Forests

16 pages, 2076 KiB

Open AccessArticle

Divergent Effects of Monoculture and Mixed Plantation on the Trade-Off Between Soil Carbon and Phosphorus Contents in a Degraded Hilly Land

by Xiaojuan Gu, Zhihang He, Linyunhui Liu, Zhenyuan Zhang, Jiahui Wu and Qifeng Mo

Forests 2024, 15(12), 2255; https://doi.org/10.3390/f15122255 (registering DOI) - 22 Dec 2024

Abstract

Carbon (C) and phosphorus (P) in soil are closely related to plantation types in afforestation practices. However, the trade-off between soil C and P in response to different restoration patterns on degraded hilly land is still not clear. In this study, four restoration [...] Read more.

Carbon (C) and phosphorus (P) in soil are closely related to plantation types in afforestation practices. However, the trade-off between soil C and P in response to different restoration patterns on degraded hilly land is still not clear. In this study, four restoration patterns, including natural recovered shrubland (NS), Castanopsis hystrix plantation (CH), 10-species mixed plantation (10MX), and 30-species mixed plantation (30MX) were selected, and the physicochemical properties and readily oxidized carbon (ROC) in different layers of 1 m depth soil were measured to understand the effects of natural restoration and artificial afforestation on soil P and C pool and their trade-off on degraded hilly land in southern China. The results indicate that the total P (TP) content in each soil layer was observed to follow the order of CH > 10MX > 30MX > NS, with monoculture (CH) exhibiting higher levels of TP than mixed plantation. However, the soil C storage of NS (59.61 t hm⁻²) and 30MX (57.71 t hm⁻²) was similar, while that of 10MX boasted the highest C storage (64.99 t hm⁻²) of the four restoration patterns, with CH being the lowest (42.75 t hm⁻²). In deep soil layers (20–100 cm), the 10MX plantation presented the highest for both the C pool index (CPI) and C pool management index (CMI). Moreover, the structural equation model (SEM) revealed that the soil CMI was directly regulated by the levels of soil-available P and total N, while soil C pool activity was directly influenced by soil pH. Thus, our study suggests that compared to mixed plantations, the monoculture plantation (CH) demonstrates lower P uptake and utilization, resulting in a higher soil P content. Furthermore, 10MX plantation showed a superior C fixation capacity over those with 30MX and monoculture plantations. These suggests that the trade-off between soil C and P contents was commonly observed among different plantation restoration patterns. Therefore, afforestation with different tree composition and nutrient regulation is necessary for maintaining the balance between soil C and P and keeping the sustainability of plantation management in the degraded hilly lands. Full article

(This article belongs to the Special Issue Carbon, Nitrogen, and Phosphorus Storage and Cycling in Forest Soil)

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17 pages, 8450 KiB

Open AccessArticle

MaxEnt-Based Habitat Suitability Assessment for Vaccinium mandarinorum: Exploring Industrial Cultivation Opportunities

by Xuxu Bao, Peng Zhou, Min Zhang, Yanming Fang and Qiang Zhang

Forests 2024, 15(12), 2254; https://doi.org/10.3390/f15122254 (registering DOI) - 22 Dec 2024

Abstract

Vaccinium mandarinorum Diels, a wild blueberry species distributed in the south of the Yangtze River in China, holds significant ecological and commercial value. Understanding its potential distribution and response to climate change is crucial for effective resource utilization and scientific introduction. By using [...] Read more.

Vaccinium mandarinorum Diels, a wild blueberry species distributed in the south of the Yangtze River in China, holds significant ecological and commercial value. Understanding its potential distribution and response to climate change is crucial for effective resource utilization and scientific introduction. By using the Maximum Entropy (MaxEnt) model, we evaluated V. mandarinorum’s potential distribution under current (1970–2000) and future climate change scenarios (2041–2060, 2061–2080, and 2081–2100) based on 216 modern distribution records and seven bioclimatic variables. The results showed that the MaxEnt model could effectively simulate the historical distribution and suitability degree of V. mandarinorum. The top two major environmental variables were precipitation of the driest quarter and annual precipitation, considering their contribution rates of 61.3% and 23.4%, respectively. Currently, the high suitability areas were mainly concentrated in central and northern Jiangxi province, central and southern Zhejiang province, southern Anhui province, central and northern Fujian province, and the border areas of Hunan and Guangxi provinces, covering 21.5% of the total suitable area. Future projections indicate that habitat will shift to higher latitudes and altitudes and that habitat quality will decline. Strategies are required to protect current V. mandarinorum populations and their habitats. The study results could provide an important theoretical reference for the optimization of planting distribution and ensure the sustainable production of the blueberry industry. Full article

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

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19 pages, 2627 KiB

Open AccessArticle

How Does the Mulching Management of Phyllostachys Praecox Affect Soil Enzyme Activity and Microbial Nutrient Limitation in Karst Bamboo Forest Ecosystems?

by Long Tong, Lianghua Qi, Lijie Chen, Fengling Gan, Qingping Zeng, Hongyan Li, Bin Li, Yuan Liu, Ping Liu, Xiaoying Zeng, Lisha Jiang, Xiaohong Tan and Hailong Shi

Forests 2024, 15(12), 2253; https://doi.org/10.3390/f15122253 (registering DOI) - 22 Dec 2024

Abstract

Phyllostachys praecox is a valuable tree species in karst ecosystems, but improper mulching practices can worsen soil degradation. Understanding soil nutrient limitations is crucial for successful restoration and sustainable development. However, it remains unclear whether and how mulching management of Phyllostachys praecox affects [...] Read more.

