Editor’s Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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15 pages, 4497 KiB  
Article
Botryosphaeriaceae Species Associated with Stem Canker, Shoot Blight and Dieback of Fraxinus ornus in Italy
Forests 2024, 15(1), 51; https://doi.org/10.3390/f15010051 - 26 Dec 2023
Viewed by 874
Abstract
A severe dieback of flowering ash (Fraxinus ornus L.) has been observed in north-central Italy in the last decades. Symptoms include typical sunken, light-brown cankers on the stem and branches; vascular discoloration; tip and shoot dieback; and foliage necroses. The disease was [...] Read more.
A severe dieback of flowering ash (Fraxinus ornus L.) has been observed in north-central Italy in the last decades. Symptoms include typical sunken, light-brown cankers on the stem and branches; vascular discoloration; tip and shoot dieback; and foliage necroses. The disease was more evident at the beginning of the growing season, and more severe on young regeneration. Six Botryosphaeriaceae species were consistently isolated from symptomatic plant tissues: Botryosphaeria dothidea, Diplodia fraxini, Diplodia subglobosa, Dothiorella iberica, Dothiorella omnivora and Neofusicoccum parvum. B. dothidea and D. fraxini expressed higher aggressiveness and showed a widespread incidence, being the species most frequently associated with cankers; the other four species were less virulent and more erratic, occurring mainly on succulent branch tips and foliage. Isolates were characterized using morphological and molecular approaches (colony/conidial phenotyping and rDNA-ITS genotyping). Phylogenetic analysis provided congruent phylogenies depicting the relationships of the six taxa with the most closely related conspecifics. Pathogenicity tests on 2-year-old seedlings confirmed the higher virulence of B. dothidea and D. fraxini. Extensive, multi-year field surveys at different sites supported the hypothesis that climatic vagaries, mainly heat, water and drought stresses, impaired tree health and vigor, facilitating infection and pervasive colonization by these Botryosphaeriaceae species. Environmental stressors are thus the key factor bringing the six fungal pathogens together in a multitrophic interaction with F. ornus in a novel, lethal fashion. Full article
(This article belongs to the Special Issue Forest Pathology and Entomology—Series II)
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13 pages, 2099 KiB  
Article
Temporal Variability in Soil Greenhouse Gas Fluxes and Influencing Factors of a Primary Forest on the Eastern Qinghai-Tibetan Plateau
Forests 2023, 14(11), 2255; https://doi.org/10.3390/f14112255 - 16 Nov 2023
Viewed by 704
Abstract
Soil greenhouse gas (GHG) fluxes relate to soil carbon and nitrogen budgets and have a significant impact on climate change. Nevertheless, the temporal variation and magnitude of the fluxes of all three major GHGs (CO2, CH4 and N2O) [...] Read more.
Soil greenhouse gas (GHG) fluxes relate to soil carbon and nitrogen budgets and have a significant impact on climate change. Nevertheless, the temporal variation and magnitude of the fluxes of all three major GHGs (CO2, CH4 and N2O) and their influencing factors have not been elucidated clearly in primary forests on the eastern Qinghai-Tibetan Plateau. Herein, field chamber GHG fluxes from May to November, soil microbial community and enzyme activity were analyzed in a fir-dominated (Abies fargesii var. faxoniana) primary forest. The emission rates of CO2 and N2O ranged between 64.69–243.22 mg CO2 m−2 h−1 and 1.69–5.46 ug N2O m−2 h−1, exhibiting a temporally unimodal pattern with a peak in July. The soil acted as a CH4 sink, and the uptake rate varied between 52.96 and 84.67 μg CH4 m−2 h−1 with the higher uptake rates in June and November. The temporal variation in the CO2 flux was significantly correlated with the geometric mean of enzyme activities, suggesting that the soil CO2 flux was determined by microbial activity rather than soil microbial biomass. The soil N2O flux was positively related to nitrate concentration with marginal significance, probably because N2O was a byproduct of nitrification and denitrification processes. The soil CH4 uptake was closely associated with methanotrophic biomass (18:1ω7c). The results highlight divergent temporal dynamics of GHG fluxes owing to different driving mechanisms and an important CH4 sink in the primary forest soil, helping to evaluate the carbon and nitrogen budgets of primary forests on the eastern Qinghai-Tibetan Plateau. Full article
(This article belongs to the Section Forest Soil)
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12 pages, 1891 KiB  
Article
Impact of Chemical Composition on Eucalyptus Wood Clones for Sustainable Energy Production
Forests 2023, 14(11), 2240; https://doi.org/10.3390/f14112240 - 14 Nov 2023
Viewed by 958
Abstract
The energy potential of wood biomass is significantly shaped by its chemical composition. Analyzing the chemical composition of wood biomass and understanding the correlations between these parameters and wood combustibility are essential stages in the selection process of Eucalyptus clones tailored for firewood [...] Read more.
