Forests

18 pages, 4891 KiB

Open AccessArticle

Monitoring Forest Disturbances and Associated Driving Forces in Guangdong Province Using Long-Term Landsat Time Series Images

by Lin Qiu, Zhongbing Chang, Xiaomei Luo, Songjia Chen, Jun Jiang and Li Lei

Forests 2025, 16(1), 189; https://doi.org/10.3390/f16010189 - 20 Jan 2025

Viewed by 608

Abstract

Research on monitoring forest disturbances and analyzing its driving factors is crucial for the sustainable management of forest ecosystems. To quantitatively identify the spatial distribution and dynamic changes of forest disturbance and its driving factors in Guangdong Province from 1990 to 2019, the [...] Read more.

Research on monitoring forest disturbances and analyzing its driving factors is crucial for the sustainable management of forest ecosystems. To quantitatively identify the spatial distribution and dynamic changes of forest disturbance and its driving factors in Guangdong Province from 1990 to 2019, the long-term Landsat time series imagery and the LandTrendr change detection algorithm were utilized. The impact of forest disturbances on four types of landscape fragmentation (attrition, perforation, shrinkage, and subdivision) was analyzed using the Forman index. The Geodetector model was used to analyze the driving factors of forest disturbance from human activity and the natural environment. The results showed that the LandTrendr algorithm achieved a Kappa coefficient of 0.79, with an overall accuracy of approximately 82.59%. The findings indicate a consistent increase in shrinkage patches, both in quantity and area. Spatially, the centroids of forest fragmentation processes exhibited a clear inland migration trend, reflecting the growing ecological pressures faced by inland forest ecosystems. Furthermore, interactions among driving factors, particularly between population density and economic factors, significantly amplified their combined impacts. The correlation between forest disturbances and socio-economic factors revealed distinct regional variations, highlighting significant differences in forest disturbance dynamics across cities with varying levels of economic development. This study provides critical insights into the spatiotemporal dynamics of forest disturbances under rapid urbanization and economic development. It lays the groundwork for sustainable forest management strategies in Guangdong Province and may contribute to global discussions on managing forest ecosystems during periods of rapid socio-economic transformation. Full article

(This article belongs to the Section Urban Forestry)

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14 pages, 3060 KiB

Open AccessArticle

Attitudes Toward Paying for Recreation in Urban Forests: A Comparison Between Warsaw and Lisbon’s Young Populations

by Agnieszka Mandziuk, Beata Fornal-Pieniak, Dagmara Stangierska-Mazurkiewicz, Katarzyna Widera, Maria Bihunova, Pedro Miguel Ramos Arsenio, Emila Janeczko, Barbara Żarska and Stanisław Parzych

Forests 2025, 16(1), 188; https://doi.org/10.3390/f16010188 - 20 Jan 2025

Viewed by 493

Abstract

Urban forests are essential recreational spaces that enhance cultural heritage, foster social integration, and provide economic benefits through local tourism. Their significance for recreation has grown due to increased leisure time, better access to information, and heightened concerns about mental and physical well-being. [...] Read more.

Urban forests are essential recreational spaces that enhance cultural heritage, foster social integration, and provide economic benefits through local tourism. Their significance for recreation has grown due to increased leisure time, better access to information, and heightened concerns about mental and physical well-being. This study seeks to evaluate social preferences for funding recreational activities in urban forests in Warsaw and Lisbon, focusing on their appearance and societal significance. Utilizing the Contingent Valuation Method (CVM), the research assessed individuals’ willingness to pay (WTP) for recreational access. Advanced techniques such as logistic regression and discriminant analysis were employed to identify the factors influencing WTP in Poland and Portugal. In Poland, WTP is primarily affected by preferences related to the appearance of forests, particularly the distinction between natural forests and those equipped with more infrastructure. In contrast, in Portugal, WTP tends to decrease with a greater appreciation for natural forests and a belief in the necessity of investing in urban forestry. The findings indicate that various social factors, such as the appearance of forests and perceived maintenance requirements, influence people’s willingness to fund urban forests. However, conducting research with only younger respondents limits the ability to generalize these findings to older populations. Full article

(This article belongs to the Special Issue Forest Utilization—Recreation and Leisure Development)

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20 pages, 5098 KiB

Open AccessArticle

Comprehensive Evaluation of Germplasm Resources in Various Goji Cultivars Based on Leaf Anatomical Traits

by Zijun Yang, Guoli Dai, Ken Qin, Jiali Wu, Zhonghua Wang and Cuiping Wang

Forests 2025, 16(1), 187; https://doi.org/10.3390/f16010187 - 20 Jan 2025

Viewed by 490

Abstract

The leaf is a critical organ for assimilation in plants, and the anatomical structure of the leaf can reflect the adaptability of plants to their environment to a certain extent. The research objects in this investigation were 36 different cultivars (lines) of goji [...] Read more.

The leaf is a critical organ for assimilation in plants, and the anatomical structure of the leaf can reflect the adaptability of plants to their environment to a certain extent. The research objects in this investigation were 36 different cultivars (lines) of goji germplasm resources. The structure and stoma condition of healthy leaves were the subject of a comparative investigation. Significant variations in leaf structural indices and stoma were identified among various goji cultivars (lines). The leaves of goji were the thickest and possessed the lowest stoma density. The resilience of goji germplasm resources was assessed using the main component analysis approach and the membership function. The results showed that LR (L. ruthenicum Murr.) and LCy (L. cylindricum Kuang) exhibited the strongest resistance. Goji resistance is significantly influenced by thickness of the upper cuticle (TUC) and thickness of the lower cuticle (TLC), according to the analytical results for several leaf anatomical indicators and stress resistance. By analyzing the wax content of 13 different goji cultivars (lines) and field infection results, it was found that Tianjing 3 had the highest wax content, the smallest average number of galls, and the smallest infection area. This suggests that Tianjing 3 has the strongest resistance to Aceria pallida, and that its insect resistance is correlated with its wax content. This study offers a thorough assessment of 36 goji germplasm resources’ resilience, providing a point of reference for the selection and propagation of resistant cultivars within these resources. Full article

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

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21 pages, 4371 KiB

Open AccessArticle

Synergizing Wood Science and Interpretable Artificial Intelligence: Detection and Classification of Wood Species Through Hyperspectral Imaging

by Yicong Qi, Yin Zhang, Shuqi Tang and Zhen Zeng

Forests 2025, 16(1), 186; https://doi.org/10.3390/f16010186 - 19 Jan 2025

Viewed by 738

Abstract

With the increasing demand for wood in the wood market and the frequent trade of high-value wood, the accurate identification of wood varieties has become essential. This study employs two hyperspectral imaging systems—visible and near-infrared spectroscopy (VNIR) and short-wave infrared spectroscopy (SWIR)—in combination [...] Read more.

With the increasing demand for wood in the wood market and the frequent trade of high-value wood, the accurate identification of wood varieties has become essential. This study employs two hyperspectral imaging systems—visible and near-infrared spectroscopy (VNIR) and short-wave infrared spectroscopy (SWIR)—in combination with a deep learning model to propose a method for wood species identification. Spectral data from wood samples were obtained through hyperspectral imaging technology, and classification was performed using a combination of convolutional neural networks (CNNs) and Transformer models. Multiple spectral preprocessing and feature extraction techniques were applied to enhance data quality and model performance. The experimental results show that the full-band modeling is significantly better than the feature-band modeling in terms of classification accuracy and robustness. Among them, the classification accuracy of SWIR reaches 100%, the number of model parameters is 1,286,228, the total size of the model is 4.93 MB, and the Floating Point Operations (FLOPs) is 1.29 M. Additionally, the Shapley Additive Explanation (SHAP) technique was utilized for model interpretability, revealing key spectral bands and feature regions that the model emphasizes during classification. Compared with other models, CNN-Transformer is more effective in capturing the key features. This method provides an efficient and reliable tool for the wood industry, particularly in wood processing and trade, offering broad application potential and significant economic benefits. Full article

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

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14 pages, 2657 KiB

Open AccessArticle

Study on Salt-Ion Content and Biomass Distribution Characteristic of Different Organs of Poacynum pictum in Different Water–Salt Habitats

by Wenxiang Fu, Xuemin He, Yudong Chen, Zhenying Ma, Junfang Zhou and Qingbin Xu

Forests 2025, 16(1), 185; https://doi.org/10.3390/f16010185 - 19 Jan 2025

Viewed by 650

Abstract

In natural saline habitats, the impact of the salt-ion content absorbed by halophytes on their biomass development remains unclear. This research investigated Poacynum pictum (Schrenk) Baill., a typical halophyte in the Ebinur Lake Wetland Reserve. P. pictum was collected from three water–salt habitats: [...] Read more.

