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18 pages, 3425 KiB  
Article
A Predictive Model for Traffic Noise Reduction Effects of Street Green Spaces with Variable Widths of Coniferous Vegetation
by Qi Meng, Olga Evgrafova and Mengmeng Li
Forests 2025, 16(2), 238; https://doi.org/10.3390/f16020238 (registering DOI) - 26 Jan 2025
Abstract
Street green spaces can effectively attenuate traffic noise, but the crucial role of coniferous trees and shrubs in the reduction in green space noise has not been systematically explored. Therefore, in this study, the aim was to determine the mechanism of the influence [...] Read more.
Street green spaces can effectively attenuate traffic noise, but the crucial role of coniferous trees and shrubs in the reduction in green space noise has not been systematically explored. Therefore, in this study, the aim was to determine the mechanism of the influence of plant morphological characteristics and planting forms on the noise reduction effect using field measurements of the noise reduction effect of 36 street green spaces planted with coniferous trees and shrubs. It was found that for the same width of street green spaces, the noise reduction effects of planting single and multiple trees were significantly different, and this difference increased with an increase in street green space width. The noise reduction effect of planting low shrubs in street green spaces was significantly different from that of planting common shrubs of the same width, and their difference increased with an increase in the street green space width. The factors that significantly affected the noise reduction effect of the 5 m wide street green space were tree height, crown width, and DBH, and all of them were positively correlated. In addition, the noise reduction effect of the street green space planted with conifers was affected by the road and pavement widths. Finally, in this study, a stepwise regression model was constructed for the noise reduction effect of street green spaces based on plant morphological parameters, planting methods, and physical characteristics of the road to quantify the crucial role of each factor in the noise reduction effect of street green spaces. The results of this study can provide plant noise reduction strategies for urban landscape planning and design to create a healthy urban acoustic environment. Full article
(This article belongs to the Special Issue Soundscape in Urban Forests - 2nd Edition)
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19 pages, 563 KiB  
Article
Analysis of Wood Density to Compare the Amount of Accumulated Carbon Dioxide in the Stems of Selected Non-Native Tree Species in Poland
by Radosław Wąsik
Forests 2025, 16(2), 223; https://doi.org/10.3390/f16020223 - 24 Jan 2025
Viewed by 206
Abstract
One of the priorities in European policy is the greater use of wood. In this context, it is important to know the total amount of CO2 absorbed by the tree and accumulated in the wood. In the timber industry, butt logs are [...] Read more.
One of the priorities in European policy is the greater use of wood. In this context, it is important to know the total amount of CO2 absorbed by the tree and accumulated in the wood. In the timber industry, butt logs are mainly processed. The aim of this study is to analyze diameter at breast height (DBH), wood density (WD), and the amount of CO2 in grand fir (GF), Douglas fir (DF), northern red oak (NRO), and black locust (BL) wood. The DBH and bark thickness were measured, and cores were taken to study WD and calculate the amount of CO2. Analyses were conducted in three age classes of trees. It was found that in the youngest age class, DF had a significantly larger DBH compared to NRO and BL, and GF had a significantly larger DBH compared to NRO. The wood density of coniferous species was significantly lower compared to broadleaved species. DF absorbed the most CO2. In Class III, DF had significantly larger DBH and significantly lower wood density compared to NRO and BL. DF absorbed significantly more CO2 compared to NRO. In Classes IV and V, DF had larger DBH compared to NRO and lower wood density. The amount of CO2 absorbed by both species was similar. Taking into account the amount of absorbed CO2, the durability of the wood, and aspects related to sustainable forest management of the four studied non-native tree species, Douglas fir seems to be the best choice for cultivation in Polish forests. Full article
19 pages, 5018 KiB  
Article
Relationships Between Saproxylic Beetle Microhabitat Occurrences and Forest State Indicators
by László Zoltán, Tamás Németh, Soma Horváth, Sándor Bérces, Zoltán Elek and Tibor Standovár
Forests 2025, 16(2), 195; https://doi.org/10.3390/f16020195 - 21 Jan 2025
Viewed by 479
Abstract
The use of proxies in habitat assessments has become widespread in recent decades. We used forest state descriptive data from a large-scale project (SCP) as proxies to investigate the occurrence of habitats suitable for some protected saproxylic beetles. We searched for pre-defined tree-related [...] Read more.