The energy potential of wood biomass is significantly shaped by its chemical composition. Analyzing the chemical composition of wood biomass and understanding the correlations between these parameters and wood combustibility are essential stages in the selection process of Eucalyptus clones tailored for firewood production and energy generation. In this study, we aimed to evaluate the impact of chemical composition on the direct combustibility of Eucalyptus clones. We examined the structural chemical composition and conducted proximate analysis, including fixed carbon, volatile material, and ash, to investigate the relationship between proximate composition and wood combustibility parameters. Our findings revealed significant correlations between wood chemical composition and combustibility parameters. In particular, lignin content, ethanol-soluble extractives, and xylose demonstrated inverse relationships with the parameters of maximum combustion rate, combustion characteristic index, and ignition index. Conversely, holocellulose content, cold-water-soluble extractives, and glucose exhibited direct correlations with the same combustibility parameters. Furthermore, fixed carbon and volatile matter contents demonstrated direct and inverse correlations, respectively, with ignition temperature. These findings have significant implications for enhancing the efficiency and sustainability of biomass energy production. Full article
(This article belongs to the Section Wood Science and Forest Products)
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14 pages, 3360 KiB  
Article
Utilizing SIFT-MS and GC-MS for Phytoncide Assessment in Phytotron: Implications for Indoor Forest Healing Programs
Forests 2023, 14(11), 2235; https://doi.org/10.3390/f14112235 - 13 Nov 2023
Viewed by 3365
Abstract
This study addresses the growing need for phytoncide studies, driven by the demand to design indoor forest healing programs, including virtual reality experiences, for patients unable to visit actual forests. Previous studies have struggled to establish consistent phytoncide emission patterns in outdoor forest [...] Read more.
This study addresses the growing need for phytoncide studies, driven by the demand to design indoor forest healing programs, including virtual reality experiences, for patients unable to visit actual forests. Previous studies have struggled to establish consistent phytoncide emission patterns in outdoor forest environments owing to varying microclimates and abiotic factors. In addition, the traditional gas chromatography–mass spectroscopy (GC-MS) method presents field measurement challenges, whereas the selected ion flow tube (SIFT)-MS method offers improved efficiency. This study concentrated on a controlled phytotron environment and compared the GC-MS and SIFT-MS findings, revealing similar emission trends with slightly higher SIFT-MS concentrations. Daily phytoncide emissions fluctuated with light intensity and abiotic stressors. Both methods consistently detected pinenes, primarily emitted by Pinus strobus L. seedlings, in the phytotron. Statistical analysis confirmed the compatibility between GC-MS and SIFT-MS results, supporting the use of SIFT-MS for forest phytoncide assessment. In the second phase, the phytoncide emissions were assessed indoors, outdoors, and in the phytotron, highlighting the superiority of the phytotron under controlled conditions. Despite certain limitations, this study underscores the value of phytotron-based measurements for indoor forest healing programs and the potential adoption of SIFT-MS in future field-based phytoncide research. Full article
(This article belongs to the Special Issue Forest, Trees, Human Health and Wellbeing)
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14 pages, 4437 KiB  
Article
Assessing the Potential of Urban Trees to Accumulate Potentially Toxic Elements: A Network Approach
Forests 2023, 14(11), 2116; https://doi.org/10.3390/f14112116 - 24 Oct 2023
Viewed by 922
Abstract
In urbanized areas, mitigating the negative effects of pollutants from various anthropogenic sources is one of the most important issues in planning urban functioning and development. In this sense, urban vegetation plays one of the most important roles. The aim of this study [...] Read more.
In urbanized areas, mitigating the negative effects of pollutants from various anthropogenic sources is one of the most important issues in planning urban functioning and development. In this sense, urban vegetation plays one of the most important roles. The aim of this study was to investigate the performance of network analysis (NA) as a novel and potential method for determining different associations between potentially toxic elements (PTEs) in leaves of urban trees, their accumulation capacity and ecophysiological response to different types of pollution in urban environments. The results of NA showed that there is no association between elements in species that have lower or higher efficiency in uptake of PTEs, leading to the conclusion that the elements do not depend on mutual association but on accumulation itself. It was also found that there are differences in the content of photosynthetic pigments and carotenoids among the studied species, but these differences are not reflected in the values of the photosynthetic efficiency parameters. Overall, the studied species have good ecophysiological potential for growth and existence in the urban environment, despite the varying ability to accumulate elements and the different associations between them. This is the first study to investigate the interactions between PTEs in leaves of urban tree species using NA and provides a good basis for future research under different environmental conditions. Full article
(This article belongs to the Special Issue The Response of Trees to Air Pollution in Urban Forests)
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13 pages, 10700 KiB  
Article
Evaluation of Forestry Component Survival in Plots of the Program “Sembrando Vida” (Sowing Life) Using Drones
Forests 2023, 14(11), 2117; https://doi.org/10.3390/f14112117 - 24 Oct 2023
Viewed by 1004
Abstract
Reforestation is one of the main actions undertaken to mitigate the effects of climate change. In Mexico, the Federal Government program “Sembrando Vida” (Sowing Life) is currently the most important reforestation effort. It aims to recoup forest cover and achieve food [...] Read more.
