensing technology, ecological monitoring, and forestry management, as it yields precise forest structure and tree parameters, providing essential data support for forest resource management, evaluation, and sustainable development. Nevertheless, forest 3D reconstruction now encounters obstacles including higher equipment costs, reduced data collection efficiency, and complex data processing. This work introduces a unique deep learning model, CPH-Fmnet, designed to enhance the accuracy and efficiency of 3D reconstruction in intricate forest environments. CPH-Fmnet enhances the FPN Encoder-Decoder Architecture by meticulously incorporating the Channel Attention Mechanism (CA), Path Aggregation Module (PA), and High-Level Feature Selection Module (HFS), alongside the integration of the pre-trained Vision Transformer (ViT), thereby significantly improving the model’s global feature extraction and local detail reconstruction abilities. We selected three representative sample plots in Haidian District, Beijing, China, as the study area and took forest stand sequence photos with an iPhone for the research. Comparative experiments with the conventional SfM + MVS and MVSFormer models, along with comprehensive parameter extraction and ablation studies, substantiated the enhanced efficacy of the proposed CPH-Fmnet model in addressing difficult circumstances such as intricate occlusions, poorly textured areas, and variations in lighting. The test results show that the model does better on a number of evaluation criteria. It has an RMSE of 1.353, an MAE of only 5.1%, an r value of 1.190, and a forest reconstruction rate of 100%, all of which are better than current methods. Furthermore, the model produced a more compact and precise 3D point cloud while accurately determining the properties of the forest trees. The findings indicate that CPH-Fmnet offers an innovative approach for forest resource management and ecological monitoring, characterized by cheap cost, high accuracy, and high efficiency.
]]>Forests doi: 10.3390/f15111859
Authors: Doyun Song Sujin Park Yeonhee Lee Geonwoo Kim
Background and objectives: Forest environments provide various healing benefits for humans and have been widely studied. Nevertheless, the field of forest management for forest healing remains relatively understudied. The purpose of this study is to utilize thermal environmental simulation to derive forest management scenarios that are optimized for forest healing. Methods: This study focused on the Seogwipo Experimental Forest on Jeju Island, Korea. Three-dimensional forest models were generated based on field surveys. Thermal environment simulations were conducted using Grasshopper with the Ladybug and Honeybee plug-ins, and the thermal comfort levels of six forest management scenarios were evaluated using the Universal Thermal Climate Index (UTCI). Results: The simulation results showed that, among all the scenarios, only scenario (c), “10% thinning in the buffer zone”, led to an improvement in thermal comfort. Additionally, the study identified discrepancies in thermal comfort between different forest management scenarios. Conclusions: In the management of forests for healing forestry purposes, the distinction of forest zones by use and the application of different forest management scenarios have thermal comfort implications. Thus, the methodology could be employed in forest management for forest healing purposes.
]]>Forests doi: 10.3390/f15111858
Authors: Fenglu Liu Wenhao Chen Qinhui Wang Jiawei Xiao
The objective of this paper is to propose a non-destructive resistance detection imaging algorithm for log knots based on improved inverse-distance-weighted interpolation algorithm, i.e., the eccentric circle-based inverse-distance-weighted (ECIDW) method, to predict the size, shape, and position of internal knots of logs; evaluate its precision and accuracy; and both lay a theoretical foundation and provide a scientific basis for predicting and assessing knots in standing trees. Six sample logs with natural knots were selected for this study. Resistance measurements were performed on the log cross-sections using a digital bridge, and resistance tomography was conducted using the improved ECIDW algorithm, which combines the azimuth search method with the eccentric circle search method. The results indicated that both the conventional inverse-distance-weighted (IDW) algorithm and the ECIDW algorithm accurately predicted the positions of the knots. However, neither algorithm was able to predict the shape of the knots with high precision, leading to some discrepancies between the predicted and actual knot shapes. The relative error (Dt1) between the knot areas measured by the IDW algorithm and the actual knot areas ranged from 18.97% to 88.34%. The relative error (Dt2) for the knot areas predicted by the ECIDW algorithm ranged from 1.82% to 74.16%. The average prediction accuracy for the knot areas using the IDW algorithm was 51.58%, compared to 72.90% using the ECIDW algorithm. This indicates that the ECIDW algorithm has higher accuracy in predicting knot areas compared to the conventional IDW algorithm. The ECIDW algorithm proposed in this paper provides a more reasonable and accurate prediction and evaluation of knots inside logs. Compared to the conventional IDW algorithm, the ECIDW algorithm demonstrates greater precision and accuracy in predicting the shape and size of knots. While the resistance method shows significant potential for predicting internal knots in logs and standing trees, further improvements to the algorithm were needed to enhance the imaging effects and the precision and accuracy of knot area and shape predictions.
]]>Forests doi: 10.3390/f15111857
Authors: Maolin Li Yingda Wu Yilin Liu Yu Zhang Qiang Yu
Lightning-induced forest fires frequently inflict substantial damage on forest ecosystems, with the Daxing’anling region in northern China recognized as a high-incidence region for such phenomena. To elucidate the occurrence patterns of forest fires caused by lightning and to prevent such fires, this study employs a multifaceted approach, including statistical analysis, kernel density estimation, and spatial autocorrelation analysis, to conduct a comprehensive examination of the spatiotemporal distribution patterns of lightning-induced forest fires in the Greater Khingan Mountains region from 2016–2020. Additionally, the geographical detector method is utilized to assess the explanatory power of three main factors: climate, topography, and fuel characteristics associated with these fires, encompassing both univariate and interaction detections. Furthermore, a mixed-methods approach is adopted, integrating the Zhengfei Wang model with a three-dimensional cellular automaton to simulate the spread of lightning-induced forest fire events, which is further validated through rigorous quantitative verification. The principal findings are as follows: (1) Spatiotemporal Distribution of Lightning-Induced Forest Fires: Interannual variability reveals pronounced fluctuations in the incidence of lightning-induced forest fires. The monthly concentration of incidents is most significant in May, July, and August, demonstrating an upward trajectory. In terms of temporal distribution, fire occurrences are predominantly concentrated between 1:00 PM and 5:00 PM, conforming to a normal distribution pattern. Spatially, higher incidences of fires are observed in the western and northwestern regions, while the eastern and southeastern areas exhibit reduced rates. At the township level, significant spatial autocorrelation indicates that Xing’an Town represents a prominent hotspot (p = 0.001), whereas Oupu Town is identified as a significant cold spot (p = 0.05). (2) Determinants of the Spatiotemporal Distribution of Lightning-Induced Forest Fires: The spatiotemporal distribution of lightning-induced forest fires is influenced by a multitude of factors. Univariate analysis reveals that the explanatory power of these factors varies significantly, with climatic factors exerting the most substantial influence, followed by topographic and fuel characteristics. Interaction factor analysis indicates that the interactive effects of climatic variables are notably more pronounced than those of fuel and topographical factors. (3) Three-Dimensional Cellular Automaton Fire Simulation Based on the Zhengfei Wang Model: This investigation integrates the fire spread principles from the Zhengfei Wang model into a three-dimensional cellular automaton framework to simulate the dynamic behavior of lightning-induced forest fires. Through quantitative validation against empirical fire events, the model demonstrates an accuracy rate of 83.54% in forecasting the affected fire zones.
]]>Forests doi: 10.3390/f15111856
Authors: Alexandra Ferencz-Havel Dénes Saláta György Orosz Gergely Halász Eszter Tormáné Kovács
Recreation and nature-based tourism targeting forests are important cultural services provided by forests, and are also considered non-productive social functions of forests. Many factors influence the demand for forest recreation and tourism that are worth exploring for each forest area. The main aim of our study was to compare the results of visitor surveys related to two mountainous forested areas (Börzsöny and Cserhát) that are both located near to the capital city of Budapest but have different characteristics regarding the forests, accessibility, and the level of tourism infrastructure and services. The questionnaires focused on the characteristics of the visits, perceptions of visitors regarding the values of the areas, and the development needs besides the characteristics of the respondents. In addition to basic statistics, Chi2 and Fisher’s exact tests were used to detect the differences between the two sites. Despite the different characteristics of the study areas, the main results were quite similar at both sites. Most respondents came from Budapest or within a 60 km distance of the sites by car with family and friends, mainly for hiking and nature walks, and spent less than a day in the areas. The state of forests was perceived as good in both areas. Landscape and fresh air were the most attracting factors for visiting both sites. There was a demand for more guided tours, and regarding tourism infrastructure development needs, benches and toilets ranked high at both sites. However, there were also some slight differences between the sites. For example, Börzsöny was visited more frequently, and railway and bicycle were more often used to access this site. Pleasant climate, easy access and fresh air were more important reasons to visit Börzsöny, and it was more associated with wilderness. In Cserhát, low prices and cultural values seemed more important reasons to visit; Hollókő as a world heritage site was highlighted, and more nature-related and other tourism development needs were mentioned regarding this site. These differences were probably due to the different characteristics of the forests (more mosaic forests in Cserhát), the level of the public transportation network, tourist infrastructure and services (higher in Börzsöny), and cultural heritage (more important in Cserhát). Based on our results, Cserhát needs more development in tourism infrastructure and services, while in Börzsöny, the development of a visitor management plan would be useful to harmonize the different uses of the forest.
]]>Forests doi: 10.3390/f15111855
Authors: Xiaoling Chen Yulan Dong Zijue Wang Qinghui Xia Xingxing Dong Shaopeng Zhang Shuiyuan Cheng
Cyclocarya paliurus (Batalin) Iljinskaja is a rare, endemic tree species in China. The leaves of C. paliurus contain a high concentration of biologically active compounds, and they are often used to make herbal tea. Exogenous selenium (Se) enrichment can promote the levels of active ingredients in C. paliurus. To explore the effects of exogenous Se enrichment, this study applied different concentrations of sodium selenite solution on the leaves (0, 40, 80, 120, 160, and 300 mg/L) and measured the changes in Se, secondary metabolites, soluble sugar, soluble protein, starch, and trace elements in the leaves at different treatment times. The results showed that with the increase in the concentration of sodium selenite spray, the selenium content in the leaves of C. paliurus gradually increased, and high selenium concentrations could cause seedling burning to the leaf surface (>160 mg/kg). When the selenium treatment concentration was 80 mg/kg, the selenium content reached the maximum value of the selenium-rich tea standard (4 mg/kg). The content of polyphenols and most elements reached their maxima under the treatment of 40 mg/L Na2SeO3, except for Mg and Mn, which peaked at 300 mg/L. The content of soluble sugars (38.1 mg/g) and starch reached their maxima under relatively high selenium treatment concentrations, whereas soluble protein (10.63 mg/g) exhibited its maximum value in the control group. The optimal harvest time was mainly concentrated in the 10–20 day treatment period. The objective of this research is to investigate the effects of exogenous selenium application on the nutritional quality of C. paliurus leaves. The findings will provide guidance for the effective cultivation of selenium-enriched Poria cocos as a medicinal and health-promoting product.
]]>Forests doi: 10.3390/f15111854
Authors: Zhewei Hu Caiyi Zhao Wenbing Ji Rongrong Ying Xiaoyu Zhang Shu Jin
Precipitation is a key factor affecting plant growth and development in seasonally arid regions. However, most of the traditional hydrological methods mainly select typically sunny days for sampling, and the immediate water absorption strategy of plants during and after rainfall is still unclear. This study used stable hydrogen and oxygen isotope technology to study the soil moisture absorption rates of Robinia pseudoacacia and the soil moisture content at different soil layers at different sampling times (0, 6, 12, 18 and 24 h) after rainfall. The results showed that the moisture content of the shallow soil layer decreased, while that of the deep soil layer increased over time after rainfall. R. pseudoacacia mainly utilized water from the 0–20 and 20–40 cm soil layers at 6 h after rainfall, which accounted for 36.52% and 22.25% of the rainfall, respectively. At 24 h, the 40–60, 60–80 and 80–100 cm soil layers contributed 25.25%, 18.44% and 24.45% of the water content, respectively. The shallow soil layer retained more rainfall within 6 h after rain fell, and the water retention ratio of the medium–shallow soil layer (0–60 cm) increased to 48.4%, retaining more water at 14–20 h. At 12 h, the medium–shallow soil layer (0–60 cm), runoff and groundwater constituted 37.1%, 14.4% and 15.7% of the precipitation, respectively, and rainfall retained in the deep soil layer (60–100 cm) accounted for 32.8%. In summary, R. pseudoacacia tends to use a large amount of shallow soil water in seasonally arid regions when precipitation supplements the surface soil moisture content and it utilizes deep soil water when the rainfall infiltrates and recharges the deep soil layer. Since R. pseudoacacia is sensitive to precipitation, it can quickly adjust its water absorption depth range during the short-term rainfall period to absorb as much precipitation as possible.
]]>Forests doi: 10.3390/f15111853
Authors: Yeji Choi Sugwang Lee Somi Yun Dae Taek Lee
Forest trail difficulty levels must be investigated to promote their safe usage. However, exercise-based physiological changes are difficult to estimate in a forest environment. Hence, studies comparing indoor and outdoor environmental activities are required. We aimed to investigate the physiological traits associated with different usage grades of national forest trails in the Republic of Korea. We conducted both field and indoor experiments to measure different variables of 20 healthy participants aged 40–50 years to evaluate the exercise intensity and physiological effects of hiking on these trails. Significant variations in physiological responses were observed based on trail difficulty, with the highest heart rate and energy expenditure recorded during the most challenging uphill segments. Specifically, the heart rate increased from 115.4 ± 13.7 bpm in easy segments to 140.3 ± 15.6 bpm in difficult segments, whereas energy expenditure ranged from 404.1 ± 112.2 kcal/h to 518.1 ± 131.0 kcal/h. This study highlights the importance of considering both objective trail difficulty and users’ physiological reactions, including perceived exertion, to enhance user safety and optimize the health benefits of national forest trails. These findings provide essential data for developing comprehensive exercise programs and improving the national forest trail usage grade system.
]]>Forests doi: 10.3390/f15111851
Authors: Renata Nowińska Aneta Czarna
Highlights: Though not highly invasive, bulb and corm ornamental plants can escape cultivation and naturalize in new areas. Studying their naturalization is key to understanding their ecological impact and managing biodiversity. Objectives: This study aimed to document the first naturalization case of Crocus tommasinianus Herb. in Poland and assess the morphological variability of the naturalized population under different environmental conditions. Another objective was to identify diagnostic features in seed testa ornamentation to distinguish C. tommasinianus from related species (C. vernus (L.) Hill. and C. scepusiensis (Rehmann et Wol.) Borbás ex Kulcz.). Methods: The morphometric studies were performed within four subpopulations of C. tommasinianus differing in environmental conditions, determined with Ellenberg indices. Multivariate tests, ANOVA, and post-hoc tests were used to determine the morphometric diversity of specimens and to relate them to environmental factors. Seed micro-ornamentation was examined using a scanning electron microscope. Results: Light and temperature were negatively correlated, while moisture, soil pH, and nitrogen were positively correlated with many morphological traits. Plants spreading into forest ecosystems exhibited better-developed features (larger leaves and flowers) than those in former cultivation sites, indicating higher survival potential. The seed coat is papillate, with distinct differences in the shape, size, and secondary sculpture of the papillae compared to C. vernus and C. scepusiensis. Given that floristic studies often occur during the fruiting period of crocuses, testa ornamentation is crucial for identifying the studied species. Conclusions: The observed naturalization of C. tommasinianus demonstrates the high morphological plasticity of plants, which makes them capable of colonizing new areas, including forest habitats.
