Forests

25 pages, 1127 KiB

Open AccessArticle

Pedunculate Oak (Quercus robur L.) Crown Defoliation as an Indicator of Timber Value

by Branko Ursić and Dinko Vusić

Forests 2025, 16(7), 1111; https://doi.org/10.3390/f16071111 - 4 Jul 2025

Pedunculate oak (Quercus robur L.), an ecologically and economically important tree species has been significantly affected by oak dieback in recent years. Since one of the symptoms of oak dieback is crown defoliation, this research aimed to determine the quantity, quality, average [...] Read more.

Pedunculate oak (Quercus robur L.), an ecologically and economically important tree species has been significantly affected by oak dieback in recent years. Since one of the symptoms of oak dieback is crown defoliation, this research aimed to determine the quantity, quality, average tree value, and wood defects that influence grading in different stages of oak dieback indicated by tree crown defoliation degree. The research was conducted in a 62- and 116-year-old stand of the lowland Croatian forest. In total, 115 pedunculate oak trees were sampled and processed in 983 logs that were analyzed. The prescribed single-entry volume tables underestimate harvesting volume by 5.45% on site A and 6.16% on site B, while the calculation of net harvesting volume underestimates net volume by 0.26% on site A and overestimates net volume on site B by 4.59%. The analysis of wood defect presence showed that insect holes, rot, and covered knots were the main reasons for the degradation of quality class. Dead trees showed a decreased average tree value in DBH classes 32.5–42.5 cm compared to the healthy trees. Based on the findings of this research, tree crown defoliation degree could be used as a timber quality and average tree value indicator. Full article

(This article belongs to the Section Wood Science and Forest Products)

22 pages, 2426 KiB

Open AccessArticle

Urea Fertilization Buffered Acid-Inhibiting Effect on Litter Decomposition in Subtropical Plantation Forests of Southern China

by Yonghui Lin, Xiangshi Kong, Zaihua He and Xingbing He

Forests 2025, 16(7), 1110; https://doi.org/10.3390/f16071110 - 4 Jul 2025

Abstract

Acid deposition, a major environmental issue causing soil acidification and microbial suppression, impacts forest nutrient cycling. Meanwhile, nitrogen (N) fertilization is widely applied in subtropical forests, yet its interaction with acid deposition on litter decomposition is unclear. We conducted a field experiment using [...] Read more.

Acid deposition, a major environmental issue causing soil acidification and microbial suppression, impacts forest nutrient cycling. Meanwhile, nitrogen (N) fertilization is widely applied in subtropical forests, yet its interaction with acid deposition on litter decomposition is unclear. We conducted a field experiment using two common tree species, Cunninghamia lanceolata and Cinnamomum camphora, and applied three acid deposition levels (0, 0.25, and 0.50 g H⁺ m⁻² month⁻¹) and four N fertilization levels (0, 3, 6, and 9 g N m⁻² year⁻¹) in a factorial design. Our results showed that acid deposition alone significantly reduced litter decomposition rates, with maximum mass loss decreasing by 23.6% for Cunninghamia and 36.3% for Cinnamomum (p < 0.05). Urea fertilization alone also suppressed decomposition, reducing maximum mass loss by 27.3% for Cunninghamia and 37.3% for Cinnamomum (p < 0.05). However, when combined, urea fertilization mitigated the suppressive effect of acid deposition, particularly under severe acid conditions, where maximum mass loss increased by 18.5% for Cunninghamia and 43.1% for Cinnamomum (p < 0.05). Acid deposition reduced microbial respiration and enzyme activities related to carbon cycling, while urea fertilization showed both positive and negative effects depending on the acid levels (p < 0.05). Urea can enhance the litter layer’s acid-buffering capacity, offering potential management insights for acid deposition-affected forests. Further research on microbial mechanisms across ecosystems is recommended. Full article

(This article belongs to the Special Issue Belowground Carbon Flux in Forests: Carbon Emission, Storage and Beyond)

26 pages, 1407 KiB

Open AccessArticle

The Binary Moderating Effect of Forest New Quality Productive Forces on the Efficiency of Forest Ecosystem Services Value Realization

by Tingyu Yang, Hongliang Lu and Ali Raza

Forests 2025, 16(7), 1109; https://doi.org/10.3390/f16071109 - 4 Jul 2025

Abstract

The realization of forest ecological functions value is an important path for implementing the “Two Mountains” theory. Improving the efficiency of forest ecological functions and benefits value realization faces several challenges, such as an underdeveloped value evaluation system that makes it difficult to [...] Read more.