Phyllostachys praecox is a valuable tree species in karst ecosystems, but improper mulching practices can worsen soil degradation. Understanding soil nutrient limitations is crucial for successful restoration and sustainable development. However, it remains unclear whether and how mulching management of Phyllostachys praecox affects soil enzyme stoichiometry and nutrient limitation in karst areas. Here, we conducted a field experiment in Chongqing karst bamboo forest ecosystems with four mulching treatments: 1-year (T1), 2-years (T2), 1-year and recovery and 1-year (T3), and no mulching (CK). We investigated the activities of the C-acquiring enzyme β-1,4-glucosidase (BG), N-acquiring enzymes L-leucine aminopeptidase (LAP) and β-1,4-N-acetylglucosaminidase (BNA), as well as P-acquiring enzyme phosphatase activity (AP), to assess the limitations of C, N or P and identify the main factors influencing soil microbial nutrient limitation. Compared with the CK treatment, both the T2 and T3 management treatments significantly increased the SOC, TN, MBC, and MBN. Furthermore, the soil enzyme stoichiometric ratio in the karst bamboo forests deviated from the global ecosystem ratio of 1:1:1. T1 > T3 > CK > T2 presented higher values of C/(C + N) and C/(C + P), with T1 having values that were 1.10 and 1.12 greater than those of T2, respectively. Additionally, there was a significant negative correlation between microbial C and N limitations and total nutrients, but a positive correlation with microbial biomass ratios. In conclusion, changes in mulching management of Phyllostachys praecox affect soil enzyme stoichiometry activities and their ratios by influencing total nutrients and microbial biomass ratios. This study suggests an alternate year cover pattern (mulching in one year and resting in the next) as a scientific management approach for bamboo forests, contributing to a better understanding of nutrient limitation mechanisms in karst bamboo forest ecosystems. Full article

(This article belongs to the Special Issue Carbon, Nitrogen, and Phosphorus Storage and Cycling in Forest Soil)

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20 pages, 8060 KiB

Open AccessArticle

The Wheel of Vegetation: A Spatial and Temporal Story of Vegetation Evolution in the Shennongjia Forest District

by Xueli Wang, Xiaolong Du, Chunyan Zhao, An Luo, Hui Chen, Shaobin Li and Hewei Du

Forests 2024, 15(12), 2252; https://doi.org/10.3390/f15122252 (registering DOI) - 22 Dec 2024

Abstract

As one of the most well-preserved areas in the vertical band spectrum of vegetation in central China and even in the northern hemisphere at the same latitude, the vegetation in Shennongjia Forest District is vital to global ecological balance. In order to fully [...] Read more.

As one of the most well-preserved areas in the vertical band spectrum of vegetation in central China and even in the northern hemisphere at the same latitude, the vegetation in Shennongjia Forest District is vital to global ecological balance. In order to fully understand the vegetation change in the study area, remotely sensed data since 1990, combined with the Sen-MK test, Geo detector, and LandTrendr algorithm, were used to analyze the vegetation distribution characteristics and change trends. The results showed that: (1) the overall NDVI in the study area displayed an upward trend. (2) Vegetation disturbance occurred frequently before 2000 and decreased significantly after 2000. The most severely disturbed year was 1991 when the disturbed area amounted to 4.0851 km², accounting for 16.76% of the total disturbed area. The analysis of the topographic environment reveals that most of the vegetation disturbances occur in areas with slopes of 15–25° and elevations of 1500–2000 m, which indicates that these areas have frequent human activity. (3) The explanatory power of different influences on vegetation changes varied, with altitude having the most significant effect and the superposition of two influences increasing the effect on vegetation change. Over the past 30 years, vegetation in the Shennongjia Forest District has shown a general trend of recovery, with natural forest protection initiatives playing a critical role in mitigating disturbance. This comprehensive study of vegetation changes in Shennongjia offers a valuable research paradigm for forest conservation and sustainable development in temperate forests at similar latitudes, providing significant insights into the protection and management of similar ecosystems. Full article

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

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26 pages, 8482 KiB

Open AccessArticle

Improving European Black Pine Stem Volume Prediction Using Machine Learning Models with Easily Accessible Field Measurements

by Maria J. Diamantopoulou and Aristeidis Georgakis

Forests 2024, 15(12), 2251; https://doi.org/10.3390/f15122251 (registering DOI) - 21 Dec 2024

Abstract

Reliable prediction of tree stem volume is crucial for effective forest management and ecological assessment. Traditionally, regression models have been applied to estimate forest biometric variables, yet they often fall short when handling the complex, non-linear patterns typical of biological data, potentially introducing [...] Read more.