]]>Forests doi: 10.3390/f15111852
Authors: Juan Diego Restrepo Giorgia Bottaro Linda Barci Lucila Marcela Beltrán Martín Londoño-Behaine Mauro Masiero
Forest ecosystem services are critical for maintaining ecological balance and supporting human well-being from different perspectives. However, rapid land use changes driven by agricultural expansion, urbanization, and industrial activities have significantly altered forest ecosystems, degrading the services they provide. We here conduct an ecosystem service assessment through biophysical and economic estimates for a multipurpose Andean water sub-basin in western Colombia. We compare a business as usual (BAU) with a forest nature-based solution (NbS) scenario focused on forest landscape restoration. The research employed participatory methods for the NbS selection and economic valuation techniques to evaluate water flow regulation, water provisioning, water purification, and food provisioning services. Results show that the NbS scenario yielded a net positive economic impact across most evaluated ecosystem services, with notable trade-offs. Specifically, the NbS scenario increased water retention by 2.9% compared to BAU. Water flow regulation demonstrated the most substantial economic benefit, increasing by EUR 11.39 million/year in the NbS scenario. On the other hand, the food provisioning service presented a reduction of EUR 3.2 million/year in the NbS scenario. These findings highlight the potential of forest-based NbS to address the Water–Energy–Food–Ecosystem (WEFE) nexus challenges. The study’s outcomes provide valuable insights for policymakers and practitioners, supporting the development of Payment for Ecosystem Services schemes and integrating ecosystem service valuation into land use planning and decision-making processes.
]]>Forests doi: 10.3390/f15111850
Authors: Jiahui Zhong Hongwen Yao Wei Liu Yong Zhang Jie Lin Jiang Jiang Chaorui Wang
Forest ecosystems, as the primary component of terrestrial ecosystems, provide essential ecosystem services (ESs) critical for sustainable human development. However, changes in climate and vegetation can alter these forest ESs. Understanding the complex relationships between regional climate, vegetation, and ESs is key to ensuring the sustainable management of forest ESs. Therefore, this study, using Baishanzu National Park as a case example, analyzed the impacts of regional climate and vegetation dynamics (vegetation coverage, forest type, and forest structure) on forest ESs, specifically water yield (WY), soil conservation (SC), net primary productivity (NPP), and habitat quality (HQ). The results indicate that from 2000 to 2020, the forest Composite Index of Ecosystem Services (CIES) in Baishanzu National Park increased. Climate and vegetation dynamics have significant effects on forest ESs. Specifically, changes in WY and SC are primarily influenced by climate change, while changes in NPP and HQ are mainly affected by changes in forest type and structure. Complex trade-offs and synergies exist among different ESs, and the driving mechanisms of climate and vegetation changes on ES variations are also complex, involving both direct and indirect effects, with significant spatial heterogeneity. This study provides important references for the sustainable management and appropriate restoration of regional forest ESs.
]]>Forests doi: 10.3390/f15111849
Authors: Jing Huang Peihao Song Xiaojuan Liu Ang Li Xinyu Wang Baoguo Liu Yuan Feng
Urbanization has significantly altered urban landscape patterns, leading to a continuous reduction in the proportion of green spaces. As critical carbon sinks in urban carbon cycles, urban green spaces play an indispensable role in mitigating climate change. This study aims to evaluate the carbon capture and storage potential of urban green spaces in Luohe, China, and identify the landscape factors influencing carbon sequestration. The research combines on-site data collection with high-resolution remote sensing, utilizing the i-Tree Eco model to estimate carbon sequestration rates across areas with varying levels of greenery. The study reveals that the carbon sequestration capacity of urban green spaces in Luohe City is 1.30 t·C·ha−1·yr−1. Among various vegetation indices, the Enhanced Vegetation Index (EVI) explains urban green space carbon sequestration most effectively through an exponential model (R2 = 0.65, AIC = 136.5). At the city-wide scale, areas with higher greening rates, better connectivity, and more complex edge morphology exhibit superior carbon sequestration efficiency. The explanatory power of key landscape indices on carbon sequestration is 78% across the study area, with variations of 71.5%, 62%, and 84.9% for low, medium, and high greening rate areas, respectively. Moreover, when greening rates reach a certain threshold, maintaining and optimizing the quality of existing green spaces becomes more critical than simply expanding the green area. These insights provide valuable guidance for urban planners and policymakers on enhancing the ecological functions of urban green spaces during urban development.
]]>Forests doi: 10.3390/f15111848
Authors: Ke Lu Mili Liu Kui Hu Yang Liu Yiming He Huihui Bai Zhongyu Du Yizhong Duan
The genus of Prunus subg. Amygdalus are endangered Tertiary-relict plants that are an essential source of woody plant oil. In order to provide a theoretical basis for better protection and utilization of species in the Prunus subg. Amygdalus. This study collected global distribution information for six species within the Prunus subg. Amygdalus, along with data on 29 environmental and climatic factors. The Maximum Entropy (MaxEnt) model was used to simulate the globally suitable distribution areas for these species within the subgenus. The suitable results showed that the area under the test curve (AUC) values of the simulation results were more than 0.8, indicating that the simulation results have high accuracy. Temperature, precipitation, UV-B, and altitude were critical environmental factors affecting the distribution of each species in Prunus subg. Amygdalus. Currently, the distribution area of six species in this genus, from largest to smallest, is Prunus triloba (Lindl.) Ricker, Prunus tenella Batsch, Prunus amygdalus Batsch, Prunus pedunculata Maxim, Prunus mongolica Maxim and Prunus tangutica (Batal.) Korsh. The simulation results of distribution areas showed that under the ssp2.45 and ssp5.85 scenarios, the potential distribution areas of P. amygdalus, P. tangutica, and P. pedunculata all show a decreasing trend, while the distribution areas of P. mongolica and P. tenella, and P. triloba exhibit an increasing trend. The general distribution of P. amygdalus, P. mongolica, and P. tenella will trend to transfer in a northwest direction. P. tangutica and P. pedunculata were affected by other environmental factors (such as slope, altitude, and soil pH), and the distribution area has a tendency to move northeastward. The P. triloba moved to the southwest. The spatiotemporal distribution patterns of Prunus subg. Amygdalus can be used as a reference for forest management and to formulate species conservation strategies.
]]>Forests doi: 10.3390/f15111847
Authors: Efrain Velasco-Bautista Antonio Gonzalez-Hernandez Martin Enrique Romero-Sanchez Vidal Guerra-De La Cruz Ramiro Perez-Miranda
The design of a sampling unit, whether a simple plot or a subplot within a clustered structure, including shape and size, has received little attention in inferential forestry research. The use of auxiliary variables from remote sensing impacts the precision of estimators from both model-assisted and model-based inference perspectives. In both cases, model parameters are estimated from a sample of field plots and information from pixels corresponding to these units. In studies assisted by remote sensing, the shape of the plot used to fit regression models (typically circular) often differs from the shape of the population elements for prediction, where the area of interest is divided into equal tessellated parts. This raises interest in understanding the effect of the sampling unit shape on the mean of variables in forest stands of interest. Therefore, the objective of this study was to evaluate the effect of circular and square subplots, concentrically overlapped and arranged in an inverted Y cluster structure, over tree density, basal area, and aboveground biomass in a managed temperate forest in central Mexico. We used a Multivariate Generalised Linear Mixed Model, which considers the Gamma distribution of the variables and accounts for spatial correlation between Secondary Sampling Units nested within the Primary Sampling Unit. The main findings of this study indicate that the type of secondary sampling unit of the same area and centroid, whether circular or square, does not significantly affect the mean tree density (trees), basal area (m2), and aerial biomass.
]]>Forests doi: 10.3390/f15111846
Authors: Frederik O. Kammel Alexander Reiterer
Forests and trees provide a variety of essential ecosystem services. Maintaining them is becoming increasingly important, as global and regional climate change is already leading to major changes in the structure and composition of forests. To minimize the negative effects of storm damage risk, the tree and stand characteristics on which the storm damage risk depends must be known. Previous work in this field has consisted of tree-pulling tests and targets attached to selected branches. They fail, however, since the mass of such targets is very high compared to the mass of the branches, causing the targets to influence the tree’s response significantly, and because they cannot model dynamic wind loads. We, therefore, installed a multi-camera system consisting of nine cameras that are mounted on four masts surrounding a tree. With those cameras acquiring images at a rate of 10 Hz, we use photogrammetry and a semi-automatic feature-matching workflow to deduce a 3D model of the tree crown over time. Together with motion sensors mounted on the tree and tree-pulling tests, we intended to learn more about the wind-induced tree response of all dominant aerial tree parts, including the crown, under real wind conditions, as well as dampening processes in tree motion.
]]>Forests doi: 10.3390/f15111845
Authors: Marcel Riedl Martin Němec Vilém Jarský
This paper examines the socio-economic significance of forest visits and the collection of forest berries and mushrooms (FBMs) in the Czech Republic, emphasising their role in enhancing human well-being and contributing to regional economies. Over a 30-year period, data were collected on the quantities and economic values of FBMs, alongside the intensity of forest visits by the Czech population. This study incorporates a detailed analysis of time series data on FBM collection, exploring trends and fluctuations in the harvested quantities and their economic value. A Lorenz curve analysis reveals significant disparities in the distribution of economic benefits, with a small segment of the population accounting for the majority of the FBM-derived value. Additionally, the research investigates the impact of forest visitation on well-being at the regional level, highlighting the relationship between forest access, visitation intensity, and public health benefits. This study also examines visitors’ expectations, motivations, and perceptions regarding an ideal forest for visitation, providing recommendations for effective marketing strategies. Furthermore, the study explores the contribution of FBMs to net income across different regions, demonstrating substantial regional variation in their economic importance. Notably, the analysis shows that the value of FBMs represents approximately 37% of the net income generated by traditional forestry activities, underscoring its significant economic potential. The findings emphasise the potential of territorial marketing strategies to enhance well-being, particularly in economically disadvantaged regions, and advocate for sustainable forest management practices to protect these valuable resources and ensure equitable access to the benefits provided by forest ecosystems.
]]>Forests doi: 10.3390/f15111844
Authors: Suzhen Yang Qinhua Fang Dian Zhang Lusita Meilana Harrison Odion Ikhumhen Xue Zhang Xiaoyan Jiang Boding Lin
Nature-based solutions (NbSs) of biodiversity conservation and ecosystem restoration have been paid increasing attention as an essential approach to slow down climate change. However, to what degree an NbS approach will contribute to the combined effects of human intervention and climate change has not been well studied. From a habitat quality perspective, we set four NbS scenarios to analyze whether the NbS—mangrove restoration in particular—will be enough for climate change in Xiamen Bay of Fujian Province, China. The habitat quality module of the InVEST model (InVEST-HQ) and the Sea Level Affecting Marshes Model (SLAMM) were used to simulate the spatial-temporal changes in habitat types and habitat quality. Results show that (1) rising sea levels will cause coastal squeeze effects, impacting habitat quality due to erosion and inundation in the study area; (2) mangrove restoration is an effective way to mitigate climate change effects and to increase habitat quality; and (3) further analysis of the effectiveness of mangrove restoration shows that the consideration of mangrove fragmentation effects and sea-use impacts are necessary. The findings in this study will enrich the international discussion of NbSs to climate change in coastal areas.
]]>Forests doi: 10.3390/f15111843
Authors: John R. Butnor Cornelia Pinchot Wilson Melike Bakır Anthony W. D’Amato Charles E. Flower Christopher F. Hansen Stephen R. Keller Kathleen S. Knight Paula F. Murakami
The American elm (Ulmus americana L.), once a dominant species in North American floodplain forests, has suffered significant population declines due to Dutch elm disease (DED). Despite this, some elms persist, potentially exhibiting disease resistance and climate-adaptive traits that could facilitate restoration. Understanding these traits is crucial for selecting genotypes suited to current and future climatic conditions, particularly in colder regions. This study evaluated the mid-winter cold tolerance of American elm genotypes across a climatic gradient to ascertain evidence of local climate adaptation. We used relative electrolyte leakage (REL) to assess mid-winter cold tolerance of current-year shoots on eleven survivor genotypes from New England and one susceptible, control genotype from Ohio. The lethal temperature, at which 50% of cellular leakage occurs (LT50), was determined and compared with 30-year climate data to identify potential climate adaptation. Genotypes from colder regions exhibited greater cold hardiness, indicating local adaptation to climate. Observed mid-winter LT50 values (−42.8 °C to −37.7 °C) were in excess of the 30-year minimum air temperature, even at the coldest source location. This calls into question whether mid-winter cold tolerance is the critical period for injury to American elm and more attention should be given to environmental conditions that cause de-acclimation to cold. By understanding the adaptive capacity of American elm, managers can better select mother trees for regional seed orchards, ensuring the long-term success of restoration initiatives.
]]>Forests doi: 10.3390/f15111842
Authors: Andromachi Mitani Vasiliki Kamperidou Paschalina Terzopoulou
Wood is a valuable material with incomparable advantages, though it is susceptible to biotic and abiotic factors action that affect it adversely and shorten its service life. In the current study, the surface modification of oak wood is carried out through brief immersion in a solution of acrylic polymer Paraloid B72, in which silica dioxide nanoparticles in the form of nanopowder were dissolved at different contents (1, 2, 3, and 4% w/v of the solution) aiming at the elimination of wood material hygroscopicity, and the protection and improvement of other properties. Specifically, the modified and unmodified wood specimens were characterized in terms of physical characteristics (density, equilibrium moisture content, colour, and surface roughness), hygroscopic properties (swelling and absorption percentage) and accelerated weathering performance using xenon light and cycles of moisturizing and drying. The results revealed the dimensional stability of the samples and a significant increase in the hydrophobicity of the modified wood, as well as a significant increase in the resistance to the ageing/weathering factors of oak wood, which was proportional to the increase in the presence of nanoparticles in the Paraloid B72 solution. The colour of the treated samples slightly changed towards darker shades, more reddish and yellowish (with L* to decrease, while a* and b* to slightly increase), though the treated wood revealed higher colour stability. The surface roughness parameters (Ra, Rq, and Rz) increased significantly, restricting the wide application of the treated wood in indoor or outdoor applications where surface roughness constitutes a critical factor. The findings of the current work contribute not only to the production of longer-lasting wood and timber structures, but also to the conservation of the existing weathered heritage timber structures.
