Forests

20 pages, 1571 KiB

Open AccessArticle

Rubber-Based Agroforestry Ecosystems Enhance Soil Enzyme Activity but Exacerbate Microbial Nutrient Limitations

by Wenxian Xu, Yingying Zhang, Tahir Ashar, Yumiao Cao, Changgeng Kuang, Xinwei Guo, Rui Sun, Wenjie Liu, Zhixiang Wu and Qiu Yang

Forests 2024, 15(10), 1827; https://doi.org/10.3390/f15101827 (registering DOI) - 19 Oct 2024

Abstract

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 [...] Read more.

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 (EEA_C), nitrogen (N)-acquiring enzyme (EEA_N), and phosphorus (P)-acquiring enzyme (EEA_P) 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. Full article

(This article belongs to the Special Issue Stress Resistance of Rubber Trees: From Genetics to Ecosystem, 2nd Edition)

22 pages, 2472 KiB

Open AccessArticle

DASR-Net: Land Cover Classification Methods for Hybrid Multiattention Multispectral High Spectral Resolution Remote Sensing Imagery

by Xuyang Li, Xiangsuo Fan, Jinlong Fan, Qi Li, Yuan Gao and Xueqiang Zhao

Forests 2024, 15(10), 1826; https://doi.org/10.3390/f15101826 (registering DOI) - 19 Oct 2024

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Topic Challenges, Development and Frontiers of Smart Agriculture and Forestry—2nd Volume)

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19 pages, 9049 KiB

Open AccessArticle

Spatiotemporal Evolution and Driving Factors of Land Use Carbon Emissions in Jiangxi Province, China

by Fangyun Dai, Mingjin Zhan, Xingjuan Chen, Xiaoling Yang and Ping Ouyang

Forests 2024, 15(10), 1825; https://doi.org/10.3390/f15101825 (registering DOI) - 19 Oct 2024

Abstract

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, [...] Read more.

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. Full article

(This article belongs to the Topic Forest Carbon Sequestration and Climate Change Mitigation)

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27 pages, 17698 KiB

Open AccessArticle

Multi-Scenario Simulation of Land Use and Assessment of Carbon Stocks in Terrestrial Ecosystems Based on SD-PLUS-InVEST Coupled Modeling in Nanjing City

by Qingyun Xu and Kongqing Li

Forests 2024, 15(10), 1824; https://doi.org/10.3390/f15101824 (registering DOI) - 18 Oct 2024

Viewed by 295

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Topic Climate Change and Environmental Sustainability, 3rd Volume)

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23 pages, 12865 KiB

Open AccessArticle

FGYOLO: An Integrated Feature Enhancement Lightweight Unmanned Aerial Vehicle Forest Fire Detection Framework Based on YOLOv8n

by Yangyang Zheng, Fazhan Tao, Zhengyang Gao and Jingyan Li

Forests 2024, 15(10), 1823; https://doi.org/10.3390/f15101823 - 18 Oct 2024

Viewed by 160

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Wildfire Monitoring and Risk Management in Forests)

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14 pages, 6742 KiB

Open AccessArticle

Exploring Functional Gene XsPDAT1’s Involvement in Xanthoceras sorbifolium Oil Synthesis and Its Acclimation to Cold Stress

by Juan Wang, Hongqian Ren, Zetao Shi, Fesobi Olumide Phillip, Sisi Liu, Weiyang Zhang, Xingqiang Wang, Xueping Bao and Jinping Guo

Forests 2024, 15(10), 1822; https://doi.org/10.3390/f15101822 - 18 Oct 2024

Viewed by 200

Abstract

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, [...] Read more.