Reliable prediction of tree stem volume is crucial for effective forest management and ecological assessment. Traditionally, regression models have been applied to estimate forest biometric variables, yet they often fall short when handling the complex, non-linear patterns typical of biological data, potentially introducing biases and errors. Tree stem volume, a critical metric in forest biometrics, is generally estimated through easily measured parameters such as diameter at breast height (d) and total tree height (h). This study investigates advanced machine learning (ML) techniques—Extreme Gradient Boosting (XGBoost), epsilon-Support Vector Regression (ε-SVR), and Random Forest regression (RFr)—to predict the stem volume of European black pine (Pinus nigra) on Mount Olympus, Greece, using basic field measurements. Machine learning (ML) approaches demonstrated substantial improvements in prediction accuracy compared to traditional non-linear regression-based models (RMs). Notably, XGBoost significantly enhanced predictive performance by reducing the Furnival index (FI) by as much as 42.3% (from 1.1859 to 0.1056) and 21.3% (from 0.1475 to 0.1161) in the test and fitting datasets, respectively, for the single-entry model. For the double-entry model, XGBoost achieved FI reductions of 40.5% (from 0.1136 to 0.0676) and 41.3% (from 0.1219 to 0.0715) in the test and fitting datasets, respectively. These findings highlight the potential of ML models to improve the accuracy of forest inventory predictions, thereby supporting more effective and data-driven forest management strategies. Full article

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

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15 pages, 2335 KiB

Open AccessArticle

Genetic Diversity and Structure of Higher-Resin Trees of Pinus oocarpa Schiede in Mexico: Implications for Genetic Improvement

by Miguel Ángel Vallejo-Reyna, Mario Valerio Velasco-García, Viridiana Aguilera-Martínez, Hilda Méndez-Sánchez, Liliana Muñoz-Gutiérrez, Martín Gómez-Cárdenas and Adán Hernández-Hernández

Forests 2024, 15(12), 2250; https://doi.org/10.3390/f15122250 (registering DOI) - 21 Dec 2024

Abstract

Pinus oocarpa Schiede is the most widely distributed conifer in the Americas. In Mexico, it inhabits diverse environments and is the primary pine species utilized for resin production, prompting the establishment of a genetic improvement program (GIP). Preserving a broad genetic diversity is [...] Read more.

Pinus oocarpa Schiede is the most widely distributed conifer in the Americas. In Mexico, it inhabits diverse environments and is the primary pine species utilized for resin production, prompting the establishment of a genetic improvement program (GIP). Preserving a broad genetic diversity is fundamental to the success of the GIP. This study aimed to assess the genetic diversity and structure of trees selected for their high resin yield. A total of 146 trees from 15 provenances within three populations (MX-MIC, MX-MEX, and MX-OAX) constituting the selection population of the GIP were evaluated. Five SSR microsatellite markers (PtTX3013, NZPR1078, PtTX2146, PtTX3107, and PtTX3034) were used to determine key indicators of genetic diversity and structure. All three populations exhibited high genetic diversity; however, the heterozygosity observed was lower than the expected heterozygosity. Genetic structure analysis revealed the presence of two distinct genetic groups: the Transverse Volcanic Axis (MX-MIC and MX-MEX) and the Sierra Madre del Sur (MX-OAX). Most of the genetic diversity (87.42%) was found within provenances. Gene flow was high among provenances within the same genetic group but limited between provenances from different groups. The findings suggest that GIPs should be tailored to each genetic region, with a focus on within-provenance selection to maintain genetic diversity. Full article

(This article belongs to the Special Issue Forest Tree Breeding, Testing, and Selection)

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18 pages, 5716 KiB

Open AccessArticle

Study on Novel Modified Phenolic Foams with Added Pine Wood Sawdust

by Jianwei Ling, Shiyu Lu, Shouqing Liu, Xuemei Li and Jianxiang Liu

Forests 2024, 15(12), 2249; https://doi.org/10.3390/f15122249 (registering DOI) - 20 Dec 2024

Abstract

The use of low-cost agricultural and forestry waste for the preparation of modified phenolic foam (MPF) has attracted widespread attention and has shown promising prospects. This study proposes a novel method for producing MPF using pine sawdust. The full components of pine wood [...] Read more.