In natural saline habitats, the impact of the salt-ion content absorbed by halophytes on their biomass development remains unclear. This research investigated Poacynum pictum (Schrenk) Baill., a typical halophyte in the Ebinur Lake Wetland Reserve. P. pictum was collected from three water–salt habitats: high water and high salt (Habitat 1), medium water and medium salt (Habitat 2), and low water and low salt (Habitat 3). This study aimed to quantify the salt-ion content and biomass in different P. pictum organs, analyze their distribution under varying water–salt habitats, and explore the mechanism of the relationship between salt-ion content and biomass. The results showed the following: (1) With the decrease in water–salt habitats, the Na⁺ contents of aboveground organs decreased, whereas root Na⁺ content increased. The aboveground organs’ Ca²⁺ contents exhibited the ranking Habitat 2 > Habitat 3 > Habitat 1. The Ca²⁺ and Mg²⁺ contents followed a similar pattern, with leaves showing the highest concentrations, and the Ca²⁺ and Mg²⁺ contents in roots exhibited a declining trend with the decrease in water–salt habitats. The Cl⁻ content was predominant in the leaves and stems of all water–salt habitats. This indicates that P. pictum can maintain an ionic state in the body and resist habitat stress through the separation and absorption of salt ions in different organs. (2) With the decrease in water–salt habitats, the leaf, twig, stem, and total biomass of P. pictum demonstrated a gradually decreasing trend, and the root biomass initially increased and then decreased. This reveals that P. pictum can adapt to high–saline habitats and achieve normal growth and development, and that suitable water and salt conditions are important for underground accumulation. (3) The Na⁺ content in leaves, twigs, and stems had a significant positive effect on the biomass of these organs, making it the most influential factor, and the root biomass was primarily affected by root Ca²⁺. These findings indicate that P. pictum adapted to saline habitats by adjusting its ion uptake and biomass, and the Na⁺ in aboveground organs and Ca²⁺ in roots are critical for biomass development in their respective organs. This study provides valuable insights into the adaptation strategies of halophytes in salinized environments and highlights the importance of specific ions’ accumulation for biomass maintenance. Full article

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

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15 pages, 9308 KiB

Open AccessArticle

Climate Change Drives the Adaptive Distribution and Habitat Fragmentation of Betula albosinensis Forests in China

by Huayong Zhang, Yue Zhou, Xiande Ji, Zhongyu Wang and Zhao Liu

Forests 2025, 16(1), 184; https://doi.org/10.3390/f16010184 - 19 Jan 2025

Viewed by 680

Abstract

Betula albosinensis serves as an important constructive and afforestation tree species in mountainous areas. Its suitable habitat and habitat quality are highly vulnerable to the climate. However, few studies have centered on the shrinkage, expansion, and habitat fragmentation of B. albosinensis forests under [...] Read more.

Betula albosinensis serves as an important constructive and afforestation tree species in mountainous areas. Its suitable habitat and habitat quality are highly vulnerable to the climate. However, few studies have centered on the shrinkage, expansion, and habitat fragmentation of B. albosinensis forests under climate change. In this study, the Random Forest model was employed to predict current and future trends of shrinking and expanding of B. albosinensis, while a composite landscape index was utilized to evaluate the habitat fragmentation in the highly suitable habitats of B. albosinensis. The results indicated that suitable habitats for B. albosinensis were primarily concentrated in the vicinities of the Qinling, Qilian, and Hengduan Mountains, situated in western China. The most influential factor affecting the distribution of B. albosinensis was temperature seasonality (Bio4). In future scenarios, the center of distribution of B. albosinensis was projected to shift towards the west and higher altitudes. The total suitable habitats of B. albosinensis were anticipated to expand under the scenarios of SSP370 and SSP585 in the 2090s, while they were expected to contract under the remaining scenarios. Although these results indicated that the suitable areas of habitat for B. albosinensis were relatively intact on the whole, fragmentation increased with climate change, with the highest degree of fragmentation observed under the SSP585 scenario in the 2090s. The findings of this study provide a foundation for the protection of montane vegetation, the maintenance of montane biodiversity, and the evaluation of species’ habitat fragmentation. Full article

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

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15 pages, 2185 KiB

Open AccessArticle

The Short-Term Impact of Logging Intensity on the Stand State of Middle-Aged Masson Pine (Pinus massoniana Lamb.) Plantations

by Jing Tu, Zhongwen Zhao and Zongzheng Chai

Forests 2025, 16(1), 183; https://doi.org/10.3390/f16010183 - 19 Jan 2025

Viewed by 463

Abstract

By assessing the short-term impact that various logging intensities have on stand state in middle-aged P. massoniana plantations, this investigation aimed to establish a theoretical foundation to support the judicious management of Pinus massoniana plantations. Five distinct logging intensity categories were delineated (0%, [...] Read more.

By assessing the short-term impact that various logging intensities have on stand state in middle-aged P. massoniana plantations, this investigation aimed to establish a theoretical foundation to support the judicious management of Pinus massoniana plantations. Five distinct logging intensity categories were delineated (0%, 10%, 20%, 30%, 40%). To construct a robust stand-state evaluation framework, nine representative indicators across the three dimensions of structure, vitality, and diversity were selected. We scrutinized the short-term impacts of logging intensity by employing the unit circle method. The findings revealed that (1) four indicators—stand density, tree health, species composition, and species diversity—exhibited pronounced sensitivity to logging intensity. These four exhibited significant improvements in the short-term post-logging (p < 0.05). Conversely, the indicators of species evenness, diameter distribution, height distribution, tree dominance, and stand growth exhibited a more subdued response to logging intensity. These five necessitated an extended period to begin to improve. (2) The comprehensive evaluation values measuring the stand state of middle-aged P. massoniana plantations initially ascended but then subsequently descended as logging intensity escalated. The stand-state zenith was pinpointed at an approximate 30% logging intensity. (3) A highly significant linear correlation emerged between the unit circle method results and the principal component analysis results in evaluating stand state (R² = 0.909, p < 0.001), and the unit circle method proved to be more intuitive and responsive. In summation, logging intensity exerted a substantial influence on stand state in middle-aged P. massoniana plantations, with moderate logging (circa 30% logging intensity) enhancing stand state the most. The unit circle method proficiently and effectively illuminated the short-term effects of logging intensity on the stand dynamics of middle-aged P. massoniana plantations, so it thereby may provide invaluable guidance for the formulation of specific forest management strategies. Full article

(This article belongs to the Special Issue Growth and Stand Dynamics of Unmanaged and Managed Forests Under Global Change)

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18 pages, 5849 KiB

Open AccessArticle

Growth, Productivity, and Nutrient Return of a Mixed Plantation of Fast-Growing Eucalyptus Hybrid and Acacia auriculiformis Trees in Thailand

by Jetsada Wongprom, Narinthorn Jumwong, Pattama Sangvisitpirom, Sapit Diloksumpun and La-ongdao Thaopimai

Forests 2025, 16(1), 182; https://doi.org/10.3390/f16010182 - 19 Jan 2025

Viewed by 628

Abstract

Mixed-species plantations involving Eucalyptus and Acacia trees are an effective alternative for managing sustainable plantations. In this study, we evaluated the growth, productivity, nutrient return, and soil properties of a mixed Eucalyptus hybrid (Eucalyptus camaldulensis Dehnh. × E. urophylla S.T. Blake; E) and [...] Read more.