]]>Forests doi: 10.3390/f15111841
Authors: Yubo Tao Yutong Xia Xiao Zheng Hui Ding Yanming Fang Chenlei Tian Pei Ma
The relationship between biodiversity and ecosystem function is crucial for understanding the structure and processes of subtropical forest ecosystems. However, the extent to which biodiversity influences subtropical forest biomass remains unclear. This study applies Bayesian causal inference to explore causal relationships between forest Aboveground Biomass (AGB) and its potential driving factors (biodiversity factors, biotic factors and abiotic factors) based on Huangshan Forest Dynamics Plots. Furthermore, hypothetical interventions are introduced to these driving factors within the causal network to estimate their potential impact on AGB. The causal relationship network reveals that species diversity and functional diversity are the most direct factors influencing AGB, whereas phylogenetic diversity exerts only an indirect effect. Biotic and abiotic factors also contribute indirect effects on AGB, potentially by influencing other mediating indexes. Intervention analysis shows that with low-level interventions on direct influencing factors, the probability of low AGB is as high as 84%. As the intervention level increases to high, the probability of low AGB decreases by 36%. Moreover, AGB demonstrates a particularly sensitive response to changes in Rao’s quadratic entropy (RaoQ) intervention levels, more so than to other factors, highlighting its critical role in maintaining forest biomass. Therefore, we contend that functional diversity, due to its direct reflection of species’ roles in ecosystem processes, is a more accurate measure of the impact of biodiversity on biomass compared to species or phylogenetic diversity and the interplay between abiotic and biotic factors and biodiversity should not be overlooked. This approach offers a powerful tool for exploring causal relationships, thereby providing a more nuanced and accurate understanding of the relationship between biodiversity and forest ecosystem function.
]]>Forests doi: 10.3390/f15111840
Authors: Yun-Han Tseng Chih-Ming Ku Wen-Shiung Huang Chung-Ching Huang Homer C. Wu Chi-Ming Hsieh
This research aims to verify the relationships between destination ij3dentity, environmental concern, and environmentally responsible behavior (ERB), based on the Cognition–Affect–Behavior (C–A–B) model, in the Sun-Link-Sea Forest Recreation Area (SLSFRA) in Taiwan. This study also aims to address the gap in understanding whether tourists’ family structure, with or without children, influences the impact of destination identity on their environmental concerns and ERB. A total of 431 samples were collected through convenience sampling and analyzed using structural equation modeling. The findings indicated that destination identity significantly influenced environmental concern, which in turn affected the general and specific ERB. Environmental concern acted as a mediator between destination identity and ERB. Specifically, tourists who strongly identified with the destination were more inclined to be concerned that its environmental condition influenced their travel experience, encouraging them to take action to protect the environment. Families with children who had greater environmental concern exhibited stronger general and specific environmentally responsible behavior (ERB) compared to families without children, who were more influenced by the impact of forest destination identity on their ERB. Practical implications for management and future research suggestions are proposed for relevant organizations and researchers.
]]>Forests doi: 10.3390/f15111839
Authors: Jimeng Liu Aristeidis Kastridis Erwen Xu Wenmao Jing Xiaofeng Ren Rui Ma Rongxin Wang Wenli Zheng Xiaohu Yang
Soil heterogeneity observed in the alpine environment plays a very important role in the growth of forest recruitment. However, the mechanisms by which the biomass accumulation and allocation patterns of forest recruitment respond to such environmental differences are unclear, which hinders a thorough understanding of climate change’s impact on forest biomass. We hypothesized that soil heterogeneity influences the distribution of Qinghai spruce recruitment biomass along with elevation. In the frame of this study, carried out in the northern Tibetan Plateau, forest Qinghai spruce recruitment data were combined with soil data derived from 24 sample plots, while permutation multifactor ANOVA and multiple linear regression were utilized to reveal the characteristics of forest recruits’ above- and below-ground biomass and their allocation patterns in response to soil heterogeneity. According to the results, the soil heterogeneity mainly affected the distribution characteristics of recruits’ above- and below-ground biomass at different elevations, while the recruits’ root–shoot ratio variability was influenced by a combination of soil and other environmental factors. Soil organic carbon (SOC) had the greatest effect on the variability of the above- and below-ground biomass of spruce recruits, with R2 of 0.280 and 0.257, respectively. Soil organic carbon and soil moisture content (SMC) had a significant effect on the variability of the root–shoot ratio, with R2 of 0.168 and 0.165, respectively. Soil total nitrogen (TN) and soil organic carbon were the main influencing factors of the above-ground biomass of forest recruits, with contribution rates of 43.15% and 35.28%, respectively. Soil total nitrogen and soil organic carbon were also the main factors influencing the below-ground biomass of forest recruits, with contribution rates of 42.52% and 37.24%, respectively, and both of them had a positive effect on biomass accumulation, and the magnitude of the influence varied with the elevation gradient. Soil moisture content was the main influence factor of spruce recruits’ root–shoot ratio, with a contribution rate of 54.12%. Decreasing soil moisture content would significantly increase the root–shoot ratio of spruce recruits and promote plants to allocate more biomass to root growth. Changes in elevation not only affected the intensity of the effect of soil factors on spruce recruitment biomass and its allocation pattern but even led to a change in the positive and negative effects.
]]>Forests doi: 10.3390/f15101838
Authors: Marina Milović Branislav Kovačević Saša Orlović Zoran Galić Milan Drekić Saša Pekeč Bratislav Matović
Dieback and decline of Norway spruce (Picea abies (L.) Karst.) tree stands on Mtn. Kopaonik are caused by a combination of abiotic and biotic factors. Ectomycorrhizal (ECM) fungi have stabilizing effects on forest trees that are under environmental stress. The aim of our study was to analyze the differences between ECM fungal communities, the number of fine roots, and the abundance of exploration types (ETs) in differently declined Norway spruce stands on Mtn. Kopaonik (Serbia). Three sites were selected: one with no tree decline recorded; one with a moderate decline of trees; and one with a massive decline of trees. Different degrees of tree decline in the studied spruce stands did not affect the number of ECM taxa, the diversity indices, or the percentage of vital fine roots. However, the number of old, non-turgescent, and nonmycorrhizal roots was higher in the spruce stands with tree decline. The ECM community composition differed between the studied sites, but the sites with tree decline had more ECM taxa in common. The ECM taxa of a long-distance ET were significantly more abundant in the spruce stands affected by tree decline.
]]>Forests doi: 10.3390/f15101837
Authors: Wei Xiong Junfei Xue Lin Wang Dagang Li
In recent years, research on interfacial photothermal water evaporation has been thriving. Due to its inherent porosity, exceptional hydrophilicity, and renewable characteristics, wood has garnered significant attention as a material for interfacial photothermal evaporation absorbers. In order to enhance the cellular channels of poplar and improve its water migration capacity, Trichoderma spiralis was selected to inoculate and culture poplar specimens from different sections for 3, 5, and 7 weeks. Simultaneously, a solar radiation intensity of 1 kW·m−2 was simulated to perform photothermal evaporation tests on the specimens. This validated the water migration capabilities of different sections of poplar treated with Trichoderma spiralis under light and heat exposure. The characteristic changes were analyzed using electron microscope scanning, infrared spectrum analysis, X-ray photoelectron spectroscopy analysis, surface infiltration performance, and automatic specific surface porosity. The results suggested that the moderate degradation of cellulose and hemicellulose in poplar by Trichoderma spiralis could dredge the cell channels and improve the permeability of poplar, particularly with regard to lateral permeability. The maximum photothermal evaporation rate of the poplar specimen reached 1.18 kg m−2 h−1, while the evaporation efficiency increased to 72.2%.
]]>Forests doi: 10.3390/f15101836
Authors: Liang Qiao Qingbin Zhang Jiyue Li Zhuizhui Guan Qian He
Short-term fertilization may provide limited improvements in tree growth and demonstrate suboptimal fertilizer efficiency; however, its benefits often fall short of expectations. Unfortunately, research addressing the sustained impacts of prolonged fertilization (e.g., beyond five years) on trees’ developmental dynamics and productivity remains relatively scarce. This study focused on a 7-year-old Catalpa bungei plantation located in Jinan City, Shandong Province, China. The study employed two fertilization techniques: hole fertilization (HF) and integrated water and fertilizer application (WF), with a no-fertilization treatment serving as the control (CK). The findings revealed that the WF significantly enhanced stand productivity. When comparing the different treatments, the productivity of WF stands demonstrated a remarkable increase of 39.7% compared to HF stands and 55.1% compared to CK stands. After five years of fertilization, the stands treated with WF exhibited a significant increase in volume accumulation, reaching 112.36 m3·hm−2. Additionally, the productivity of these WF-fertilized stands achieved an impressive 41.75 m3·hm−2·a−1. Fertilization notably enhanced the nitrogen content in the leaves and fine roots of C. bungei, as well as the potassium content in the coarse roots. These nutrients were found to be more concentrated in the corresponding organs within the WF stands. Over the entire growth cycle, there was a substantial consumption of key nutrients, with leaf nitrogen, phosphorus, and potassium contents decreasing by 30.5%, 18.8%, and 47.3%, respectively. Similarly, the coarse root potassium and fine root phosphorus content decreased by 24.7% and 24.4%, respectively. The enhancement in leaf nitrogen content following fertilization significantly contributed to increases in tree height, breast height diameter (DBH), and individual tree volume. Similarly, the enrichment of potassium in the branches and coarse roots was associated with improvements in DBH and tree volume. To maximize forest stand productivity, the WF fertilization method demonstrated superior results compared to HF. Therefore, WF should be prioritized in future fertilization experiments for C. bungei.
]]>Forests doi: 10.3390/f15101835
Authors: Yuqian Sun Guangzhao Wu Pin Li
Urban forests, as an integral part of nature-based solutions (NBS), are significant contributors to improving urban air quality, delivering ecological service functions and environmental benefits to human health and well-being. Suitable urban forest management, including proper species selection, needs to be defined to efficiently reduce air pollutants in cities, with a focus on the removal ability of the main air pollutants (PM2.5, PM10, O3, and NO2), the ecological adaptability to O3 and NO2, and allergenic effects. This study ranked 73 urban greening tree species in northern Chinese cities based on their ability to maximize air quality and minimize disservices. This study proposed a novel Species-Specific Air Purification Index (S-API), which is suitable for air quality improvement for tree/shrub species. Urban managers are recommended to select species with an S-API > 1.47—that is, species that have a high removal capacity of PM2.5, PM10, O3, and NO2, are O3- and NO2-tolerant, and are non-allergenic (e.g., Castanea mollissima Blume, Ginkgo biloba L., Hibiscus syriacus L., Ilex chinensis Sims, Juniperus procumbens (Endl.) Iwata et Kusaka, Liriodendron chinense (Hemsl.) Sarg., Morus alba L., Styphnolobium japonicum (L.) Schott, Syringa oblata Lindl., and Ulmus pumila L.). The S-API of urban greening species thus represents a potentially useful metric for air pollutant risk assessment and for selecting appropriate species for urban greening in cities facing serious air pollution challenges.
]]>Forests doi: 10.3390/f15101834
Authors: Adriano Reis Prazeres Mascarenhas Carine Setter Mário Vanoli Scatolino Rafael Carvalho do Lago Felipe Gomes Batista Dayane Targino de Medeiros Carolina Aparecida dos Santos Alberto Ricley do Vale Rafael Rodolfo de Melo Gustavo Henrique Denzin Tonoli
Coffee is one of the most consumed commodities globally, and its harvests generate large quantities of wood waste with low industrial value. This study aimed to explore the potential of residual Coffea arabica wood to produce lignocellulose microfibrils and lignocellulose nanofibrils (LCMF/LCNF) and biodegradable films with possible application in packaging. The fibers were treated with 5% NaOH and fibrillated in an ultrarefiner until they formed a gel. The resulting suspensions were used to create films whose physical, morphological, optical, and mechanical properties were analyzed. The NaOH treatment removed extractives and exposed hemicelluloses, allowing the gel point to be reached with just seven passes through the ultrarefiner, saving energy (~4700 kWh/t). More than 65% of the fibers had diameters of less than 100 nm and little sedimentation after 8 h. The films were flexible, thin (24.5 µm), with a high density (~1100 kg/m3) and good resistance to grease, as well as a water vapor permeability of ~1230 g/m2/day, suitable for packaging bread, fruit, and vegetables. However, the higher wettability of the surface may limit its use in humid environments. The films showed moderate tensile strength (~25 MPa) but low puncture resistance (~7 N mm), making them suitable for biodegradable packaging.
]]>Forests doi: 10.3390/f15101833
Authors: Audrey J. Hicks Jerald T. Garrett Christopher A. Gabler
Tamaulipan thornscrub forests (thornforests) have high ecological and economic values, yet over 90% of these forests have been lost, and they remain threatened, making them a conservation hotspot. For decades, federal, state, NGO, and corporate entities have been acquiring land and actively or passively restoring these forests, but results have been mixed and seldom monitored. This study characterized and quantified faunal communities of restored thornforest habitats in south Texas and examined the relationships between restored faunal communities and key site characteristics and environmental factors. We surveyed and analyzed mammal, bird, Lepidoptera, and herptile communities within 12 restored sites in the Lower Rio Grande Valley of southernmost Texas, USA. The site and environmental factors that influenced animal community composition, richness, diversity, and abundance varied widely among taxa. Time since restoration began and method of restoration influenced many community metrics, whereas patch size and extent of isolation influenced few. Several aspects of restored plant communities were influential, especially ground layer diversity, and high invasive plant cover negatively impacted many animal community metrics. If actively restoring a site, efforts to control invasive plants, foster native plant diversity, and provide a nearby water source are likely the most effective ways to promote faunal recolonization.
]]>Forests doi: 10.3390/f15101832
Authors: Yulong Hao Junhu Dai Mengyao Zhu Lijuan Cao Khurram Shahzad
Numerous studies have reported phenological changes and their driving mechanisms in spring flowering plants. However, there is little research on the shifts of winter flowering phenology and its response to forcing and chilling requirements. Based on the China Phenological Observation Network (CPON) ground observation data from nine sites over the past 20 years, we explored the spatial and temporal variation patterns of flowering plants and their response to chilling and forcing in wintersweet (Chimonanthus praecox L.), a common winter flowering plant species in temperate and subtropical zones of China. We used three chilling models (chilling hour, Utah, and dynamic models) and the growing degree hours (GDHs) model to calculate each site’s daily chilling and forcing. Using the partial least squares (PLSs) regression approach, we established the relationship between the first flowering date (FFD) and pre-season chilling and forcing in wintersweet, based on which we identified chilling and forcing periods and calculated chilling and forcing requirements. This study found that the FFD of wintersweet in China showed an overall advancement trend during the last 20 years. Still, there were temporal and spatial differences in the FFD of wintersweet among different sites. The PLS results showed that wintersweet also had periods of chilling and forcing, both of which co-regulated wintersweet flowering. We found the forcing and chilling requirements of wintersweet varied significantly from site to site. The higher the latitude is, the more chilling requirements are needed. The chilling requirements for wintersweet were about 6.9–34.9 Chill Portions (CPs) and 1.4–21.6 CP in the temperate and subtropical zones, respectively, with corresponding forcing requirements of 3.2–1922.9 GDH and 965.3–8482.6 GDH, respectively. In addition, we found that the temperature requirements of wintersweet were correlated by a negative exponential relationship, suggesting that chilling and forcing requirements have an antagonistic effect on initiating flowering phenology. Our results could help us understand how flowering dates of winter flowering plants respond to climate change.