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. Full article

(This article belongs to the Special Issue Abiotic and Biotic Stress Responses in Trees Species)

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20 pages, 16040 KiB

Open AccessArticle

Unveiling Anomalies in Terrain Elevation Products from Spaceborne Full-Waveform LiDAR over Forested Areas

by 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 and Felix Morsdorf

Forests 2024, 15(10), 1821; https://doi.org/10.3390/f15101821 - 17 Oct 2024

Viewed by 255

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Methodology and Theory of Forest Parameters Estimation Using Multi-Source Remote Sensing)

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16 pages, 3442 KiB

Open AccessArticle

Parameter Estimations on Measurement Accuracy for Thermal Conductivity of Wood Using the Transient Plane Source Method

by Hongxu Meng, Xinxin Yu, Bonan Chen, Pengyuan Ren and Jingyao Zhao

Forests 2024, 15(10), 1820; https://doi.org/10.3390/f15101820 - 17 Oct 2024

Viewed by 229

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Wood Properties: Measurement, Modeling, and Future Needs)

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16 pages, 4303 KiB

Open AccessArticle

Evaluation of Carbon Sequestration and Oxygen-Release Potential of Six Mulberry Tree Varieties During Summer

by Kaixin Zhang, Yujie Yang, Zeyang Zhai, Yao Fang, Meiyu He, Jialing Cheng, Yue Tian, Xu Cao and Li Liu

Forests 2024, 15(10), 1819; https://doi.org/10.3390/f15101819 - 17 Oct 2024

Viewed by 271

Abstract

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 [...] Read more.

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 (W_CO₂), oxygen release per unit leaf area (W_O₂), carbon sequestration per unit land area (P_CO₂), and oxygen release per unit land area (P_O₂). Zhongsang 1302 showed the greatest potential for CSOR among the six mulberry varieties. The P_CO₂ 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 (P_N) 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. Full article

(This article belongs to the Section Forest Ecology and Management)

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29 pages, 11521 KiB

Open AccessArticle

Constructing a Future Green Space Ecological Network Based on Multi-Scenario Urban Expansion: A Case Study of Chengdu, Sichuan, China

by Yushu Luo, Yuan Zhou, Bei Li, Pengyao Li, Li Zhang and Shunbin Ning

Forests 2024, 15(10), 1818; https://doi.org/10.3390/f15101818 - 17 Oct 2024

Viewed by 235

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Urban Green Infrastructure and Urban Landscape Ecology)

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23 pages, 10567 KiB

Open AccessArticle

Landscape Dynamics, Succession, and Forecasts of Cunninghamia lanceolata in the Central Producing Regions of China

by Zejie Liu, Yongde Zhong, Zhao Chen, Juan Wei, Dali Li and Shuangquan Zhang

Forests 2024, 15(10), 1817; https://doi.org/10.3390/f15101817 - 17 Oct 2024

Viewed by 235

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)

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16 pages, 10129 KiB

Open AccessArticle

Study on the Effects of Temperature and Relative Humidity on the Hygroscopic Properties of Palm Leaf Manuscripts

by Wenjie Zhang, Shan Wang and Hong Guo

Forests 2024, 15(10), 1816; https://doi.org/10.3390/f15101816 - 17 Oct 2024

Viewed by 234

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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16 pages, 3910 KiB

Open AccessArticle

Soil Enzyme Activities and Microbial Nutrient Limitation of Various Temperate Forest Types in Northeastern China

by Ruihan Xiao, Beixing Duan, Changlei Dai and Yu Wu

Forests 2024, 15(10), 1815; https://doi.org/10.3390/f15101815 - 17 Oct 2024

Viewed by 289

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Forest Soil)

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19 pages, 13917 KiB

Open AccessArticle

TCSNet: A New Individual Tree Crown Segmentation Network from Unmanned Aerial Vehicle Images

by Yue Chi, Chenxi Wang, Zhulin Chen and Sheng Xu

Forests 2024, 15(10), 1814; https://doi.org/10.3390/f15101814 - 17 Oct 2024

Viewed by 232

Abstract

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. [...] Read more.