The use of proxies in habitat assessments has become widespread in recent decades. We used forest state descriptive data from a large-scale project (SCP) as proxies to investigate the occurrence of habitats suitable for some protected saproxylic beetles. We searched for pre-defined tree-related microhabitats (TreMs) suitable for saproxylic beetles in 1 ha quadrats in the Börzsöny Mts., Hungary. We compared the frequency of each microhabitat type with the aggregated values of the forest state proxies. Our results suggest that the average number of snags with DBH = 21–50 cm and the frequency of lying deadwood with Ø > 35 cm can adequately represent the occurrence of all beetle microhabitats studied. In most cases, the frequency of plots with species richness of live canopy trees with DBH > 35 cm and the amount of lying dead wood were also good indicators. The TreM indicators of the SCP alone can detect the presence of specialist beetles requiring cavities. The stands with a better forest state had more protected saproxylic beetles. The practical implementation of our work is based on the optimization of the resources required for monitoring. In surveys prepared to cover large areas, it is easier to monitor the habitat of saproxylic beetles with the help of individual proxies. Full article
(This article belongs to the Section Forest Biodiversity)
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18 pages, 5849 KiB  
Article
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 503
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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13 pages, 3746 KiB  
Article
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 399
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 (CO2) 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 (CO2) 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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16 pages, 1905 KiB  
Article
Investigating LiDAR Metrics for Old-Growth Beech- and Spruce-Dominated Forest Identification in Central Europe
by Devara P. Adiningrat, Andrew Skidmore, Michael Schlund, Tiejun Wang, Haidi Abdullah and Marco Heurich
Remote Sens. 2025, 17(2), 251; https://doi.org/10.3390/rs17020251 - 12 Jan 2025
Viewed by 640
Abstract
Old-growth forests are essential for maintaining biodiversity, as they are formed by the complexity of diverse forest structures, such as broad variations in tree height and diameter (DBH) and conditions of living and dead trees, leading to various ecological niches. However, many efforts [...] Read more.
Old-growth forests are essential for maintaining biodiversity, as they are formed by the complexity of diverse forest structures, such as broad variations in tree height and diameter (DBH) and conditions of living and dead trees, leading to various ecological niches. However, many efforts of old-growth forest mapping from LiDAR have targeted only one specific forest structure (e.g., stand height, basal area, or stand density) by deriving information through a large number of LiDAR metrics. This study introduces a novel approach for identifying old-growth forests by optimizing a set of selected LiDAR standards and structural metrics. These metrics effectively capture the arrangement of multiple forest structures, such as canopy heterogeneity, multilayer canopy profile, and canopy openness. To determine the important LiDAR standard and structural metrics in identifying old-growth forests, multicollinearity analysis using the variance inflation factor (VIF) approach was applied to identify and remove metrics with high collinearity, followed by the random forest algorithm to rank which LiDAR standard and structural metrics are important in old-growth forest classification. The results demonstrate that the LiDAR structural metrics (i.e., advanced LiDAR metrics related to multiple canopy structures) are more important and effective in distinguishing old- and second-growth forests than LiDAR standard metrics (i.e., height- and density-based LiDAR metrics) using the European definition of a 150-year stand age threshold for old-growth forests. These structural metrics were then used as predictors for the final classification of old-growth forests, yielding an overall accuracy of 78%, with a true skill statistic (TSS) of 0.58 for the test dataset. This study demonstrates that using a few structural LiDAR metrics provides more information than a high number of standard LiDAR metrics, particularly for identifying old-growth forests in mixed temperate forests. The findings can aid forest and national park managers in developing a practical and efficient old-growth forest identification and monitoring method using LiDAR. Full article
(This article belongs to the Special Issue LiDAR Remote Sensing for Forest Mapping)
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26 pages, 5460 KiB  
Article
Assessing Methods to Measure Stem Diameter at Breast Height with High Pulse Density Helicopter Laser Scanning
by Matthew J. Sumnall, Ivan Raigosa-Garcia, David R. Carter, Timothy J. Albaugh, Otávio C. Campoe, Rafael A. Rubilar, Bart Alexander, Christopher W. Cohrs and Rachel L. Cook
Remote Sens. 2025, 17(2), 229; https://doi.org/10.3390/rs17020229 - 10 Jan 2025
Viewed by 517
Abstract
Technological developments have allowed helicopter airborne laser scanning (HALS) to produce high-density point clouds below the forest canopy. We present a tree stem classification method that combines linear shape detection and model-based clustering, using four discrete methods to estimate stem diameter. Stem horizontal [...] Read more.