]]>Forests doi: 10.3390/f15101831
Authors: Xiaofang Wang Yiming Song Xiangju Zhang Heping Hou Yongsheng Li
The Shangqiu Yellow River Ancient Course National Forest Park, the only national forest park in China created entirely from man-made forests, plays a critical role in ecological conservation. Our research employed plot surveys and quantitative ecological methods, including a diversity index analysis and importance value analysis, to investigate the diversity of arboreal, shrub, and herbaceous plants. This study revealed the composition and distribution of plant communities and analyzed invasive species. It identified dominant plant families, genera, and species and evaluated the types, distribution, and characteristics of invasive plants. We documented 70 families, 177 genera, and 254 species, highlighting that local environmental factors and human activities significantly affect the composition and distribution of plant communities. The presence of 29 invasive plant species poses a risk to the ecosystem. We constructed a phylogenetic tree of the plant community based on rbcL (ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit) gene sequences, revealing the evolutionary relationships among species, and evaluated the community’s stability using the NTI (nearest taxon index) and NRI (net relatedness index). This research aims to provide a scientific foundation for conserving plant diversity and promoting sustainable development, and it can inform ecological protection and biodiversity studies in similar regions.
]]>Forests doi: 10.3390/f15101830
Authors: Yong Liu Jiake Chen Cunxin Li Xiangna Han Hao Wang Jinsong Bai Xiaohua Liu
Block lifting is a key step in stabilizing and removing fragile remains at archaeological excavation sites. Due to its favorable working properties and adhesive effect, menthol has recently been proposed as a volatile binding medium for temporary consolidation in archaeological conservation. This paper presents a case study on the use of menthol in the extraction and restoration of a large wooden coffin lid, approximately 1.9 m long and 0.9 m wide, from tomb 11 (M11) at Xie’ertala, located east of a Xie’ertala town in Hailar City, Inner Mongolia, dating to the 7th to 10th centuries CE. This coffin lid had fragmented into numerous wooden pieces, and was preserved in a relatively arid steppe environment, necessitating the extraction of the lid as a consolidated block. The use of menthol for consolidating and lifting the highly fragmented wooden coffin lid was intended to preserve critical archaeological information while avoiding damage to the underlying objects. An analysis of the physicochemical properties of these wooden remains suggests that the timber used for the coffin lid belongs to a common pine species from the Hulunbuir region. The degradation of the coffin lid was relatively mild, as shown by Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscope (SEM) results. Dynamic Vapor Sorption (DVS) tests indicated that the hygroscopicity of the archaeological wood was 23.4%, compared to 21.1% for the reference sample, demonstrating good environmental stability. The safety of menthol as a treatment for fragile wooden remains was evaluated by comparing changes in the morphological and porosity characteristics of the coffin lid before and after menthol treatment. After treatment, the widths of the fissures remained largely unchanged, with all relative variations being less than 1%, and the porosity as well as pore size distribution of the wood showed negligible changes. Gas Chromatography–Mass Spectrometry (GC-MS) results showed that only 0.6% of menthol residue remained after 8 days of sublimation. This pilot study demonstrates that menthol is a safe temporary consolidant for block lifting and offers a promising alternative to the widely used cyclododecane. In conclusion, this research provided a new approach for conservators to safely lift similarly large and fragile wood remains during archaeological excavations.
]]>Forests doi: 10.3390/f15101829
Authors: Minglong Yin Ting Gao Yuhao Zhao Ruiqiang Ni Peijin Zheng Yuyao Zhao Jinshan Zhang Kun Li Chuanrong Li
Accurate estimation of biomass and carbon stocks in forest ecosystems is critical for understanding their roles in carbon sequestration and climate change mitigation. Currently, the development of stand biomass models and carbon stock estimation at the regional scale has emerged as a prominent research priority. In this study, 225 Populus spp. (poplar) trees in Shandong Province, China, were destructively sampled to obtain the biomass of their components. Two models (MS1 and MS2) were developed using allometric equations and the seemingly unrelated regression (SUR) method to ensure additive properties across tree components. The model evaluation employed the leave-one-out jackknife (LOO) method, considering statistics such as adjusted R-squared (Ra2), root mean square error (RMSE), mean absolute percent error (MAPE), and mean absolute error (MAE). The results from our models demonstrated high accuracy, with MS2 slightly outperforming MS1 after incorporating tree height as an independent variable. The models reliably estimated component-specific biomass and carbon stocks, with distinct variations observed in the carbon content among foliage (47.14 ± 2.07%), branches (47.26 ± 2.48%), stems (47.67 ± 2.21%), and roots (46.37 ± 2.78%). Carbon stocks in poplar plantations increased with the diameter class, ranging from 5 to 35 cm and correspondingly from 3.670 to 172.491 Mg C ha−1. As the diameter class increases, the carbon allocation strategy of poplars aligns with the CSR strategy, transitioning from prioritizing growth competition to emphasizing self-stabilization. Our research proposes a robust framework for assessing biomass and carbon stocks in poplar plantations, which is essential for evidence-based forest management strategies.
]]>Forests doi: 10.3390/f15101828
Authors: Charuta Murkute Mostafa Sayeed Franz Pucha-Cofrep Galo Carrillo-Rojas Jürgen Homeier Oliver Limberger Andreas Fries Jörg Bendix Katja Trachte
High mountain rainforests are vital in the global energy and carbon cycle. Understanding the exchange of energy and carbon plays an important role in reflecting responses to climate change. In this study, an eddy covariance (EC) measurement system installed in the high Andean Mountains of southern Ecuador was used. As EC measurements are affected by heterogeneous topography and the vegetation height, the main objective was to estimate the effect of the sloped terrain and the forest on the turbulent energy and carbon fluxes considering the energy balance closure (EBC) and the heat storage. The results showed that the performance of the EBC was generally good and estimated it to be 79.5%. This could be improved when the heat storage effect was considered. Based on the variability of the residuals in the diel, modifications in the imbalances were highlighted. Particularly, during daytime, the residuals were largest (56.9 W/m2 on average), with a clear overestimation. At nighttime, mean imbalances were rather weak (6.5 W/m2) and mostly positive while strongest underestimations developed in the transition period to morning hours (down to −100 W/m2). With respect to the Monin–Obukhov stability parameter ((z − d)/L) and the friction velocity (u*), it was revealed that the largest overestimations evolved in weak unstable and very stable conditions associated with large u* values. In contrast, underestimation was related to very unstable conditions. The estimated carbon fluxes were independently modelled with a non-linear regression using a light-response relationship and reached a good performance value (R2 = 0.51). All fluxes were additionally examined in the annual course to estimate whether both the energy and carbon fluxes resembled the microclimatological conditions of the study site. This unique study demonstrated that EC measurements provide valuable insights into land-surface–atmosphere interactions and contribute to our understanding of energy and carbon exchanges. Moreover, the flux data provide an important basis to validate coupled atmosphere ecosystem models.
]]>Forests doi: 10.3390/f15101827
Authors: Wenxian Xu Yingying Zhang Ashar Tahir Yumiao Cao Changgeng Kuang Xinwei Guo Rui Sun Wenjie Liu Zhixiang Wu Qiu Yang
Agroforestry ecosystems are an efficient strategy for enhancing soil nutrient conditions and sustainable agricultural development. Soil extracellular enzymes (EEAs) are important drivers of biogeochemical processes. However, changes in EEAs and chemometrics in rubber-based agroforestry systems and their mechanisms of action are still not fully understood. Distribution of EEAs, enzymatic stoichiometry, and microbial nutrient limitation characteristics of rubber plantations under seven planting patterns (RM, rubber monoculture system; AOM, Hevea brasiliensis-Alpinia oxyphylla Miq; PAR, Hevea brasiliensis-Pandanus amaryllifolius Roxb; AKH, Hevea brasiliensis-Alpinia katsumadai Hayata; CAA, Hevea brasiliensis-Coffea Arabica; CCA, Hevea brasiliensis-Cinnamomum cassia (L.) D. Don, and TCA, Hevea brasiliensis-Theobroma Cacao) were analyzed to investigate the metabolic limitations of microorganisms and to identify the primary determinants that restrict nutrient limitation. Compared with rubber monoculture systems, agroforestry ecosystems show increased carbon (C)-acquiring enzyme (EEAC), nitrogen (N)-acquiring enzyme (EEAN), and phosphorus (P)-acquiring enzyme (EEAP) activities. The ecoenzymatic stoichiometry model demonstrated that all seven plantation patterns experienced C and N limitation. Compared to the rubber monoculture system, all agroforestry systems exacerbated the microbial limitations of C and N by reducing the vector angle and increasing vector length. P limitation was not detected in any plantation pattern. In agroforestry systems, progression from herbs to shrubs to trees through intercropping results in a reduction in soil microbial nutrient constraints. This is primarily because of the accumulation of litter and root biomass in tree-based systems, which enhances the soil nutrient content (e.g., soil organic carbon, total nitrogen, total phosphorus, and ammonium nitrogen) and accessibility. Conversely, as soil depth increased, microbial nutrient limitations tended to become more pronounced. Partial least squares path modelling (PLS-PM) indicated that nutrient ratios and soil total nutrient content were the most important factors influencing microbial C limitation (−0.46 and 0.40) and N limitation (−0.30 and −0.42). This study presented novel evidence regarding the constraints and drivers of soil microbial metabolism in rubber agroforestry systems. Considering the constraints of soil nutrients and microbial metabolism, intercropping of rubber trees with arboreal species is recommended over that of herbaceous species to better suit the soil environment of rubber plantation areas on Hainan Island.
]]>Forests doi: 10.3390/f15101826
Authors: Xuyang Li Xiangsuo Fan Jinlong Fan Qi Li Yuan Gao Xueqiang Zhao
The prompt acquisition of precise land cover categorization data is indispensable for the strategic development of contemporary farming practices, especially within the realm of forestry oversight and preservation. Forests are complex ecosystems that require precise monitoring to assess their health, biodiversity, and response to environmental changes. The existing methods for classifying remotely sensed imagery often encounter challenges due to the intricate spacing of feature classes, intraclass diversity, and interclass similarity, which can lead to weak perceptual ability, insufficient feature expression, and a lack of distinction when classifying forested areas at various scales. In this study, we introduce the DASR-Net algorithm, which integrates a dual attention network (DAN) in parallel with the Residual Network (ResNet) to enhance land cover classification, specifically focusing on improving the classification of forested regions. The dual attention mechanism within DASR-Net is designed to address the complexities inherent in forested landscapes by effectively capturing multiscale semantic information. This is achieved through multiscale null attention, which allows for the detailed examination of forest structures across different scales, and channel attention, which assigns weights to each channel to enhance feature expression using an improved BSE-ResNet bilinear approach. The two-channel parallel architecture of DASR-Net is particularly adept at resolving structural differences within forested areas, thereby avoiding information loss and the excessive fusion of features that can occur with traditional methods. This results in a more discriminative classification of remote sensing imagery, which is essential for accurate forest monitoring and management. To assess the efficacy of DASR-Net, we carried out tests with 10m Sentinel-2 multispectral remote sensing images over the Heshan District, which is renowned for its varied forestry. The findings reveal that the DASR-Net algorithm attains an accuracy rate of 96.36%, outperforming classical neural network models and the transformer (ViT) model. This demonstrates the scientific robustness and promise of the DASR-Net model in assisting with automatic object recognition for precise forest classification. Furthermore, we emphasize the relevance of our proposed model to hyperspectral datasets, which are frequently utilized in agricultural and forest classification tasks. DASR-Net’s enhanced feature extraction and classification capabilities are particularly advantageous for hyperspectral data, where the rich spectral information can be effectively harnessed to differentiate between various forest types and conditions. By doing so, DASR-Net contributes to advancing remote sensing applications in forest monitoring, supporting sustainable forestry practices and environmental conservation efforts. The findings of this study have significant practical implications for urban forestry management. The DASR-Net algorithm can enhance the accuracy of forest cover classification, aiding urban planners in better understanding and monitoring the status of urban forests. This, in turn, facilitates the development of effective forest conservation and restoration strategies, promoting the sustainable development of the urban ecological environment.
]]>Forests doi: 10.3390/f15101825
Authors: Fangyun Dai Mingjin Zhan Xingjuan Chen Xiaoling Yang Ping Ouyang
Analyzing the spatiotemporal changes and influencing factors of carbon emissions generated by land use is of great importance for improving land use structure and promoting regional low-carbon economic development. This study, based on remote sensing and statistical yearbook data from 1995 to 2020, calculated the carbon emissions from land use in Jiangxi Province, China. Multiple spatial analysis methods and the logarithmic mean Divisia index were used to elucidate the spatiotemporal evolution and driving factors of carbon emissions, and the findings revealed the following: (1) The spatiotemporal changes in land use in Jiangxi Province during 1995–2020 were substantial as forest land accounted for 65% of the entire land area, while construction land increased by 98.1%. Cultivated land decreased the most, followed by forest land. (2) There was a fourfold rise in carbon emissions in Jiangxi Province, driven primarily by construction land, and northern areas produced higher carbon emissions compared with central and southern regions. Forest land was the main carbon sink. (3) Economic development (257.36%) and the impact of the proportion of construction land (211.31%) were the primary factors contributing to the increase in carbon emissions from land use, while other factors had inhibitory effects. This study transformed the macroscale low-carbon development strategy of cities into targeted local policies, and the research theories and methods adopted could provide scientific reference for other regions in urgent need of carbon reduction worldwide.
]]>Forests doi: 10.3390/f15101824
Authors: Qingyun Xu Kongqing Li
In the context of achieving the goal of carbon neutrality, exploring the changes in land demand and ecological carbon stocks under future scenarios at the urban level is important for optimizing regional ecosystem services and developing a land-use structure consistent with sustainable development strategies. We propose a framework of a coupled system dynamics (SD) model, patch generation land-use simulation (PLUS) model, and integrated valuation of ecosystem services and trade-offs (InVEST) model to dynamically simulate the spatial and temporal changes of land use and land-cover change (LUCC) and ecosystem carbon stocks under the NDS (natural development scenario), EPS (ecological protection scenario), RES (rapid expansion scenario), and HDS (high-quality development scenario) in Nanjing from 2020 to 2040. From 2005 to 2020, the expansion rate of construction land in Nanjing reached 50.76%, a large amount of ecological land shifted to construction land, and the ecological carbon stock declined dramatically. Compared with 2020, the ecosystem carbon stocks of the EPS and HDS increased by 2.4 × 106 t and 1.5 × 106 t, respectively, with a sizable ecological effect. It has been calculated that forest and cultivated land are the two largest carbon pools in Nanjing, and the conservation of both is decisive for the future carbon stock. It is necessary to focus on enhancing the carbon stock of forest ecosystems while designating differentiated carbon sink enhancement plans based on the characteristics of other land types. Fully realizing the carbon sink potential of each ecological functional area will help Nanjing achieve its carbon neutrality goal. The results of the study not only reveal the challenges of ecological conservation in Nanjing but also provide useful guidance for enhancing the carbon stock of urban terrestrial ecosystems and formulating land-use planning in line with sustainable development strategies.
]]>Forests doi: 10.3390/f15101823
Authors: Yangyang Zheng Fazhan Tao Zhengyang Gao Jingyan Li
To address the challenges of complex backgrounds and small, easily confused fire and smoke targets in Unmanned Aerial Vehicle (UAV)-based forest fire detection, we propose an improved forest smoke and fire detection algorithm based on YOLOv8. Considering the limited computational resources of UAVs and the lightweight property of YOLOv8n, the original model of YOLOv8n is improved, the Bottleneck module is reconstructed using Group Shuffle Convolution (GSConv), and the residual structure is improved, thereby enhancing the model’s detection capability while reducing network parameters. The GBFPN module is proposed to optimize the neck layer network structure and fusion method, enabling the more effective extraction and fusion of pyrotechnic features. Recognizing the difficulty in capturing the prominent characteristics of fire and smoke in a complex, tree-heavy environment, we implemented the BiFormer attention mechanism to boost the model’s ability to acquire multi-scale properties while retaining fine-grained features. Additionally, the Inner-MPDIoU loss function is implemented to replace the original CIoU loss function, thereby improving the model’s capacity for detecting small targets. The experimental results of the customized G-Fire dataset reveal that FGYOLO achieves a 3.3% improvement in mean Average Precision (mAP), reaching 98.8%, while reducing the number of parameters by 26.4% compared to the original YOLOv8n.
