Forests

13 pages, 1148 KiB

Open AccessArticle

Volatile Organic Compounds (VOCs) in Mediterranean Oak Forests of Hungarian Oak (Quercus frainetto Ten) Affected by Dieback Phenomena

by Marisabel Mecca, Luigi Todaro, Maurizio D’Auria, Santain Settimio Pino Italiano, Adriano Sofo and Francesco Ripullone

Forests 2024, 15(6), 1072; https://doi.org/10.3390/f15061072 - 20 Jun 2024

Viewed by 1074

Abstract

In recent years, long periods of drought and heat waves have become increasingly frequent, causing forest dieback phenomena that make stands more sensitive to biotic stressors. How trees may respond to extreme climatic events and which metabolites are involved under stress conditions is [...] Read more.

In recent years, long periods of drought and heat waves have become increasingly frequent, causing forest dieback phenomena that make stands more sensitive to biotic stressors. How trees may respond to extreme climatic events and which metabolites are involved under stress conditions is still not clear. In this study, using Solid Phase Micro-Extraction (SPME)-GC/MS, we analysed how dieback (D) and non-dieback (ND) Hungarian oak trees from the San Paolo Albanese site respond to these climatic dynamics, focusing on volatile organic compounds (VOCs). For each group of trees, three wood samples were taken, and each was divided into four sub-samples with five growth rings and subjected to SPME and increase in basal area (BAI) analysis of the last 20 years. Dieback trees had a lower number of leaves, and this condition may translate into less photosynthesis, less organic matter production, and lower reserves of carbohydrates being available for growth. Indeed, D trees showed lower radial increases and a lower content of aldehydes, terpenes, and fatty acids than ND trees, indicating a better health of ND trees compared to D trees. Meanwhile, D trees showed a reduction in terpenes, such as α-pinene, γ-eudesmol, and cyperene (with significant insecticidal activity), a reduction in aromatic aldehydes, such as furfural and 5-methylfurfural, and an increase in silanols (with antimicrobial function). Considering the different compounds’ contents between D and ND trees, our study could be useful for detecting bio-indicators to identify an early warning signal of dieback phenomena. Full article

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

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25 pages, 10483 KiB

Open AccessArticle

Stability Analysis of Planetary Rotor with Variable Speed Self Rotation and Uniform Eccentric Revolution in the Rubber Tapping Machinery

by Jianhua Cao, Bo Fan, Suwei Xiao and Xin Su

Forests 2024, 15(6), 1071; https://doi.org/10.3390/f15061071 - 20 Jun 2024

Viewed by 877

Abstract

Natural rubber is a critical material that is essential to industry and transportation. In order to reduce the cost of rubber tapping and improve the efficiency and profitability of rubber production, the 4GXJ-2 portable electric rubber cutter and automatic rubber tapping robot have [...] Read more.

Natural rubber is a critical material that is essential to industry and transportation. In order to reduce the cost of rubber tapping and improve the efficiency and profitability of rubber production, the 4GXJ-2 portable electric rubber cutter and automatic rubber tapping robot have been developed. In their vibration tool holder, the planetary rotor with variable speed self rotation and uniform eccentric revolution is the most important transmission component, and its instability will cause irregular vibration of the tapping tool, thereby reducing the accuracy of vibration cutting and increasing noise. Base on the ANCF (Absolute Nodal Coordinate Formulation) 3D-beam element and 3D REF (3D Ring on Elastic Foundation), a novel eccentric 3D REF model of a planetary rotor is proposed. By introducing multiple coordinate systems, the coupled motion of uniform eccentric revolution, variable speed self rotation and flexible deformation is decomposed and the influences of these motions on the centrifugal force and Coriolis force are more clearly derived. The model is degraded and validated by comparing with other examples of a rotating circular ring model and uniformly eccentrically revolving annular plate. According to the Floquet theory and Runge−Kutta method, the unstable region of revolution speed of a planetary rotor in rubber tapping machinery is predicted as [817 rad/s, 909 rad/s], [1017 rad/s, 1095 rad/s] and [1263 rad/s,1312 rad/s]. Compared with the rubber-tapping experiment of rubber tapping machinery, the validity of the proposed model is further verified. This model provides important design references for the speed settings of those rubber tapping machines. Full article

(This article belongs to the Special Issue Advances in the Study of Wood Mechanical and Physical Properties)

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19 pages, 2052 KiB

Open AccessArticle

Comparison of Planted Pine versus Natural Mix Forests in Nepal

by Hari Prasad Pandey, Tek Narayan Maraseni and Shila Pokhrel

Forests 2024, 15(6), 1070; https://doi.org/10.3390/f15061070 - 20 Jun 2024

Cited by 1 | Viewed by 1259

Abstract

This study aimed to compare the socio-environmental benefits of one of the most widely planted forest species, i.e., Pinus roxburghii (Sarg., hereafter ‘Pine’ or ‘Pinus’) with naturally regenerated mixed forests in two community forests of Nepal. By analyzing tree rings, we [...] Read more.

This study aimed to compare the socio-environmental benefits of one of the most widely planted forest species, i.e., Pinus roxburghii (Sarg., hereafter ‘Pine’ or ‘Pinus’) with naturally regenerated mixed forests in two community forests of Nepal. By analyzing tree rings, we estimate biomass production, carbon accumulation, and growth enhancement in both forest types using regression models, offering insights into sustainable forest management. Pinus forests exhibit instant social benefits through direct economic conversion and a higher rate of carbon sequestration. However, the lack of perpetuated production, due to unimodal stand structures, necessitates anthropogenic interventions for long-term sustainability. Challenges such as the absence of natural regeneration, frequent fires, limited undergrowth, limited species diversity, and likely soil erosion hinder long-term sustainability in Pinus forests. In contrast, natural regenerated mixed forests offer slow carbon sequestration with less opportunity for immediate economic conversion, yet they maintain a proportional age-class distribution and experience minimal fire incidence, abundant regeneration, higher biodiversity, and lower regeneration costs. Although no abrupt environmental disasters were observed through the dendrochronological assessment, a significant positive correlation (p < 0.05) was found between age and girth at breast height, biomass, and volume of the forests. This study underscores the crucial role of human intervention beyond conventional management focusing on the protection motive to production-oriented forests in optimizing the socio-economic and environmental benefits of both forest types in the changing socio-environmental challenges through informed management planning. Full article

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

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15 pages, 2706 KiB

Open AccessArticle

Coastal Forest Change and Shoreline Erosion across a Salinity Gradient in a Micro-Tidal Estuary System

by Lori E. Gorczynski, A. Reuben Wilson, Ben K. Odhiambo and Matthew C. Ricker

Forests 2024, 15(6), 1069; https://doi.org/10.3390/f15061069 - 20 Jun 2024

Viewed by 878

Abstract

Coastal Zone Soil Survey mapping provides interpretive information that can be used to increase coastal resiliency and quantify how coastal ecosystems are changing over time. North Carolina has approximately 400,500 ha of land within 500 m of the tidal coastline that is expected [...] Read more.

Coastal Zone Soil Survey mapping provides interpretive information that can be used to increase coastal resiliency and quantify how coastal ecosystems are changing over time. North Carolina has approximately 400,500 ha of land within 500 m of the tidal coastline that is expected to undergo some degree of salinization in the next century. This study examined 33 tidal wetlands in the Albemarle–Pamlico Sound along a salinity gradient to provide a coastal zone mapping framework to quantify shoreline change rates. The primary ecosystems evaluated include intact tidal forested wetlands (average water salinity, 0.15–1.61 ppt), degraded “ghost forest” wetlands (3.51–8.28 ppt), and established mesohaline marshes (11.73–15.47 ppt). The average shoreline rate of change (m/yr) was significantly different among estuary ecosystems (p = 0.004), soil type (organic or mineral) (p < 0.001), and shore fetch category (open or protected) (p < 0.001). From 1984 to 2020, a total of 2833 ha of land has been submerged due to sea level rise in the Albemarle–Pamlico Sound with the majority (91.6%) of this loss coming from tidal marsh and ghost forest ecosystems. The results from this study highlight the importance of maintaining healthy coastal forests, which have higher net accretion rates compared to other estuarine ecosystems. Full article

(This article belongs to the Special Issue Coastal Forest Dynamics and Coastline Erosion, 2nd Edition)

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19 pages, 4261 KiB

Open AccessArticle

A Scientometric Analysis and Visualization of Forest Soil Contamination Research from Global Perspectives

by Qingyu Wu, Yifei Cao, Ting Yu, Jinglin Yang, Siyu Fan, Chonglin Feng, Zhiming Liu and Chao Huang

Forests 2024, 15(6), 1068; https://doi.org/10.3390/f15061068 - 20 Jun 2024

Viewed by 972

Abstract

Forest soil contamination is a significant problem with risks to ecosystems and human health. It reduces soil quality, hampers plant growth, and disrupts ecosystems. To understand current research and identify future directions, this study analyzed 2659 documents on forest soil contamination published on [...] Read more.