The use of low-cost agricultural and forestry waste for the preparation of modified phenolic foam (MPF) has attracted widespread attention and has shown promising prospects. This study proposes a novel method for producing MPF using pine sawdust. The full components of pine wood powder and its liquefied products were used as raw materials, and the resin was modified with a silane coupling agent (KH560), triethylene glycol (TEG), and nylon 66 (PA66). Subsequently, three novel MPFs were successfully fabricated using a transplanted core foaming technique, and their material properties were subsequently investigated. The results showed that all three MPFs exhibited excellent compressive strength and flame retardancy, with compressive strength ranging from 5.93 MPa to 12.22 MPa and oxygen index values between 36.2% and 41.5%. In terms of water resistance, the MPFs significantly outperformed traditional phenolic foam (PF); in particular, the addition of 4% KH560 and PA66 reduced the water absorption rate to as low as 2.5%. Furthermore, the powdering rate and thermal conductivity of all MPFs were significantly reduced, with chalking rates decreasing by 28.57% to 50%. This research presents a novel method for preparing MPF using agroforestry waste as a partial replacement for phenol. This approach achieves high-value utilization of pine sawdust while maintaining the performance of the MPF, thus broadening the avenues for MPF production. Full article

(This article belongs to the Special Issue Advanced Research and Technology on Biomass Materials in Forestry)

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23 pages, 1358 KiB

Open AccessArticle

Multisilva: A Web-Based Decision Support System to Assess and Simulate the Provision of Forest Ecosystem Services at the Property Level

by Claudio Petucco, Laurent Chion, Jérémy Ludwig, Tomás Navarrete Gutiérrez, Benedetto Rugani and Jacek Stankiewicz

Forests 2024, 15(12), 2248; https://doi.org/10.3390/f15122248 (registering DOI) - 20 Dec 2024

Abstract

Forests provide a variety of ecosystem services (ESs) that contribute to a society’s wellbeing. ES provision depends on the structure and evolution of forest ecosystems and is influenced by forest management. Society’s increasing need for ESs requires these complex ecological dynamics to be [...] Read more.

Forests provide a variety of ecosystem services (ESs) that contribute to a society’s wellbeing. ES provision depends on the structure and evolution of forest ecosystems and is influenced by forest management. Society’s increasing need for ESs requires these complex ecological dynamics to be understood and integrated in forest management and planning. We present the decision support system (DSS) Multisilva for multifunctional forest management. The Multisilva DSS is a web-based application that comprises two tools: the Mapping tool and the Simulation tool. The first tool provides spatial statistics and maps of the current provision of ESs at the forest property level. The Simulation tool compares two alternative, user-defined management scenarios over time and returns the biophysical estimations of ESs and the economic costs for each alternative. Multisilva is calibrated for Luxembourg, though it can be adapted for other temperate forest regions. Full article

(This article belongs to the Special Issue Economy and Sustainability of Forest Natural Resources)

25 pages, 3083 KiB

Open AccessArticle

Classification Model of Site Quality for Mixed Forests Based on the TWINSPAN Method and Site Form in Southwestern Zhejiang

by Ruoyun Wu, Chen Dong, Chengwei Zhang, Weifang Gao, Xinyu Zheng and Xiongwei Lou

Forests 2024, 15(12), 2247; https://doi.org/10.3390/f15122247 (registering DOI) - 20 Dec 2024

Abstract

The evaluation of site quality for mixed forests is a comprehensive approach to analyzing forest site conditions and tree species growth performance. Accurate site quality assessment is crucial for understanding and enhancing the ecological functions and productivity potential of forests. This study focuses [...] Read more.

The evaluation of site quality for mixed forests is a comprehensive approach to analyzing forest site conditions and tree species growth performance. Accurate site quality assessment is crucial for understanding and enhancing the ecological functions and productivity potential of forests. This study focuses on mixed forests in Lishui City, Zhejiang Province. Using the Two-way Indicator Species Analysis (TWINSPAN) method, coniferous mixed forest, broadleaved mixed forest, and mixed coniferous–broadleaved forests in the region were classified into 15 forest types. Site form models for each type were then constructed using the Algebraic Difference Approach (ADA) to categorize site quality levels. Subsequently, a site quality classification model was developed by integrating site and climatic factors, employing four machine learning algorithms: Random Forest (RF), K-Nearest Neighbors (KNN), Support Vector Machine (SVM), and XGBoost. This model effectively facilitated the evaluation of site quality in mixed forests. The results showed that, across the 15 forest types, the site form models based on the ADA method achieved R² values greater than 0.634, indicating accuracy in capturing tree height growth trends in mixed forests. For site quality classification, all four models (RF, KNN, SVM, and XGBoost) achieved overall accuracies above 0.77. Among these, the machine learning models ranked in effectiveness for site quality classification as follows: XGBoost > RF > SVM > KNN. These findings suggest that the site form model is a suitable criterion for classifying site quality in mixed forests in Lishui City, Zhejiang Province, and that the XGBoost-based model demonstrates strong classification accuracy. This study provides a scientific basis for site-adapted tree selection and advances information on mixed forest management. Full article

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

15 pages, 1002 KiB

Open AccessArticle

Is the Concentric Plot Design Reliable for Estimating Structural Parameters of Forest Stands?

by Martin Kománek, Robert Knott, Jan Kadavý and Michal Kneifl

Forests 2024, 15(12), 2246; https://doi.org/10.3390/f15122246 (registering DOI) - 20 Dec 2024

Abstract

Monitoring forest stands using sampling techniques offers a valuable alternative to conventional forest condition assessment methods in Central Europe. While these designs are optimized for assessing production parameters, their effectiveness for structural characteristics remains unclear. This study evaluates various plot designs to determine [...] Read more.