]]>Forests doi: 10.3390/f15101822
Authors: Juan Wang Hongqian Ren Zetao Shi Fesobi Olumide Phillip Sisi Liu Weiyang Zhang Xingqiang Wang Xueping Bao Jinping Guo
Phospholipid: diacylglycerol acyltransferase (PDAT) is crucial in triacylglycerol (TAG) synthesis as it represents the final rate-limiting step of the acyl-CoA-independent acylation reaction. PDAT not only regulates lipid synthesis in plants, but also plays an important function in improving stress tolerance. In this study, the full-length coding sequence (CDS) of XsPDAT1, totaling 2022 base pairs and encoding 673 amino acids, was cloned from Xanthoceras sorbifolium. The relative expression of XsPDAT1 was significantly and positively correlated with oil accumulation during seed kernel development; there were some differences in the expression patterns under different abiotic stresses. Transgenic Arabidopsis thaliana plants overexpressing XsPDAT1 were obtained using the Agrobacterium-mediated method. Under low-temperature stress, the transgenic plants exhibited a smaller decrease in chlorophyll content, a smaller increase in relative conductivity, and a larger increase in POD enzyme activity and proline content in the leaves compared with the wild type. Additionally, lipid composition analysis revealed a significant increase in unsaturated fatty acids, such as oleic (C18:1) and linoleic (C18:2), in the seeds of transgenic plants compared to the wild type. These results suggest that XsPDAT1 plays a dual role in regulating the ratio of fatty acid composition and low-temperature stress in plants.
]]>Forests doi: 10.3390/f15101821
Authors: Hailan Jiang Yi Li Guangjian Yan Weihua Li Linyuan Li Feng Yang Anxin Ding Donghui Xie Xihan Mu Jing Li Kaijian Xu Ping Zhao Jun Geng Felix Morsdorf
Anomalies displaying significant deviations between terrain elevation products acquired from spaceborne full-waveform LiDAR and reference elevations are frequently observed in assessment studies. While the predominant focus is on “normal” data, recognizing anomalies within datasets obtained from the Geoscience Laser Altimeter System (GLAS) and the Global Ecosystem Dynamics Investigation (GEDI) is essential for a comprehensive understanding of widely used spaceborne full-waveform data, which not only facilitates optimal data utilization but also enhances the exploration of potential applications. Nevertheless, our comprehension of anomalies remains limited as they have received scant specific attention. Diverging from prevalent practices of directly eliminating outliers, we conducted a targeted exploration of anomalies in forested areas using both transmitted and return waveforms from the GLAS and the GEDI in conjunction with airborne LiDAR point cloud data. We unveiled that elevation anomalies stem not from the transmitted pulses or product algorithms, but rather from scattering sources. We further observed similarities between the GLAS and the GEDI despite their considerable disparities in sensor parameters, with the waveforms characterized by a low signal-to-noise ratio and a near exponential decay in return energy; specifically, return signals of anomalies originated from clouds rather than the land surface. This discovery underscores the potential of deriving cloud-top height from spaceborne full-waveform LiDAR missions, particularly the GEDI, suggesting promising prospects for applying GEDI data in atmospheric science—an area that has received scant attention thus far. To mitigate the impact of abnormal return waveforms on diverse land surface studies, we strongly recommend incorporating spaceborne LiDAR-offered terrain elevation in data filtering by establishing an elevation-difference threshold against a reference elevation. This is especially vital for studies concerning forest parameters due to potential cloud interference, yet a consensus has not been reached within the community.
]]>Forests doi: 10.3390/f15101820
Authors: Hongxu Meng Xinxin Yu Bonan Chen Pengyuan Ren Jingyao Zhao
In order to enhance the reliability and accuracy of the results from the transient plane source (TPS) method for measuring the thermal conductivity of wood, this paper investigates setting parameters and measurement methods to improve measurement accuracy. Criteria are proposed to determine the optimal parameters such as the power output, heating time, and time window. The measurement results of the TPS method and the HFM method are compared. The results show that the total to characteristic time, temperature increase in the probe, mean deviation, and temperature drift graph are valid indicators for evaluating the detection reliability of the TPS method. The optimal parameters for measuring the thermal conductivity of wood using the TPS method are as follows: power output of 0.05 or 0.1 W, heating time of 120 s, and time window covering 60% to 80% of the heating time. The thermal conductivity measured with the TPS method was higher than that measured by the steady-state method in all grain angle directions. The standard uncertainties after optimization were 18.9% to 59.5% lower than before optimization. The optimized TPS measurement method can be applied to other tree species as well.
]]>Forests doi: 10.3390/f15101819
Authors: Kaixin Zhang Yujie Yang Zeyang Zhai Yao Fang Meiyu He Jialing Cheng Yue Tian Xu Cao Li Liu
Human activities lead to an increase in greenhouse gases in the environment, among which carbon dioxide (CO2) is one of the most prominent, giving rise to global warming and climate change. Climate change, along with the resulting environmental degradation, is one of the most challenging difficulties faced by humanity in the twenty-first century. The forest ecosystem, with plants being its most important component, plays a pivotal role in regulating climate. Carbon sequestration and oxygen release (CSOR) by plants are major ecological service functions that play an important role in mitigating the negative impacts of the greenhouse effect and help to achieve carbon peaking and neutrality. The CSOR of mulberry (Morus spp.), a species of economic and ecological significance, is not yet understood. Six mulberry tree varieties were selected to evaluate their CSOR potential during summer. We took into consideration whole-plant diurnal assimilation amounts (P), carbon sequestration per unit leaf area (WCO2), oxygen release per unit leaf area (WO2), carbon sequestration per unit land area (PCO2), and oxygen release per unit land area (PO2). Zhongsang 1302 showed the greatest potential for CSOR among the six mulberry varieties. The PCO2 value of the Zhongsang 1302 variety was 1531.84 g·m−2 during summer, followed by Suhu 16 (1380.12 g·m−2), Husang 32 (1005.63 g·m−2), Zhongsang 9703 (990.01 g·m−2), Yu 711 (940.43 g·m−2), and Jin 10 (848.29 g·m−2). Moreover, the Pearson correlation and path analyses showed that photosynthetic rate (PN) and leaf area index (LAI) mainly affect the overall CSOR potential in mulberry. These findings not only enrich theoretical research on CSOR in mulberry, but also serve as an important reference for the use of different mulberry tree varieties in improving climate conditions and achieving carbon peaking and neutrality.
]]>Forests doi: 10.3390/f15101818
Authors: Yushu Luo Yuan Zhou Bei Li Pengyao Li Li Zhang Shunbin Ning
As urban spaces expand, changes in land use significantly affect the structure and function of urban ecosystems, particularly with challenges such as green space reduction and uneven distribution. This study focused on the central urban area of Chengdu, China, simulating and forecasting various urban development scenarios for 2035, including cultivated land protection (CP), economic development (ED), ecological priority (EP), and natural development (ND). The construction of green space ecological networks followed a systematic process, incorporating key methods such as ecological source identification, landscape resistance surface construction, and ecological corridor extraction. The connectivity of these ecological networks was assessed using the space syntax. The results indicated that: (1) Construction land expanded across all scenarios, with the ED scenario having the largest area, while the EP scenario resulted in a significant increase in green space. (2) Ecological corridors were established under every scenario, with the EP scenario featuring the most extensive and well-connected network, linking urban green patches with surrounding natural areas. (3) The EP scenario’s ecological network displayed integration, choice, connectivity, and depth values that indicate the most complete and stable network structure. This study provides a comprehensive analysis of green space ecological network changes under different urban development strategies, offering valuable insights for optimizing urban green space planning and management.
]]>Forests doi: 10.3390/f15101817
Authors: Zejie Liu Yongde Zhong Zhao Chen Juan Wei Dali Li Shuangquan Zhang
Cunninghamia lanceolata (Lamb.) Hook accounts for 12% of the total forest area in southern China, second only to Masson pine forests, and is an important part of the forest landscape in this region, which has a significant impact on the overall forest structure in southern China. In this study, we used kernel density analysis, landscape index calculation, variance test, and Markov prediction to analyze and forecast the evolution trend of landscape pattern in the central area of C. lanceolata in ten years. The objective is to investigate the change trend of the spatial pattern of C. lanceolata landscape in the long time series and its possible impact on zonal vegetation, as well as the macro-succession trend of C. lanceolata under the current social and economic background, and to make a scientific and reasonable prediction of its future succession trend. The current and future forecast results show that the landscape fragmentation degree of C. lanceolata is intensified, the erosion of bamboo forest is continuously intensified, and the landscape quality is continuously low. These results provide a reference for the future development direction of C. lanceolata and emphasize the need for targeted C. lanceolata management strategies in the future development of C. lanceolata, emphasizing the strengthening of monitoring, controlling harvesting, and managing bamboo competition in order to balance wood production with landscape quality and ecosystem stability.
]]>Forests doi: 10.3390/f15101816
Authors: Wenjie Zhang Shan Wang Hong Guo
Palm Leaf Manuscripts are an invaluable part of the cultural heritage of the world. Due to their strong hygroscopic properties, Palm Leaf Manuscripts are particularly susceptible to fluctuations in environmental humidity. Therefore, studying the hygroscopic behavior of these manuscripts and understanding how it changes under different environmental conditions is crucial for exploring their intrinsic properties, aging mechanisms, and the development of effective conservation strategies. In this study, we employed the dynamic vapor sorption (DVS) method to investigate the changes in the hygroscopic properties of Palm Leaf Manuscripts under conditions of high temperature and high humidity. The results indicate that high-temperature environments reduce the number of adsorption sites and the hygroscopicity of palm leaves, weakening their physical adsorption and capillary action towards moisture while increasing the hysteresis in desorption, thereby enhancing the stability of palm leaves in fluctuating humidity conditions. Conversely, high-humidity environments increase the number of adsorption sites and the hygroscopicity of the leaves, strengthening their physical adsorption and capillary action, and reducing the hysteresis in desorption. The extent of these changes increases with the aging time of the manuscripts. The surface energy test results of the samples similarly indicate that exposure to high-temperature environments reduces both surface energy and hygroscopicity, while high-humidity environments increase surface energy and hygroscopicity. The infrared spectroscopy results show that in high-temperature environments, the crystallinity of cellulose within the palm leaves increases, whereas in high-humidity environments and under the influence of fungal erosion, both the cellulose and hemicellulose in the Palm Leaf Manuscripts undergo significant degradation, with the amorphous regions of cellulose degrading more than the crystalline regions.
]]>Forests doi: 10.3390/f15101815
Authors: Ruihan Xiao Beixing Duan Changlei Dai Yu Wu
Soil enzymes mediate organic matter decomposition and nutrient cycling, and their stoichiometry can indicate microbial nutrient demands. However, research on the variations in soil enzymes and microbial nutrient limitation under different temperate forest types still lacks insight. In this study, we sampled soils under five typical forest types (including Betula platyphylla Suk. forest, Fraxinus mandschurica Rupr forest, Larix gmelinii (Rupr.) Kuzen. forest, Populus davidiana Dode forest, and Pinus koraiensis Siebold et Zucc.forest) in the temperate climatic region of northeast China. Soil enzyme activities and soil microbial community composition and diversity were determined for each, and vector analysis was used to quantify the value of microbial limitation. The results showed that soil enzyme activity, enzyme stoichiometry, and microbial community structure were significantly different among the five temperate forest types. The ratios of soil C:N:P acquiring enzyme activity were close to 1:1:1. All the forests showed prevalent P limitation over N limitation (all vector angles > 45°), and the degree of impact varied among different forest types. Redundancy analysis (RDA) and Pearson’s test demonstrated that soil enzyme activities and microbial nutrient limitation were mainly determined by soil physical properties and microbial community. These results contribute to understanding the mechanisms that link plant composition, soil enzyme activity, and microbial nutrient limitation in temperate forests.
]]>Forests doi: 10.3390/f15101814
Authors: Yue Chi Chenxi Wang Zhulin Chen Sheng Xu
As the main area for photosynthesis in trees, the canopy absorbs a large amount of carbon dioxide and plays an irreplaceable role in regulating the carbon cycle in the atmosphere and mitigating climate change. Therefore, monitoring the growth of the canopy is crucial. However, traditional field investigation methods are often limited by time-consuming and labor-intensive methods, as well as limitations in coverage, which may result in incomplete and inaccurate assessments. In response to the challenges encountered in the application of tree crown segmentation algorithms, such as adhesion between individual tree crowns and insufficient generalization ability of the algorithm, this study proposes an improved algorithm based on Mask R-CNN (Mask Region-based Convolutional Neural Network), which identifies irregular edges of tree crowns in RGB images obtained from drones. Firstly, it optimizes the backbone network by improving it to ResNeXt and embedding the SENet (Squeeze-and-Excitation Networks) module to enhance the model’s feature extraction capability. Secondly, the BiFPN-CBAM module is introduced to enable the model to learn and utilize features more effectively. Finally, it optimizes the mask loss function to the Boundary-Dice loss function to further improve the tree crown segmentation effect. In this study, TCSNet also incorporated the concept of panoptic segmentation, achieving the coherent and consistent segmentation of tree crowns throughout the entire scene through fine tree crown boundary recognition and integration. TCSNet was tested on three datasets with different geographical environments and forest types, namely artificial forests, natural forests, and urban forests, with artificial forests performing the best. Compared with the original algorithm, on the artificial forest dataset, the precision increased by 6.6%, the recall rate increased by 1.8%, and the F1-score increased by 4.2%, highlighting its potential and robustness in tree detection and segmentation.
]]>Forests doi: 10.3390/f15101813
Authors: Xinguang Cao Pei-ken Kao Yingjun Li Zheng Zhao Hongbing Hu Jing Hu Di Zhang Keyan Fang
The frequency and severity of extreme hydroclimatic events in humid southeastern China have increased in the past half century, which is a serious concern. In this research, we used wood samples from 134 trees growing in the southeast coastal region of China (SECC) to reconstruct the Standardized Precipitation Evapotranspiration Index (SPEI) for the last 173 years (1843–2015 CE). Our reconstruction explained 41.6% of the variance contained in the November SPEI at a 7 month scale for the period 1957–2015. 17 extremely wet and 16 extremely dry events, 8 dry and 9 wet periods have been identified since 1843, and the most severe drought, coinciding with historical records, occurred in 1869 and 1870. The reconstruction reveals. Although the results reveal a modest upward trend in the SPEI and a predominance of extreme wet events over droughts throughout the period, the 20th century accounted for nine of the summers classified as extremely dry. Strong agreement between the current reconstruction and existing hydroclimatic reconstructions in southeastern China implied that our reconstruction exhibited high reliability. The composite anomalies of circulation during the period from May to November (MJJASON) indicate that the temporal variability in the SPEI reconstruction might be modulated by the local Hadley cell. These findings underscore the effectiveness of tree-ring-derived indices for reconstructing hydroclimatic trends in China’s humid regions and enhance our understanding of these changes within a long-term framework.