Forest soil contamination is a significant problem with risks to ecosystems and human health. It reduces soil quality, hampers plant growth, and disrupts ecosystems. To understand current research and identify future directions, this study analyzed 2659 documents on forest soil contamination published on the Web of Science from 1970 to 2023. Using bibliometrics, this study systematically analyzed the knowledge structure, research hotspots, and development trends in forest soil pollution. China, the United States, and Poland were the top contributors, with 11.28%, 8.42%, and 7.15% of publications, respectively. Despite fewer publications, the Netherlands and Sweden had significant research influence. The Chinese Academy of Sciences had the most publications. The primary research topics included heavy metals, ecosystems, deposition, air pollution, and organic matter. Keyword cluster and burst analysis highlighted the importance of heavy metals, microbial communities, atmospheric deposition, and organic matter. Notably, microplastics emerged as a notable gap in the existing research by highly cited papers analysis, indicating they can be a future research focus. Overall, this paper provides a comprehensive analysis of forest soil contamination, offering insights into current research themes and emerging trends. Full article

(This article belongs to the Special Issue Soil Contamination in Forest Ecosystem)

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15 pages, 3770 KiB

Open AccessArticle

Seed Conservation Methods According to the Prediction of Suitable Distribution of Endangered Conifer Abies nephrolepis Maxim.

by Da Hyun Lee, Chung Youl Park, Jun Hyeok Kim, Hyeon Min Kim, Jun Gi Byeon, Wan Geun Park, Sun Hee Hong and Chae Sun Na

Forests 2024, 15(6), 1067; https://doi.org/10.3390/f15061067 - 20 Jun 2024

Viewed by 986

Abstract

This study predicted habitat distribution changes according to the current distribu seedtion 14 and future climate using the MaxEnt model for endangered Abies nephrolepis Maxim., which is vulnerable to 15 climate change and is a least-concerned species. This study aimed to predict the [...] Read more.

This study predicted habitat distribution changes according to the current distribu seedtion 14 and future climate using the MaxEnt model for endangered Abies nephrolepis Maxim., which is vulnerable to 15 climate change and is a least-concerned species. This study aimed to predict the current distribution and future habitat distribution changes of the endangered A. nephrolepis under climate change using the MaxEnt model. The purpose was to predict the future habitat of the declining A. nephrolepis, to identify the necessity of in situ conservation, and to devise appropriate ex situ seed storage methods. The study utilized climate data from 513 GPS coordinates of A. nephrolepis habitats in South Korea to predict the changes in habitat distribution using the MaxEnt model. The seeds used in the seed experiment were collected from Pyeongchang-gun, Gangwon-do, Republic of Korea in 2019. After confirming an initial seed filling, germination tests were performed under constant temperatures of 15, 20, and 25 °C and alternating day/night temperatures of 25/5, 25/10, 25/10, 20/15, 25/15, 30/15, and 35/15 °C. The seed germination conditions were investigated under 10 different temperature settings. For the determination of storage behavior, seeds were dried at a consistent temperature of 15 °C and relative humidity (eRH) levels of 15, 20, 30, 40, and 50%. Subsequently, the seeds were stored for three months at temperatures of −20 °C and 5 °C, and the vitality tests of the seeds were conducted. Based on these experiments, the storage characteristics of seeds were identified. The results indicated that in all SSP scenarios, it is predicted that A. nephrolepis will become extinct in its habitat by the 2090s. Therefore, it has been shown that on-site and ex situ conservation is necessary. As a result of the seed germination characteristics, the highest germination rate (52.5 ± 16.01%) was achieved at a constant temperature of 20 °C, followed by 25 °C (50.0 ± 10.81%) and 25/10 °C (47.5 ± 4.79%). The highest viability was obtained under 20% eRH (64.0 ± 0%) but was not statistically different from that determined immediately after seed collection. The moisture content was approximately 4.33% fresh weight under 15% eRH at 15 °C. A. nephrolepis seeds are classified as orthodox-type seeds, which do not lose viability at 3%–7% moisture content and after drying under 15% eRH conditions at 15 °C. In conclusion, it can be observed that the seeds can be stored long-term at −20 °C. This research was conducted as a basic study to predict the habitat distribution of the endangered species A. nephrolepis and to establish seed conservation methods. According to the results, it is deemed necessary to conduct both domestic and international analyses of the habitat of A. nephrolepis. In addition, the germination and storage characteristics of A. nephrolepis seeds were confirmed, and based on this, effective seed conservation methods were suggested. Full article

(This article belongs to the Special Issue Forest Species Distribution, Diversity and Growth under Climate Change)

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14 pages, 4390 KiB

Open AccessArticle

Relationship between Green Space and Mortality in the Cities of the Yangtze River Delta Urban Agglomeration

by Mengxue Li, Yanping Wen and Guang Hu

Forests 2024, 15(6), 1066; https://doi.org/10.3390/f15061066 - 20 Jun 2024

Viewed by 700

Abstract

Intense work pressure and unhealthy lifestyles significantly threaten urban public health. Urban designs have quickly developed, such as the introduction of green space (GS), which has been suggested to improve public health. Prior epidemiological studies have investigated GS and mortality and have generally [...] Read more.

Intense work pressure and unhealthy lifestyles significantly threaten urban public health. Urban designs have quickly developed, such as the introduction of green space (GS), which has been suggested to improve public health. Prior epidemiological studies have investigated GS and mortality and have generally found potential benefits. However, these studies were primarily conducted in developed Western countries and the potential effects of GS on mortality in developing Asian countries are poorly understood. In this study, our goal was to investigate the effect of GS landscape attributes and socioeconomic conditions on all-cause mortality in 41 cities in the Yangtze River Delta urban agglomeration. Nine GS variables and seven socioeconomic variables were collected. An optimal general linear model with the selected variables was established using LASSO regression to explore the direction and relative importance of GSs and socioeconomic conditions for urban public health. The results showed that (1) socioeconomic conditions and GS jointly affect all-cause mortality, (2) people with greater personal wealth suffered less health risk, and (3) regularly shaped and highly connected GSs decreased the risk to public health. These findings suggest that reasonable GS policies and planning strategies are effective approaches for improving public health in Chinese cities. Full article

(This article belongs to the Special Issue Urban Forests and Human Health)

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14 pages, 3579 KiB

Open AccessArticle

Unraveling the Role of Bacteria in Nitrogen Cycling: Insights from Leaf Litter Decomposition in the Knyszyn Forest

by Nataliia Khomutovska, Iwona Jasser and Valery A. Isidorov

Forests 2024, 15(6), 1065; https://doi.org/10.3390/f15061065 - 20 Jun 2024

Viewed by 865

Abstract

Microorganisms are vital in leaf litter decomposition and contribute significantly to global nutrient cycling. However, there is a need for improved understanding of the taxonomic and functional diversity of litter-associated bacteria. The Knyszyn Forest comprises a unique ecosystem providing diverse microhabitats for microorganisms [...] Read more.