Mixed-species plantations involving Eucalyptus and Acacia trees are an effective alternative for managing sustainable plantations. In this study, we evaluated the growth, productivity, nutrient return, and soil properties of a mixed Eucalyptus hybrid (Eucalyptus camaldulensis Dehnh. × E. urophylla S.T. Blake; E) and Acacia auriculiformis A. Cunn. ex Benth. plantation (A) and Eucalyptus hybrid and A. auriculiformis plantations. The mixed Eucalyptus hybrid and A. auriculiformis plantation included three ratios at E33:A67, E50:A50, and E67:A33, while the Eucalyptus (E100) and A. auriculiformis (A100) plantations were established on degraded lands in the Had Wanakorn Forestry Research and Student Training Station, Prachuap Khiri Khan province, Thailand. Three replications within a plot size of 20 × 20 m² were designed to plant Eucalyptus hybrid and A. auriculiformis seedlings at a spacing of 2 × 3 m². The diameters at breast height (DBH) and height (H) of the Eucalyptus hybrid and A. auriculiformis were measured and monitored after planting for five years. The aboveground biomass of the five-year-old mixed and monoculture plantations was then estimated. Litterfall production and nutrient return from the mixed and monoculture plantations were measured for three years. In addition, soil samples at depths of 0–5, 5–10, and 10–20 cm were collected to analyze the soil’s chemical properties. Differences in growth, aboveground biomass, litterfall production, nutrient return, and soil properties were analyzed and tested using Tukey’s HSD. The results indicated that both the DBH and H of the Eucalyptus hybrid in the mixed and monoculture plantations were not significantly different (p > 0.05). Similarly, the DBH and H of A. auriculiformis in each treatment were also not significantly different (p > 0.05). However, the DBH and H of the Eucalyptus hybrid were higher than those of A. auriculiformis. The aboveground biomass for the mixed plantation ratios E50:A50, E100, E67:A33, and E33:A67 was not significantly different, while the stem biomass was the highest in E100. Litterfall production was influenced by the proportion of the Eucalyptus hybrid relative to A. auriculiformis, but the monoculture A100 plantation had the highest litter production. The nitrogen return estimated for the mixed plantation was between A100 and E100. Similarly, the total nitrogen in the topsoil (0–5 cm) of the mixed plantation was higher than that in the monoculture E100 plantation. These results indicate that mixing A. auriculiformis with Eucalyptus can improve soil nutrients and nutrient cycling and increase nutrient returns, suggesting that mixed plantations are an effective option for sustainable plantation management and can mitigate the negative environmental impacts of Eucalyptus monocultures. Full article

(This article belongs to the Special Issue Forest Stand and Biomass Management)

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19 pages, 10551 KiB

Open AccessArticle

Structure Effects on Mechanical Properties of a Novel Engineered Wood Product: Cross-Laminated-Thick Veneers Based on Infinite Splicing Technology

by Yuxin Yang, Juan Hu, Xinguang Ning, Yahui Zhang, Yingqi He, Yingchun Gong, Wenji Yu and Yuxiang Huang

Forests 2025, 16(1), 181; https://doi.org/10.3390/f16010181 - 19 Jan 2025

Viewed by 531

Abstract

With increasing global concern over carbon emissions in the construction industry, cross-laminated-thick veneer (CLTV) has emerged as an innovative green building material with significant potential to promote the achievement of “dual-carbon” goals. This study developed a groove and tenon splicing technique for thick [...] Read more.

With increasing global concern over carbon emissions in the construction industry, cross-laminated-thick veneer (CLTV) has emerged as an innovative green building material with significant potential to promote the achievement of “dual-carbon” goals. This study developed a groove and tenon splicing technique for thick veneers, enabling infinite splicing of the length direction and the preparation of a large-size CLTV measuring 12 m (length) × 3.25 m (width) × 105 mm (thickness). The mechanical properties of CLTV were studied in relation to splice position, assembly pattern of grain directions, and layer combinations. The results showed that increasing the number of // layers (// or ⊥ indicates grain direction of layer parallel or perpendicular to the length direction of CLTV) and using high-level layers significantly improved the compressive strength and reduced the coefficient of variation of CLTV. In terms of bending properties, reasonable splice distribution, placing // layers away from the neutral axis, and elevating layer level dramatically enhanced CLTV performance. Furthermore, the study revealed the synergistic effect among these design elements. The effects of layer level and the number of // layers on mechanical properties varied depending on splice arrangement and assembly pattern of grain directions, highlighting the importance of efficient structural design and raw material selection. This study addresses the limitations of traditional cross-laminated timber in raw material selection and production efficiency. Through structural innovation, it offers a solution for physical design and performance regulation, enabling the application of larger CLTV in wood structures and presenting new ideas for using fast-growing wood to reduce construction emissions. Full article

(This article belongs to the Special Issue Measurement and Enhancement of Wood Mechanical and Chemical Properties, 2nd Edition)

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21 pages, 8422 KiB

Open AccessArticle

Impact of Thermal Treatment and Accelerated Aging on the Chemical Composition, Morphology, and Properties of Spruce Wood

by František Kačík, Jozef Kúdela, Eva Výbohová, Tereza Jurczyková, Iveta Čabalová, Lukáš Adamčík, Elena Kmeťová and Danica Kačíková

Forests 2025, 16(1), 180; https://doi.org/10.3390/f16010180 - 19 Jan 2025

Viewed by 685

Abstract

Thermal modification improves the properties of wood, especially its stability and durability. We thermally treated spruce wood with the Thermowood process at three temperatures (160 °C, 180 °C, and 210 °C) and subjected it to accelerated aging in wet mode. We evaluated the [...] Read more.

Thermal modification improves the properties of wood, especially its stability and durability. We thermally treated spruce wood with the Thermowood process at three temperatures (160 °C, 180 °C, and 210 °C) and subjected it to accelerated aging in wet mode. We evaluated the chemical composition (wet chemistry, infrared spectroscopy), color, surface morphology, and wetting of the wood surface with water. Thermal treatment caused a significant decrease in hemicelluloses (up to 72.39% at a temperature of 210 °C), which initiated an increase in the content of more resistant wood components—cellulose and lignin. With accelerated aging, the hemicellulose content decreased by another 5%. The most significant differences between the infrared spectra of thermally modified wood before and after exposure to accelerated aging were in the absorption bands of lignin (1509 and 1596 cm⁻¹) and in the region of carbonyl groups between 1800 and 1630 cm⁻¹. Thermal treatment also caused a change in the color of the wood to dark brown; the overall color difference ΔE increased several times. The thermal-induced shortening of polysaccharide fibers and reduction in their width were even more manifested during accelerated aging. This work contains new knowledge about the properties critical for the reuse of thermally modified wood after accelerated aging, simulating the end of its life cycle. Full article

(This article belongs to the Special Issue Transformation of Wood after Processing and Modification)

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20 pages, 11582 KiB

Open AccessArticle

Assessment of Forest Route Planning Capabilities Using Various Spatial Data Sources: A Case Study of the Mazovia Region, Poland

by Wojciech Dawid and Krzysztof Pokonieczny

Forests 2025, 16(1), 179; https://doi.org/10.3390/f16010179 - 18 Jan 2025

Viewed by 614

Abstract

This study examines the effectiveness of various spatial data sources and pathfinding algorithms for route determination in forested environments, focusing on the Mazovia region of Poland. Accurate and efficient forest route planning is critical for both military operations and crisis management, highlighting the [...] Read more.

This study examines the effectiveness of various spatial data sources and pathfinding algorithms for route determination in forested environments, focusing on the Mazovia region of Poland. Accurate and efficient forest route planning is critical for both military operations and crisis management, highlighting the need for reliable data and robust algorithms. The analysis centers on three primary spatial data sources that can support forest routing: the civilian Topographic Objects Database (TOD) and OpenStreetMap (OSM), along with the military-specific Vector Map Level 2 (VML2). Two commonly used pathfinding algorithms, Dijkstra and A* (the latter with six heuristic variations), were tested to assess their suitability and performance in these contexts. This study was conducted across ten of the largest forested areas in Mazovia, with route determinations performed between selected pairs of start and end points within each forest area. The findings indicate that the TOD database yielded the most stable and consistent routes, while the A* algorithm with Euclidean distance heuristics proved to be the fastest among the tested variants. In contrast, OSM data presented challenges due to inconsistencies, resulting in some routes being undeterminable, where connections between start and end points were lacking. These results underscore the importance of data quality and algorithm selection in effective forest route planning. Full article

(This article belongs to the Special Issue Modeling of Vehicle Mobility in Forests and Rugged Terrain)

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18 pages, 3216 KiB

Open AccessArticle

Natural Regeneration, Genetic Diversity, and Provenance of Introduced Fagus sylvatica L. Stands in Latvia

by Dainis Edgars Ruņģis, Darius Danusevičius, Rūta Kembrytė-Ilčiukienė, Līga Jansone, Marta Kempf and Āris Jansons

Forests 2025, 16(1), 178; https://doi.org/10.3390/f16010178 - 18 Jan 2025

Viewed by 516

Abstract

European beech (Fagus sylvatica L.) has a wide distribution range through Central and Western Europe, and is tolerant to a range of environmental factors and shade. Due to the high wood quality and growth rate, there is increasing interest in the cultivation [...] Read more.