]]>Forests doi: 10.3390/f15101812
Authors: Hanjiao Zhang Xu Zhang Yulong Ding Feiyi Huang Zhuoyu Cai Shuyan Lin
With the increasing pollution caused by plastic products, people’s awareness of environmental protection has gradually increased. Based on the advantages of China’s bamboo resources and bamboo industry, the International Network for Bamboo and Rattan launched the ‘Utilizing bamboo as a sustainable alternative to plastic’ initiative in November 2022 to accelerate the implementation of the United Nations 2030 Agenda for Sustainable Development. This initiative provides a nature-based solution for global sustainable development, which will have a profound impact on promoting global green development, industrial science and technology, social services, cultural exchanges, and other fields. It has a huge market capacity and application potential. This study aims to understand the research status, hotspots, development trends, and prospects of this initiative. WoS and China National Knowledge Infrastructure (CNKI) were searched for the relevant literature on ‘utilizing bamboo as a sustainable alternative to plastic bamboo as plastic’ and ‘bamboo resources’ from the establishment of the database to 2024. Bibliometric methods and VOSviewer were used to analyze 1855 literatures with the above two keywords published in the Web of Science core set database from 2000 to 2024. A visual analysis was performed on the number of publications, national research institutions, researchers, number of citations, and research topics of the literature. For example, China, the United States, and India ranked in the top three in terms of the number of articles published, with 1103, 267, and 167, respectively. China had the highest number of citations, reaching 26,607. At the same time, the literature with ‘bamboo’ as the keyword in CNKI was analyzed to understand the species of bamboo currently studied. A literature investigation was carried out around the resource cultivation of the bamboo industry in our country, and it was found that the research on ‘use bamboo as plastic’ and ‘bamboo resources’ had been valued by scholars at home and abroad, and had formed a relatively stable research group. Using scientific and technological innovation to improve the product quality of ‘bamboo instead of plastic’, expanding its application scope and market demand, and realizeing the sustainable industry development of ‘bamboo instead of plastic’ is the current research hotspot and the future development direction.
]]>Forests doi: 10.3390/f15101811
Authors: Ting Ren Chang Peng Yuan Lu Yun Jia Bin Li
The genus Pourthiaea Decne., a deciduous woody group with high ornamental value, belongs to the family Rosaceae. Here, we reported newly sequenced plastid genome sequences of Pourthiaea beauverdiana (C. K. Schneid.) Hatus., Pourthiaea parvifolia E. Pritz., Pourthiaea villosa (Thunb.) Decne., and Photinia glomerata Rehder & E. H. Wilson. The plastomes of these three Pourthiaea species shared the typical quadripartite structures, ranging in size from 159,903 bp (P. parvifolia) to 160,090 bp (P. beauverdiana). The three Pourthiaea plastomes contained a pair of inverted repeat regions (26,394–26,399 bp), separated by a small single-copy region (19,304–19,322 bp) and a large single-copy region (87,811–87,973 bp). A total of 113 unique genes were predicted for the three Pourthiaea plastomes, including four ribosomal RNA genes, 30 transfer RNA genes, and 79 protein-coding genes. Analyses of inverted repeat/single-copy boundary, mVISTA, nucleotide diversity, and genetic distance showed that the plastomes of 13 Pourthiaea species (including 10 published plastomes) are highly conserved. The number of simple sequence repeats and long repeat sequences is similar among 13 Pourthiaea species. The three non-coding regions (trnT-GGU-psbD, trnR-UCU-atpA, and trnH-GUG-psbA) were the most divergent. Only one plastid protein-coding gene, rbcL, was under positive selection. Phylogenetic analyses based on 78 shared plastid protein-coding sequences and 29 nrDNA sequences strongly supported the monophyly of Pourthiaea. As for the relationship with other genera in our phylogenies, Pourthiaea was sister to Malus in plastome phylogenies, while it was sister to the remaining genera in nrDNA phylogenies. Furthermore, significant cytonuclear discordance likely stems from hybridization events within Pourthiaea, reflecting complex evolutionary dynamics within the genus. Our study provides valuable genetic insights for further phylogenetic, taxonomic, and species delimitation studies in Pourthiaea, as well as essential support for horticultural improvement and conservation of the germplasm resources.
]]>Forests doi: 10.3390/f15101810
Authors: Qing Shang Yanchun Liu
As one of the main terrain factors, the slope aspect generally shows remarkable effects on microclimate and vegetation distribution. The purpose of this study was to determine the potential effects of the slope aspect on soil respiration and the soil microbial community in a temperate mountain forest. A field investigation was carried out in a mountain oak forest located at different slope aspects (northeast, northwest, southeast, and southwest), and soil respiration was continuously measured for 12 months. The soil’s bacterial and fungal taxa were analyzed during the growing season. Our results showed that average soil respiration on the southwest and southeast slope aspects was 72.9% higher than the average on the northeast and northwest slope aspects. The coefficient of variation of soil respiration had the highest value on the northwest aspect (20.9%) and the lowest value on the southeast aspect (6.9%). The southeast slope had significantly higher soil respiration and temperature sensitivity compared to the other three slope aspects. The slope aspect substantially affected the soil’s bacterial and fungal r/K strategy, showing the lowest values on the northwest aspect and the highest values on the southeast aspect. Differences in bacterial r/K, the ratio of microbial biomass carbon (MBC) to soil organic carbon (SOC), and SOC among slope aspects contributed to a 43%, 38%, and 32% variation in soil respiration, respectively. The variation of soil temperature across slope aspects showed an indirect effect on soil respiration through changing bacterial r/K and MBC/SOC. Our findings highlight that terrain plays a critical role in regulating the spatial heterogeneity of soil respiration in mountain forests, which could be explained by the differences in SOC and microbial community composition across slope aspects.
]]>Forests doi: 10.3390/f15101809
Authors: Saaruj Khadka Hong S. He Sougata Bardhan
White oak mortality is a significant concern in forest ecosystems due to its impact on biodiversity and ecosystem functions. Understanding the factors influencing white oak mortality is crucial for effective forest management and conservation efforts. In this study, we aimed to investigate the spatial pattern of WOM rates across the eastern US and explore the underlying processes behind the observed spatial patterns. Multicycle forest inventory and analysis data were compiled to capture all white oak plots. WOM data were selected across plot systems that utilized declining basal areas between two periods. Ripley’s K function was used to study the spatial pattern of WOM rates. Results showed clustered patterns of WOM rates at local and broad scales that may indicate stand-level competition and regional variables affecting white oaks’ dynamics across southern and northern regions. Results also indicated random patterns at broad scales, suggesting variations in topographic and hydrological conditions across the south and northern regions. However, the central region indicated both clustered and random patterns at the local scale that might be associated with inter-species competition and the possibility of environmental heterogeneity, respectively. Furthermore, uniform patterns of WOM rate at a broad scale across all regions might suggest regions with spatially homogeneous environmental factors acting on the dynamics of white oaks. This research might be helpful in identifying impacted areas of white oaks at varying scales. Future research is needed to comprehensively assess biotic and abiotic factors at various spatial scales aimed at mitigating WOM.
]]>Forests doi: 10.3390/f15101808
Authors: Fernanda Borges de Lima Álvaro Nogueira de Souza Eraldo Aparecido Trondoli Matricardi Luiz Moreira Coelho Júnior Ingrid Borges de Lima Agadir Jhonatan Mosmann Cleria Regina do Nascimento Mossmann Cláudio Júnior Oliveira Gomes
This study aimed to assess the financial viability of forest concessions in the state of Pará, Brazil. Two Forest Management Units (FMUs) were analyzed: FMU-2, located in Saracá-Taquera National Forest, and FMU-3, located in Caxiuanã National Forest. Financial indicators were evaluated under different timber productivity scenarios (20 m3/ha and 25.8 m3/ha). At a logging intensity of 20 m3/ha, FMU-2 was not financially viable. However, both FMUs were financially viable at 25.8 m3/ha. Sensitivity analysis demonstrated that FMU-2 requires a logging intensity of over 22 m3/ha and a sawmill yield efficiency of at least 45%. The ideal cost for sawn wood would be USD 226.53/m3, with royalties of USD 16.00/m3. FMU-3 consistently demonstrated positive financial results, despite fluctuations in production costs. The financial viability of investing in forest concessions in state of Pará depends largely on forest productivity, sawmill yield, royalties, and sawn wood costs.
]]>Forests doi: 10.3390/f15101807
Authors: Lixia He Yang Yang Junjun Ma Boxuan Yuan Fengyan Fang Juanying Wang Mei Wang Aifang Li Jinxian Chen Shugang Hui Xuchu Wang
Natural rubber is a crucial industrial material, and it is primarily harvested from the latex of the rubber tree Hevea brasiliensis by tapping the tree trunk. During the regular tapping process, mechanical damage seriously affects latex reproduction and rubber yield, but the molecular mechanisms on tapping stimulation remain unclear. In this study, we firstly determined the changed physiological markers on latex regeneration, overall latex yield, and latex flow time during the tapping process. Then, we combined proteomics and transcriptomics analyses of latex during tapping and identified 3940 differentially expressed genes (DEGs) and 193 differentially expressed proteins (DEPs). Among them, 773 DEGs and 120 DEPs displayed a persistent upregulation trend upon tapping. It is interesting that, in the detected transcription factors, basic helix-loop-helix (bHLH) family members occupied the highest proportion among all DEGs, and this trend was similarly observed in DEPs. Notably, 48 genes and 34 proteins related to natural rubber biosynthesis were identified, and most members of small rubber particle protein (SRPP) and rubber elongation factor (REF) showed a positive response to tapping stimulation. Among them, SRPP6 and REF5 showed significant and sustained upregulation at the gene and protein levels following tapping, indicating their pivotal roles for post-tapping rubber biosynthesis. Our results deepen the comprehension of the regulation mechanism underlying tapping and provide candidate genes and proteins for improving latex production in the Hevea rubber tree in future.
]]>Forests doi: 10.3390/f15101806
Authors: Xue Wei Hua Li Wenhui Chen
Forests provide goods and services while maintaining ecological security. However, the market does not adequately reflect their economic benefits, posing a significant challenge to the Payments for Forest Ecosystem Services (PFES). The involvement of multiple stakeholders with varying responsibilities and interests complicates collaboration and hinders effective governance. This study proposes an integrated approach using stakeholder analysis, social network analysis, and evolutionary game analysis to explore the collaborative governance of stakeholders in PFES. Through field surveys, the study empirically investigates PFES in China, demonstrating the effectiveness of this integrated approach. The results indicate the following: (i) Stakeholders are classified into three categories; the key stakeholders include the central and local governments, forest managers, and paying users. (ii) Stakeholders still need to strengthen collaboration. Local governments, forest managers, their employees, and communities exert widespread influence; paying users and research institutions have high efficiency in resource sharing. (iii) Five evolutionarily stable strategies are observed at different stages. Government intervention is crucial for changing the stagnant state. Benefits and government incentives have a positive impact on stakeholder collaborative governance. The research findings offer theoretical insights to enhance stakeholder collaboration and promote the development of the PFES. Key strategies include addressing key stakeholders’ needs, diversifying incentives, and establishing an accessible information platform.
]]>Forests doi: 10.3390/f15101805
Authors: Sotirios J. Trigkas Nikoleta Eleftheriadou Maria C. Boukouvala Anna Skourti Maria Koukouli Nickolas G. Kavallieratos
The European spongy moth, Lymantria dispar dispar (L.) (Lepidoptera: Erebidae), originating from Eurasia, is found in Europe, Africa, and North America. Its polyphagous larvae infest deciduous and coniferous trees, causing severe damage during mass outbreak years. Thus, it is listed as one of the top 100 invasive alien species worldwide. The management and containment of this pest vary significantly between Europe and North America, with North America exhibiting a more robust response regarding the containment of the outbreaks. This study evaluates the current state of the European Union (EU-27) forests’ legal, political and cooperative protection frameworks concerning L. dispar dispar. We identified active and potential new stakeholders to assess the level of national and international collaboration in forest protection. We conducted a SWOT analysis to propose new strategies and solutions, aiming for enhanced cooperation in protecting EU forests from L. dispar dispar outbreaks. Our findings highlight the potential of new monitoring and reporting technologies and the importance of increased social and political awareness through social media and public campaigns. These measures would enable more centralized and coordinated efforts among member states. A few of the most significant results in each category of SWOT analysis are as follows: for strengths, a well-established network of EU and national stakeholders exists; for opportunities, emerging innovative technologies, such as IoT, AI, and 5G, are transforming our approach to forest protection; for weaknesses, there is a lack of informed choices regarding proactive measures to contain the outbreak due to a lack of centralized EU coordination and the inefficiencies of national state policies. Finally, the numerous threats to the well-being of EU forests competing for the attention of institutions and relevant stakeholders is by far one of the most important parameters regarding the threats to the EU’s forest protection. The study advocates for a unified, technologically advanced approach to manage and mitigate L. dispar dispar impacts in European forests, emphasizing the need for strengthened international cooperation and the strategic implementation of innovative solutions.
]]>Forests doi: 10.3390/f15101804
Authors: Alexandro Dias Martins Vasconcelos Jéssica Cristina Barbosa Ferreira Rennan Oliveira Meira Inaê Mariê de Araújo Silva-Cardoso Joane dos Santos Neves Anderson Marcos de Souza André Luís Xavier de Souza Jonny Everson Scherwinski-Pereira
The palm Euterpe precatoria holds great social, cultural, and environmental importance. The heart of palm and the fruit are the main products used for industrialization due to their energetic properties. Thus, the aim of this study was to establish a suspension cultivation protocol for the species using different explant sources. For this, eight lineages of E. precatoria embryogenic calluses were tested, with five in liquid medium Murashige and Skoog (MS) with 5 μM Picloram and three for comparison in semisolid medium MS with 20 μM Picloram and 5 μM 2iP. The growth curve was obtained by weighing the calli from 60 to 180 days of cultivation. The Gompertz model was applied, and growth kinetics were evaluated. At 100 days, the contents of total soluble sugars (TSSs) and total soluble proteins (TSPs) were determined. Principal components (PCA) were measured. According to the analysis of the data, the cultivation of E. precatoria lineages in liquid medium was successfully carried out, and the establishment was achieved. The model can be considered adequate since the R2 values found describe more than 90% of the growth kinetics of the lineages. In the liquid system, lineages L1 (from leaf explants and multiplied in semisolid medium—SM), L2 (from leaf explants and multiplied in SM), and L6 (from zygotic embryo explants and multiplied in liquid medium—LM) showed the shortest time to double the biomass accumulation. Multivariate analysis reveals a significant increase in masses in liquid cultures, represented by lineages L6 and L2. There was statistical difference in the amount of TSSs extracted; the highest TSS levels were observed in lineages cultivated in LM. The protein content found was very low, showing statistical differences among the lineages. In this work, the establishment and multiplication of embryogenic calli of E. precatoria are described for the first time, and they emerge as viable alternatives for the vegetative propagation of the species.