Microorganisms are vital in leaf litter decomposition and contribute significantly to global nutrient cycling. However, there is a need for improved understanding of the taxonomic and functional diversity of litter-associated bacteria. The Knyszyn Forest comprises a unique ecosystem providing diverse microhabitats for microorganisms in central Europe, similar to the southwestern taiga in many respects. This study presents the results of high-throughput sequencing performed for Betula pendula, B. pubescens, and Carpinus betulus litter-associated microbial communities from northern Poland. Microbial assemblage composition and structure at different stages of litter decomposition revealed the domination of phyllosphere-associated taxa of Sphingomonas and Pseudomonas in bacterial communities in the early stages. Meanwhile, at the later stages of decomposition, the representation of soil-associated bacterial communities, such as Pedobacter, was higher. This study identifies key bacteria (Pedobacter, Mucilaginibacter, and Luteibacter) as pivotal in nutrient cycling through cellulose and hemicellulose decomposition, dominating later decomposition phases. Taxonomic analysis based on functional markers associated with nitrogen metabolism highlights the pivotal role of specific Pseudomonadota (Proteobacteria) taxa in driving nitrogen cycling dynamics during litter decomposition. Most of these taxa were unclassified at the genus level, particularly in the later stages of litter decomposition, and are crucial in mediating nitrogen transformation processes, underscoring their significance in ecosystem nutrient cycling. Full article

(This article belongs to the Topic Litter Decompositions: From Individuals to Ecosystems)

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21 pages, 1170 KiB

Open AccessArticle

Impact of Forest City Selection on Green Total Factor Productivity in China under the Background of Sustainable Development

by Yameng Wang, Fan Zou, Wenqing Guo, Weinan Lu and Yuanjie Deng

Forests 2024, 15(6), 1064; https://doi.org/10.3390/f15061064 - 20 Jun 2024

Viewed by 1372

Abstract

In the critical period of strengthening the construction of ecological civilization, the construction of forest cities has become an important measure to promote urban ecosystem restoration and achieve sustainable development. Based on the mechanism of forest city promoting green development, the construction of [...] Read more.

In the critical period of strengthening the construction of ecological civilization, the construction of forest cities has become an important measure to promote urban ecosystem restoration and achieve sustainable development. Based on the mechanism of forest city promoting green development, the construction of a national forest city is regarded as a “quasi-natural experiment”. Using China’s urban panel data from 2005 to 2019, the impact of national forest city construction on urban green total factor productivity was evaluated using Multistage asymptotic double difference. The results show that National Forest Cities with environmental regulation can significantly promote regional green total factor productivity, which is still valid after a series of Robustness tests. Mechanism analysis shows that forest city construction not only affects territorial spatial planning but also forms a linkage with green technology innovation, mutual promotion and mutual promotion to jointly promote the sustainable development goals. This paper argues that building a national forest city is an important measure to achieve China’s sustainable development goals in the new era, but in the process of policy implementation, it is necessary to implement the national forest city selection system according to local conditions. Full article

(This article belongs to the Special Issue Contribution of Forestry Ecological Restoration Projects to the Realization of Sustainable Development Goals)

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19 pages, 4886 KiB

Open AccessArticle

Identification of Catalpa bungei Aquaporin Gene Family Related to Low Temperature Stress

by Tianyi Li, Jing Zhang, Hongtao Zhang, Shance Niu, Ji Qian, Zhaoyang Chen, Tianyi Ma, Yu Meng and Bao Di

Forests 2024, 15(6), 1063; https://doi.org/10.3390/f15061063 - 20 Jun 2024

Viewed by 781

Abstract

Low temperatures pose a significant threat to plant growth and development. Studies have shown that aquaporins (AQPs), as the main functional proteins on the cell membrane regulating water ingress and egress, play a vital role in maintaining dynamic water balance when plants face [...] Read more.

Low temperatures pose a significant threat to plant growth and development. Studies have shown that aquaporins (AQPs), as the main functional proteins on the cell membrane regulating water ingress and egress, play a vital role in maintaining dynamic water balance when plants face cold stress. Catalpa bungei, an important timber and ornamental tree species, has its cultivation range significantly limited by its poor cold tolerance. However, no study has been found aiming to identify its aquaporin gene family. This study aims to fill this gap using two C. bungei cultivars with differing cold tolerance as experimental material: “Qiuza 1”, which is less cold-tolerant, and “Qiuza 2”, which is more cold-tolerant. The plants were subjected to low-temperature stress at 4 °C for 24 h. Using high-throughput molecular sequencing technology, a transcriptome sequencing of the leaves was performed at 0, 6, 12, and 18 h of cold stress. Fifteen candidate aquaporin genes in C. bungei (CbAQP) were identified. Phylogenetic analysis showed that the CbAQP gene family is divided into five subfamilies: 5 PIPs, 4 TIPs, 3 NIPs, 2 SIPs, and 1 XIP. By analyzing AQPs related to cold stress in other plants and the expression patterns of CbAQP genes, 12 CbAQP genes related to cold stress were identified. The genes that responded positively include CbPIP2;5, CbPIP1;2, CbTIP4;1, and CbNIP2;1. The results provide a foundation for further analysis of the biological functions of candidate CbAQP genes related to cold tolerance and offer theoretical support for improving seedling quality, cold-resistant genetic breeding, and expanding its distribution range. Full article

(This article belongs to the Special Issue Strategies for Tree Improvement under Stress Conditions — 2nd Edition)

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20 pages, 10719 KiB

Open AccessArticle

Spatio-Temporal Assessment of Heterogeneity by Logging Intensity in a Federal Concession Area in the Brazilian Amazon

by Afonso Henrique Moraes Oliveira, Lucas José Mazzei de Freitas, Mauro Mendonça Magliano, José Humberto Chaves, Carlos Tadeu dos Santos Dias and Lucieta Guerreiro Martorano

Forests 2024, 15(6), 1062; https://doi.org/10.3390/f15061062 - 19 Jun 2024

Viewed by 1015

Abstract

The logging intensity often does not take into account the spatial heterogeneity of the forest volume of commercial native species in the Brazilian Amazon. This study aims to evaluate the spatio-temporal heterogeneity distribution by assessing logging intensity and its effects on the volumetric [...] Read more.

The logging intensity often does not take into account the spatial heterogeneity of the forest volume of commercial native species in the Brazilian Amazon. This study aims to evaluate the spatio-temporal heterogeneity distribution by assessing logging intensity and its effects on the volumetric stock and abundance of commercial species, with a focus on sustainable management practices. This study was conducted in the Saracá-Taquera National Forest in the Brazilian Amazon. Forest inventory data, elevation, and PlanetScope satellite images were integrated into a geographic information system. The information was aggregated into regular 1-hectare cells for the times before, during, and after logging (t0, t1, and t2). The unsupervised classification algorithm k-means with four clusters was used to analyze heterogeneity. Before logging, areas with higher commercial volumes were distant from water bodies, while areas with lower elevation had lower wood stocks. Logging intensity was generally low, concentrating on a few trees per hectare. Logging in the study area revealed a heterogeneous spatial distribution by intensifying in areas with the highest wood stocks. These results suggest that, in addition to the recommended logging intensity according to legislation, forest heterogeneity should be considered by the manager, promoting adaptive strategies to ensure the conservation of forest resources. Full article

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

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17 pages, 3071 KiB

Open AccessArticle

The Effects of Different Vegetation Restoration Models on Soil Quality in Karst Areas of Southwest China

by Han-Biao Ou, Xiong-Sheng Liu, Shuo-Xing Wei, Yi Jiang, Feng Gao, Zhi-Hui Wang, Wei Fu and Hu Du

Forests 2024, 15(6), 1061; https://doi.org/10.3390/f15061061 - 19 Jun 2024

Viewed by 765

Abstract

Rocky desertification is a devastating process in Karst areas of Southwest China and induces serious fragmentation in ecosystems. Therefore, vegetation restoration and the scientific evaluation of soil quality are key restorative strategies in these areas. In this study, a natural closed forest and [...] Read more.