European beech (Fagus sylvatica L.) has a wide distribution range through Central and Western Europe, and is tolerant to a range of environmental factors and shade. Due to the high wood quality and growth rate, there is increasing interest in the cultivation of this species in Northern Europe, and European beech is appropriate for closer-to-nature forestry management practices, where shade-tolerant species are essential. Latvia is located to the north of the natural range of European beech, but stands have been successfully established in the 19th century, using reproductive material of unknown origin. This study investigated the natural regeneration, genetic diversity, population structure, and provenance of Latvian F. sylvatica populations from two areas in western Latvia—Skede and Kaleti. Parent–offspring analyses did not identify a decrease in genetic diversity parameters in the naturally regenerated offspring, indicating that natural regeneration has not decreased the genetic viability of these populations. The three stands located in Skede were genetically very similar (pairwise Fst values ranged from 0.004 to 0.007). The Kaleti stand was more differentiated from the Skede stands (pairwise Fst values with the Skede stands ranged from 0.047 to 0.051), and the genetic diversity was low (H_e = 0.638). This is probably a result of the use of reproductive material collected from a very limited number of individuals to establish this stand, which also prevented the determination of the origin of this material. The Skede stand was compared to German, Polish, and Swedish F. sylvatica populations, and a Bayesian clustering analysis indicated that the most likely provenance of the Skede stand in Latvia was from southern Germany. Full article

(This article belongs to the Special Issue Advances in Tree Improvement and Biotechnology: Paving the Way for a Sustainable Forestry)

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20 pages, 10382 KiB

Open AccessArticle

Radial Variation in Colorimetric Parameters, Chemical Composition, and Biological Resistance of Teak Wood Extracted from 13- and 22-Year-Old Teak Trees

by Camila Mendes Campos, Waldelaine Rodrigues Hoffmann, Francyele dos Santos Correia, Elaine Cristina Lengowski, Márcio José da Silva, Ricardo Natalino, Aylson Costa Oliveira and Bárbara Luísa Corradi Pereira

Forests 2025, 16(1), 177; https://doi.org/10.3390/f16010177 - 18 Jan 2025

Viewed by 483

Abstract

This study aimed to evaluate the influence of age on the colorimetric parameters, chemical composition, and biological resistance of teak heartwood, transition zone, and sapwood. Samples of 13- and 22-year-old trees were collected from fast-growing commercial plantations in Mato Grosso, Brazil. From the [...] Read more.

This study aimed to evaluate the influence of age on the colorimetric parameters, chemical composition, and biological resistance of teak heartwood, transition zone, and sapwood. Samples of 13- and 22-year-old trees were collected from fast-growing commercial plantations in Mato Grosso, Brazil. From the heartwood, transition zone, and sapwood sections, we determined the CIEL*a*b* system colorimetric parameters and extractive contents and performed Py-CG/MS analysis and an accelerated degradation assay with the xylophagous fungus Trametes versicolor (L.) Lloyd. The 22-year-old wood presented greater redness and lower yellowness, and the heartwood was darker, with greater redness and lower yellowness than the other radial positions. The average content of total extractives varied between ages: 7.83% (13years) and 8.23% (22years). A total of 119 compounds were identified in teak wood, of which 51 presented areas greater than 1%. Quinones were identified in the heartwood and transition zone, with similar values between ages and approximately 7% in the heartwood. Although the durability increased significantly with age, the magnitude was slight. Wood from 22-year-old trees exhibited a lower average mass loss (10.30%) compared to wood from 13-year-old trees (12.68%). In contrast, differences between regions were more pronounced. Sapwood showed a mass loss of 22.5%, transition zone wood of 10.14%, and heartwood of 1.86%. We concluded that age influenced the colorimetric parameters, chemical composition, and biological resistance of teak wood. Teak heartwood from fast-growing plantations, both from final harvesting (22-years-old) and from thinning (13-years-old), is indicated for uses that require high biological resistance. Full article

(This article belongs to the Special Issue Wood Durability and Protection)

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17 pages, 6888 KiB

Open AccessArticle

Seasonal Dynamics of Periderm Maintenance and Phellogen Re-Initiation in Aesculus hippocastanum

by Anna Brzostowska, Edyta M. Gola and Elżbieta Myśkow

Forests 2025, 16(1), 176; https://doi.org/10.3390/f16010176 - 18 Jan 2025

Viewed by 517

Abstract

The periderm plays a crucial role in trees, acting as a barrier protecting internal tissues against biotic and abiotic stresses, thus having an impact on tree physiology, ecology, and general performance. It consists of the meristematic phellogen, whose activity gives rise to suberized [...] Read more.

The periderm plays a crucial role in trees, acting as a barrier protecting internal tissues against biotic and abiotic stresses, thus having an impact on tree physiology, ecology, and general performance. It consists of the meristematic phellogen, whose activity gives rise to suberized phellem (cork) cells outwardly and the parenchymatous phelloderm inwardly. Despite the periderm importance, intra-annual and seasonal changes in phellogen activity and phellem and phelloderm differentiation are poorly recognized. Therefore, we aimed to compare periderm development and functioning in successive years in horse chestnut, utilizing standard histological methods. We distinguished six stages of periderm development, including phellogen initiation and the differentiation of its derivatives. In the following years, the phellogen was active for a similar period, but produced fewer derivative cells. Importantly, some phellogen cells lost their meristematic characteristics before the end of the season and differentiated into phellem. To maintain periderm integrity, the remaining phelloderm cells underwent divisions, leading to phellogen re-initiation. Alternatively, when all periderm cells differentiated into the phellem, the new (subsidiary) phellogen originated from the underneath collenchyma. We postulate that phellogen re-initiation could be a mechanism ensuring the functional integrity of the periderm and discuss the role of phelloderm or collenchyma cells in this process. Full article

(This article belongs to the Section Urban Forestry)

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21 pages, 2056 KiB

Open AccessArticle

More than Just Chilling and Forcing: Deconstructing the Climate Windows and Drivers of Leaf Emergence and Fall in Woody Plant Species

by Álvaro Rubio-Cuadrado and J. Julio Camarero

Forests 2025, 16(1), 175; https://doi.org/10.3390/f16010175 - 17 Jan 2025

Viewed by 435

Abstract

Climate warming is impacting vegetation productivity and plant leaf phenology, but the precise climate drivers and windows of key leaf phenological phases, such as emergence and fall, are still not well understood. Recent intensive computational approaches based on pinpointing the optimal climate window [...] Read more.

Climate warming is impacting vegetation productivity and plant leaf phenology, but the precise climate drivers and windows of key leaf phenological phases, such as emergence and fall, are still not well understood. Recent intensive computational approaches based on pinpointing the optimal climate window of leaf phenophases by maximizing the signal could help to advance in this question. In this study, we assess the climate variables, the climate windows, and the type of relationship (linear or nonlinear) that drive leaf emergence and fall in 21 deciduous and 13 evergreen woody plant species inhabiting two sites in Mediterranean Spain. We used precipitation, solar radiation, and different temperature measures, including forcing and chilling, as climate variables. We found that forcing variables were the best predictors of leaf phenology, but other temperature variables, as well as precipitation and radiation, were also important. However, chilling was not a good predictor. Most selected models showed nonlinear relationships. The best thresholds for calculating forcing were different from those commonly used. In addition, the best climate window for leaf phenology was species-specific and contingent on climatic and phenological conditions. This optimum climate window often covered longer periods than those usually considered in phenology studies. Our approach could be used to assess and better forecast future plant phenological responses to climate warming. Full article

(This article belongs to the Special Issue Woody Plant Phenology in a Changing Climate, 2nd Edition)

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19 pages, 3640 KiB

Open AccessArticle

Changes in the Timing of Autumn Leaf Senescence of Maple and Ginkgo Trees in South Korea over the Past 30 Years: A Comparative Assessment of Process-Based, Linear Regression, and Machine-Learning Models

by Sukyung Kim, Minkyu Moon and Hyun Seok Kim

Forests 2025, 16(1), 174; https://doi.org/10.3390/f16010174 - 17 Jan 2025

Viewed by 511

Abstract

Changes in vegetation activities driven by climate change serve as both a sensitive indicator and a key driver of climate impacts, underscoring the need for accurate phenological predictions. Delays in leaf senescence due to rising air temperatures increase the risk of damage from [...] Read more.