The realization of forest ecological functions value is an important path for implementing the “Two Mountains” theory. Improving the efficiency of forest ecological functions and benefits value realization faces several challenges, such as an underdeveloped value evaluation system that makes it difficult to quantify ecological value, a weak policy system lacking effective incentive mechanisms, and unclear ecological property rights leading to unfair benefits distribution. Forest new quality productive drivers are a key factor in promoting high-quality forestry development, and can effectively address several issues hindering the efficiency of forest ecological functions and benefits value realization. Forest ecological functions and benefits are divided into tangible forest products and intangible ecological services, with the efficiency of realizing their economic and welfare values reflecting the input–output status of forest ecological value. This paper constructs an indicator system for assessing the modern productive capacity in forestry and the efficiency of forest ecological value realization, and uses a two-stage network DEA model and a double fixed effects model for empirical analysis. The study finds that the advanced drivers of forestry productivity significantly enhance the efficiency of forest ecological economic value realization but constrain the efficiency of ecological welfare value realization, with significant regional differences. As a moderating variable, enhancing the resilience of the industry chain can significantly deepen the effect throughout the process, while improving the informatization level of residents can weaken the constraints of forest new quality productive drivers on the efficiency of forest ecological welfare value realization. Therefore, this paper offers targeted recommendations aimed at providing theoretical support and practical guidance for optimizing the efficiency of forest ecological value realization. Full article

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

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15 pages, 1019 KiB

Open AccessArticle

Genotypic Variability in Growth and Leaf-Level Physiological Performance of Highly Improved Genotypes of Pinus radiata D. Don Across Different Sites in Central Chile

by Sergio Espinoza, Marco Yáñez, Carlos Magni, Eduardo Martínez-Herrera, Karen Peña-Rojas, Sergio Donoso, Marcos Carrasco-Benavides and Samuel Ortega-Farias

Forests 2025, 16(7), 1108; https://doi.org/10.3390/f16071108 - 4 Jul 2025

Abstract

Pinus radiata D. Don is planted in South Central Chile on a wide range of sites using genetically improved genotypes for timber production. As drought events are expected to increase with ongoing climatic change, the variability in gas exchange, which could impact growth [...] Read more.

Pinus radiata D. Don is planted in South Central Chile on a wide range of sites using genetically improved genotypes for timber production. As drought events are expected to increase with ongoing climatic change, the variability in gas exchange, which could impact growth and water use, needs to be evaluated. In this study, we assessed the genotypic variability of leaf-level light-saturated photosynthesis (A_sat), stomatal conductance (g_s), transpiration (E), intrinsic water use efficiency (iWUE), and Chlorophyll a fluorescence (OJIP-test parameters) among 30 P. radiata genotypes (i.e., full-sib families) from third-cycle parents at age 6 years on three sites in Central Chile. We also evaluated tree height (HT), diameter at breast height (DBH), and stem index volume (VOL). Families were ranked for HT as top-15 and bottom-15. In the OJIP-test parameters we observed differences at the family level for the maximum quantum yield of primary PSII photochemistry (Fv/Fm), the probability that a photon trapped by the PSII reaction center enters the electron transport chain (ψ_Eo), and the potential for energy conservation from photons captured by PSII to the reduction in intersystem electron acceptors (PI_ABS). Fv/Fm, PI_ABS, and ψ_Eo ranged from 0.82 to 0.87, 45 to 95, and 0.57 to 0.64, respectively. Differences among families for growth and not for leaf-level physiology were detected. DBT, H, and VOL were higher in the top-15 families (12.6 cm, 8.4 m, and 0.10 m³, respectively) whereas A_sat, g_s, E, and iWUE were similar in both the top-15 and bottom-15 families (4.0 μmol m⁻² s⁻¹, 0.023 mol m⁻² s⁻¹, 0.36 mmol m⁻² s⁻¹, and 185 μmol mol m⁻² s⁻¹, respectively). However, no family by site interaction was detected for growth and leaf-level physiology. The results of this study suggest that highly improved genotypes of P. radiata have uniformity in leaf-level physiological rates, which could imply uniform water use at the stand-level. The family variation found in PI_ABS suggests that this parameter could be incorporated to select genotypes tolerant to environmentally stressful conditions. Full article

(This article belongs to the Special Issue Water Use Efficiency of Forest Trees)

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22 pages, 5340 KiB

Open AccessArticle

Vegetation Growth Carryover and Lagged Climatic Effect at Different Scales: From Tree Rings to the Early Xylem Growth Season

by Jiuqi Chen, Yonghui Wang, Tongwen Zhang, Kexiang Liu, Kailong Guo, Tianhao Hou, Jinghui Song, Zhihao He and Beihua Liang

Forests 2025, 16(7), 1107; https://doi.org/10.3390/f16071107 - 4 Jul 2025

Abstract

Vegetation growth is influenced not only by current climatic conditions but also by growth-enhancing signals and preceding climate factors. Taking the dominant species, Juniperus seravschanica Kom, in Tajikistan as the research subject, this study combines tree-ring width data with early xylem growth season [...] Read more.