]]>Forests doi: 10.3390/f15101803
Authors: Li Wang Xueyan Zhao Guoyu Liu Qing Wang Fangyuan Wang Yan Li
Leaf-trait variation has traditionally been focused on both within and among species along environmental gradients, while leaf age has received less attention. By measuring leaf morphological, stomatal, and stoichiometric traits of 40 coexisting woody species in temperate forest in northern China, we analyzed their variation pattern and the correlations among different plant life forms and leaf age. We found that leaf age has significant effects on leaf functional traits. The young leaves of both shrub and tree species revealed a lower stoma density (SD) and a higher stoma length (SL), stoma width (SW), and leaf N content (LNC) than mature leaves. Shrub species have a higher SLA and SD than tree species for both young and mature leaves. The traits of young leaves generally revealed a higher variation than those of mature leaves. Although correlations between traits are similar between young leaves and mature leaves, the slopes of the SLA–SD and SD–LNC relationships were significantly affected by leaf age. These findings elucidate the adaptive changes of leaf traits during leaf maturation and underscore the trade-off between stomatal safety and efficiency, as well as the trade-off between leaf hydraulic and economic traits in temperate woody species during leaf development. We conclude that variation in leaf traits with age may play a potentially important role in understanding the ecological function of woody species in temperate forests.
]]>Forests doi: 10.3390/f15101802
Authors: Angela Balzano Maks Merela Veronica de Micco
Wood, a natural lignocellulosic polymer, plays several important roles in trees, including water conduction, structural support, and nutrient storage [...]
]]>Forests doi: 10.3390/f15101801
Authors: Tiantian Zhu Qinghe Li
Background: The restoration of the degraded sandy grasslands in Hulun Buir is crucial for maintaining the local ecological balance and sustainable development. Caragana microphylla Lam., a shrub species widely employed in the restoration of sandy vegetation. It is essential to understand its impact on the understory vegetation and soil properties during this process. Methods: This study employed ANOVA, Pearson correlation, and redundancy analysis to systematically analyze the impact of C. microphylla on the three critical stages of desertified grassland vegetation recovery: semi-fixed dunes, fixed dunes, and sandy grasslands. It provided strategies for the restoration of desertified grassland vegetation and offered additional theoretical evidence for the role of vegetation in promoting the recovery of sandy lands. Results: (1) As the degree of vegetation recovery in desertified grasslands increases, the species richness of understory vegetation, Shannon–Wiener index, community height, and biomass also increase. Both the community height and biomass within shrublands are higher than outside, with species richness within the shrublands being higher than outside during the semi-fixed and fixed-sand land stages. (2) In both the 0~10 cm and 10~20 cm soil layers, soil water content showed an increasing trend, peaking in the sandy grassland stage (1.2%), and was higher within the shrublands than outside. The soil water content at 10~20 cm was higher than in the 0~10 cm layer. In both layers, clay and silt content gradually increased with the degree of vegetation recovery in the sandy land, and higher within the shrublands than outside, while the opposite was true for sand content. (3) In both soil layers, soil organic carbon gradually increased with the degree of vegetation recovery, peaking in the sandy grassland stage (4.12 g·kg−1), and was higher within the shrublands than outside. Total nitrogen increased from the semi-fixed-sand land stage to the fixed-sand land stage, with higher levels within the shrublands than outside at all stages. Soil pH within the shrublands decreased as the degree of vegetation recovery increased. There was no significant change in the total phosphorus content. (4) In both soil layers, soil physicochemical characteristics accounted for 59.6% and 46.9% of the vegetation changes within and outside the shrublands, respectively, with the main influencing factors being the soil particle size, total nitrogen, soil water content, and soil organic carbon. Conclusions: In the process of sandy grassland restoration, C. microphylla facilitates the growth and development of vegetation by enhancing the underlying soil physicochemical properties, specifically regarding the soil particle size distribution, soil water content, soil organic carbon, and total nitrogen.
]]>Forests doi: 10.3390/f15101800
Authors: Jiaxing Guo Huadong Xu Yan Zhong Kuanjie Yu
Accurately measuring the moisture content (MC) of square timber is crucial for ensuring the quality and performance of wood products in wood processing. Traditional MC detection methods have certain limitations. Therefore, this study developed a one-dimensional convolutional neural network (1D-CNN) model based on the first 8 nanoseconds of ground-penetrating radar (GPR) signals to predict the MC of square timber. The study found that the mixed-species model exhibited effective predictive performance (R2 = 0.9864, RMSE = 0.0393) across the tree species red spruce, Dahurian larch, European white birch, and Manchurian ash (MC range 0%–133.1%), while single-species models showed even higher accuracy (R2 ≥ 0.9876, RMSE ≤ 0.0358). Additionally, the 1D-CNN model outperformed other algorithms in automatically capturing complex patterns in GPR full-waveform amplitude data. Moreover, the algorithms based on full-waveform amplitude data demonstrated significant advantages in detecting wood MC compared to those based on a traditional time–frequency feature parameter. These results indicate that the 1D-CNN model can be used to optimize the drying process and detect the MC of load-bearing timber in construction and bridge engineering. Future work will focus on expanding the dataset, further optimizing the algorithm, and validating the models in industrial applications to enhance their reliability and applicability.
]]>Forests doi: 10.3390/f15101799
Authors: Chunxian Tang Xiandie Jiang Guiying Li Dengsheng Lu
Eucalyptus plantations with fast growth and short rotation play an important role in improving economic conditions for local farmers and governments. It is necessary to map and update eucalyptus distribution in a timely manner, but to date, there is a lack of suitable approaches for quickly mapping its spatial distribution in a large area. This research aims to develop a uniform procedure to map eucalyptus distribution at a regional scale using the Sentinel-2 imagery on the Google Earth Engine (GEE) platform. Different seasonal Senstinel-2 images were first examined, and key vegetation indices from the selected seasonal images were identified using random forest and Pearson correlation analysis. The selected key vegetation indices were then normalized and summed to produce new indices for mapping eucalyptus distribution based on the calculated best cutoff values using the ROC (Receiver Operating Characteristic) curve. The uniform procedure was tested in both experimental and test sites and then applied to the entire Fujian Province. The results indicated that the best season to distinguish eucalyptus forests from other forest types was winter. The composite indices for eucalyptus–coniferous forest separation (CIEC) and for eucalyptus–broadleaf forest separation (CIEB), which were synthesized from the enhanced vegetation index (EVI), plant senescing reflectance index (PSRI), shortwave infrared water stress index (SIWSI), and MERIS terrestrial chlorophyll index (MTCI), can effectively differentiate eucalyptus from other forest types. The proposed procedure with the best cutoff values (0.58 for CIEC and 1.29 for CIEB) achieved accuracies of above 90% in all study sites. The eucalyptus classification accuracies in Fujian Province, with a producer’s accuracy of 91%, user’s accuracy of 97%, and overall accuracy of 94%, demonstrate the strong robustness and transferability of this proposed procedure. This research provided a new insight into quickly mapping eucalyptus distribution in subtropical regions. However, more research is still needed to explore the robustness and transferability of this proposed method in tropical regions or in other subtropical regions with different environmental conditions.
]]>Forests doi: 10.3390/f15101798
Authors: Yin Wu Ziyang Hou Yanyi Liu Wenbo Liu
Leaf moisture content (LMC) directly affects the life activities of plants and becomes a key factor to evaluate the growth status of plants. To explore a low-cost, real-time, rapid, and accurate method for LMC detection, this paper employs Ultra-High-Frequency Radio-Frequency Identification (UHF RFID) sensor technology. By reading the tag information attached to the back of leaves, the parameters of the RSSI, phase, and reading distance of the tags are collected. In this paper, we propose an enhanced Multi-Feature Fusion algorithm based on Hyperdimensional Computing (HDC) called MFFHDC. In our proposed method, the real-valued features are encoded into hypervectors and then combined with Multi-Linear Discriminant Analysis (MLDA) for the feature fusion of different features. Finally, a retraining method based on Cosine Annealing with Warm Restarts (CAWR) is proposed to improve the model and further enhance its accuracy. Tests conducted in the experimental forest show that the proposed mechanism can effectively predict the LMC. The model’s Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and Coefficient of Determination (R2) reached 0.0195, 0.0255, and 0.9131, respectively. Additionally, comparisons with other methods demonstrate that the presented system performs excellently in most aspects. As a lightweight model, this study shows great practical application value, particularly for the limited data volume and low hardware costs.
]]>Forests doi: 10.3390/f15101797
Authors: Siyuan Zou Jiawei Zhang Xiaodong Wu Liquan Song Qilong Liu Ruifeng Xie Shuying Zang
Understanding the stability of soil organic matter (SOM) is essential for making accurate predictions regarding carbon release rates. However, there is limited information on the role of chemical composition of dissolved organic matter (DOM) in SOM stability. To address this gap, the peatland soil profile in the discontinuous frozen soil region of Northeast China was selected as the focus of this research, and a comprehensive analysis was conducted on the differences between the molecular composition of DOM and the stability of SOM. The results indicate a significant carbon accumulation phenomenon near the permafrost table. Through analyses using TG-50, δ13C, and δ15N, it was determined that SOM near the permafrost table exhibits high stability, whereas SOM within the permafrost layer demonstrates poor stability. Investigations utilizing UV-vis, 3D-EEM, FT-IR, and 1H-NMR technologies revealed that DOM near the permafrost table is of high quality and highly aromatic. Furthermore, compared to near the permafrost table, humic acid materials in the permafrost layer decreased by 17%, while protein materials increased by 17%. These findings offer a novel perspective on the understanding of SOM stability in peatland soil profiles within discontinuous permafrost regions.
]]>Forests doi: 10.3390/f15101796
Authors: Lucas Clay Marzieh Motallebi Thomas L. O’Halloran
As climate change intensifies, the need to conserve ecosystem services and our natural resources increases. Nature-based solutions projects that focus on sequestering carbon can also have significant impacts on the ecosystem services in the project area. Herein, we describe a method to quantify ecosystem services via the Integrated Valuation of Ecosystem Services and Tradeoffs (Version 3.14) model. We use those quantitative methods to show where carbon projects and other restoration projects could increase certain ecosystem services through best practices. Using the Edisto River Basin in South Carolina as a study site, we developed a spatial additionality model that shows where water retention, carbon, and sediment retention can be improved. InVEST modeling showed high levels of sediment export and water yield, with 0.12 tons/acre of sediment exported and 256.3 cm/acre of water yielded downstream on average. The model indicates that over 70,000 acres comprised of parcels greater than 20 contiguous acres could implement management to increase ecosystem service provisioning. This model output shows spatially where best management practices can be implemented to achieve positive outcomes and where carbon projects could be implemented to derive additional co-benefits. Furthermore, it can be used as a tool for measurement and verification as data is updated.
]]>Forests doi: 10.3390/f15101795
Authors: Wenqin Bao Yongbao Shen Julian C. Verdonk
Tilia miqueliana is an endemic species belonging to the genus Tilia L. (Tiliaceae) in China, which is known for its fragrant flowers and nectar, but the dynamic changes in metabolites during its growth and development are still unclear. In this study, the metabolic profiles from T. miqueliana flowers at three developmental stages were detected by performing an ultra-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (UPLC-ESI-MS/MS)-based widely targeted metabolomic analysis. A total of 1138 metabolites were detected, with 288 Differentially Accumulated Metabolites (DAMs) determined, flavonoids accounting for the largest proportion. The trend analysis showed that DAMs present seven distinctive patterns, and subclass 5 obtained the largest amount with continuously increased relative content during flower development. The Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation and enrichment analysis of DAMs showed different overlap and variability in metabolic pathways, indicating different directions of flavonoids’ metabolic flux in the three developmental stages. A correlation network analysis further revealed five core metabolites that played essential roles in flavonoid biosynthesis. This research provides comprehensive insights into the exploitation and utilization of T. miqueliana as well as a scientific basis for phylogenetic studies of the genus Tilia.
]]>Forests doi: 10.3390/f15101794
Authors: Xinguo Zhang Qixiang Zhang
The smellscape of garden plants plays a crucial role in promoting human well-being. Despite this, empirical data on the specific effects of distinct stimulation methods on public health remain insufficient. The objective of this research is to investigate the influence of three distinct sensory modalities, olfactory, visual, and their combined effect, on both physiological and psychological reactions to a pine forest’s smellscape. A sample of 95 college students was selected, with data collected through both physiological and psychological measurements. The analysis focused on variables such as blood pressure (BP), pulse rate (P), pulse pressure (PP), skin conductance (SC), brainwave patterns (α, β), the odor emotion semantic differential (SD), and the State Anxiety Inventory (S-AI) scale. The results reveal that in the pine forest aroma environment, the central nervous system shows a compromise effect during olfactory–visual interaction, with greater autonomic nervous system (ANS) activation compared with either stimulus alone, suggesting cumulative effects. Psychologically, the influence of olfactory interaction on anxiety fell between that of visual and olfactory stimulation. Participants consistently reported that the combination of both the sight and scent of a pine forest was the most invigorating. Furthermore, research revealed that combining olfactory and visual stimuli led to a more profound amplification of positive environmental perceptions compared with when each sense was engaged individually. These findings lay the groundwork for understanding how garden plant aromas contribute to human well-being.
]]>Forests doi: 10.3390/f15101793
Authors: Xudong Lu Jianchao Guo Jiadong Chen Hui Wu Qin Zuo Yizhuang Chen Jinlin Lai Shaodong Liu Maoyuan Wang Peng Zhang Shi Qi
In rubber plantations, understory coverage is often disrupted by human activities, which increases the risk of soil erosion under intense rainfall typical of tropical islands. Evaluating the effectiveness of soil and water conservation measures (SWCMs) is crucial for effectively conserving subcanopy resources. This study focused on Hainan Island’s rubber plantations, where nine different SWCMs were implemented, and the runoff and sediment yield were monitored during the rainy season using runoff plots. Through correlation analysis, we identified the primary rainfall characteristic factors leading to soil and water loss on rubber plantation slopes. Path analysis was then used to quantify the impacts of these characteristic factors. The results showed that the SWCMs were significantly more effective in erosion reduction (68.55%) than in runoff reduction (58.95%). Of all the measures, comprehensive SWCMs proved most effective in controlling runoff (71.34%), followed by engineering SWCMs (62.03%) and biological SWCMs (43.51%). Comprehensive SWCMs were also found to be effective in erosion reduction, with a rate of 77.84%, surpassing engineering and biological SWCMs by 7.23% and 20.66%, respectively. Notably, the combination of narrow terraces, contour trenches, and grass planting was the most effective, achieving runoff-reduction rates of 80.94% and erosion-reduction rates of 85.27%. This combination is recommended as a primary prevention method. Rainfall and maximum 30-min intensity (I30) were identified as key variables affecting the efficacy of SWCMs, with rainfall positively correlating with runoff yield and I30 being more closely linked to sediment production. This study provides valuable insights for developing erosion control strategies for sloping garden lands in similar regions and lays theoretical foundations for future ecological restoration projects.