Technological developments have allowed helicopter airborne laser scanning (HALS) to produce high-density point clouds below the forest canopy. We present a tree stem classification method that combines linear shape detection and model-based clustering, using four discrete methods to estimate stem diameter. Stem horizontal size was estimated every 25 cm below the living crown, and a cubic spline was used to estimate where there were gaps. Individual stem diameter at breast height (DBH) was estimated for 77% of field-measured trees. The root mean square error (RMSE) of DBH estimates was 7–12 cm using stem circle fitting. Adapting the approach to use an existing stem taper model reduced the RMSE of estimates (<1 cm). In contrast, estimates that were produced from a previously existing DBH estimation method (PREV) could be achieved for 100% of stems (DBH RMSE 6 cm), but only after location-specific error was corrected. The stem classification method required comparatively little development of statistical models to provide estimates, which ultimately had a similar level of accuracy (RMSE < 1 cm) to PREV. HALS datasets can measure broad-scale forest plantations and reduce field efforts and should be considered an important tool for aiding in inventory creation and decision-making within forest management. Full article
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19 pages, 4707 KiB  
Article
Coppice and Coppice-with-Standard Stands Systems: Implications for Forest Management and Biodiversity
by Sajad Ghanbari, Pedro Álvarez-Álvarez, Ayeshe Esmaili, Samira Sasanifar, Seyed Mohmmad Moein Sadeghi, Kiomars Sefidi and Ivan Eastin
Forests 2025, 16(1), 116; https://doi.org/10.3390/f16010116 - 10 Jan 2025
Viewed by 486
Abstract
Examining forest stand structures is crucial for effective forest management, as it provides essential insights into current conditions and informs future strategies. Coppice systems, a historic forest management practice with centuries of documented use across various regions, play a vital role in supporting [...] Read more.
Examining forest stand structures is crucial for effective forest management, as it provides essential insights into current conditions and informs future strategies. Coppice systems, a historic forest management practice with centuries of documented use across various regions, play a vital role in supporting unique flora and fauna, making them integral to conservation efforts. This study has two primary objectives: (i) to evaluate how various forest management approaches impact species composition and structural characteristics of forest stands, and (ii) to assess and compare diversity within these stands using a range of indices. In this research, two management systems in Iran’s Arasbaran forests were compared: the traditional coppice system and the coppice-with-standard (CWS) stands system. Fieldwork was conducted in 24 sample plots for each management system, where quantitative indicators and biodiversity indices were employed to evaluate and compare stand characteristics. The findings revealed that the CWS system exhibited higher mean values for tree height, diameter at the breast height (DBH), and basal area compared to the coppice system. Coppice stands had a sprout clump density of 546 per hectare, primarily composed of Quercus macranthera, while the CWS stands had a combined tree and sprout clump density of 421 per hectare. Diversity assessments showed that species diversity, as measured by Pielou’s index, was higher in the coppice system (1.42) than in the CWS system (1.01). However, species richness, represented by the Menhinik index, was lower in both systems, with values of 0.31 for the coppice system and 0.19 for the CWS system. These results suggest that the CWS system is more effective in promoting growth and stand development, whereas the coppice system may better support biodiversity. The findings have practical implications for forest managers and policymakers in Iran and other regions with similar forest ecosystems. For instance, if the objective is to enhance biodiversity and ecosystem resilience, the coppice system—with its higher diversity indices—may be the preferred choice. On the other hand, if the aim is to boost timber production while maintaining a baseline level of biodiversity, the CWS system could be more suitable. Full article
(This article belongs to the Section Forest Ecology and Management)
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14 pages, 9481 KiB  
Article
The One-Fault Dimension-Balanced Hamiltonian Problem in Toroidal Mesh Graphs
by Justie Su-Tzu Juan, Hao-Cheng Ciou and Meng-Jyun Lin
Symmetry 2025, 17(1), 93; https://doi.org/10.3390/sym17010093 - 9 Jan 2025
Viewed by 444
Abstract
Finding a Hamiltonian cycle in a graph G = (V, E) is a well-known problem. The challenge of finding a Hamiltonian cycle that avoids these faults when faulty vertices or edges are present has been extensively studied. When the edge [...] Read more.