Vegetation growth is influenced not only by current climatic conditions but also by growth-enhancing signals and preceding climate factors. Taking the dominant species, Juniperus seravschanica Kom, in Tajikistan as the research subject, this study combines tree-ring width data with early xylem growth season data (from the start of xylem growth to the first day of the NDVI peak month), simulated using the Vaganov–Shashkin (V-S) model, a process-based tree-ring growth model. This study aims to explore the effects of vegetation growth carryover (VGC) and lagged climatic effects (LCE) on tree rings and the early xylem growth season at two different scales by integrating tree-ring width data and xylem phenology simulations. A vector autoregression (VAR) model was employed to analyze the response intensity and duration of VGC and LCE. The results show that the VGC response intensity in the early xylem growth season is higher than that of tree-ring width. The LCE duration for both the early xylem growth season and tree-ring width ranges from 0 to 11 (years or seasons), with peak LCE response intensity observed at a lag of 2–3 (years or seasons). The persistence of the climate lag effect on vegetation growth has been underestimated, supporting the use of a lag of 0–3 (years or seasons) to study the long-term impacts of climate. The influence of VGC on vegetation growth is significantly stronger than that of LCEs; ultimately indicating that J. seravschanica adapts to harsh environments by modulating its growth strategy through VGC and LCE. Investigating the VGC and LCE of multi-scale xylem growth indicators enhances our understanding of forest ecosystem dynamics. Full article

(This article belongs to the Special Issue Tree-Ring Analysis: Response and Adaptation to Climate Change)

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26 pages, 1917 KiB

Open AccessArticle

A System Dynamics Approach to Resilience Analysis in the Sino-Russian Timber Supply Chain

by Chenglin Ma, Changjiang Liu, Jiajia Feng and Lin Zhang

Forests 2025, 16(7), 1106; https://doi.org/10.3390/f16071106 - 4 Jul 2025

Abstract

In the context of global timber supply chains facing policy adjustments, resource fluctuations, and market uncertainties, this study focuses on the resilience of the Sino-Russian timber supply chain. A system dynamics (SD) model is developed to analyze the dynamic evolution of the key [...] Read more.

In the context of global timber supply chains facing policy adjustments, resource fluctuations, and market uncertainties, this study focuses on the resilience of the Sino-Russian timber supply chain. A system dynamics (SD) model is developed to analyze the dynamic evolution of the key segments. By integrating the entropy weight–TOPSIS method, the research quantitatively assesses overall supply chain resilience by synthesizing data from four capability dimensions—Russian logistics and transportation capability, Russian primary wood processing capability, Sino-Russian timber import–export capability, and Heilongjiang furniture sales capability—over the 2017–2033 period. Results indicate a “first decline, then rise” trajectory for resilience, with a minimum normalized resilience index of 0.1549 recorded in 2021, followed by a gradual recovery and sustained strengthening thereafter. Among evaluated segments, Russian logistics demonstrates the strongest short-term shock resistance (36.2% reduction in minimum resilience), while Heilongjiang’s sales segment exhibits optimal long-term recoverability (the normalized resilience index increased by an average of 0.0363 units per year during the recovery phase). Based on these findings, a “short-term logistics enhancement–long-term demand-driven” strategy is proposed to improve resilience, providing actionable insights for the high-quality development of the Sino-Russian timber supply chain. Full article

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

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22 pages, 4448 KiB

Open AccessArticle

Can Shape–Size–Increment Models Guide the Sustainable Management of Araucaria Forests? Insights from Selected Stands in Southern Brazil

by André Felipe Hess, Veraldo Liesenberg, Laryssa Demétrio, Laio Zimermann Oliveira, Marchante Olímpio Assura Ambrósio, Emanuel Arnoni Costa and Polyana da Conceição Bispo

Forests 2025, 16(7), 1105; https://doi.org/10.3390/f16071105 - 4 Jul 2025

Abstract

Sustainable Forest Management (SFM) requires the building of relationships among diameter increment, shape, and size (ISS), and increment–age variables to identify critical changes in forest structure and dynamics. This understanding is essential for maintaining forest productivity, structural and species diversity, stability, and sustainability. [...] Read more.

Sustainable Forest Management (SFM) requires the building of relationships among diameter increment, shape, and size (ISS), and increment–age variables to identify critical changes in forest structure and dynamics. This understanding is essential for maintaining forest productivity, structural and species diversity, stability, and sustainability. This study focused on measuring, reporting, and modeling these relationships for Araucaria angustifolia (Bertol.) Kuntze, across various diameters and three stands, located at different rural properties in southern Brazil. A random sample of 186 individual trees was acquired; the trees were measured for multiple dendrometric variables, and several morphometric indices were calculated. Additionally, two cores were extracted from each tree using an increment borer, enabling the measurement of growth rings and annual diameter increments. These were modeled using generalized linear models to assess the relationships among them and to quantify changes in forest structure and dynamics. The results revealed the dominance of A. angustifolia and a decline in the increment rate with increasing age, shape, and size in both old and young trees, indicating potential risks to the structure and dynamics of these unmanaged forests. Therefore, the models constructed in this study can guide conservation-by-use efforts and ensure the long-term continuity and productivity of forest remnants at selected rural properties, where A. angustifolia trees are predominant. Full article

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

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14 pages, 2494 KiB

Open AccessArticle

Colour Homogenisation and Photostability of Beech Wood (Fagus sylvatica L.) as Affected by Mild Steaming and Light-Induced Natural Ageing

by Zuzana Vidholdová, Gabriela Slabejová and Eva Výbohová

Forests 2025, 16(7), 1104; https://doi.org/10.3390/f16071104 - 4 Jul 2025

Abstract

This study investigates the impact of mild steaming (105 °C and 120 °C for 12 h) on the colour characteristics and chemical stability of beech wood (Fagus sylvatica L.) during natural indoor ageing. Untreated and steamed samples of mature wood and false [...] Read more.