]]>Forests doi: 10.3390/f15101792
Authors: Fang Wang Baodong Cheng Minghua Tian Xiao Meng
China is the world’s largest importer of logs, possessing the scale to exert significant influence in the international market. This paper uses a fixed-effect variable coefficient Pricing-to-Market panel model to measure China’s market power in log import trade. It also utilizes the Almost Ideal Demand System model from an elasticity perspective to explore the market behavior characteristics of various source countries in China’s log import trade, thereby validating the mechanism of market power. The results indicate that: ① China’s main trading partners can be categorized into four groups according to their market power in the log import trade. Specifically, China holds superlative market power in log imports from Indonesia, Malaysia, and Myanmar; holds strong market power in log imports from Russia, the Democratic Republic of the Congo, and Mozambique; holds weak market power in log imports from Papua New Guinea, Equatorial Guinea, France, Germany, Australia, and New Zealand; and holds no market power in Japan, Cameroon, and the United States. ② As China’s expenditure on log imports increases, there is a tendency to purchase high-quality precious wood and a greater concern for the legality of market transactions. Consequently, China is anticipated to augment its imports from source countries with no or weak market power. ③ The simple price elasticity of log imports from each source country is negative. Source countries with stronger market power tend to increase prices to achieve higher total revenue, while those with weaker market power are more inclined to lower prices to achieve the same. ④ Log products from various source countries are complementary in the Chinese market, indicating that China’s substantial demand for logs relies on the simultaneous supply from multiple countries and diverse wood types. Based on the existence or absence of market power in China’s log import trade, this paper provides targeted insights into enhancing international market power and reducing trade losses.
]]>Forests doi: 10.3390/f15101791
Authors: Benas Šilinskas Edgaras Linkevičius Marius Aleinikovas Lina Beniušienė Mindaugas Škėma
Forest growth under changing environmental conditions has been a major concern worldwide. The estimations of forests’ growth trends may provide significant insight on changing the value of Norway spruce (Picea abies (L.) H. Karst.) forests. The purpose of this study was to estimate the growth dynamics of thinned and un-thinned spruce stands in Lithuania by assessing their standing volume, gross volume yield, and stand density. For this purpose, two pure Norway spruce sites, established in 1990 and 1992, were selected. The thinning treatment scheme for each trial, comprised of five distinct stand density variants and eight different yield parameters, were analysed for each plot. Control plots exhibited the smallest growth in diameter, whereas stands that had been thinned once at a young age displayed the largest diameter increment (peak—1.4 cm/year). An increasing trend in tree stem volume was registered in all thinning treatment plots. The greatest competition index was found in the control plots, indicating an exceptionally high competition (peak—4.6–5.1) between trees for growth space. The competition index was four times smaller (2.0) in the moderately thinned stand. Intensifying natural mortality rate and signs of growth stabilization in the control plots (un-thinned) cannot guarantee them the positions of the highest productivity and accumulated stand volume in the future compared with thinned spruce stands.
]]>Forests doi: 10.3390/f15101790
Authors: Marina Viorela Marcu Stelian Alexandru Borz
The performance of timber harvesting equipment is important for local operational planning and for making decisions on the way in which the forests should be opened up. However, there are many options used to extract timber, and there is a high variability in their performance. Forwarding is commonly used and became an attractive option for low-access forests. A controlled experiment was set up in this study to see how the configuration of the trails, characterized in terms of slope and surface condition, and the extraction direction (uphill or downhill) may affect the performance of forwarding operations. GNSS (Global Navigation Satellite System) data were collected at a rate of 5 s for five replications of moving empty downhill and uphill, respectively, on a dirt trail, measuring 250 m in length and having a slope of about 11%. The same experiment was run with the machine loaded at full capacity, then four replications with the machine loaded and unloaded moving downhill and uphill, respectively, were performed on a forest road resembling a rocky trail, which measured 390 in length and had a slope of about 4%. GNSS data were used to extract the moving speed for all the tested conditions with the aim to compute the cycle time, and the payload volume estimate was used to estimate efficiency, and productivity, depending on extraction distance in a range of 50 to 1000 m. For the first trail, statistical comparison tests indicated significant differences in the speed of uphill and downhill movement, for both empty and loaded conditions, whereas for the second trail, there were no significant differences in speed. In addition, on the second trail, the sustained speed was almost double. These were reflected sharply in the cycle time, efficiency, and productivity, depending on extraction distance and trail condition. These findings are important for decision making on local operational planning and forest opening up.
]]>Forests doi: 10.3390/f15101789
Authors: Valentyna Dyshko Ivan Ustskiy Piotr Borowik Tomasz Oszako
Pine stands affected by root and butt rot (Heterobasidion annosum s.l.) contain pines (Pinus sylvestris L.) that can survive for a long time without showing external symptoms of the disease (‘conditionally resistant’ refers to trees that survive without symptoms despite infection). The establishment of stands from the seeds of such trees can significantly increase the effectiveness of artificial afforestation. Since the growth and development of pine trees is determined to a certain extent by the number of cotyledons after seed germination, this article examines this trait in the progeny of trees that are potentially resistant and those that have already been attacked by root pathogens. The number of cotyledons and the resilience of trees is fascinating and not generally known. Presumably, the number of cotyledons can be linked to disease resistance based on increased vigour. Biologically, a larger area for carbon assimilation leads to better photosynthetic efficiency and the production of more assimilates (sugars) necessary to trigger defence processes in the event of infection. From an ecological point of view, this can give tree populations in areas potentially threatened by root system diseases a chance of survival. The aim of this study was to analyze the potential of using the number of cotyledons and other seedling characteristics to predict the resistance of trees to root and butt rot disease. The collected data show that the seedlings from the group of diseased trees exhibited lower growth rates and vigour. However, the seedlings from the group of potentially resistant trees are similar to the control, meaning the trees that show no disease symptoms because they have not come into contact with the pathogen. Our observations suggest that monitoring germinating cotyledons could serve as an early diagnostic tool to identify disease-resistant pines, although further research is needed.
]]>Forests doi: 10.3390/f15101788
Authors: Di Dong Qing Gao Huamei Huang
Mangroves are one of the world’s most productive and ecologically important ecosystems, and they are threatened by the widespread invasion of Spartina alterniflora Loisel in China. As few studies have examined the spatial pattern differences of S. alterniflora invasion and the nearby mangroves in different latitudes, we chose the Zhangjiang Estuary and the Dandou Sea, two representative mangrove–salt marsh ecotones in the north and south of the Tropic of Cancer, as the study areas for comparison. The object-based image analysis and visual interpretation methods were combined to construct fine-scale mangrove and S. alterniflora maps using high-resolution satellite imagery from 2005 to 2019. We applied spatial analysis, centroid migration, and landscape indexes to analyze the spatio–temporal distribution changes of mangroves and S. alterniflora in these two ecotones over time. We used the landscape expansion index to investigate the S. alterniflora invasion process and expansion patterns. The annual change rates of mangrove and S. alterniflora areas in the Zhangjiang Estuary showed a continuous growth trend. However, the mangrove areas in the Dandou Sea showed a fluctuating trend of increasing, decreasing, and then increasing again, while S. alterniflora areas kept rising from 2005 to 2019. Spartina alterniflora showed larger annual change rates compared with mangroves, indicating rapid S. alterniflora invasion in the intertidal zones. The opposite centroid migration directions of mangroves and S. alterniflora and the decreasing distances between the mangrove and S. alterniflora centroids indirectly revealed the fierce competition between mangroves and S. alterniflora for habitat resources. Both regions saw a decrease in mangrove patch integrality and connectivity. The integrality of mangrove patches in the Zhangjiang Estuary was always higher than those in the Dandou Sea. We observed the growth stage (2011–2014) and outbreak stage (2014–2019) of S. alterniflora expansion in the Zhangjiang Estuary and the outbreak stage (2005–2009) and plateau stage (2009–2019) of S. alterniflora expansion in the Dandou Sea. The expansion pattern of S. alterniflora varies in time and place. Since the expansion of S. alterniflora in the outbreak stage is rapid, with a large annual change rate, early warning of S. alterniflora invasion is quite important for the efficient and economical removal of the invasive plant. Continuous and accurate monitoring of S. alterniflora is highly necessary and beneficial for the scientific management and sustainable development of coastal wetlands.
]]>Forests doi: 10.3390/f15101787
Authors: Binhao Liu Wenyuan Liao Tianyu Zhang Yue Yu Bihui Dai Dewen Liu Shaozhi Chen Bingjin Li
Bamboo beams are often reinforced with built-in steel sections to enhance their strength and load-bearing capacity. In this paper, we studied the effect of different parameters, including the location of the hole, the hole size, and the thicknesses of the steel and bamboo, on the mechanical properties of reinforced beams. The damage patterns, deformation characteristics, and force-transfer mechanisms, as well as the mechanical properties of reinforced beams with different hole shapes, underwent non-linear finite element analysis. The damage sustained by the reinforced bamboo beam differed from that of the traditional bamboo beam; two diagonal points formed a plastic hinge, mainly during the process of shear damage to the hole. It was determined that the hole size and the thickness of the bamboo have the greatest influence on the mechanical properties of the reinforced beam. The damage characteristics of the composited beams with different holes are similar; the bearing capacity of reinforced beams with open square holes is reduced by 10%–25%compared with circular holes.
]]>Forests doi: 10.3390/f15101786
Authors: Simon Marks Christopher Surfleet Bwalya Malama
This study quantifies the transpiration of encroached lodgepole pine (Pinus contorta var. murryana (Grev. & Balf.) Engelm.) in a montane meadow using pre-restoration sap-flow measurements. Lodgepole pine transpiration and its response to environmental variables were examined in Rock Creek Meadow (RCM), Southern Cascade Range, CA, USA. Sap-flow data from lodgepole pines were scaled to the meadow using tree survey data and then validated with MODIS evapotranspiration estimates for the 2019 and 2020 growing seasons. A modified Jarvis–Stewart model calibrated to 2020 sap-flow data analyzed lodgepole pine transpiration’s correlation with solar radiation, air temperature, vapor pressure deficit, and soil volumetric water content. Model validation utilized 2021 growing season sap-flow data. Calibration and validation employed a Markov Chain Monte Carlo (MCMC) approach through the DREAM(ZS) algorithm with a generalized likelihood (GL) function, enabling parameter and total uncertainty assessment. The model’s scaling was compared with simple scaling estimates. Average lodgepole pine transpiration at RCM ranged between 220.6 ± 25.3 and 393.4 ± 45.7 mm for the campaign (mid-July 2019 to mid-August 2020) and 100.2 ± 11.5 to 178.8 ± 20.7 mm for the 2020 partial growing season (April to mid-August), akin to MODIS ET. The model aligned well with observed normalized sap-velocity during the 2020 growing season (RMSE = 0.087). However, sap-velocity, on average, was underpredicted by the model (PBIAS = −6.579%). Model validation mirrored calibration in performance metrics (RMSE = 0.1233; PBIAS = −2.873%). The 95% total predictive uncertainty confidence intervals generated by GL-DREAM(ZS) enveloped close to the theoretically expected 95% of total observations for the calibration (94.5%) and validation (81.8%) periods. The performance of the GL-DREAM(ZS) approach and uncertainty assessment in this study shows promise for future MJS model applications, and the model-derived 2020 transpiration estimates highlight the MJS model utility for scaling sap-flow measurements from individual trees to stands of trees.
]]>Forests doi: 10.3390/f15101784
Authors: Xingjian Dun Yuchen Liu Fengjie Lian Wentai Zhao Wei Su Wei Zhao Zhihao Tian Yanhui Qiao Peng Gao Zhenxiang Zhang
Forest gaps alter the environmental conditions of forest microclimates and significantly affect the biogeochemical cycle of forest ecosystems. This study examined how forest gaps and non-gap areas affect soil’s physical properties and eco-stoichiometric characteristics. Relevant theories and methods were employed to analyze the impact of forest gaps on nutrient cycling in Pinus densiflora Sieb. (PDS) and Robinia pseudoacacia L. (RPL) forests located in the Taishan Mountains. The results revealed that (1) forest gaps significantly enhanced the soil physical properties of PDS and RPL forests compared to non-gap areas (NPs). Notably, the bulk density of the soil decreased by 53%–12%, particularly in the surface layer (0–20 cm). Additionally, its non-capillary porosity increased by 44%–65%, while the clay and silt content rose by 39%–152% and 24%–130%, respectively. Conversely, the sand content decreased significantly, by 24%–32% (p < 0.05). (2) The contents of C, N, and P in the gap soil of PDS forests showed a significant increase compared to those in non-gap soil, with increases of 56%–131% for carbon, 107%–1523% for nitrogen, and 100%–155% for phosphorus. There was a significant drop of 10%–33% and 39%–41% in their C:N and C:P ratios, respectively (p < 0.05). The contents of C and P in the gap soil of the Robinia pseudo acacia L. Forest increased significantly, by 14%–22% and 34.4%–71%, respectively. Its C:P and N:P ratios significantly increased, by 14% to 404% and 11% to 41%, respectively (p < 0.05). (3) Compared with NPs, the forest gap significantly reduced the soil electrical conductivity and increased the soil pH. Additionally, compared to the soil at the gap’s edge, the surface soil in the gap’s center had noticeably higher concentrations of C, N, and P. (4) Key variables affecting the soil pH, silt content, bulk density, and overall porosity in forest gaps include the concentrations of carbon (C), nitrogen (N), and phosphorus (P) present and their ecological stoichiometric ratios. The findings showed that forest gaps had a considerable impact on the soil’s physical characteristics and ecological stoichiometry. They also had a high potential for providing nutrients, which might aid in the establishment of plantation plants.
]]>Forests doi: 10.3390/f15101785
Authors: Guolei Li Guohua Liu Changlai Liu
(1) Background: The genus Phyllostachys belongs to the subfamily Bambusoideae within the family Gramineae. Bamboos of this genus are distinguished by their remarkable genetic traits, including exceptional resistance to both cold and drought conditions. These species possess considerable economic, ecological, and aesthetic value, finding extensive use in forestry and landscape design across China. (2) Methods: This study employed Illumina’s second-generation sequencing technology to sequence the chloroplast genomes of eight Phyllostachys species, followed by their assembly and annotation. (3) Results: The chloroplast genomes of the genus exhibit a characteristic tetrad structure with an average sequence length of 139,699 bp and an average GC content of 38.9%. A total of 130 genes have been annotated across eight bamboo species, comprising 75 protein-coding genes, 28 tRNA genes, and four rRNA genes. Global alignment and nucleotide polymorphism analyses indicate that the chloroplast genome of Phyllostachys is highly conserved overall. The boundaries of the four chloroplast regions are relatively conserved and exhibit minimal differences. Among these regions, three coding region genes—atpH, trnQ-UUG, and petB—and five non-coding regions—rpl32-trnL-UAG, rpl14-rpl16, rpl22-rps19, rps12-clpP, and trnR-UCU-trnM-CAU—exhibit high polymorphism and can be used as potential hotspot areas for subsequent research. A total of 266 simple sequence repeat (SSR) loci were identified by SSR analysis in the chloroplast genomes of eight bamboo species; the largest number of mononucleotide repeats was 154, predominantly consisting of A/T. Codon bias in the chloroplast genomes of the eight bamboo species indicates a preference for codons ending with A and U. Additionally, the UUA codon, which encodes leucine (Leu), is positioned between codons encoding phenylalanine (Phe), lysine (Lys), leucine (Leu), serine (Ser), and tyrosine (Tyr), indicating certain differences among these species. (4) Conclusions: This study aims to offer novel insights into the population genetics, phylogenetic relationships, and evolutionary patterns of Phyllostachys.
]]>