Finding a Hamiltonian cycle in a graph G = (V, E) is a well-known problem. The challenge of finding a Hamiltonian cycle that avoids these faults when faulty vertices or edges are present has been extensively studied. When the edge set of G is partitioned into k dimensions, the problem of dimension-balanced Hamiltonian cycles arises, where the Hamiltonian cycle uses approximately the same number of edges from each dimension (differing by at most one). This paper studies whether a dimension-balanced Hamiltonian cycle (DBH) exists in toroidal mesh graphs Tm,n when a single vertex or edge is faulty, called the one-fault DBH problem. We establish that Tm,n is one-fault DBH, except in the following cases: (1) both m and n are even; (2) one of m and n is 3, while the other satisfies mod 4 = 3 and is greater than 6; (3) one of m and n is odd, while the other satisfies mod 4 = 2. Additionally, this paper resolves a conjecture from prior literature, thereby providing a complete solution to the DBP problem on Tm,n. Full article
(This article belongs to the Section Mathematics)
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22 pages, 5691 KiB  
Article
Optimizing Thermal Comfort in Urban Squares of Hot-Humid Regions: A Case Study Considering Tree Growth, Species, and Planting Intervals
by Yixuan Xiao, Yong Huang and Xinchen Pan
Atmosphere 2025, 16(1), 63; https://doi.org/10.3390/atmos16010063 - 9 Jan 2025
Viewed by 433
Abstract
The worsening urban thermal environment has become a critical challenge in many cities. Trees, as vital components of urban green spaces, provide multiple ecosystem services, especially in improving the microclimate. However, limited studies address how morphological changes during tree growth influence their cooling [...] Read more.
The worsening urban thermal environment has become a critical challenge in many cities. Trees, as vital components of urban green spaces, provide multiple ecosystem services, especially in improving the microclimate. However, limited studies address how morphological changes during tree growth influence their cooling benefits. This study combined the tree growth model with ENVI-met to simulate 27 scenarios in a subtropical urban square, considering three planting intervals, three urban tree species, and three growth stages to evaluate their daytime thermal impacts. The key findings include: (1) Tree size and planting intervals are more important than tree quantity in enhancing thermal comfort. (2) Reducing intervals by 2 m enhances cooling effects but minimally affects PET (physiological equivalent temperature). (3) Increasing DBH (diameter at breast height) significantly improves cooling. For every 10 cm increase in DBH, Michelia alba, Mangifera indica, and Ficus microcarpa L. f. reduced solar radiation by 19.54, 18.09, and 34.50 W/m2, and mean radiant temperature by 0.61 °C, 0.68 °C, and 1.35 °C, respectively, while decreasing PET by 0.23 °C, 0.23 °C, and 0.46 °C. These findings provide empirical evidence and practical recommendations for designing comfortable open spaces in subtropical cities. Full article
(This article belongs to the Section Biometeorology and Bioclimatology)
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12 pages, 4144 KiB  
Article
Response of Understory Plant Diversity to Edge Effects in Plantation Forests on the Loess Plateau
by Sixuan Du, Bo Zheng, Hangyu Lei, Huifeng Guo and Xiang Li
Forests 2025, 16(1), 87; https://doi.org/10.3390/f16010087 - 8 Jan 2025
Viewed by 369
Abstract
The majority of the world’s forests are located at landscape edges and are highly fragmented; the plantations on the Loess Plateau are no exception, experiencing pronounced edge effects. However, edge effects are often overlooked in assessments of carbon storage and biodiversity, and the [...] Read more.