This study investigates the impact of mild steaming (105 °C and 120 °C for 12 h) on the colour characteristics and chemical stability of beech wood (Fagus sylvatica L.) during natural indoor ageing. Untreated and steamed samples of mature wood and false heartwood were analysed for CIELAB and CIELCh colour parameters (L*, a*, b*, C*, h°) and chemical changes using ATR-FTIR spectroscopy. Steaming resulted in a significant decrease in lightness (L*) and increased a*, b*, and C* values, producing darker and more saturated reddish-brown tones. It also reduced the visual differences between mature wood and false heartwood, enhancing colour uniformity. During the light-induced ageing period, steamed wood—particularly at 105 °C—exhibited improved colour stability, maintaining chroma and hue more effectively than untreated samples. Statistically significant interaction effects between treatment, time, and tissue type revealed that the ageing-related colour changes were jointly influenced by thermal modification and the anatomical characteristics of the wood. In the FTIR spectra, the most pronounced changes were observed in the absorption bands of the aromatic skeleton and carbonyl groups (1504 and 1732 cm⁻¹). These findings confirm that mild steaming alters the original aesthetic properties and colour of beech wood when exposed to an indoor environment. Full article

(This article belongs to the Special Issue Phenomenon of Wood Colour)

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18 pages, 7356 KiB

Open AccessReview

Applied Chemical Ecology of Spruce Beetle in Western North America

by Christopher J. Fettig, Jackson P. Audley and Allen Steven Munson

Forests 2025, 16(7), 1103; https://doi.org/10.3390/f16071103 - 3 Jul 2025

Abstract

Spruce beetle (Dendroctonus rufipennis (Kirby)) is a major cause of spruce (Picea spp.) mortality in western North America. We synthesized the literature on the chemical ecology of spruce beetle, focusing on efforts to reduce host tree losses. This literature dates back [...] Read more.

Spruce beetle (Dendroctonus rufipennis (Kirby)) is a major cause of spruce (Picea spp.) mortality in western North America. We synthesized the literature on the chemical ecology of spruce beetle, focusing on efforts to reduce host tree losses. This literature dates back to the mid-20th century and focuses on spruce beetle populations in Alaska, U.S., western Canada, and the central and southern Rocky Mountains, U.S. Spruce beetle aggregation pheromone components include frontalin (1,5-dimethyl-6,8-dioxabicyclo[3.2.1]octane), seudenol (3-methyl-2-cyclohexen-1-ol), MCOL (1-methyl-2-cyclohexen-1-ol), and verbenene (4-methylene-6,6-dimethylbicyclo[3.1.1]hept-2-ene). The attraction of spruce beetle to one aggregation pheromone component is enhanced by the co-release of other aggregation pheromones and host compounds (e.g., α-pinene). Several baits that attract spruce beetles are commercially available and are used for survey and detection, population suppression, snag creation, and experimental purposes. The antiaggregation pheromone is MCH (3-methyl-2-cyclohexen-1-one), which has been evaluated for reducing colonization of felled spruce since the 1970s. Beginning in the early 2000s, MCH has been evaluated for protecting live, standing spruce from colonization by and mortality attributed to spruce beetle. With a few exceptions, significant reductions in levels of spruce beetle colonization and/or spruce mortality were reported. More recent efforts have combined MCH with other repellents (e.g., nonhost compounds) in hope of increasing levels of tree protection. Today, several formulations of MCH are registered for tree protection purposes in the U.S. and Canada. Full article

(This article belongs to the Section Forest Health)

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17 pages, 4939 KiB

Open AccessArticle

Wood Loss in the Felling and Cross-Cutting of Trees from Spruce Stands Affected by Windthrow in the Curvature Carpathians

by Mihai Ciocirlan and Vasile Răzvan Câmpu

Forests 2025, 16(7), 1102; https://doi.org/10.3390/f16071102 - 3 Jul 2025

Abstract

Windthrow determines major changes in tree stand evolution due to the felling or breaking of either isolated trees or entire stands. It has a major ecological, social and economic impact. Wood loss resulting from tree felling and cross-cutting operations is a less-studied aspect [...] Read more.