Monitoring forest stands using sampling techniques offers a valuable alternative to conventional forest condition assessment methods in Central Europe. While these designs are optimized for assessing production parameters, their effectiveness for structural characteristics remains unclear. This study evaluates various plot designs to determine their reliability in estimating structural diversity indices, including the Gini index, Artenprofile index, and Shannon index. We compared ten fixed-radius (FR) sampling designs (plot sizes: 50–1250 m²) and a concentric circle (CC) design (500 m²) employed at the Mendel University Forest Enterprise (Křtiny, Czech Republic). The CC design proved adequate for assessing production parameters and structural diversity indices like Artenprofile and Shannon. However, it showed significant limitations for the Gini index (p < 0.01), due to a smaller number of sampled trees. For the Gini index, fixed-radius plots of at least 150 m², with 200 m² being the most cost-effective size, provided the most reliable estimates. Interestingly, the CC design may also be less suitable for production parameters, where smaller fixed-radius plots (50 m²) were more effective, requiring fewer total samples despite the need for more plots. Full article

(This article belongs to the Special Issue Tree Growth and Physiological Properties Under Ongoing Global Climate Change: 2nd Edition)

17 pages, 699 KiB

Open AccessArticle

The Effect of the Vaccinium myrtillus L. Rhizosphere on the Maturity Index for Predatory Mites (Mesostigmata: Gamasina) in Assessing Anthropogenic Pollution of Forest Soils

by Gabriela Barczyk, Aleksandra Nadgórska-Socha and Marta Kandziora-Ciupa

Forests 2024, 15(12), 2245; https://doi.org/10.3390/f15122245 (registering DOI) - 20 Dec 2024

Abstract

The soil’s biological quality and its functions are closely linked. They determine the ecological processes and ecosystem services. Therefore, the heavy metal contamination of forest soils, leading to their degradation, is a major international problem. Soil is a habitat for many organisms, and [...] Read more.

The soil’s biological quality and its functions are closely linked. They determine the ecological processes and ecosystem services. Therefore, the heavy metal contamination of forest soils, leading to their degradation, is a major international problem. Soil is a habitat for many organisms, and the strong correlations between soil properties, vegetation, and soil fauna are particularly evident in the rhizosphere. Therefore, comprehensive soil monitoring must take all these elements into account. In forest soils, Vaccinium myrtillus plays a vital role. Despite this, there is still a lack of information in the literature on the interrelationship between microarthropod biodiversity, including predatory soil mites, and heavy metals in the rhizosphere zone of blueberry plants. To fill this gap, we assessed the impact of the V. myrtillus rhizosphere on soil stability and biological quality using a bioindicator based on predatory mites. We conducted the study in Poland, on selected forest sites characterised by varying degrees of soil contamination. In our study, we used a combined analysis based on the following indicators: maturity index (MI), contamination factor (CF), pollution load index (PLI), and potential ecological risk index (PERI), which allowed us to determine the level of soil contamination. We extracted 4190 Gamasina mites from soil samples. We also investigated soil properties such as pH, organic matter content, total carbon, total nitrogen, C/N ratio, and heavy metal concentrations (Cd, Cu, Zn, Pb, and Ni). Our study proved that the rhizosphere zone significantly influences the stability of the predatory soil mite community, but this influence depends on the degree of soil contamination. We found that in unpolluted or moderately polluted soil, soil mites prefer habitats with less biological activity, i.e., non-rhizosphere zones. These main results are fascinating and indicate the need for further in-depth research. Our study’s comprehensive combination of methods provides valuable information that can facilitate the interpretation of environmental results. In addition, our study can be a starting point for analysing the impact of the rhizosphere zones of many other plant species, especially those used in the reclamation or urban spaces. Full article

(This article belongs to the Section Forest Soil)

27 pages, 13231 KiB

Open AccessArticle

PosE-Enhanced Point Transformer with Local Surface Features (LSF) for Wood–Leaf Separation

by Xin Lu, Ruisheng Wang, Huaiqing Zhang, Ji Zhou and Ting Yun

Forests 2024, 15(12), 2244; https://doi.org/10.3390/f15122244 - 20 Dec 2024

Abstract

Wood–leaf separation from forest LiDAR point clouds is a challenging task due to the complex and irregular structures of tree canopies. Traditional machine vision and deep learning methods often struggle to accurately distinguish between fine branches and leaves. This challenge arises primarily from [...] Read more.