The majority of the world’s forests are located at landscape edges and are highly fragmented; the plantations on the Loess Plateau are no exception, experiencing pronounced edge effects. However, edge effects are often overlooked in assessments of carbon storage and biodiversity, and the extent and impact of these effects on Loess Plateau plantations remain inadequately understood. The objective of this study is to reveal how edge effects influence biodiversity and species composition and to examine their long-term impacts on ecosystem structure and function. Furthermore, it aims to explore the mechanisms underlying edge effects in plantation systems. Examining these effects is essential for guiding forest management practices and formulating effective biodiversity conservation strategies, thereby providing scientific insights to support the ecological restoration and sustainable management of plantations. In this study, we classified 44 sample plots into four groups according to their distances from the plantation edges to compare and analyze species composition. Additionally, we evaluated the intensity and range of edge effects on stand structure, species diversity, and carbon storage. The Shannon index of understory vegetation was used as the dependent variable, with canopy cover, edge distance, and stand density as independent variables. We used multiple linear regression to examine the effects of these factors on the Shannon index of understory vegetation (shrubs, herbs, and trees). The key findings were as follows: (1) Tree height did not exhibit edge effects across any distance range, while the Shannon index, species richness, and carbon storage showed edge effects within 54 m from the edge. Diameter at breast height (DBH), stand density, and canopy cover exhibited edge effects within 0–83 m from the edge. (2) The significance values for edge distance and canopy cover in the linear regression with the Shannon index were 0.99 and 0.51, respectively, showing no significant correlation. In contrast, stand density had a significant positive effect on the Shannon index (p = 0.03). (3) Notable differences in understory species composition were observed between the outermost and innermost groups of the plantation. Climatic conditions on the Loess Plateau exert a dominant influence on understory plants, altering species composition and abundance. High stand density appeared to moderate the microclimate, contributing to a higher understory Shannon index, but reducing carbon storage. Our findings suggest that the edge effects of plantation forests on the Loess Plateau exert varying degrees of influence on different indicators. Management decisions should be guided by the specific silvicultural objectives, whether the manager’s goals are to optimize biomass accumulation, enhance species recovery, or achieve a balance between these two goals. Full article
(This article belongs to the Section Forest Biodiversity)
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16 pages, 8023 KiB  
Article
Heartwood/Sapwood Characteristics of Populus euphratica Oliv. Trunks and Their Relationship with Soil Physicochemical Properties in the Lower Tarim River, Northwest China
by Tongyu Chen, Tayierjiang Aishan, Na Wang, Ümüt Halik and Shiyu Yao
Plants 2025, 14(2), 154; https://doi.org/10.3390/plants14020154 - 7 Jan 2025
Viewed by 314
Abstract
The characteristics of heartwood and sapwood not only reflect tree growth and site quality but also provide insights into habitat changes. This study examines the natural Populus euphratica Oliv. forest in the Arghan section of the lower Tarim River, comparing the heartwood and [...] Read more.