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. Full article

(This article belongs to the Special Issue Panoptic Segmentation of Tree Scenes from Mobile LiDAR Data)

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16 pages, 7141 KiB

Open AccessArticle

Tree-Ring-Based Hydroclimatic Variability in the Southeast Coastal Region of China

by Xinguang Cao, Pei-ken Kao, Yingjun Li, Zheng Zhao, Hongbing Hu, Jing Hu, Di Zhang and Keyan Fang

Forests 2024, 15(10), 1813; https://doi.org/10.3390/f15101813 - 17 Oct 2024

Viewed by 220

Abstract

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) [...] Read more.

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. Full article

(This article belongs to the Section Forest Hydrology)

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20 pages, 4862 KiB

Open AccessReview

Charting the Research Status for Bamboo Resources and Bamboo as a Sustainable Plastic Alternative: A Bibliometric Review

by Hanjiao Zhang, Xu Zhang, Yulong Ding, Feiyi Huang, Zhuoyu Cai and Shuyan Lin

Forests 2024, 15(10), 1812; https://doi.org/10.3390/f15101812 - 16 Oct 2024

Viewed by 311

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Forest Economics, Policy, and Social Science)

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16 pages, 6164 KiB

Open AccessArticle

Conserved Plastid Genomes of Pourthiaea Trees: Comparative Analyses and Phylogenetic Relationship

by Ting Ren, Chang Peng, Yuan Lu, Yun Jia and Bin Li

Forests 2024, 15(10), 1811; https://doi.org/10.3390/f15101811 - 16 Oct 2024

Viewed by 338

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Biodiversity in Forests: Management, Monitoring for Conservation)

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14 pages, 2787 KiB

Open AccessArticle

Differences in Soil CO₂ Efflux and Microbial Community Composition Among Slope Aspects in a Mountain Oak Forest

by Qing Shang and Yanchun Liu

Forests 2024, 15(10), 1810; https://doi.org/10.3390/f15101810 - 16 Oct 2024

Viewed by 440

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Topic Forest Carbon Sequestration and Climate Change Mitigation)

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20 pages, 3024 KiB

Open AccessArticle

Investigating the Spatial Pattern of White Oak (Quercus alba L.) Mortality Using Ripley’s K Function Across the Ten States of the Eastern US

by Saaruj Khadka, Hong S. He and Sougata Bardhan

Forests 2024, 15(10), 1809; https://doi.org/10.3390/f15101809 - 16 Oct 2024

Viewed by 419

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)

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13 pages, 768 KiB

Open AccessArticle

Determinants of Financial Viability of Forest Concession in Brazilian Amazon

by 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 and Cláudio Júnior Oliveira Gomes

Forests 2024, 15(10), 1808; https://doi.org/10.3390/f15101808 - 16 Oct 2024

Viewed by 247

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Economic and Policy Analysis in Sustainable Forest Management)

18 pages, 2920 KiB

Open AccessArticle

Transcriptomic and Proteomic Integration Reveals Key Tapping-Responsive Factors for Natural Rubber Biosynthesis in the Rubber Tree Hevea brasiliensis

by Lixia He, Yang Yang, Junjun Ma, Boxuan Yuan, Fengyan Fang, Juanying Wang, Mei Wang, Aifang Li, Jinxian Chen, Shugang Hui and Xuchu Wang

Forests 2024, 15(10), 1807; https://doi.org/10.3390/f15101807 - 16 Oct 2024

Viewed by 297

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Genetics and Molecular Biology)

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22 pages, 6101 KiB

Open AccessArticle

Collaborative Governance of Stakeholders in the Payment for Forest Ecosystem Services: An SA-SNA-EGA Approach

by Xue Wei, Hua Li and Wenhui Chen

Forests 2024, 15(10), 1806; https://doi.org/10.3390/f15101806 - 15 Oct 2024

Viewed by 357

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Forest Economics, Policy, and Social Science)