Wood–leaf separation from forest LiDAR point clouds is a challenging task due to the complex and irregular structures of tree canopies. Traditional machine vision and deep learning methods often struggle to accurately distinguish between fine branches and leaves. This challenge arises primarily from the lack of suitable features and the limitations of existing position encodings in capturing the unique and intricate characteristics of forest point clouds. In this work, we propose an innovative approach that integrates Local Surface Features (LSF) and a Position Encoding (PosE) module within the Point Transformer (PT) network to address these challenges. We began by preprocessing point clouds and applying a machine vision technique, supplemented by manual correction, to create wood–leaf-separated datasets of forest point clouds for training. Next, we introduced Point Feature Histogram (PFH) to construct LSF for each point network input, while utilizing Fast PFH (FPFH) to enhance computational efficiency. Subsequently, we designed a PosE module within PT, leveraging trigonometric dimensionality expansion and Random Fourier Feature-based Transformation (RFFT) for nuanced feature analysis. This design significantly enhances the representational richness and precision of forest point clouds. Afterward, the segmented branch point cloud was used to model tree skeletons automatically, while the leaves were incorporated to complete the digital twin. Our enhanced network, tested on three different types of forests, achieved up to 96.23% in accuracy and 91.51% in mean intersection over union (mIoU) in wood–leaf separation, outperforming the original PT by approximately 5%. This study not only expands the limits of forest point cloud research but also demonstrates significant improvements in the reconstruction results, particularly in capturing the intricate structures of twigs, which paves the way for more accurate forest resource surveys and advanced digital twin construction. Full article

(This article belongs to the Special Issue Forest Parameter Detection and Modeling Using Remote Sensing Data)

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13 pages, 7018 KiB

Open AccessArticle

Image Classification of Tree Species in Relatives Based on Dual-Branch Vision Transformer

by Qi Wang, Yanqi Dong, Nuo Xu, Fu Xu, Chao Mou and Feixiang Chen

Forests 2024, 15(12), 2243; https://doi.org/10.3390/f15122243 - 20 Dec 2024

Abstract

Tree species in relatives refer to species belonging to the same genus with high morphological similarity and small botanical differences, making it difficult to perform classification and usually requiring manual identification by experts. To reduce labor costs and achieve accurate species identification, we [...] Read more.

Tree species in relatives refer to species belonging to the same genus with high morphological similarity and small botanical differences, making it difficult to perform classification and usually requiring manual identification by experts. To reduce labor costs and achieve accurate species identification, we conducted research on the image classification of tree species in relatives based on deep learning and proposed a dual-branch feature fusion Vision Transformer model. This model is designed with a dual-branch architecture and two effective blocks, a Residual Cross-Attention Transformer Block and a Multi-level Feature Fusion method, to enhance the influence of shallow network features on the final classification and enable the model to capture both overall image information and detailed features. Finally, we conducted ablation studies and comparative experiments to validate the effectiveness of the model, achieving an accuracy of 90% on the tree relatives dataset. Full article

(This article belongs to the Special Issue Artificial Intelligence and Machine Learning Applications in Forestry—Second Edition)

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22 pages, 1798 KiB

Open AccessReview

Accounting for Land-Use Changes in Environmental Impact Assessments of Wood Products: A Review

by Charis Anaïs Kanellos, Miguel Riviere, Thierry Brunelle and David W. Shanafelt

Forests 2024, 15(12), 2242; https://doi.org/10.3390/f15122242 - 20 Dec 2024

Abstract

Environmental policy and the expansion of the bioeconomy sector has led to increased demand for wood and wood products, pressuring forests. In order to meet additional demand, foresters must either intensify forest management practices or alter forest area. One of the more observable [...] Read more.

Environmental policy and the expansion of the bioeconomy sector has led to increased demand for wood and wood products, pressuring forests. In order to meet additional demand, foresters must either intensify forest management practices or alter forest area. One of the more observable shifts in forest management comes in the form of changes in land use or land cover. Yet despite the many short- and long-term consequences of land-use change, the environmental impacts of it are less explored in forestry than in agriculture. In this paper, we conduct a literature review over the period between 1993 and 2022 to better understand how the notions of land-use and land-cover change are included in environmental impact assessments related to the production of wood and wood products. Specifically, we identified five categories of impacts studied and found a surprising dichotomy in terminology between land-use/land-cover change and changes in forest management practices. We present general trends in the methods and indicators used and discuss potential methodological and conceptual challenges inherent to this literature. Our results are particularly important in light of the growing popularity of land-use and land-cover data in research, as we highlight how they have been integrated into existing environmental impact assessment methods and how we can improve them going into the future. Full article

(This article belongs to the Special Issue Forest Dynamics under Climate and Land Use Change)

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16 pages, 4410 KiB

Open AccessArticle

Effects of Ecological Restoration Measures on Growth Renewal and Nutritional Quality of Arundinaria faberi in Degraded Habitat of Giant Panda

by Weirui Qin, Jingyi Liu, Han Pan, Yong Cheng, Xinqiang Song, Mingxia Fu, Yuanbin Zhang, Xiaofeng Luan and Biao Yang

Forests 2024, 15(12), 2241; https://doi.org/10.3390/f15122241 - 20 Dec 2024

Abstract

Restoring the degraded habitat of the giant panda (Ailuropoda melanoleuca) is of paramount importance for the conservation of the species and its forest ecosystem. However, little is known about the impact of ecological restoration interventions on the growth renewal and nutritional [...] Read more.