Windthrow determines major changes in tree stand evolution due to the felling or breaking of either isolated trees or entire stands. It has a major ecological, social and economic impact. Wood loss resulting from tree felling and cross-cutting operations is a less-studied aspect related to windthrow. Wood loss is represented by high stumps, broken or split stems, wood lost in the felling of trees that remain standing, wood lost in felling cuts that attempt to remove the stem from the root plate of partially or totally uprooted trees and wood lost as a result of stem cross-cutting. The study focused on estimating losses and their indices in a spruce tree stand located in the Curvature Carpathians. Windthrow took place in this tree stand in February 2020. The results showed that the total wood loss index is 7.747%. The main losses are represented by wood losses in high stumps (5.319%). The amount of wood loss depends on the proportion of uprooted or standing trees, ground inclination and the uprooting direction of trees as opposed to ground inclination, as well as on tree dimension. Tree volume significantly influences wood loss in high stumps (p < 0.001). The closer the uprooting direction is to the highest slope, the higher the tree stump becomes. Wood loss caused by stem breaking and splitting represents 2.280%, tree felling cuttings and stem removal from the root plate in uprooted trees account for 0.138% while loss resulting from stem cross-cutting represents 0.10%. Full article

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

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24 pages, 4442 KiB

Open AccessArticle

Time-Series Correlation Optimization for Forest Fire Tracking

by Dongmei Yang, Guohao Nie, Xiaoyuan Xu, Debin Zhang and Xingmei Wang

Forests 2025, 16(7), 1101; https://doi.org/10.3390/f16071101 - 3 Jul 2025

Abstract

Accurate real-time tracking of forest fires using UAV platforms is crucial for timely early warning, reliable spread prediction, and effective autonomous suppression. Existing detection-based multi-object tracking methods face challenges in accurately associating targets and maintaining smooth tracking trajectories in complex forest environments. These [...] Read more.

Accurate real-time tracking of forest fires using UAV platforms is crucial for timely early warning, reliable spread prediction, and effective autonomous suppression. Existing detection-based multi-object tracking methods face challenges in accurately associating targets and maintaining smooth tracking trajectories in complex forest environments. These difficulties stem from the highly nonlinear movement of flames relative to the observing UAV and the lack of robust fire-specific feature modeling. To address these challenges, we introduce AO-OCSORT, an association-optimized observation-centric tracking framework designed to enhance robustness in dynamic fire scenarios. AO-OCSORT builds on the YOLOX detector. To associate detection results across frames and form smooth trajectories, we propose a temporal–physical similarity metric that utilizes temporal information from the short-term motion of targets and incorporates physical flame characteristics derived from optical flow and contours. Subsequently, scene classification and low-score filtering are employed to develop a hierarchical association strategy, reducing the impact of false detections and interfering objects. Additionally, a virtual trajectory generation module is proposed, employing a kinematic model to maintain trajectory continuity during flame occlusion. Locally evaluated on the 1080P-resolution FireMOT UAV wildfire dataset, AO-OCSORT achieves a 5.4% improvement in MOTA over advanced baselines at 28.1 FPS, meeting real-time requirements. This improvement enhances the reliability of fire front localization, which is crucial for forest fire management. Furthermore, AO-OCSORT demonstrates strong generalization, achieving 41.4% MOTA on VisDrone, 80.9% on MOT17, and 92.2% MOTA on DanceTrack. Full article

(This article belongs to the Special Issue Advanced Technologies for Forest Fire Detection and Monitoring)

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17 pages, 2690 KiB

Open AccessArticle

The Influence of Slope Aspect on the Spatial Heterogeneity of Soil Nutrients and Seedling Regeneration in Pinus sylvestris var. mongolica Plantation Forests

by Wenbiao Duan, Jingyue Duan, Meixue Qu, Yafei Wang, Shuaiwei Zhu, Haoyu Wang and Miaoxian Mu

Forests 2025, 16(7), 1100; https://doi.org/10.3390/f16071100 - 3 Jul 2025

Abstract

In the fields of forestry, ecology, and pedology, different slope aspects exhibit significantly different microenvironments and soil conditions, which ultimately lead to disparities in seedling regeneration. Therefore, studying the effects of soil nutrients on seedling regeneration under different microenvironmental conditions can provide critical [...] Read more.

In the fields of forestry, ecology, and pedology, different slope aspects exhibit significantly different microenvironments and soil conditions, which ultimately lead to disparities in seedling regeneration. Therefore, studying the effects of soil nutrients on seedling regeneration under different microenvironmental conditions can provide critical data for the artificial promotion of natural regeneration. In July 2021, the seedling regeneration status in 900 m² artificial Pinus sylvestris var. mongolica forests with different slope aspects was investigated. Soil nutrient indices were obtained through the collection and measurement of soil samples. Geostatistics were used to quantify the spatial heterogeneity of soil nutrients at a small scale. Soil nutrient information from the seedling growth locations was acquired by combining geographic information system (GIS) technology and laboratory experiments to analyze the effects of soil nutrients on seedling regeneration. The spatial heterogeneity of soil nutrients and their effects on seedling regeneration change with different slope aspects. Even at a small scale (3 m), spatial heterogeneity remains evident. Shaded slopes are more prone to supporting biennial seedlings and older saplings, while seedlings on sunny slopes exhibit superior growth indicators (height and ground diameter). The correlation calculations and redundancy analysis (RDA) of the relationship between soil nutrients and seedling regeneration show that although the soil nutrient content inhibits seedling quantity, they can enhance seedling growth indicators, among which soil organic matter plays the most critical role. Different slope aspects affect soil nutrients and seedling spatial patterns, and increased soil nutrients can promote the natural regeneration of Pinus sylvestris var. mongolica seedlings. Full article