Rocky desertification is a devastating process in Karst areas of Southwest China and induces serious fragmentation in ecosystems. Therefore, vegetation restoration and the scientific evaluation of soil quality are key restorative strategies in these areas. In this study, a natural closed forest and a disturbed forest with three restoration models, including an evergreen broad-leaved forest, mixed forest, and deciduous forest, were investigated in Huanjiang County. More than nineteen soil properties (including physical, chemical, and biotic properties) were analyzed across treatments, and principal component analyses (PCA) were combined with a minimum data set (MDS) applied to evaluate the soil quality. Our study sought to identify a vegetation restoration model to improve the soil quality in this area. We demonstrated that soil physical and chemical properties, microbial biomass, and enzyme activities significantly differed across all of the models. Soil water content, capillary porosity, total porosity, organic carbon, total phosphorus, available phosphorus, and urease activity were high in the mixed forest, leading to better physical soil properties. Also, relatively high soil total nitrogen, total potassium, available nitrogen, available potassium, microbial biomass C and N, catalase, sucrose, and alkaline phosphatase levels were observed in the deciduous broad-leaved forest, resulting in improved soil chemical properties. Based on the minimum data set (MDS) method, six indicators, including non-capillary porosity, organic carbon, total phosphorus, pH, microbial biomass nitrogen, and urease activity, were selected to evaluate the soil quality across the models. Our data showed that, among the five models, the deciduous broad-leaved forest had the highest soil quality index (0.618), followed by the mixed forest (0.593). Stepwise regression analysis showed that soil organic carbon explained 79.9% of the variations in the soil quality indices, suggesting it was a major factor affecting the soil quality. Thus, vegetation restoration models mainly comprised of native tree species effectively improved the soil quality in Karst rocky desertification areas, with deciduous broad-leaved forests displaying the best effects, followed by mixed forests. Full article

(This article belongs to the Special Issue Forest Soil Erosion in Karst Areas: Patterns, Processes and Mechanisms)

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13 pages, 4880 KiB

Open AccessArticle

Capacity of Forests and Grasslands to Achieve Carbon Neutrality in China

by Yonge Zhang, Yang Zhao, Qingwei Chen, Yuanji Zhu, Bo Liu, Xiaoming Zhang and Xiaolin Yin

Forests 2024, 15(6), 1060; https://doi.org/10.3390/f15061060 - 19 Jun 2024

Viewed by 896

Abstract

Forests and grasslands play an important role in carbon cycling. They not only absorb CO₂ from the air through vegetation biomass and soil carbon sinks, but also reduce and control the horizontal transport of soil carbon (i.e., reinforcing soil carbon storage via [...] Read more.

Forests and grasslands play an important role in carbon cycling. They not only absorb CO₂ from the air through vegetation biomass and soil carbon sinks, but also reduce and control the horizontal transport of soil carbon (i.e., reinforcing soil carbon storage via soil conservation), thus avoiding erosion-induced CO₂ emissions. In this study, vegetation biomass and soil carbon sinks, soil carbon reinforcement and reduced carbon emissions via soil conservation by forests and grasslands were quantified on the scale of the whole of China. The analysis was based on the distribution of biomass and the soil carbon pool and soil erosion rates derived from national surveys, as well as carbon density values from field surveys and literature. In 2021, forests and grasslands in China generated 394.18 Mt C/year (y) of steady-state carbon sinks through vertical biomass and soil absorption. The biomass carbon sinks of grasslands, and those of leaves, twigs, flowers and fruits of the forests, were not taken into account when quantifying the stable biomass sink, because they can become net producers of CO₂ due to seasonal withering and carryover, or they can form soil organic carbon as potential soil carbon sinks. The amount of horizontal soil carbon reinforcement in China’s forests and grasslands in 2021 was 20.31 Mt C/y, which was positively correlated with the reduction in the water erosion area; consequently, vertical emissions of approximately 14.89–29.78 Mt of CO₂ into the atmosphere were avoided. Overall, in 2021, China’s forests and grasslands absorbed atmospheric CO₂ and reduced emissions by 1.46–1.47 Gt CO₂/y, equivalent to approximately 13% of China’s annual fossil CO₂ emissions. This study demonstrates the fact that the adoption of forest and grassland measures sequesters carbon in soil and biota and reduces the risks of CO₂ emissions by both vertical and horizontal paths, which is important for achieving carbon neutrality and mitigating climate change. Full article

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

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18 pages, 3265 KiB

Open AccessArticle

Construction of Compatible Volume Model for Populus in Beijing, China

by Shan Wang, Zhichao Wang, Zhongke Feng, Zhuang Yu and Jinshan Li

Forests 2024, 15(6), 1059; https://doi.org/10.3390/f15061059 - 19 Jun 2024

Viewed by 674

Abstract

The accurate assessment of tree volume is crucial for developing forest management plans, and this can be achieved using tree volume models. In this study, data on individual trees were collected and calculated, including the diameter at breast height (D), ground [...] Read more.

The accurate assessment of tree volume is crucial for developing forest management plans, and this can be achieved using tree volume models. In this study, data on individual trees were collected and calculated, including the diameter at breast height (D), ground diameter (DG), tree height (H), and tree volume (V). A total of 400 Populus × tomentosa Carrière, 400 Populus tomentosa Carr, and 400 Populus × canadensis Moench trees were sampled. Two compatible volume model systems were established using corresponding methods. The models consisted of the following five types: V-DH, V-D, V-DG, H-D, and DG-D. In our calculations, before the horizontal line was the dependent variable, and behind the horizontal line was the independent variable. Variations in preferences for the H-D models were observed among the tree species, with the logistic function proving the most suitable for Populus × tomentosa Carrière, Chapman–Richard function for Populus tomentosa Carr, and power function for Populus × canadensis Moench. Among the three volume models, the V-DH model exhibited a superior performance, with its R² values ranging from 0.965 to 0.984 and mean estimated error (MPE) values ranging from 1.26% to 1.78%. Following this was the V-D model, with R² values between 0.9359 and 0.9704 and MPE values between 1.71% and 2.46%. The V-DG model ranked third, with R² values ranging from 0.8746 to 0.9501 and MPE values ranging from 2.33% to 3.16%. In the H-D model, the R² and MPE values ranged from 0.4998 to 0.7851 and from 1.31% to 1.45%, respectively. For the DG-D model, the R² values ranged from 0.9563 to 0.9868 and the MPE values ranged from 0.47% to 0.68%. Comparing both compatible methods, the nonlinear seemingly uncorrelated regression (NSUR) was more effective. The three volume models demonstrated high levels of accuracy and compatibility, providing a reliable scientific foundation for forest management and the formulation of harvesting plans in Beijing, with significant practical implications. Full article

(This article belongs to the Special Issue Precise Forestry: Forest Dynamic Change Mapping, Monitoring and Modeling)

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12 pages, 2535 KiB

Open AccessArticle

The Vibration Dynamic Model for Blister Detection in Medium-Density Fiberboard

by Zhaojun Xu, Yuxuan Wang, Tian Qiu, Xinzhou Wang and Nanfeng Zhu

Forests 2024, 15(6), 1058; https://doi.org/10.3390/f15061058 - 19 Jun 2024

Viewed by 702

Abstract

Ultrasonic detection is currently used in the industry of medium-density fiberboard to detect blister defects. Due to the small detection area of a single sensor, multiple sensors need to be used, which results in high costs. Starting from elastic thin plate vibration theory, [...] Read more.

Ultrasonic detection is currently used in the industry of medium-density fiberboard to detect blister defects. Due to the small detection area of a single sensor, multiple sensors need to be used, which results in high costs. Starting from elastic thin plate vibration theory, this paper builds a vibration dynamic model to detect blisters. The size and depth of the blister area can be established by determining the natural frequency of the thin plate vibration in the blister area. In this model, if the elastic modulus and density are known, the natural frequency of the thin plate vibration at the blister place is directly proportional to the blister depth and inversely proportional to the square of the blister radius. The size and depth of the blister can be determined by measuring the first third-order natural frequency of this area of research. A total of 25 specimens with blister sizes and depths were simulated, and the natural frequencies of the specimens were measured. Subsequently, the detection model was verified by comparing its experimental data with theoretical values. The theoretical value was highly consistent with the measured data. The measured values of the first, second, and third-order natural frequencies were slightly smaller than the theoretical calculated values, with average relative deviations of −1.6%, −1.34%, and −1.03%, respectively. As the order progressed, the deviation exhibited a downward trend, and the third-order natural frequency displayed the smallest deviation and highest accuracy. The proposed vibration dynamic model can detect larger blister areas by measuring the natural frequency, which can overcome the shortcomings of small ultrasonic detection areas in current actual industries. Thus, the practical online blister detection device is expected to be further developed. Full article

(This article belongs to the Special Issue Recent Advances in Wood Identification, Evaluation and Modification)

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13 pages, 1935 KiB

Open AccessArticle

Effects of the Co-Application of Glucose, Nitrogen, and Elevated Temperature on Buried Black Soil Carbon in a Cool Temperate Deciduous Broad-Leaved Forest

by Yasuo Iimura and Daichi Tanaka

Forests 2024, 15(6), 1057; https://doi.org/10.3390/f15061057 - 19 Jun 2024

Viewed by 770

Abstract

Accurately predicting the feedback mechanisms between forest ecosystem carbon cycling and climate change is crucial for effective climate mitigation. Understanding soil organic carbon (SOC) responses to the combined impacts of plant biomass, litter, and nitrogen deposition, especially regarding temperature sensitivity, is essential but [...] Read more.