Restoring the degraded habitat of the giant panda (Ailuropoda melanoleuca) is of paramount importance for the conservation of the species and its forest ecosystem. However, little is known about the impact of ecological restoration interventions on the growth renewal and nutritional quality of Arundinaria faberi in the degraded habitat of the giant panda. Here, we implemented strip thinning and blocky thinning techniques in the Daxiangling mountain range, alongside a control group. A random forest model and multiple linear regression analysis were employed to predict changes in the growth renewal and nutritional quality of bamboo, particularly in the strip-thinned zones. The key findings were as follows: (1) Compared with the control area, strip thinning increased the number of shoots and increased the diameter and height of shoots. (2) The random forest model predicted a decline in bamboo regeneration indices in 2023 compared to 2022 under strip thinning. (3) Through thinning, the palatability and nutritional level of A. faberi were improved. (4) Long-term effects included increased tannin in leaves, decreased tannin and amino acids in shoots and culms, and increased crude fat, with changes in crude protein distribution across bamboo parts. Overall, these findings provide valuable insights for habitat restoration efforts targeting giant panda populations in the low-canopy forest ecosystems of the Daxiangling mountain range. Full article

(This article belongs to the Section Forest Biodiversity)

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13 pages, 4281 KiB

Open AccessArticle

Wind-Induced Variations in Phenology Regulate Carbon Fluxes in Two Warm-Temperate Plantation Forests

by Yue Liu, Menglin Su, Jiaxin Jin, Honghua Ruan, Jianhui Xue, Yin Sun, Shuiqiang Yu and Weifeng Wang

Forests 2024, 15(12), 2240; https://doi.org/10.3390/f15122240 - 20 Dec 2024

Abstract

Forest phenology directly reacts to global climate change, potentially regulating greenhouse gas fluxes between ecosystems and the atmosphere. To explore this phenomenon in two plain poplar (Populus spp.) forests in eastern China, we measured CO₂ fluxes and phenology at the canopy [...] Read more.

Forest phenology directly reacts to global climate change, potentially regulating greenhouse gas fluxes between ecosystems and the atmosphere. To explore this phenomenon in two plain poplar (Populus spp.) forests in eastern China, we measured CO₂ fluxes and phenology at the canopy scale based on the eddy covariance and PhenoCam technology. From 2019 to 2022, poplars in a high-speed wind site (HWS) experienced shorter maturity durations (108 ± 4.9 days vs. 152 ± 1.2 days) and an earlier date of foliar senescence (day of year: 223.8 ± 2.5 vs. 259.5 ± 0.9) than those in the low-speed wind site (LWS). The annual net CO₂ uptake in the HWS (689.65 ± 105.15 g C·m⁻²·year⁻¹) was approximately 2.4 times higher than that in the LWS (285.65 ± 81.37 g C·m⁻²·year⁻¹). Our results indicate that environmental changes like wind stress alter forest phenology that can dynamically regulate ecosystem respiration and gross primary production. Full article

(This article belongs to the Section Forest Meteorology and Climate Change)

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15 pages, 3307 KiB

Open AccessArticle

Common Species in the Subtropical Evergreen Broad-Leaved Forest: Dominance in Adaptation Mechanisms and Resource Utilization Capabilities

by Huan He, Haibao Ren, Guijing Li, Yali Ding, Xinliang Wu, Lina Wang, Ansa Rebi and Shuyu He

Forests 2024, 15(12), 2239; https://doi.org/10.3390/f15122239 - 20 Dec 2024

Abstract

When species of different abundance coexist, their ecological strategies remain uncertain. Assessing the functional diversity and niche characteristics of species with different levels of abundance contributes to understanding vegetation properties and is essential for species conservation. Based on the species abundance of 380 [...] Read more.