(This article belongs to the Section Forest Soil)

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3 pages, 517 KiB

Open AccessEditorial

Integrated Measurements for Precision Forestry

by Jia Wang, Weiheng Xu, Jincheng Liu, Zhichao Wang and Stelian Alexandru Borz

Forests 2025, 16(7), 1099; https://doi.org/10.3390/f16071099 - 2 Jul 2025

Abstract

As dynamic ecosystems, forests are facing unprecedented challenges under the pressures of climate change, land use transitions, and ecological degradation [...] Full article

(This article belongs to the Special Issue Integrated Measurements for Precision Forestry)

14 pages, 3567 KiB

Open AccessArticle

Characterization of Shoot Growth and Carbon Accumulation in Moso Bamboo Based on Different Stand Densities

by Xuan Zhang, Fengying Guan, Xiao Zhou, Zheng Li, Dawei Fu and Minkai Li

Forests 2025, 16(7), 1098; https://doi.org/10.3390/f16071098 - 2 Jul 2025

Abstract

Bamboo forests are among China’s key strategic forest resources, characterized by rapid growth and high carbon sequestration efficiency. Traditional management practices primarily aim to maximize economic benefits by regulating stand density to enhance yields of bamboo culms and shoots. However, the influence of [...] Read more.

Bamboo forests are among China’s key strategic forest resources, characterized by rapid growth and high carbon sequestration efficiency. Traditional management practices primarily aim to maximize economic benefits by regulating stand density to enhance yields of bamboo culms and shoots. However, the influence of density regulation on the growth and carbon accumulation of spring bamboo shoots remains insufficiently understood. Therefore, this study focuses on moso bamboo (Phyllostachys edulis (Carrière) J. Houzeau) stands and investigates shoot emergence during the shooting period across four stand density levels: D1 (1400 stems/ha), D2 (2000 stems/ha), D3 (2600 stems/ha), and D4 (3200 stems/ha). The study analyzes the dynamics of shoot emergence, height development, and morphological traits under varying stand densities, and explores patterns of carbon accumulation during the shooting period, thereby clarifying the effects of stand density on shoot quantity, growth quality, and carbon sequestration. The main findings are as follows: the number of emerging shoots decreased with increasing stand density, ranging from 2592 to 4634 shoots per hectare. The peak shoot emergence period in the D1 stand was extended by 3 days compared to D2 and D3, while the D4 stand entered the peak emergence period 6 days later than D2 and D3. The rapid height growth phase in D1 occurred 3 days earlier than in D2 and D3, and 6 days earlier than in D4. Results from the variable exponent taper equation indicated that spring shoots in the D2 and D4 stands had larger basal diameters, following the order D4 > D2 > D3 > D1. Shoots in the D2 stand exhibited the smallest taper, with the order being D2 < D3 < D1 < D4. During the late stage of shoot emergence (3 May to 9 May), all stands entered a period of rapid carbon accumulation per individual shoot. In the early stage, carbon accumulation followed the order D1 > D2 > D4 > D3; in the middle stage, the order shifted to D4 > D3 > D2 > D1; and in the final stage, the trend was D1 > D4 > D3 > D2. Within the 30-day investigation period, the carbon storage in spring shoots reached up to one-quarter or even one-third of the total accumulation during the growth period. The D1 stand exhibited the highest rate of increase in the proportion of individual shoot carbon storage. Full article

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

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19 pages, 2012 KiB

Open AccessArticle

Exploring the Variability in Rill Detachment Capacity as Influenced by Different Fire Intensities in a Semi-Arid Environment

by Masoumeh Izadpanah Nashroodcoli, Mahmoud Shabanpour, Sepideh Abrishamkesh and Misagh Parhizkar

Forests 2025, 16(7), 1097; https://doi.org/10.3390/f16071097 - 2 Jul 2025

Abstract

Wildfires, whether natural or human-caused, significantly alter soil properties and increase soil erosion susceptibility, particularly through changes in rill detachment capacity (Dc). This study aimed to evaluate the influence of fire intensity on key soil properties and to recognize their relationships with Dc [...] Read more.