Changes in vegetation activities driven by climate change serve as both a sensitive indicator and a key driver of climate impacts, underscoring the need for accurate phenological predictions. Delays in leaf senescence due to rising air temperatures increase the risk of damage from early frost, potentially affecting growth and survival in subsequent years. This study aimed to quantify long-term changes in leaf senescence timing for palmate maple and ginkgo trees, explore their associations with environmental factors, and compare the performance of multiple modeling approaches to identify their strengths and limitations for phenological predictions. Using data from 48 sites across South Korea (1989–2020), this study analyzed trends in the timing of leaf senescence for maple and ginkgo trees and compared the performance of process-based models (CDD_T, CDD_P, TP_T, TP_P), a linear regression model, and machine-learning models (random forest, RF; gradient-boosting decision tree, GBTD). Leaf senescence timing for both species has progressively been delayed, with ginkgo trees showing a faster rate of change (0.20 vs. 0.17 days per year, p < 0.05). Delayed senescence was observed in most regions (81% for maple and 75% for ginkgo), with statistically significant delays (p < 0.05) at half of the sites. Machine-learning models demonstrated the highest training accuracy (RMSE < 4.0 days, r > 0.90). Evaluation with independent datasets revealed that the RF and process-based TP_P (including minimum temperature and photoperiod) using a site-specific approach performed best (RMSE < 5.5 days, r > 0.75). Key environmental factors identified by RF included autumn minimum or mean temperatures and a summer photoperiod. By conducting this comparative assessment, the study provides insights into the applicability of different modeling approaches for phenology research and highlights their implications for vegetation management and climate change adaptation. Full article

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

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13 pages, 3746 KiB

Open AccessArticle

NeRF-Accelerated Ecological Monitoring in Mixed-Evergreen Redwood Forest

by Adam Korycki, Cory Yeaton, Gregory S. Gilbert, Colleen Josephson and Steve McGuire

Forests 2025, 16(1), 173; https://doi.org/10.3390/f16010173 - 17 Jan 2025

Viewed by 510

Abstract

Forest mapping provides critical observational data needed to understand the dynamics of forest environments. Notably, tree diameter at breast height (DBH) is a metric used to estimate forest biomass and carbon dioxide (

{CO}_{2}

) sequestration. Manual methods of forest mapping are [...] Read more.

Forest mapping provides critical observational data needed to understand the dynamics of forest environments. Notably, tree diameter at breast height (DBH) is a metric used to estimate forest biomass and carbon dioxide (

{CO}_{2}

) sequestration. Manual methods of forest mapping are labor intensive and time consuming, a bottleneck for large-scale mapping efforts. Automated mapping relies on acquiring dense forest reconstructions, typically in the form of point clouds. Terrestrial laser scanning (TLS) and mobile laser scanning (MLS) generate point clouds using expensive LiDAR sensing and have been used successfully to estimate tree diameter. Neural radiance fields (NeRFs) are an emergent technology enabling photorealistic, vision-based reconstruction by training a neural network on a sparse set of input views. In this paper, we present a comparison of MLS and NeRF forest reconstructions for the purpose of trunk diameter estimation in a mixed-evergreen Redwood forest. In addition, we propose an improved DBH-estimation method using convex-hull modeling. Using this approach, we achieved 1.68 cm RMSE (2.81%), which consistently outperformed standard cylinder modeling approaches. Full article

(This article belongs to the Special Issue Applications of Artificial Intelligence in Forestry: 2nd Edition)

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25 pages, 6999 KiB

Open AccessArticle

From Young to Over-Mature: Long-Term Cultivation Effects on the Soil Nutrient Cycling Dynamics and Microbial Community Characteristics Across Age Chronosequence of Schima superba Plantations

by Yangyang Sun, Yajing Zhang, Liyan Wang, Xinyu Zhang, Yuhui Jiang, Mulualem Tigabu, Pengfei Wu, Ming Li and Xia Hu

Forests 2025, 16(1), 172; https://doi.org/10.3390/f16010172 - 17 Jan 2025

Viewed by 503

Abstract

Optimizing forest management requires a comprehensive understanding of how soil properties and microbial communities evolve across different plantation ages. This study examines variations in soil nutrient dynamics, enzyme activities, and bacterial communities in Schima superba Gardn. & Champ plantations of 10, 15, 27, [...] Read more.

Optimizing forest management requires a comprehensive understanding of how soil properties and microbial communities evolve across different plantation ages. This study examines variations in soil nutrient dynamics, enzyme activities, and bacterial communities in Schima superba Gardn. & Champ plantations of 10, 15, 27, 55, and 64 years. By analyzing soil from depths of 0–20 cm, 20–40 cm, and 40–60 cm, we identified significant age-related trends in soil characteristics. Notably, nutrient contents, including total organic carbon (TOC), total phosphorus (TP), total carbon (TC), total nitrogen (TN), and nitrate nitrogen (

{NO}_{3}^{-}

-N), as well as soil water content (SWC), peaked in 55-year-old mature plantations and decreased in 64-year-old over-mature plantations. Enzyme activities, such as urease, sucrase, and acid phosphatase, decreased with soil depth and exhibited notable differences across stand ages. Microbial community analysis indicated the predominance of Acidobacteria, Chloroflexi, Proteobacteria, Actinobacteria, and Verrucomicrobiota in nutrient cycling, with their relative abundances varying significantly with age and depth. Mature and over-mature plantations exhibited higher absolute abundances of functional genes related to methane metabolism, nitrogen, phosphorus, and sulfur cycling. Reduced calcium ion levels were also linked to lower gene abundance in carbon degradation, carbon fixation, nitrogen, and phosphorus cycling, while increased TOC,

{NH}_{4}^{+}

-N,

{NO}_{3}^{-}

-N, and AP correlated with higher gene abundance in methane metabolism and phosphorus cycling. Our findings suggest that long-term cultivation of Schima superba enhances soil nutrient cycling. Calcium ion was identified as a significant factor in assessing soil properties and microbial dynamics across different stand ages, suggesting that extended plantation rotations can improve soil health and nutrient cycling. Full article

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

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23 pages, 10587 KiB

Open AccessArticle

Genome-Wide Identification and Characterization of the Homeodomain Leucine Zipper Protein (HD-Zip) Gene Family in Sea Buckthorn (Hippophae rhamnoides) Under Lead Stress

by Jiaxin Li, Na Hu, Jing Sun and Wu Zhou

Forests 2025, 16(1), 171; https://doi.org/10.3390/f16010171 - 17 Jan 2025

Viewed by 529

Abstract

This study investigates the role of sea buckthorn HD-Zip genes in response to lead stress, identifying 28 genes distributed across 10 chromosomes, which are classified into four subfamilies. Each subfamily exhibits a similar gene structure and conserved protein motifs. The HD-Zip gene family [...] Read more.

This study investigates the role of sea buckthorn HD-Zip genes in response to lead stress, identifying 28 genes distributed across 10 chromosomes, which are classified into four subfamilies. Each subfamily exhibits a similar gene structure and conserved protein motifs. The HD-Zip gene family is notably enriched in stress-responsive elements. Transcriptomic analysis revealed differential expression among the 28 members of the HD-Zip gene family in sea buckthorn, varying with different Pb ion concentrations. Upregulated genes were predominantly observed at stress concentrations of 1 g/kg and 5 g/kg, while downregulated genes were more prevalent at the 0.5 g/kg stress concentration. Covariance analysis indicated that large-scale gene duplication was the primary mechanism driving the expansion of the sea buckthorn HD-Zip gene family. Additionally, analysis of three-dimensional protein structures demonstrated high conservation within the HD-Zip gene, suggesting that certain sea buckthorn HD-Zip proteins may play significant regulatory roles in physiological functions. Scanning electron microscopy–energy-dispersive spectroscopy (SEM-EDS) analysis revealed that the majority of lead ions accumulated in the roots of the seedlings, with the lead concentration affecting the number, density, and function of leaf slits. These findings enhance our understanding of the complex regulatory mechanisms governing HD-Zip genes and will contribute to the genetic improvement of sea buckthorn for breeding under lead stress conditions. Full article

(This article belongs to the Special Issue Molecular Evolutionary Genetics Analysis in Forest Trees)

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13 pages, 3307 KiB

Open AccessArticle

Assessing Relationships Between Deer (Cervidae) Damage and Stand Structure of Scots Pine (Pinus sylvestris) Stands in Hemiboreal Latvia

by Gundega Done, Laura Ķēniņa, Didzis Elferts, Jānis Ozoliņš and Āris Jansons

Forests 2025, 16(1), 170; https://doi.org/10.3390/f16010170 - 17 Jan 2025

Viewed by 514

Abstract

Intensive forest management has promoted an increase in deer (Cervidae) population density. Various silvicultural activities, such as pre-commercial thinning, can change the feeding conditions for deer species, therefore impacting browsing pressure on target tree species. In this study, we analyzed how several factors, [...] Read more.