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17 pages, 779 KiB

Open AccessArticle

Exploring Opportunities and Challenges: SWOT Analysis for Advancing Smart Tech Solutions in Managing Lymantria dispar dispar Infestations in Forests of the European Union

by Sotirios J. Trigkas, Nikoleta Eleftheriadou, Maria C. Boukouvala, Anna Skourti, Maria Koukouli and Nickolas G. Kavallieratos

Forests 2024, 15(10), 1805; https://doi.org/10.3390/f15101805 - 15 Oct 2024

Viewed by 370

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Forest Economics, Policy, and Social Science)

25 pages, 10518 KiB

Open AccessArticle

Establishment, Multiplication, and Biochemical Analysis of Embryogenic Lines of the Amazonian Palm Euterpe precatoria Mart. under Suspension Culture

by 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 and Jonny Everson Scherwinski-Pereira

Forests 2024, 15(10), 1804; https://doi.org/10.3390/f15101804 - 15 Oct 2024

Viewed by 428

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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13 pages, 4005 KiB

Open AccessArticle

Changes in Leaf Functional Traits with Leaf Age for Coexisting Woody Species in Temperature Forest of Northern China

by Li Wang, Xueyan Zhao, Guoyu Liu, Qing Wang, Fangyuan Wang and Yan Li

Forests 2024, 15(10), 1803; https://doi.org/10.3390/f15101803 - 14 Oct 2024

Viewed by 349

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Forest Ecology and Management)

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5 pages, 640 KiB

Open AccessEditorial

Advances in Wood Anatomy: Cutting-Edge Techniques for Identifying Wood and Analyzing Its Structural Modifications

by Angela Balzano, Maks Merela and Veronica de Micco

Forests 2024, 15(10), 1802; https://doi.org/10.3390/f15101802 - 14 Oct 2024

Viewed by 633

Abstract

Wood, a natural lignocellulosic polymer, plays several important roles in trees, including water conduction, structural support, and nutrient storage [...] Full article

(This article belongs to the Special Issue Wood Anatomy and Evaluation of Wood Structures and Their Modifications)

14 pages, 8481 KiB

Open AccessArticle

Effect of Caragana microphylla Lam. on Desertified Grassland Restoration

by Tiantian Zhu and Qinghe Li

Forests 2024, 15(10), 1801; https://doi.org/10.3390/f15101801 - 14 Oct 2024

Viewed by 434

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Section Forest Soil)

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13 pages, 3778 KiB

Open AccessArticle

Preliminary Insights on Moisture Content Measurement in Square Timbers Using GPR Signals and 1D-CNN Models

by Jiaxing Guo, Huadong Xu, Yan Zhong and Kuanjie Yu

Forests 2024, 15(10), 1800; https://doi.org/10.3390/f15101800 - 14 Oct 2024

Viewed by 488

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Topic Ground Penetrating Radar (GPR) Techniques and Applications)

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17 pages, 5155 KiB

Open AccessArticle

Developing a New Method to Rapidly Map Eucalyptus Distribution in Subtropical Regions Using Sentinel-2 Imagery

by Chunxian Tang, Xiandie Jiang, Guiying Li and Dengsheng Lu

Forests 2024, 15(10), 1799; https://doi.org/10.3390/f15101799 - 13 Oct 2024

Viewed by 488

Abstract

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 [...] Read more.

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 (

{C I}_{E C}

) and for eucalyptus–broadleaf forest separation (

{C I}_{E B}

), 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

{C I}_{E C}

and 1.29 for

{C I}_{E B}

) 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. Full article

(This article belongs to the Special Issue Classification of Forest Tree Species Using Remote Sensing Technologies: Latest Advances and Improvements)

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Open AccessArticle

Leaf Moisture Content Detection Method Based on UHF RFID and Hyperdimensional Computing

by Yin Wu, Ziyang Hou, Yanyi Liu and Wenbo Liu

Forests 2024, 15(10), 1798; https://doi.org/10.3390/f15101798 - 13 Oct 2024

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Abstract

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) [...] Read more.

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. Full article

(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)

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Forests, Volume 15, Issue 10 (October 2024) – 149 articles

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