When species of different abundance coexist, their ecological strategies remain uncertain. Assessing the functional diversity and niche characteristics of species with different levels of abundance contributes to understanding vegetation properties and is essential for species conservation. Based on the species abundance of 380 plots in the Gutianshan subtropical evergreen broad-leaved forest in the Zhejiang Province of China, woody plants were categorized as common species (86 species), occasional species (87 species), and rare species (79 species). Plant functional traits, including maximum height, seed dispersal modes, first flowering stage, flowering duration, and fruit length, were used to assess the functional diversity of the community of common, occasional, and rare species, while 15 environmental factors were used to evaluate their Levins’ niche breadth and Pianka’s niche overlap. The results showed that rare species have the highest functional evenness, while functional dispersion and Rao’s quadratic entropy were higher for common species (2.05 and 5.07, respectively) compared to occasional species (1.57 and 3.10) and rare species (1.35 and 2.48). Furthermore, the 15-dimensional mean value of niche breadth of common species (ranging from 0.277 to 0.955) was also higher than that of occasional (ranging from 0.193 to 0.710) and rare species (ranging from 0.100 to 0.345), and the same trend was also observed in niche overlap. The results suggest that common species have diverse functional traits and a greater ability to adapt to the environment and use resources, whereas occasional species have a limited ability to use the environment. Rare species are evenly distributed within functional space to reduce direct competition with other species, but they thrive only under specific environmental conditions, mainly following a K reproductive strategy. Niche differentiation mechanisms are important determinants of species coexistence in subtropical evergreen broad-leaved forests. In summary, more attention and greater efforts should be paid to the conservation of rare species. Our findings could help forest managers in the restoration and conservation of subtropical forests. Full article

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

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17 pages, 2473 KiB

Open AccessArticle

The Combined Effects of Salt and Nitrogen Addition on the Chlorophyll Fluorescence, Antioxidant System, and Leaf Stoichiometry of Torreya grandis Sexes

by Yang Liu, Danyang Chen, Haochen Zhang and Songheng Jin

Forests 2024, 15(12), 2238; https://doi.org/10.3390/f15122238 - 19 Dec 2024

Abstract

Previous studies have shown that there are significant sexual differences in the physiological responses of Torreya grandis to environmental stress. However, little is known about its sex-specific differences in response to salt stress against the background of nitrogen (N) deposition. In this experiment, [...] Read more.

Previous studies have shown that there are significant sexual differences in the physiological responses of Torreya grandis to environmental stress. However, little is known about its sex-specific differences in response to salt stress against the background of nitrogen (N) deposition. In this experiment, two-year-old male and female T. grandis seedlings were used as experimental materials and exposed to moderate salt conditions and different N levels to study the effects of nitrogen addition and salt stress on the chlorophyll content, chlorophyll fluorescence parameters, antioxidant system, and leaf stoichiometry of T. grandis seedlings. With the increase in nitrogen content, the contents of proline, malondialdehyde, superoxide anion, and H₂O₂ in the leaves of T. grandis seedlings under salt conditions gradually increased. The contents of these four metabolites in the leaves of male T. grandis seedlings were almost all higher than those of the female ones. Compared with the control group, the contents of enzymatic and non-enzymatic antioxidants increased under N addition treatments, especially for the low and moderate N addition groups. The results showed that moderate concentrations of N addition can mitigate the damage caused by salt, while high concentrations of nitrogen do not. Under conditions of salt and nitrogen addition, female T. grandis seedlings outperformed male ones, as evidenced by their higher photosynthetic pigment content, enhanced antioxidant enzyme activity, reduced accumulation of intracellular cytotoxic metabolites, and higher carbon and nitrogen content in their leaves compared to those of male seedlings. The findings of this research will contribute to our understanding and offer a theoretical foundation for the cultivation of T. grandis seedlings in environments with nitrogen deposition and salinization. Full article

(This article belongs to the Topic Plant Physiological and Ecological Responses to Environmental Stress)

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19 pages, 1645 KiB

Open AccessArticle

Enhancing Forest Utilization and Quality of Life: An Integrated Approach to Promoting Forest Activities

by Seo-hyo Lee, Soojin Kim and Jeonghee Lee

Forests 2024, 15(12), 2237; https://doi.org/10.3390/f15122237 (registering DOI) - 19 Dec 2024

Abstract

This study investigates the impact of forest-activity diversity on life satisfaction using data from the 2023 Forest Recreation and Welfare Activities Survey conducted by the Korea Forest Service. Forest-activity diversity was categorized into two dimensions: experience diversity (combining forest recreation and welfare-activity experiences) [...] Read more.

This study investigates the impact of forest-activity diversity on life satisfaction using data from the 2023 Forest Recreation and Welfare Activities Survey conducted by the Korea Forest Service. Forest-activity diversity was categorized into two dimensions: experience diversity (combining forest recreation and welfare-activity experiences) and utilization diversity (the use of forest recreation and welfare facilities and programs). Hierarchical regression analysis revealed that greater diversity in forest activities and utilization significantly enhances life satisfaction. However, participants who engaged in both forest recreation and welfare activities or utilized both facilities and programs reported comparatively lower life satisfaction. The findings indicate that while activity and utilization diversity are critical in improving life satisfaction, the benefits may plateau with excessive participation. The effects of leisure activities also vary based on individual factors such as age, gender, and life context, underscoring the importance of tailored forest welfare programs. Balanced and meaningful engagement in diverse activities is essential for maximizing well-being. While forest activities generally enhance life satisfaction, programs must be inclusive and flexible to address diverse user needs. Future research should incorporate objective measures and longitudinal designs to better evaluate the long-term effects of forest welfare activities. Full article

(This article belongs to the Special Issue Forest Bathing and Forests for Public Health—Series II)

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