The characteristics of heartwood and sapwood not only reflect tree growth and site quality but also provide insights into habitat changes. This study examines the natural Populus euphratica Oliv. forest in the Arghan section of the lower Tarim River, comparing the heartwood and sapwood characteristics of P. euphratica at different distances from the river, as well as at varying trunk heights and diameters at breast height (DBH). The objective was to examine the correlation between these characteristics and the physicochemical properties of the soil to better understand the ecological response strategies of P. euphratica in arid environments. Results indicated that heartwood radius, sapwood width, sapwood area, and heartwood moisture content decreased with increasing trunk height, following the pattern: 0.3 m > 0.8 m > 1.3 m. In contrast, heartwood density increased as trunk height increased. Most of the heartwood and sapwood indicators increased with larger tree diameters. In the case of P. euphratica with a DBH of less than 45 cm, the difference in moisture content between heartwood and sapwood was not significant (p > 0.05) at heights of 0.3 m and 0.8 m. However, at a height of 1.3 m, the difference was significant (p < 0.05). Soil analysis revealed that factors such as total nitrogen, available potassium, and water content significantly influenced the physical characteristics of P. euphratica heartwood and sapwood across different sites. Redundancy analysis (RDA) further demonstrated that total nitrogen, available phosphorus, and soil moisture were significantly correlated with the physical properties of P. euphratica heartwood and sapwood, further validating the critical role of soil nutrients in shaping the wood characteristics of P. euphratica. These findings highlighted the specific adaptations of P. euphratica in the lower Tarim River to the arid desert environment, reflected in the observed relationships between soil conditions and the physical characteristics of heartwood and sapwood. Full article
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16 pages, 4973 KiB  
Article
Exploring Co-Occurrence Patterns to Understand Epiphyte–Liana Interactions
by Sergio J. Ceballos, Ezequiel Aráoz and Tobías Nicolás Rojas
Plants 2025, 14(1), 140; https://doi.org/10.3390/plants14010140 - 6 Jan 2025
Viewed by 439
Abstract
Although epiphytes and lianas share the same habitat, most research has treated these two groups independently. This study aimed to evaluate the co-occurrence of vascular epiphytes and lianas in the subtropical montane forests of northwestern Argentina. We recorded epiphyte cover and liana basal [...] Read more.
Although epiphytes and lianas share the same habitat, most research has treated these two groups independently. This study aimed to evaluate the co-occurrence of vascular epiphytes and lianas in the subtropical montane forests of northwestern Argentina. We recorded epiphyte cover and liana basal area on trees ≥ 10-cm-dbh in 120 20 × 20 m plots in the Sierra de San Javier (Tucumán, Argentina). Of the 2111 trees sampled, 727 (34%) hosted lianas, and 1095 (52%) hosted epiphytes. Both plant groups were found together on 20% of the sampled trees. The species richness of lianas and epiphytes, along with liana basal area and epiphyte cover, increased with tree diameter and reached higher values in mature forests compared to successional forests. Both groups colonized the same canopy tree species with larger diameters, whereas smaller trees were typically colonized by either lianas or epiphytes, but not both. Epiphyte species were more likely to co-occur with liana species with specialized climbing mechanisms. Tree size and forest type (mature vs. successional) emerged as key factors influencing the co-occurrence of lianas and epiphytes in these forests. This study establishes a basis for future research into the interactions between lianas and epiphytes, seeking to determine whether they co-occur in the same habitats. Full article
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17 pages, 2803 KiB  
Article
Potential of Apple Vision Pro for Accurate Tree Diameter Measurements in Forests
by Tobias Ofner-Graff, Valentin Sarkleti, Philip Svazek, Andreas Tockner, Sarah Witzmann, Lukas Moik, Ralf Kraßnitzer, Christoph Gollob, Tim Ritter, Martin Kühmaier, Karl Stampfer and Arne Nothdurft
Remote Sens. 2025, 17(1), 141; https://doi.org/10.3390/rs17010141 - 3 Jan 2025
Viewed by 565
Abstract
The determination of diameter at breast height (DBH) is critical in forestry, serving as a key metric for deriving various parameters, including tree volume. Light Detection and Ranging (LiDAR) technology has been increasingly employed in forest inventories, and the development of cost-effective, user-friendly [...] Read more.