Intensive forest management has promoted an increase in deer (Cervidae) population density. Various silvicultural activities, such as pre-commercial thinning, can change the feeding conditions for deer species, therefore impacting browsing pressure on target tree species. In this study, we analyzed how several factors, including the density of the main tree species, admixture, undergrowth, and forest type, affect deer damage intensity in pine stands, considering deer densities and regional aspects in hemiboreal Latvia. GLMM analysis, based on data from 1238 sample plots, showed that the probability of browsing damage decreases with an increase in the density of undergrowth in young (<20 years) pine stands with a dominant height below 3 m. Also, the probability of pines being damaged by deer was significantly (p = 0.001) higher in stands with fresh pre-commercial thinning than in those with no thinning. However, differences in deer density between regions also determined browsing pressure. Results indicated that undergrowth density, pre-commercial thinning, and deer density may be important drivers of damage levels, especially in the winter browsing of young pine stands on wet mineral soils. Therefore, future research should continue to evaluate applied forest management strategies in hemiboreal forests that provide additional natural food base in the form of woody plants and shrubs in winter forage to ensure more deer-adapted practices. Full article

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

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15 pages, 7129 KiB

Open AccessArticle

Exploration and Empirical Study on Spatial Distribution of SOC at the Core Area in Coastal Tamarix Forests’ Inland Side of Changyi National Marine Ecological Area

by Ruiting Liu, Ping Han, Jin Wang, Huiqian Zong, Xuewan Zhang, Qianxun Chen, Feiyong Chen, Yufeng Du, Zhao Li, Yaohui Liu, Pingjie Fu, Xiaoxiang Cheng and Jingtao Xu

Forests 2025, 16(1), 169; https://doi.org/10.3390/f16010169 - 17 Jan 2025

Viewed by 551

Abstract

The forest soil carbon pool plays a vital role in terrestrial ecosystems, being of great significance for maintaining global balance, regulating the global carbon cycle, and facilitating ecological restoration. Shandong Changyi Marine Ecological Special Protection Area is the only state-level marine special protection [...] Read more.

The forest soil carbon pool plays a vital role in terrestrial ecosystems, being of great significance for maintaining global balance, regulating the global carbon cycle, and facilitating ecological restoration. Shandong Changyi Marine Ecological Special Protection Area is the only state-level marine special protection area in China with tamarisk as the main object of protection, and it is the largest continuous and the best preserved natural tamarisk forest distribution area on the mainland coast of China. Compared to other forested areas, research on the spatial distribution of SOC at the core area in coastal Tamarix forests’ inland side appears to be relatively scarce. Based on this, this paper takes the core area of the Changyi National Marine Ecological Special Protection Zone, located on the southern coast of Laizhou Bay, as the research subject, based on the potassium dichromate oxidation-external heating, one-way ANOVA, and Bonferroni methods, analyzing the spatial distribution of the SOC content inland of coastal Tamarix forests. The research yielded the following conclusions: (1) The surface layer (0–10 cm) contributes significantly to the total SOC content within a 0–60 cm depth, accounting for at least 31% and shows notable surface accumulation. (2) The combined SOC content in the surface and subsurface layers (10–20 cm) accounts for at least 50% of the total SOC content within a 0–60 cm depth, indicating the dominance of these two soil layers in carbon storage. (3) The SOC content decreases with the soil depth at all six sampling points within the 0–60 cm range, with a marked drop from 0–10 cm to 10–20 cm. (4) One-way ANOVA and multiple comparisons reveal that the soil depth significantly affects the SOC distribution, particularly between the surface and 20–30 cm layers (p < 0.001), indicating high robustness and statistical significance. (5) Horizontally, the total SOC at 0 m is 45% lower than at 2 m in the 0–60 cm layer. The SOC in the 0–20 cm layer fluctuates significantly with distance from the shrub trunk, while the SOC in the 30–60 cm layers is low and stable, with minimal variations with depth. In addition, this study found that the SOC content in the core area of the protected area is lower than that in the common forest ecosystem. In the future, scientific ecological restoration projects and management protection methods should be used to improve soil’s carbon storage and carbon sink capacity. These findings not only validate the patterns of SOC’s spatial distribution in coastal Tamarix forest wetlands but also provide a scientific basis for carbon assessment and the formulation of ecological protection measures in coastal wetlands. Full article

(This article belongs to the Special Issue Remote Sensing Approach for Early Detection of Forest Disturbance)

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17 pages, 4349 KiB

Open AccessArticle

Mining and Expression Pattern Analysis of Genes Related to the Regulation of Flowering in Korean Pine (Pinus koraiensis)

by Junshuai Du, Dan Hou, Junfei Hao, Junping Du, Hanguo Zhang and Lei Zhang

Forests 2025, 16(1), 168; https://doi.org/10.3390/f16010168 - 17 Jan 2025

Viewed by 473

Abstract

Korean pine (Pinus koraiensis Siebold & Zucc.) is an important timber and economic tree species in northeast China. Its seeds serve as both a primary means of propagation and a significant economic product. In this study, we identified 12 full-length MADS-box genes [...] Read more.

Korean pine (Pinus koraiensis Siebold & Zucc.) is an important timber and economic tree species in northeast China. Its seeds serve as both a primary means of propagation and a significant economic product. In this study, we identified 12 full-length MADS-box genes based on the Korean pine flower-induced transcriptome data available in our laboratory. These genes were identified through multiple sequence alignment and screening for conserved structural domains. We analyzed the genetic relationships of these genes and predicted their physicochemical properties. Additionally, we examined the expression patterns of three SHORT VEGETATIVE PHASE (SVP) genes across different tissues and developmental stages of Korean pine. The results indicate that the amino acid composition, molecular weight, isoelectric point, and other physicochemical properties of the MADS-box gene family in Pinus koraiensis are generally similar, though some individual variations are observed. A total of 12 MADS-box family genes were identified from the Korean pine transcriptome, distributed across five subfamilies. Conserved motif analysis revealed that these genes share similar conserved sequences. Structural and physicochemical analyses showed that genes with similar sequences exhibited comparable characteristics. Expression levels of the SVP genes varied significantly across different developmental stages and tissues, with the expression of the three SVP genes in leaves being markedly higher than in buds (approximately 200-fold). The expression levels of these genes in leaves were not only higher than in buds but also exceeded those in other tissues. Based on these findings, we conclude that these three SVP genes primarily play a suppressive role in the process of flower bud formation, helping Korean pine maintain a juvenile state under certain conditions, and are also involved in the growth and development of its leaves. This research provides a basis for future studies on the flowering induction mechanism in Korean pine. Full article

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

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19 pages, 6455 KiB

Open AccessArticle

Assessment of Mango Canopy Water Content Through the Fusion of Multispectral Unmanned Aerial Vehicle (UAV) and Sentinel-2 Remote Sensing Data

by Jinlong Liu, Jing Huang, Mengjuan Wu, Tengda Qin, Haoyi Jia, Shaozheng Hao, Jia Jin, Yuqing Huang and Nathsuda Pumijumnong

Forests 2025, 16(1), 167; https://doi.org/10.3390/f16010167 - 17 Jan 2025

Viewed by 519

Abstract

This study proposes an Additive Wavelet Transform (AWT)-based method to fuse Multispectral UAV (MS UAV, 5 cm resolution) and Sentinel-2 satellite imagery (10–20 m resolution), generating 5 cm resolution fused images with a focus on near-infrared and shortwave infrared bands to enhance the [...] Read more.