Wildfires, whether natural or human-caused, significantly alter soil properties and increase soil erosion susceptibility, particularly through changes in rill detachment capacity (Dc). This study aimed to evaluate the influence of fire intensity on key soil properties and to recognize their relationships with Dc under controlled laboratory conditions. The research was conducted in the Darestan Forest, Guilan Province, northern Iran, a region characterized by a Mediterranean semi-arid climate. Soil samples were collected from three fire-affected conditions: unburned (NF), low-intensity fire (LF), and high-intensity fire (HF) zones. A total of 225 soil samples were analyzed using flume experiments at five slope gradients and five flow discharges, simulating rill erosion. Soil physical and chemical characteristics were measured, including hydraulic conductivity, organic carbon, sodium content, bulk density, and water repellency. The results showed that HF soils significantly exhibited higher rill detachment capacity (1.43 and 2.26 times the values compared to the LF and NF soils, respectively) and sodium content and lower organic carbon, hydraulic conductivity, and aggregate stability (p < 0.01). Strong correlations were found between Dc and various soil properties, particularly a negative relationship with organic carbon. The multiple linear equation had good accuracy (R² > 0.78) in predicting rill detachment capacity. The findings of the current study show the significant impact of fire on soil degradation and rill erosion potential. The study advocates an urgent need for effective post-fire land management, erosion control, and the development of sustainable soil restoration strategies. Full article

(This article belongs to the Special Issue Postfire Runoff and Erosion in Forests: Assessment and Management)

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18 pages, 7038 KiB

Open AccessArticle

Responses of Different Soil Microbial Communities to the Addition of Nitrogen into the Soil of Larix gmelinii var. principis-rupprechtii (Mayr) Pilg. Plantations

by Yanlong Jia, Ziyi Wang, Hongna Cui, Liu Yang, Jinping Lu, Jiaojiao Ma, Zhongqi Xu and Honglin He

Forests 2025, 16(7), 1096; https://doi.org/10.3390/f16071096 - 2 Jul 2025

Abstract

The increasing rate of atmospheric nitrogen (N) deposition caused by human activities is a global concern. A rise in N deposition can alter the soil microbial community, as demonstrated by most long-term N addition experiments. Nevertheless, it remains unknown how short-term N addition [...] Read more.

The increasing rate of atmospheric nitrogen (N) deposition caused by human activities is a global concern. A rise in N deposition can alter the soil microbial community, as demonstrated by most long-term N addition experiments. Nevertheless, it remains unknown how short-term N addition influences the early succession of the soil microbial community in forests. In this study, the responses of the soil microbial community to multi-level and short-term (one-year) N addition in the soil of Larix gmelinii var. principis-rupprechtii (Mayr) Pilg. plantations in the Yanshan Mountains were explored. We used high-throughput sequencing technology to analyze the 16S rRNA of bacteria, the ITS gene of fungi, and the nifH functional gene of N-fixing bacteria. The results revealed a decrease in N-fixing functional gene abundance (such as nifH) and a slight rise in fungal and bacterial copy number due to N addition. N addition influenced the N-fixing bacterial community but had no influence on the fungal and bacterial communities in general. It drastically decreased the diversity of N-fixing microbial communities while having little impact on the diversity of fungi and bacteria. The NO₃⁻-N concentration exhibited a negative connection with the Shannon–Wiener index of the N-fixing microbial community when it exceeded a specific limit. Actinomycetes and N-fixing bacteria were significantly negatively correlated. The changes in soil NO₃⁻-N concentration and abundance of actinomycetes were the main reasons for the decrease in N-fixing microbial community diversity. The results of this study set the groundwork for exploring the initial succession mechanisms of soil microorganisms after N addition. This study offers a scientific theoretical basis for precise management of plantations under N deposition. Full article

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

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27 pages, 13245 KiB

Open AccessArticle

LHRF-YOLO: A Lightweight Model with Hybrid Receptive Field for Forest Fire Detection

by Yifan Ma, Weifeng Shan, Yanwei Sui, Mengyu Wang and Maofa Wang

Forests 2025, 16(7), 1095; https://doi.org/10.3390/f16071095 - 2 Jul 2025

Abstract

Timely and accurate detection of forest fires is crucial for protecting forest ecosystems. However, traditional monitoring methods face significant challenges in effectively detecting forest fires, primarily due to the dynamic spread of flames and smoke, irregular morphologies, and the semi-transparent nature of smoke, [...] Read more.

Timely and accurate detection of forest fires is crucial for protecting forest ecosystems. However, traditional monitoring methods face significant challenges in effectively detecting forest fires, primarily due to the dynamic spread of flames and smoke, irregular morphologies, and the semi-transparent nature of smoke, which make it extremely difficult to extract key visual features. Additionally, deploying these detection systems to edge devices with limited computational resources remains challenging. To address these issues, this paper proposes a lightweight hybrid receptive field model (LHRF-YOLO), which leverages deep learning to overcome the shortcomings of traditional monitoring methods for fire detection on edge devices. Firstly, a hybrid receptive field extraction module is designed by integrating the 2D selective scan mechanism with a residual multi-branch structure. This significantly enhances the model’s contextual understanding of the entire image scene while maintaining low computational complexity. Second, a dynamic enhanced downsampling module is proposed, which employs feature reorganization and channel-wise dynamic weighting strategies to minimize the loss of critical details, such as fine smoke textures, while reducing image resolution. Furthermore, a scale weighted Fusion module is introduced to optimize multi-scale feature fusion through adaptive weight allocation, addressing the issues of information dilution and imbalance caused by traditional fusion methods. Finally, the Mish activation function replaces the SiLU activation function to improve the model’s ability to capture flame edges and faint smoke textures. Experimental results on the self-constructed Fire-SmokeDataset demonstrate that LHRF-YOLO achieves significant model compression while further improving accuracy compared to the baseline model YOLOv11. The parameter count is reduced to only 2.25M (a 12.8% reduction), computational complexity to 5.4 GFLOPs (a 14.3% decrease), and mAP50 is increased to 87.6%, surpassing the baseline model. Additionally, LHRF-YOLO exhibits leading generalization performance on the cross-scenario M4SFWD dataset. The proposed method balances performance and resource efficiency, providing a feasible solution for real-time and efficient fire detection on resource-constrained edge devices with significant research value. Full article