The determination of diameter at breast height (DBH) is critical in forestry, serving as a key metric for deriving various parameters, including tree volume. Light Detection and Ranging (LiDAR) technology has been increasingly employed in forest inventories, and the development of cost-effective, user-friendly smartphone and tablet applications (apps) has expanded its broader use. Among these are augmented reality (AR) apps, which have already been tested on mobile devices for their accuracy in measuring forest attributes. In February 2024, Apple introduced the Mixed-Reality Interface (MRITF) via the Apple Vision Pro (AVP), offering sensor capabilities for field data collection. In this study, two apps using the AVP were tested for DBH measurement on 182 trees across 22 sample plots in a near-natural forest, against caliper-based reference measurements. Compared with the reference measurements, both apps exhibited a slight underestimation bias of −1.00 cm and −1.07 cm, and the root-mean-square error (RMSE) was 3.14 cm and 2.34 cm, respectively. The coefficient of determination (R2) between the reference data and the measurements obtained by the two apps was 0.959 and 0.978. The AVP demonstrated its potential as a reliable field tool for DBH measurement, performing consistently across varying terrain. Full article
(This article belongs to the Special Issue Remote Sensing and Smart Forestry II)
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19 pages, 2460 KiB  
Technical Note
Multispectral, Thermal, and Hyperspectral Sensing Data Depict Stomatal Conductance in Grapevine
by Kesevan Veloo, Carlos Zúñiga Espinoza, Alberto Espinoza Salgado, Pete W. Jacoby and Sindhuja Sankaran
Remote Sens. 2025, 17(1), 137; https://doi.org/10.3390/rs17010137 - 3 Jan 2025
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Abstract
Climate-driven water challenges in the Pacific Northwest necessitate precise irrigation for sustainable vineyard management. In such scenarios, conservation of water using different approaches, including subsurface irrigation, becomes critical. Detecting crop water status becomes key to evaluating and managing such approaches. This study examines [...] Read more.
Climate-driven water challenges in the Pacific Northwest necessitate precise irrigation for sustainable vineyard management. In such scenarios, conservation of water using different approaches, including subsurface irrigation, becomes critical. Detecting crop water status becomes key to evaluating and managing such approaches. This study examines how multispectral, thermal, and hyperspectral proximal sensing data depict irrigation-induced variations in stomatal conductance in Cabernet Sauvignon vineyards during 2016 and 2017. The roles of individual and combined sensing modalities were analyzed, with key contributions including the identification of indices that characterize stomatal conductance. Data were collected at the following growth stages: 80 and 44 days before harvest (DBH) in 2016; and 64, 44, and 8 DBH in 2017. The vegetation indices analyzed included the green normalized difference vegetation index (GNDVI) and leaf area index (LAI) from multispectral data, crop water stress index (CWSI) from thermal data, and normalized difference spectral indices (NDSI) from hyperspectral data. Pearson’s correlations at 80 and 44 DBH (2016) showed significant relationships between normalized stomatal conductance and multispectral indices (LAI: r = 0.59 to 0.66, GNDVI: r = 0.41 to 0.50, both p < 0.01). NDSI pairs (1380 nm with 1570 nm, 1570 nm with 1810 nm) at 80 DBH showed significant correlations (r = −0.27, 0.31, both p < 0.05). In 2017, the thermal data showed the strongest correlation with normalized stomatal conductance (r = −0.83) at 44 DBH. In the same year, NDSI pairs exhibited stronger correlations than multispectral indices as the DBH decreased (1380 nm with 1570 nm: r = −0.58 to −0.69, 1570 nm with 1810 nm: r = 0.64 to 0.48, both p < 0.05). Combining LAI with these NDSI pairs improved stomatal conductance predictions (2016: R2 = 0.37–0.50; 2017: R2 = 0.51–0.63, both p < 0.01). These results demonstrate the precision of a multimodal sensing approach, particularly integrating multispectral and hyperspectral data, to improve irrigation strategies and promote sustainable viticulture. Full article
(This article belongs to the Special Issue Crops and Vegetation Monitoring with Remote/Proximal Sensing II)
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