Accurately predicting the feedback mechanisms between forest ecosystem carbon cycling and climate change is crucial for effective climate mitigation. Understanding soil organic carbon (SOC) responses to the combined impacts of plant biomass, litter, and nitrogen deposition, especially regarding temperature sensitivity, is essential but remains poorly understood. We conducted incubation experiments using buried black soil from a cool temperate deciduous broad-leaved forest in Japan, which has high C content and a highly stable molecular structure. The stepwise addition of glucose and a temperature increase from 15 to 35 °C accelerated SOC mineralization by 74.0 mg C kg⁻¹ with a positive priming effect (PE) during the 49-day incubation period, while the simultaneous addition of nitrogen had no significant effect on this phenomenon, with SOC mineralization measured at 75.5 mg C kg⁻¹. Conversely, glucose mineralization was significantly accelerated by 10%, from 241.0 to 261.3 mg C kg⁻¹, by stepwise nitrogen addition and temperature increase. Under the combined impacts, the Q₁₀ value of the soil increased significantly from 1.6 to 2.0 compared to that in the unmodified conditions, primarily due to the stepwise addition of glucose. We also found a strong positive correlation between activation energy (E_a) and Q₁₀. This result strongly supports the carbon quality–temperature (CQT) hypothesis. These results likely stem from interactions between SOC quality and carbon availability, suggesting that, in the future, climate change is likely to have a positive feedback effect, especially on buried black soils. Full article

(This article belongs to the Special Issue Soil Carbon and Nutrient Cycling in Forests)

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14 pages, 2712 KiB

Open AccessArticle

Characteristics and Driving Mechanisms of Understory Vegetation Diversity Patterns in Central and Southern China

by Yaqin Xiao, Yuxin Tian, Qingan Song and Nan Deng

Forests 2024, 15(6), 1056; https://doi.org/10.3390/f15061056 - 18 Jun 2024

Viewed by 776

Abstract

Large-scale forest restoration projects significantly reduce the net rates of forest loss. However, as a key component of forest restoration, planted forests have failed to restore biodiversity. China has implemented a large-scale afforestation program, which includes pure planted forests in particular, leading to [...] Read more.

Large-scale forest restoration projects significantly reduce the net rates of forest loss. However, as a key component of forest restoration, planted forests have failed to restore biodiversity. China has implemented a large-scale afforestation program, which includes pure planted forests in particular, leading to various changes in ecosystem processes. Despite this, a comprehensive analysis of understory vegetation diversity patterns in these pure planted forests is still lacking. This study aimed to analyze the data on understory vegetation diversity from three typical pure and natural forest ecosystems of Hunan ecological forests to reveal their diversity patterns. The results revealed no significant difference in the understory diversity index between natural and pure forest types, although natural forests had a bigger species pool. The Zipf–Mandelbrot model was a better fit for species abundance distribution. The fitted results suggested that both environmental filtering and neutral processes affected the species abundance distribution and pure understory communities during restoration succession. Natural forests had the most stable understory diversity structure, whereas pure Phyllostachys heterocycla (Carr.) Mitford forests had the least stable structure. Multivariate regression tree analysis identified indicator species for each community. The gradient boosting model indicated that isothermality and slope direction were the most important factors affecting diversity. The β-diversity analysis showed that community establishment in the four forest types was affected via different mechanisms. The findings of this study have significant implications for understanding the impact of afforestation on the mechanisms for maintaining diversity. Full article

(This article belongs to the Section Forest Biodiversity)

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41 pages, 12862 KiB

Open AccessReview

Forest Aboveground Biomass Estimation and Inventory: Evaluating Remote Sensing-Based Approaches

by Muhammad Nouman Khan, Yumin Tan, Ahmad Ali Gul, Sawaid Abbas and Jiale Wang

Forests 2024, 15(6), 1055; https://doi.org/10.3390/f15061055 - 18 Jun 2024

Cited by 2 | Viewed by 1754

Abstract

Remote sensing datasets offer robust approaches for gaining reliable insights into forest ecosystems. Despite numerous studies reviewing forest aboveground biomass estimation using remote sensing approaches, a comprehensive synthesis of synergetic integration methods to map and estimate forest AGB is still needed. This article [...] Read more.

Remote sensing datasets offer robust approaches for gaining reliable insights into forest ecosystems. Despite numerous studies reviewing forest aboveground biomass estimation using remote sensing approaches, a comprehensive synthesis of synergetic integration methods to map and estimate forest AGB is still needed. This article reviews the integrated remote sensing approaches and discusses significant advances in estimating the AGB from space- and airborne sensors. This review covers the research articles published during 2015–2023 to ascertain recent developments. A total of 98 peer-reviewed journal articles were selected under the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Among the scrutinized studies, 54 were relevant to spaceborne, 22 to airborne, and 22 to space- and airborne datasets. Among the empirical models used, random forest regression model accounted for the most articles (32). The highest number of articles utilizing integrated dataset approaches originated from China (24), followed by the USA (15). Among the space- and airborne datasets, Sentinel-1 and 2, Landsat, GEDI, and Airborne LiDAR datasets were widely employed with parameters that encompassed tree height, canopy cover, and vegetation indices. The results of co-citation analysis were also determined to be relevant to the objectives of this review. This review focuses on dataset integration with empirical models and provides insights into the accuracy and reliability of studies on AGB estimation modeling. Full article

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

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24 pages, 5631 KiB

Open AccessArticle

Siberian Pine and Larch Response to Warming-Drying Climate in the Southern Boundary of Their Range

by Ilya A. Petrov, Viacheslav I. Kharuk, Alexey S. Golyukov, Sergei T. Im, Sergei O. Ondar and Alexander S. Shushpanov

Forests 2024, 15(6), 1054; https://doi.org/10.3390/f15061054 - 18 Jun 2024

Cited by 1 | Viewed by 962

Abstract

Trees’ growth and areal responses to changing climate are primarily expected within the edges of the species range. Here, we compared the responses of Siberian pine (Pinus sibirica Du Tour), a moisture-sensitive species, and drought-resistant larch (Larix sibirica Ledeb.) at the [...] Read more.

Trees’ growth and areal responses to changing climate are primarily expected within the edges of the species range. Here, we compared the responses of Siberian pine (Pinus sibirica Du Tour), a moisture-sensitive species, and drought-resistant larch (Larix sibirica Ledeb.) at the southern part of their ranges in the Siberian Mountains (the Tannu-Ola Ridge). We study the species’ growth and proportion in the forests from forest-steppe to treeline ecotone along the elevation gradient. These studies are based on radial growth index (GI) analysis and GI dependence on the climate variables. We used satellite time series to detect the land cover changes (areas of larch and Siberian pine, as well as shrubs and birch). We compared trees’ GI before and after warming “restart” in the late 1990s. Generally, GI dependence on the air temperature was negative at elevations below c. 1600 m a.s.l., whereas GI dependence on the moisture variables (precipitation, vapor pressure deficit, and soil moisture) was positive for both species. Above 1600 m, increasing air temperatures stimulated species growth, whereas the influence of moisture variables was negative (for larch) or neutral (for Siberian pine). After the warming restart, the GI of both conifers increased in moisture-sufficient high elevations and treeline ecotone, whereas within low elevations (<1300 m), the GI was stagnant or suppressed. Both species’, especially Siberian pine, negative growth dependence on air temperature and positive dependence on the moisture variables strongly increased since the warming restart. We found a risen growth dependence of both species on the soil-stored water during the previous year (September–October), which smoothed moisture stress at the beginning of the growing season. Yet both species’ growth also suffered as a result of early spring warms. We found that larch is migrating in both uphill and downhill directions, while Siberian pine is migrating uphill only. Forests loss occurred at low elevations (<1300 m), whereas forest and shrub gain occurred at high (>2000 m) ones. The upper boundary of the forests and shrubs is migrating uphill at rates of about 0.8 and 0.3 m/y, respectively. We observed a decrease in Siberian pine proportion in the forests, whereas areas of larch and birch strongly increased (by 150% and 100%, respectively), which indicates the retreat of Siberian pine from its southern habitat. We suggested afforestation of the areas of Siberian pine mortality by the drought-tolerant larch species. Full article