This study proposes an Additive Wavelet Transform (AWT)-based method to fuse Multispectral UAV (MS UAV, 5 cm resolution) and Sentinel-2 satellite imagery (10–20 m resolution), generating 5 cm resolution fused images with a focus on near-infrared and shortwave infrared bands to enhance the accuracy of mango canopy water content monitoring. The fused Sentinel-2 and MS UAV data were validated and calibrated using field-collected hyperspectral data to construct vegetation indices, which were then used with five machine learning (ML) models to estimate Fuel Moisture Content (FMC), Equivalent Water Thickness (EWT), and canopy water content (CWC). The results indicate that the addition of fused Sentinel-2 data significantly improved the estimation accuracy of all parameters compared to using MS UAV data alone, with the Genetic Algorithm Backpropagation Neural Network (GABP) model performing best (R² = 0.745, 0.859, and 0.702 for FMC, EWT, and CWC, respectively), achieving R² improvements of 0.066, 0.179, and 0.210. Slope, canopy coverage, and human activities were identified as key factors influencing the spatial variability of FMC, EWT, and CWC, with CWC being the most sensitive to environmental changes, providing a reliable representation of mango canopy water status. Full article

(This article belongs to the Topic Remote Sensing in Water Resources Management Models, 2nd Volume)

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13 pages, 1778 KiB

Open AccessArticle

Enhanced Properties of Cryptomeria japonica (Thunb ex L.f.) D.Don from the Azores Through Heat-Treatment

by Bruno Esteves, Lina Nunes, Rogério Lopes and Luísa Cruz-Lopes

Forests 2025, 16(1), 166; https://doi.org/10.3390/f16010166 - 17 Jan 2025

Viewed by 514

Abstract

This study evaluates the chemical, physical, mechanical, and biological properties of untreated and heat-treated Cryptomeria japonica (Thunb ex L.f.) D.Don wood from the Azores, Portugal. Heat treatment was performed at 212 °C for 2 h following the Thermo-D class protocol. Chemical analysis revealed [...] Read more.

This study evaluates the chemical, physical, mechanical, and biological properties of untreated and heat-treated Cryptomeria japonica (Thunb ex L.f.) D.Don wood from the Azores, Portugal. Heat treatment was performed at 212 °C for 2 h following the Thermo-D class protocol. Chemical analysis revealed an increase in ethanol soluble extractives and lignin content after heat treatment, attributed to hemicellulose degradation and condensation reactions. Dimensional stability improved significantly, as indicated by reduced swelling coefficients and higher anti-swelling efficiency (ASE), particularly in the tangential direction. Heat-treated wood demonstrated reduced water absorption and swelling, enhancing its suitability for applications requiring dimensional stability. Mechanical tests showed a decrease in bending strength by 19.6% but an increase in the modulus of elasticity (MOE) by 49%, reflecting changes in the wood’s structural integrity. Surface analysis revealed significant color changes, with darkening, reddening, and yellowing, aligning with trends observed in other heat-treated woods. Biological durability tests indicated that both untreated and treated samples were susceptible to subterranean termite attack, although heat-treated wood exhibited a higher termite mortality rate, suggesting potential long-term advantages. This study highlights the impact of heat treatment on Cryptomeria japonica wood, emphasizing its potential for enhanced stability and durability in various applications. Full article

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

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17 pages, 3811 KiB

Open AccessArticle

The Entry of Pollinating Fig Wasps Plays a Pivotal Role in the Developmental Phase and Metabolic Expression Changes in Ficus hookeriana Figs

by Ying Zhang, Yunfang Guan, Zongbo Li, Yan Wang, Changqi Chen, Xiaoyan Yang and Yuan Zhang

Forests 2025, 16(1), 165; https://doi.org/10.3390/f16010165 - 16 Jan 2025

Viewed by 541

Abstract

The fig (the syconium of the Ficus tree) and its pollinating fig wasp represent exceptional examples for researching plant–insect interactions due to their remarkable specificity in species interaction and mutually beneficial symbiotic relationship. However, the mechanisms underlying the developmental process of monoecious figs [...] Read more.

The fig (the syconium of the Ficus tree) and its pollinating fig wasp represent exceptional examples for researching plant–insect interactions due to their remarkable specificity in species interaction and mutually beneficial symbiotic relationship. However, the mechanisms underlying the developmental process of monoecious figs in response to the entry of pollinating fig wasps (pollinators) and the metabolic changes occurring during this process remain elusive. Our study employed a combination of controlled experiments in the field and LC-MS methods to investigate the impact of pollinating fig wasp entry on the developmental phase of figs, as well as the metabolic alterations occurring during this process. A total of 381 metabolites and 155 differential metabolites were identified, with the predominant classes of metabolites being organic acids, lipids, and benzene aromatic compounds. The results suggest that in the absence of wasp entry, the receptive phase of fig would exhibit an extended duration. However, upon the entry of fig wasps, the receptive phase of figs would terminate within a span of 1 to 2 days, concomitant with substantial fluctuations in the composition and proportions of metabolites within the fig. Our research focuses on the analysis of linoleic acid metabolism, phenylpropanoid biosynthesis, and flavonoid biosynthesis pathways. Our findings suggest that the entry of wasps triggers alterations in the metabolic regulatory mechanisms of figs. Prior to wasp entry, metabolites primarily regulate fig growth and development. However, after wasp entry, metabolites predominantly govern lipid accumulation and the establishment of defense mechanisms, indicating a transition in fig development. This metabolic perspective explains why figs promptly enter an interflower phase that is not attractive to pollinating fig wasps after their entry, and how figs achieve reproductive balance through the regulation of different metabolic pathways. This study provides scientific evidence for elucidating the stability mechanism of the fig wasp mutualistic system. Full article

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

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32 pages, 8559 KiB

Open AccessArticle

MultiProduct Optimization of Cedrelinga cateniformis (Ducke) Ducke in Different Plantation Systems in the Peruvian Amazon

by Juan Rodrigo Baselly-Villanueva, Andrés Fernández-Sandoval, Evelin Judith Salazar-Hinostroza, Gloria Patricia Cárdenas-Rengifo, Ronald Puerta, Tony Steven Chuquizuta Trigoso, Yennifer Lisbeth Rufasto-Peralta, Geomar Vallejos-Torres, Gianmarco Goycochea Casas, Carlos Alberto Araújo Junior, Gerónimo Quiñónez-Barraza, Pedro Álvarez-Álvarez and Helio Garcia Leite

Forests 2025, 16(1), 164; https://doi.org/10.3390/f16010164 - 16 Jan 2025

Viewed by 852

Abstract

This study addressed multi-product optimization in Cedrelinga cateniformis plantations in the Peruvian Amazon, aiming to maximize volumetric yields of logs and sawn lumber. Data from seven plantations of different ages and types, established on degraded land, were analyzed by using ten stem profile [...] Read more.

This study addressed multi-product optimization in Cedrelinga cateniformis plantations in the Peruvian Amazon, aiming to maximize volumetric yields of logs and sawn lumber. Data from seven plantations of different ages and types, established on degraded land, were analyzed by using ten stem profile models to predict taper and optimize wood use. In addition, the structure of each plantation was evaluated using diameter distributions and height–diameter ratios; log and sawn timber production was optimized using SigmaE 2.0 software. The Garay model proved most effective, providing high predictive accuracy (adjusted R² values up to 0.963) and biological realism. Marked differences in volumetric yield were observed between plantations: older and more widely spaced plantations produced higher timber volumes. Logs of optimal length (1.83–3.05 m) and larger dimension wood (e.g., 25.40 × 5.08 cm) were identified as key contributors to maximizing volumetric yields. The highest yields were observed in mature plantations, in which the total log volume reached 508.1 m³ha⁻¹ and the sawn lumber volume 333.6 m³ha⁻¹. The findings demonstrate the power of data-driven decision-making in the timber industry. By combining precise modeling and optimization techniques, we developed a framework that enables sawmill operators to maximize log and lumber yields. The insights gained from this research can be used to improve operational efficiency and reduce waste, ultimately leading to increased profitability. These practices promote support for smallholders and the forestry industry while contributing to the long-term development of the Peruvian Amazon. Full article

(This article belongs to the Special Issue Advances in Technology and Solutions for Wood Processing)

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33 pages, 3634 KiB

Open AccessReview

Biopolymers Derived from Forest Biomass for the Sustainable Textile Industry

by Juliana C. Dias, Susana Marques, Pedro C. Branco, Thomas Rodrigues, Cristiana A. V. Torres, Filomena Freitas, Dmitry V. Evtyugin and Carla J. Silva

Forests 2025, 16(1), 163; https://doi.org/10.3390/f16010163 - 16 Jan 2025

Viewed by 632

Abstract

In line with environmental awareness movements and social concerns, the textile industry is prioritizing sustainability in its strategic planning, product decisions, and brand initiatives. The use of non-biodegradable materials, obtained from non-renewable sources, contributes heavily to environmental pollution throughout the textile production chain. [...] Read more.