(This article belongs to the Special Issue Forest Fires Prediction and Detection—2nd Edition)

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21 pages, 2738 KiB

Open AccessArticle

Effects of Fire on Soil Bacterial Communities and Nitrogen Cycling Functions in Greater Khingan Mountains Larch Forests

by Yang Shu, Wenjie Jia, Pengwu Zhao, Mei Zhou and Heng Zhang

Forests 2025, 16(7), 1094; https://doi.org/10.3390/f16071094 - 2 Jul 2025

Abstract

Investigating the effects of fire disturbance on soil microbial diversity and nitrogen cycling is crucial for understanding the mechanisms underlying soil nitrogen cycling. This study examined the fire burn site of the Larix gmelinii forest in the Greater Khingan Mountains, Inner Mongolia, to [...] Read more.

Investigating the effects of fire disturbance on soil microbial diversity and nitrogen cycling is crucial for understanding the mechanisms underlying soil nitrogen cycling. This study examined the fire burn site of the Larix gmelinii forest in the Greater Khingan Mountains, Inner Mongolia, to analyze the impact of varying fire intensities on soil nitrogen, microbial communities, and the abundance of nitrogen cycle-related functional genes after three years. The results indicated the following findings: (1) Soil bulk density increased significantly following severe fires (7.06%~10.84%, p < 0.05), whereas soil water content decreased with increasing fire intensity (6.62%~19.42%, p < 0.05). The soil total nitrogen and ammonium nitrogen levels declined after heavy fires but increased after mild fires; (2) Mild fire burning significantly increased soil bacterial diversity, while heavy fire had a lesser effect. Dominant bacterial groups included Xanthobacteraceae, norank_o_norank_c_AD3, and norank_o_Elsterales. Norank_o_norank_c_AD3 abundance decreased with burn intensity (7.90% unburned, 3.02% mild fire, 2.70% heavy fire). Conversely, norank_o_Elsterales increased with burning (1.23% unburned, 5.66% mild fire, 5.48% heavy fire); (3) The abundance of nitrogen-fixing nifH functional genes decreased with increasing fire intensity, whereas nitrification functional genes amoA-AOA and amoA-AOB exhibited the opposite trend. Light-intensity fires increased the abundance of denitrification functional genes nirK, nirS, and nosZ, while heavy fires reduced their abundance; (4) The correlation analysis demonstrated a strong association between soil bacteria and denitrification functional genes nifH and amoA-AOA, with soil total nitrogen being a key factor influencing the nitrogen cycle-related functional genes. The primary bacterial groups involved in soil nitrogen cycling were Proteobacteria, Actinobacteria, and Chloroflexi. These findings play a critical role in promoting vegetation regeneration and rapid ecosystem restoration in fire-affected areas. Full article

(This article belongs to the Section Forest Soil)

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15 pages, 2140 KiB

Open AccessArticle

Plant-Dwelling Spider Assemblages in Managed and Protected Primeval Deciduous Stands of Białowieża Forest, Poland

by Marzena Stańska, Tomasz Stański and Barbara Patoleta

Forests 2025, 16(7), 1093; https://doi.org/10.3390/f16071093 - 1 Jul 2025

Abstract

The Białowieża Forest is home to both primary forests under strict protection and commercial forests, which provides an opportunity to compare them in terms of the number of individuals, number of species, and composition of different animal assemblages. The main goal of our [...] Read more.

The Białowieża Forest is home to both primary forests under strict protection and commercial forests, which provides an opportunity to compare them in terms of the number of individuals, number of species, and composition of different animal assemblages. The main goal of our study was to compare spider assemblages inhabiting herbaceous vegetation in these two types of forest stands. Spiders were sampled using a sweep net in an oak–lime–hornbeam forest, an ash–alder forest, and an alder carr. More spiders were found in unmanaged stands compared to managed stands, but a significant difference was found only in the alder carr. Total species richness did not significantly vary between managed and unmanaged stands in all forest types. In the oak–lime–hornbeam forest, more species per sample were found in commercial stands compared to primeval stands, while the result was the opposite for the alder carr. Our research did not show a clear negative impact of forest management on plant-dwelling spiders. The impact of forest management was evident in the case of the riparian forest, where the managed stand was characterized by low canopy cover as a result of logging carried out years ago, which is likely to have resulted in differences in family composition. Full article

(This article belongs to the Special Issue Species Diversity and Habitat Conservation in Forest)

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