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13 pages, 15265 KiB

Open AccessArticle

Effects of Soil Microorganisms on Carbon Sequestration under Different Mixed Modification Models in Pinus massoniana L. Plantation

by Meng Chen, Congjun Yuan, Shuang He, Jin Chen, Jun Luo, Fangjun Ding and Guohua Yan

Forests 2024, 15(6), 1053; https://doi.org/10.3390/f15061053 - 18 Jun 2024

Viewed by 885

Abstract

In forests, microbial populations in the soil can directly influence the decomposition of carbon from surface plants, promoting carbon storage and stability. However, in sustainable forest management, it is still unclear how soil microorganisms under different plantation types affect organic carbon sequestration and [...] Read more.

In forests, microbial populations in the soil can directly influence the decomposition of carbon from surface plants, promoting carbon storage and stability. However, in sustainable forest management, it is still unclear how soil microorganisms under different plantation types affect organic carbon sequestration and whether the mechanisms of influence are the same. In this research, we focused on four mixed forests and pure Pinus massoniana-planted forest in the state-owned forest farm of Dushan County. Three replicated plots were set up for each model, and soil samples were collected from different layers (0–20 cm, 20–40 cm, and 40–60 cm), totaling 45 samples. We elucidated the effects of soil microorganisms on carbon sequestration under five mixed modification models of P. massoniana and further explored the mechanisms by which microbial functional communities regulate soil carbon sequestration under different mixed models through molecular sequencing and collinear network analysis. Variance analysis indicated that the soil organic carbon (SOC) of the same soil layer varied significantly, and there were also significant differences in the composition of soil bacterial and fungal microbial communities. Moreover, the bacterial community was more sensitive to changes in the vegetation environment, while the fungal community structure was more resistant to changes in the soil environment. Correlation analysis indicated that the diversity and composition of the bacterial community had more positive effects on soil organic carbon than those of the fungal community. Linear fitting and redundancy analysis (RDA) showed that particulate organic carbon (POC) in soil had the strongest correlation with SOC content. Soil microorganisms affected the storage and stability of soil carbon mainly by regulating the conversion of litter (carbon sources) into POC. The soil environment of different mixed models had different effects on soil carbon accumulation. Both correlation and collinearity network analyses indicated that soil microbial functional groups could enhance carbon storage by regulating readily oxidizable carbon (EOC) and POC content in mixed forest plantations. The results of our study provide a sound basis for replanting a reasonable forest model structure to improve forest carbon storage. Full article

(This article belongs to the Section Forest Soil)

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18 pages, 2067 KiB

Open AccessArticle

Evaluation of Different Modeling Approaches for Estimating Total Bole Volume of Hispaniolan Pine (Pinus occidentalis Swartz) in Different Ecological Zones

by Santiago W. Bueno-López, Luis R. Caraballo-Rojas and Juan G. Torres-Herrera

Forests 2024, 15(6), 1052; https://doi.org/10.3390/f15061052 - 18 Jun 2024

Viewed by 589

Abstract

Pinus occidentalis (Swartz) is the primary timber species in the Dominican Republic (DR). Despite its economic importance, studies conducted on this species are scarce, making it difficult to estimate current inventory levels. This study aims to enhance the accuracy of estimating the total [...] Read more.

Pinus occidentalis (Swartz) is the primary timber species in the Dominican Republic (DR). Despite its economic importance, studies conducted on this species are scarce, making it difficult to estimate current inventory levels. This study aims to enhance the accuracy of estimating the total bole volume of P. occidentalis in different ecological zones (EZs) within La Sierra, evaluating and comparing two established volume equations—combined variable (CV) and Schumacher and Hall (S&H) across nine modeling variants. An indicator variables analysis determined the necessity of distinct equations for two EZs. Fitting included both linear and nonlinear models. Our comprehensive statistical analysis included goodness-of-fit metrics to evaluate each model variant’s performance rigorously. The second modeling variant (SH02) for the SH equation was most effective in the Dry Ecological Zone, showing superior performance in both the fitting and validation phases. Similarly, the third modeling variant (SH03) for the SH equation emerged as the best fit for the Combined Intermediate and Humid Ecological Zones, achieving the lowest overall ranking sum among tested variants. SH02 and SH03 provide reliable and precise volume estimations, allowing for the optimization of forestry management practices for P. occidentalis trees. The SH models outperformed the CV model variants’ consistency in parameter estimation. This tailored approach ensures more accurate volume predictions, which is crucial for sustainable management and conservation efforts. Full article

(This article belongs to the Special Issue Forest Biometrics, Inventory, and Modelling of Growth and Yield)

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15 pages, 3579 KiB

Open AccessArticle

Woody Plant Structural Diversity Changes across an Inverse Elevation-Dependent Warming Gradient in a Subtropical Mountain Forest

by Yuqiao Su, Xianhua Gan, Weiqiang Zhang, Guozhang Wu and Fangfang Huang

Forests 2024, 15(6), 1051; https://doi.org/10.3390/f15061051 - 18 Jun 2024

Viewed by 756

Abstract

Examining the changes in woody plant structural diversity along an inverse elevation-dependent warming gradient will enhance our mechanistic understanding of how warming affects forest communities because such an inverse elevational gradient reflects a warming trend in a mountain landscape. Here, we investigated the [...] Read more.

Examining the changes in woody plant structural diversity along an inverse elevation-dependent warming gradient will enhance our mechanistic understanding of how warming affects forest communities because such an inverse elevational gradient reflects a warming trend in a mountain landscape. Here, we investigated the effects of warming on the patterns of species composition and structural diversity in a subtropical broadleaved forest. We calculated a warming index based on elevational difference and modeled the aspect-related potential incident radiation (PDIR) using nonparametric multiplicative regression. We tested the changes in structural diversity of three communities for significant differences along the warming gradient. We associated both the warming index and PDIR with the principal components and tested their relationships for significant differences. We found that trees of different sizes varied in their response to the warming gradient. While a significant decreasing trend was exhibited in both species diversity and size diversity for trees of all sizes and for adult trees along the warming gradient, no significant changes in seedlings were found, and the average basal area value was the highest for the warmest community. Our findings demonstrated that a short-range elevational gradient was adequate to separate the communities in species composition and structural diversity. Patterns of structural diversity along the warming gradient varied in size classes. The community at a higher elevation had more indicator species that were unique in separating the community from others. Principal component analysis showed that the first two principal components were negatively correlated with the warming index, indicating that warming destabilized species composition and community structure. Our study suggests that warming is the major driver of changes in structural diversity and species composition of woody plant communities in a subtropical broadleaved forest and that warming may promote tree productivity at the community level but reduce structural diversity at the quadrat level. Full article

(This article belongs to the Special Issue Advances in Forest Cover Change and Its Ecological and Environmental Effects—2nd Edition)

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16 pages, 7035 KiB

Open AccessArticle

A Lightweight Pine Wilt Disease Detection Method Based on Vision Transformer-Enhanced YOLO

by Quanbo Yuan, Suhua Zou, Huijuan Wang, Wei Luo, Xiuling Zheng, Lantao Liu and Zhaopeng Meng

Forests 2024, 15(6), 1050; https://doi.org/10.3390/f15061050 - 18 Jun 2024

Cited by 2 | Viewed by 1058

Abstract

Pine wilt disease (PWD) is a forest disease characterized by rapid spread and extremely high lethality, posing a serious threat to the ecological security of China’s forests and causing significant economic losses in forestry. Given the extensive forestry area, limited personnel for inspection [...] Read more.