In line with environmental awareness movements and social concerns, the textile industry is prioritizing sustainability in its strategic planning, product decisions, and brand initiatives. The use of non-biodegradable materials, obtained from non-renewable sources, contributes heavily to environmental pollution throughout the textile production chain. As sustainable alternatives, considerable efforts are being made to incorporate biodegradable biopolymers derived from residual biomass, with reasonable production costs, to replace or reduce the use of synthetic petrochemical-based polymers. However, the commercial deployment of these biopolymers is dependent on high biomass availability and a cost-effective supply. Residual forest biomass, with lignocellulosic composition and seasonably available at low cost, constitutes an attractive renewable resource that might be used as raw material. Thus, this review aims at carrying out a comprehensive analysis of the existing literature on the use of residual forest biomass as a source of new biomaterials for the textile industry, identifying current gaps or problems. Three specific biopolymers are considered: lignin that is recovered from forest biomass, and the bacterial biopolymers poly(hydroxyalkanoates) (PHAs) and bacterial cellulose (BC), which can be produced from sugar-rich hydrolysates derived from the polysaccharide fractions of forest biomass. Lignin, PHA, and BC can find use in textile applications, for example, to develop fibers or technical textiles, thus replacing the currently used synthetic materials. This approach will considerably contribute to improving the sustainability of the textile industry by reducing the amount of non-biodegradable materials upon disposal of textiles, reducing their environmental impact. Moreover, the integration of residual forest biomass as renewable raw material to produce advanced biomaterials for the textile industry is consistent with the principles of the circular economy and the bioeconomy and offers potential for the development of innovative materials for this industry. Full article

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

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12 pages, 3873 KiB

Open AccessArticle

Snowfall Change Had Different Effects on Litter Decomposition for Two Typical Desert Species in Different Periods

by Tingting Xie, Lishan Shan and Chengpeng Zhao

Forests 2025, 16(1), 162; https://doi.org/10.3390/f16010162 - 16 Jan 2025

Viewed by 359

Abstract

In desert ecosystems, litter decomposition is the primary source of soil nutrients and is strongly affected by extreme climate events, which may influence desert plant survival and species diversity. To date, the effects of snowfall changes on litter decomposition in desert species remain [...] Read more.

In desert ecosystems, litter decomposition is the primary source of soil nutrients and is strongly affected by extreme climate events, which may influence desert plant survival and species diversity. To date, the effects of snowfall changes on litter decomposition in desert species remain poorly understood. Here, a snowfall manipulation experiment was conducted in Northwest China that included snowfall addition and removal treatments, as well as a natural snowfall control. Compared to the control, snowfall addition increased the amount of litter mass lost for Salsola passerina and Reaumuria soongarica during the snow-covered period by 21.54% and 21.8%, respectively. In contrast, snowfall addition effects differed between species during the snow-free period. More carbon was released from the S. passerina litter in the snowfall addition treatment during the snow-free period. Similarly, during the snow-covered period, more carbon and nitrogen were released from the R. soongorica litter in the snowfall addition treatment. Overall, the proportion of litter mass lost (from the annual total) increased with snowfall addition in the snow-covered period but was reduced with snowfall addition in the snow-free period. In the snow-covered period, the snowfall addition treatment affected litter mass loss to the same extent in both species but impacted S. passerina more strongly than R. soongorica in the snow-free period due to differences in soil urease activity. Changes in snowfall, therefore, significantly influenced litter decomposition in both desert species, but these effects differed between the snow-covered and snow-free period, particularly for litter with a higher C:N ratio. Full article

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

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21 pages, 3056 KiB

Open AccessArticle

Expression of Secondary Sexual Dimorphism in the Diurnal Course of Leaf Gas Exchanges Is Modified by the Rhythmic Growth of Ilex paraguariensis Under Monoculture and Agroforestry

by Miroslava Rakočević, Eunice Reis Batista, Rafael Leonardo de Almeida, Ivar Wendling and Rafael Vasconcelos Ribeiro

Forests 2025, 16(1), 161; https://doi.org/10.3390/f16010161 - 16 Jan 2025

Viewed by 523

Abstract

Dioecious species show a division of labor expressed through the differentiated manifestation of resource acquisition. We hypothesized that the expression of secondary sexual dimorphism (SSD) in the leaf gas exchange of yerba mate would be more intensive in females than in males to [...] Read more.

Dioecious species show a division of labor expressed through the differentiated manifestation of resource acquisition. We hypothesized that the expression of secondary sexual dimorphism (SSD) in the leaf gas exchange of yerba mate would be more intensive in females than in males to permit females the carbon investments necessary to finish the reproductive cycle. This species can present two growth units annually (GU1-fall and GU2-spring) intercalated with two rest periods (R1-summer and R2-winter). The leaf area index (LAI) and the diurnal courses of leaf photosynthesis (A_net), stomatal conductance (g_s), leaf transpiration (E), intercellular CO₂ concentration (C_i), water use efficiency (WUE), and instantaneous carboxylation efficiency (A_net/C_i) were estimated in female and male plants of yerba mate during four periods of annual rhythmic growth in monoculture (MO) and agroforestry (AFS). Leaf gas exchanges varied over the annual rhythmic growth and were more intensive under MO than under AFS. A_net, A_net/C_i ratios, and WUE were higher in females than in males during the summer (R1) and spring (GU2). Also, g_s and E were more intensive in females than males during the summer. Oppositely, higher WUE in males than in females was observed during the fall (GU1) and winter (R2), with males also showing a higher A_net/C_i ratio during the winter and higher E during the spring (GU2). Despite the strong effect of the cultivation system on LAI and leaf gas exchange traits over the diurnal course, SSD expression was rarely modified by the cultivation system, being expressed only in MO for E during the spring (GU2) and WUE during the winter (R2). High WUE in males during the winter would benefit plants during cold and dry periods, improving the balance between carbon acquisition and water loss through transpiration. On the other hand, high A_net during the summer and spring could be considered as a general fitness strategy of female plants to improve photoassimilate supply and support their additional reproduction costs. Full article

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

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22 pages, 11131 KiB

Open AccessArticle

Risk Modeling for the Emergence of the Primary Outbreak Area of the Siberian Moth Dendrolimus sibiricus Tschetv. in Coniferous Forests of Central Siberia

by Andrey A. Goroshko, Svetlana M. Sultson, Evgenii I. Ponomarev, Denis A. Demidko, Olga A. Slinkina, Pavel V. Mikhaylov, Andrey I. Tatarintsev, Nadezhda N. Kulakova and Natalia P. Khizhniak

Forests 2025, 16(1), 160; https://doi.org/10.3390/f16010160 - 16 Jan 2025

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Abstract

In the southern taiga of Siberia, periodic outbreaks of the Siberian moth Dendrolimus sibrircus Tschetv. have been observed. The outbreaks result in the defoliation of Siberian fir Abies sibirica Ledeb. and Siberian pine Pinus sibirica Du Tour. stands across approximately one million hectares, [...] Read more.

In the southern taiga of Siberia, periodic outbreaks of the Siberian moth Dendrolimus sibrircus Tschetv. have been observed. The outbreaks result in the defoliation of Siberian fir Abies sibirica Ledeb. and Siberian pine Pinus sibirica Du Tour. stands across approximately one million hectares, leading to dieback of the affected forests. This is largely attributable to the inability to promptly identify the onset of the pest population growth in a timely manner, particularly in the context of expansive forest areas with limited accessibility. It is feasible to enhance the efficacy of monitoring Siberian moth populations by discerning stands with the highest propensity for damage and concentrating efforts on these areas. To achieve this, we employed machine learning techniques, specifically gradient boosting, support vector machines, and decision trees, training models on two sets of predictors. One of the datasets was obtained through a field study conducted in forest stands during the previous outbreak of the Siberian moth (2015–2018), while the other was derived from the analysis of remote sensing data during the same period. In both 2015 and 2016, the defoliation was most accurately predicted using gradient boosting (XGB algorithm), with ROC-AUC values reaching 0.89–0.94. The most significant predictors derived from the ground data were the proportions of Siberian fir, Siberian spruce Picea obovata Ledeb., and Scots pine Pinus sylvestris L., phytosociological data, tree age, and site quality. Among the predictors obtained from the analysis of remote sensing data, the distance to disturbed forest stands was identified as the most significant, while the proportion of dark coniferous species (A. sibirica, P. sibirica, or Picea obovata Ledeb.), the influx of solar radiation (estimated through the CHILI index), and the position in the relief (mTPI index) were also determined to be important. Full article

(This article belongs to the Special Issue Management of Forest Pests and Diseases—2nd Edition)

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Forests, Volume 16, Issue 1 (January 2025) – 189 articles

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