Pine wilt disease (PWD) is a forest disease characterized by rapid spread and extremely high lethality, posing a serious threat to the ecological security of China’s forests and causing significant economic losses in forestry. Given the extensive forestry area, limited personnel for inspection and monitoring, and high costs, utilizing UAV-based remote sensing monitoring for diseased trees represents an effective approach for controlling the spread of PWD. However, due to the small target size and uneven scale of pine wilt disease, as well as the limitations of real-time detection by drones, traditional disease tree detection algorithms based on RGB remote sensing images do not achieve an optimal balance among accuracy, detection speed, and model complexity due to real-time detection limitations. Consequently, this paper proposes Light-ViTeYOLO, a lightweight pine wilt disease detection method based on Vision Transformer-enhanced YOLO (You Only Look Once). A novel lightweight multi-scale attention module is introduced to construct an EfficientViT feature extraction network for global receptive field and multi-scale learning. A novel neck network, CACSNet(Content-Aware Cross-Scale bidirectional fusion neck network), is designed to enhance the detection of diseased trees at single granularity, and the loss function is optimized to improve localization accuracy. The algorithm effectively reduces the number of parameters and giga floating-point operations per second (GFLOPs) of the detection model while enhancing overall detection performance. Experimental results demonstrate that compared with other baseline algorithms, Light-ViTeYOLO proposed in this paper has the least parameter and computational complexity among related algorithms, with 3.89 MFLOPs and 7.4 GFLOPs, respectively. The FPS rate is 57.9 (frames/s), which is better than the original YOLOv5. Meanwhile, its [email protected]:0.95 is the best among the baseline algorithms, and the recall and [email protected] slightly decrease. Our Light-ViTeYOLO is the first lightweight method specifically designed for detecting pine wilt disease. It not only meets the requirements for real-time detection of pine wilt disease outbreaks but also provides strong technical support for automated forestry work. Full article

(This article belongs to the Special Issue Applications of Artificial Intelligence in Forestry)

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13 pages, 4264 KiB

Open AccessArticle

The Potential Distribution Prediction of the Forestry Pest Cyrtotrachelus buqueti (Guer) Based on the MaxEnt Model across China

by Chun Fu, Zhiling Wang, Yaqin Peng and Zhihang Zhuo

Forests 2024, 15(6), 1049; https://doi.org/10.3390/f15061049 - 18 Jun 2024

Cited by 1 | Viewed by 829

Abstract

Exploring the geographical distribution of forestry pests is crucial for formulating pest management strategies. Cyrtotrachelus buqueti (Guer) stands out as one of the primary pests among China’s forestry hazards. This study employs the MaxEnt model, along with 19 bioclimatic variables and habitat characteristics, [...] Read more.

Exploring the geographical distribution of forestry pests is crucial for formulating pest management strategies. Cyrtotrachelus buqueti (Guer) stands out as one of the primary pests among China’s forestry hazards. This study employs the MaxEnt model, along with 19 bioclimatic variables and habitat characteristics, to predict the current and future distribution of C. buqueti under three typical emission scenarios for 2050 and 2070 (2.6 W/m² (SSP1-2.6), 7.0 W/m² (SSP3-7.0), and 8.5 W/m² (SSP5-8.5)). Among the 19 bioclimatic variables, BIO 14 (precipitation of the driest month), BIO 8 (mean temperature of the wettest quarter), Elev, slope, and aspect were identified as significant contributors. These five variables are critical environmental factors affecting the suitability of habitats for C. buqueti and are representative of its potential habitat. The results indicate that C. buqueti predominantly inhabits southern regions such as Chongqing, Guizhou, Yunnan, Sichuan, Guangxi, Shaanxi, Hubei, Hainan, and Taiwan. Among them, Chongqing, Guizhou, and Yunnan are the primary distribution areas of high suitability. In the future, the centroid’s movement direction will generally shift southward, with an expansion trend observed in the distribution areas of each province. This study enhances researchers’ understanding of forestry pest dynamics and promotes proactive management strategies to mitigate their impact on forest ecosystems and agricultural productivity. Full article

(This article belongs to the Special Issue Biological Control of Forest Pests: Patterns, Mechanisms, and Prospects)

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11 pages, 4768 KiB

Open AccessArticle

The Culprit behind the Mass Death of Mangroves: Egrets or Rats (Rattus losea)?

by Yunhong Xue, Wenai Liu, Lianghao Pan, Yancheng Tao, Xin Liao, Qiuxia Liang, Huiying Wu and Weiguo Jiang

Forests 2024, 15(6), 1048; https://doi.org/10.3390/f15061048 - 18 Jun 2024

Viewed by 839

Abstract

Mangroves play a crucial role in maintaining coastal ecological balance. This study focused on the impact of branch-breaking behavior on the mortality of Rhizophora stylosa in the Guangxi Shankou Mangrove Reserve. However, we found mangrove mortality in areas devoid of egret habitation, prompting [...] Read more.

Mangroves play a crucial role in maintaining coastal ecological balance. This study focused on the impact of branch-breaking behavior on the mortality of Rhizophora stylosa in the Guangxi Shankou Mangrove Reserve. However, we found mangrove mortality in areas devoid of egret habitation, prompting a reevaluation of our research hypothesis. Further investigation suggested that nesting behavior was the primary cause of mangrove mortality. A comparison of the data from areas with egrets (Egretta garzetta, Ardea intermedia) and lesser rice-field rats (Rattus losea) activity indicated significant mechanical damage caused by rats to mangroves as the main cause of mortality. Additionally, we found that the biological characteristics of R. stylosa, particularly its stunted growth and recovery abilities after branch breaking, were key factors affecting its survival. These findings imply that rat-induced mortality may not occur in other less susceptible mangrove species. The results contradict assumptions regarding the impact of egret behavior and highlight the importance of the biological characteristics of R. stylosa. This offers fresh insights into mangrove conservation and management, emphasizing the need for ongoing observation and hypotheses verification. Future studies should explore the influence of lesser rice-field rats’ activity and the intrinsic characteristics of R. stylosa on the ecosystem’s long-term stability. Full article

(This article belongs to the Section Forest Health)

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18 pages, 2174 KiB

Open AccessArticle

Analyzing the Eucalyptus Timber Value Chain in Thailand: Profit Distribution and Opportunities for Improvement

by Aerwadee Premashthira, Kitipong Tangkit, Warayost Lamaisri, Nopparat Kaakkurivaara, Chakrit Na Takuathung, Trairat Neimsuwan, Narinthorn Jumwong, Ponthep Meunpong and Tomi Kaakkurivaara

Forests 2024, 15(6), 1047; https://doi.org/10.3390/f15061047 - 18 Jun 2024

Viewed by 1510

Abstract

The Thai forestry sector relies greatly on Eucalyptus as a raw material. The rapid expansion of plantations during the last few decades and the high demand for Eucalyptus for several purposes has led to numerous supply chain practices. A comprehensive understanding of the [...] Read more.

The Thai forestry sector relies greatly on Eucalyptus as a raw material. The rapid expansion of plantations during the last few decades and the high demand for Eucalyptus for several purposes has led to numerous supply chain practices. A comprehensive understanding of the Eucalyptus value chain is lacking in Thailand, which has consequences for optimization, sustainability, and profitability aspects. This study analyzed actors and their activities along the value chain and estimated added value and profit margin benefit distributions. The study method involved a value chain analysis approach, whereby input data were collected from the following groups: seedling suppliers and developers, farmers and tree growers, timber traders and collectors, intermediaries, processors, wholesalers, and consumers via key informant interviews, in-depth interviews, and group discussions. The results revealed the vertical integration of Eucalyptus timber businesses, where sapling breeders were the major input suppliers with a significant role in the value chain based on the role of controlling the majority of seedling production, promoting cultivation, and ensuring the raw material supply for the pulp industry through a full-cycle membership program. Total gross marketing margin was highest (90.6%) in the path of the pulp mill industry and lowest in the path of the biomass power plant (73.4%). The profit share of growers varied between 9.9% and 26.6% depending on the path and chain. The overall benefit distribution analysis demonstrated a positive gross profit margin but minor distribution to the growers. Our study determined that decision-makers should create supportive programs, funding opportunities, and infrastructural support for research and development, capacity building, and regulation to ensure suitable benefits for all actors in the Eucalyptus timber value chain in Thailand. Full article

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

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24 pages, 13312 KiB

Open AccessArticle

A Multi-Criterion Evaluation Process for Determining Cost-Effective Harvesting Systems in Fragmented Boreal Forests

by Léo Painchaud and Luc LeBel

Forests 2024, 15(6), 1046; https://doi.org/10.3390/f15061046 - 17 Jun 2024

Cited by 2 | Viewed by 882

Abstract

Nordic forests, like those found in Canada, used to consist of large and relatively homogeneous mature stands. Such a spatial pattern allows for harvest operations to be highly concentrated, minimizing procurement costs. However, the growing fragmentation of these forests makes planning difficult and [...] Read more.

Nordic forests, like those found in Canada, used to consist of large and relatively homogeneous mature stands. Such a spatial pattern allows for harvest operations to be highly concentrated, minimizing procurement costs. However, the growing fragmentation of these forests makes planning difficult and increases the costs of road building and machinery relocation. While operational solutions have been developed in regions with small harvest areas, their transferability to different settings is unknown. Finding the most suitable combination of equipment for a given context is challenging considering the multitude of possibilities. The objective of this study is to identify, from all possible options, a subset of harvest systems expected to perform well in fragmented boreal forests. The results from this research are two-fold. First, a comprehensive review of forest machines and harvest systems is provided. Second, a multi-criteria decision analysis (MCDA) methodology is proposed to evaluate the alternatives. In a boreal forest context, the conventional harvester-forwarder system (CTL) was ranked among the best solutions, along with mild adaptations of the usual configurations. Several whole-tree (WT) system configurations were also highly ranked. While the results are specific to the case studied, the review and selection methodology can serve in different operational contexts. Full article

(This article belongs to the Special Issue Sustainable Forest Operations Planning and Management)

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13 pages, 12826 KiB

Open AccessArticle

Virulence and Pathological Characteristics of a New Metarhizium anisopliae Strain against Asian Long-Horn Beetle Anoplophora glabripennis Larvae

by Ji-Yang Zheng, Chun-Cheng Jian and Dun Wang

Forests 2024, 15(6), 1045; https://doi.org/10.3390/f15061045 - 17 Jun 2024

Viewed by 813

Abstract

The Asian long-horn beetle (ALB) is a serious wood-boring insect. Continuous isolation of different fungal strains is vital for using fungi for the control of ALB. The virulence and pathological characteristics of a new Metarhizium anisopliae strain DES3 isolated from the desert afforestation [...] Read more.

The Asian long-horn beetle (ALB) is a serious wood-boring insect. Continuous isolation of different fungal strains is vital for using fungi for the control of ALB. The virulence and pathological characteristics of a new Metarhizium anisopliae strain DES3 isolated from the desert afforestation stands against the larvae of ALB were assessed in this study. The corrected mortality reached 100% at the conidial concentration of 10⁹ and 10⁸ conidia/mL, and 91.11 ± 4.44% at 10⁷ conidia/mL. Similarly, the LC/LT showed high virulence as well. Meanwhile, the virulence of a commercial M. anisopliae strain against the ALB larvae was evaluated. The corrected mortality was only 33.33% at 10⁹ conidia/mL, and less than 10% at 10⁸ conidia/mL. The pathological characteristics after infection by the M. anisopliae strain DES3 were evident, mainly embodied in the rupture of the adipose tissue, muscle tissue, and midgut. But there was no obvious change after infection by the commercial M. anisopliae strain. In conclusion, these results establish that the M. anisopliae strain DES3 has high virulence in a dosage-dependent manner against ALB larvae, indicating the potential of fungal strain DES3 to be developed as biopesticide for biocontrol of A. glabripennis. Full article

(This article belongs to the Section Forest Health)

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11 pages, 4330 KiB

Open AccessArticle

Involvement of the Transporter CgTrk1 in Potassium Uptake, Invasive Growth, and Full Virulence in Colletotrichum gloeosporioides

by Zhi Wang, Jiyun Yang, Meiling Sun, Yuting Pan and Lin Huang

Forests 2024, 15(6), 1044; https://doi.org/10.3390/f15061044 - 17 Jun 2024

Viewed by 782

Abstract

Colletotrichum gloeosporioides is one of the more economically important pathogen causing anthracnose on crops and trees worldwide. As an essential mineral nutrient, potassium play a vital role for fundamental cellular processes in organisms. In this study, a high-affinity potassium transporter CgTrk1 was identified [...] Read more.

Colletotrichum gloeosporioides is one of the more economically important pathogen causing anthracnose on crops and trees worldwide. As an essential mineral nutrient, potassium play a vital role for fundamental cellular processes in organisms. In this study, a high-affinity potassium transporter CgTrk1 was identified in C. gloeosporioides. Cytological examinations revealed that CgTrk1 was localized in the plasma membrane. The gene deletion mutant of CgTRK1 significantly depressed the potassium uptake. CgTrk1 is also required for vegetative growth, appressorium development, invasive growth, and full virulence. The data also indicate that CgTrk1 plays dominant roles in potassium uptake and pathogenicity rather than its homologous protein CgTrk2. These results imply that the potassium transporter CgTrk1 is involved in invasive growth and full virulence in C. gloeosporioides. Full article

(This article belongs to the Special Issue Diversity, Taxonomy and Functions of Forest Microorganisms)

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21 pages, 4299 KiB

Open AccessArticle

A Hybrid Method for Individual Tree Detection in Broadleaf Forests Based on UAV-LiDAR Data and Multistage 3D Structure Analysis

by Susu Deng, Sishuo Jing and Huanxin Zhao

Forests 2024, 15(6), 1043; https://doi.org/10.3390/f15061043 - 17 Jun 2024

Cited by 2 | Viewed by 1208

Abstract

Individual tree detection and segmentation in broadleaf forests have always been great challenges due to the overlapping crowns, irregular crown shapes, and multiple peaks in large crowns. Unmanned aerial vehicle (UAV)-borne light detection and ranging (LiDAR) is a powerful tool for acquiring high-density [...] Read more.

Individual tree detection and segmentation in broadleaf forests have always been great challenges due to the overlapping crowns, irregular crown shapes, and multiple peaks in large crowns. Unmanned aerial vehicle (UAV)-borne light detection and ranging (LiDAR) is a powerful tool for acquiring high-density point clouds that can be used for both trunk detection and crown segmentation. A hybrid method that combines trunk detection and crown segmentation is proposed to detect individual trees in broadleaf forests based on UAV-LiDAR data. A trunk point distribution indicator-based approach is first applied to detect potential trunk positions. The treetops extracted from a canopy height model (CHM) and the crown segments obtained by applying a marker-controlled watershed segmentation to the CHM are used to identify potentially false trunk positions. Finally, the three-dimensional structures of trunks and branches are analyzed at each potentially false trunk position to distinguish between true and false trunk positions. The method was evaluated on three plots in subtropical urban broadleaf forests with varying proportions of evergreen trees. The F-score in three plots ranged from 0.723 to 0.829, which are higher values than the F-scores derived by a treetop detection method (0.518–0.588) and a point cloud-based individual tree segmentation method (0.479–0.514). The influences of the CHM resolution (0.25 and 0.1 m) and the data acquisition season (leaf-off and leaf-on) on the final individual tree detection result were also evaluated. The results indicated that using the CHM with a 0.25 m resolution resulted in under-segmentation of crowns and higher F-scores. The data acquisition season had a small influence on the individual tree detection result when using the hybrid method. The proposed hybrid method needs to specify parameters based on prior knowledge of the forest. In addition, the hybrid method was evaluated in small-scale urban broadleaf forests. Further research should evaluate the hybrid method in natural forests over large areas, which differ in forest structures compared to urban forests. Full article

(This article belongs to the Topic Individual Tree Detection (ITD) and Its Applications)

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Forests, Volume 15, Issue 6 (June 2024) – 181 articles

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