Reforestation is one of the main actions undertaken to mitigate the effects of climate change. In Mexico, the Federal Government program “Sembrando Vida” (Sowing Life) is currently the most important reforestation effort. It aims to recoup forest cover and achieve food self-sufficiency through the establishment of agroforestry systems. The evaluation of tree survival in reforested areas helps to identify achievements and failures, as well as aspects of the program that require improvement. However, given the magnitude of this program, evaluation using traditional methodologies is labor-intensive and costly. In this context, drones equipped with high-resolution cameras are a promising tool. The objective of this study was to evaluate the feasibility of using drones to monitor tree survival in reforested areas. This study was conducted in 12 randomly chosen plots, benefited by the “Sembrando Vida” program, located on the Purépecha Plateau in the state of Michoacán, in central–western Mexico. Field surveys with GPS were conducted to record the total number of live and dead forest-tree seedlings. Simultaneously, high-resolution images were captured using a DJI Phantom 4 Pro drone equipped with an RGB camera for subsequent visual interpretation in a geographic information system to determine the status of each seedling and calculate the rates of survival. ANOVA was performed to compare the survival calculated using the drone images compared to that recorded in the field. No significant difference was found between survival estimated using the drone and that recorded directly in the field in any of the study plots, although the drone overestimated survival by an average of 6%, mostly due to the presence of dead seedlings that had already lost their foliage and were thus missed when scoring the RGB image. It is therefore concluded that the estimation of survival using drones is a reliable method. For future research, it is recommended to evaluate machine-learning algorithms in terms of detecting both living and dead trees in reforested sites. It is also recommended to use multispectral thermal cameras and LiDAR technology to broaden the knowledge of the different levels of vigor/stress present in the vegetation. Full article
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16 pages, 3931 KiB  
Article
Responses of Stream Water Temperature to Water Levels in Forested Catchments of South Korea
Forests 2023, 14(10), 2085; https://doi.org/10.3390/f14102085 - 18 Oct 2023
Viewed by 831
Abstract
Event flow characteristics were evaluated based on temperature and level of stream water in 22 forested catchments (area: 13.2–281.4 ha) to investigate sustainable flood management measures. Temperature and stream water levels were during 346 rainfall events in the summer season (July–September) from 2020 [...] Read more.
Event flow characteristics were evaluated based on temperature and level of stream water in 22 forested catchments (area: 13.2–281.4 ha) to investigate sustainable flood management measures. Temperature and stream water levels were during 346 rainfall events in the summer season (July–September) from 2020 to 2022. Rising stream water levels responded to falling stream water temperature between ≤100 and >100 ha forested catchments in two types of time of concentration. Stream water temperature decreased by 3.0 °C when the stream water level increased by up to 0.9 m during rainfall events. Falling stream water temperature at two types of time of concentration was negatively correlated with total precipitation and rising stream water level. Based on the relatively high value of regression and cumulative frequency distribution, the estimated rising stream water level was appropriate in small catchments (≤100 ha) when the stream water temperature decreased, and the stream water level increased during rainfall events. Rising stream water levels and falling stream water temperatures are responses to catchment-scale effects, which are influenced by the nature and rapidity of the hydrological responses. Therefore, the results of the present study indicate that spatial and temporal differences in thermal responses of stream water temperature to water levels were controlled by catchment-scale effects under rapidly changing rainfall. Full article
(This article belongs to the Special Issue Hydrology and Ecosystem Services in Forests)
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19 pages, 1911 KiB  
Article
Modeling Above-Ground Carbon Dynamics under Different Silvicultural Treatments on the McDonald–Dunn Research Forest
Forests 2023, 14(10), 2090; https://doi.org/10.3390/f14102090 - 18 Oct 2023
Viewed by 12578
Abstract
Forest management decisions affect carbon stock and rates of sequestration. One subject of debate is the rotation age that will optimize sequestration over extended periods. Some argue that shorter rotations facilitate greater sequestration rates due to the accelerated growth rates of younger trees [...] Read more.
Forest management decisions affect carbon stock and rates of sequestration. One subject of debate is the rotation age that will optimize sequestration over extended periods. Some argue that shorter rotations facilitate greater sequestration rates due to the accelerated growth rates of younger trees compared to mature or old-growth trees. Others maintain that frequent harvesting will not allow forest carbon to rebound after each subsequent rotation, and thus more extended periods between clearcutting is the superior choice. These contrasting viewpoints are mirrored regarding the impact of thinning treatments, in that either thinning will enhance forest carbon uptake by facilitating improved and sustained r growth of residual trees or removing any above-ground biomass will outweigh the yields. This study aims to compare the different suites of management decisions and identify practical combinations of rotation ages and thinning applications that will optimize carbon sequestration while meeting other objectives over a 240-year projection timeframe. Stand development under different harvest rotations and thinning specifications was modeled using a Forest Vegetation Simulator (FVS). We found that site productivity was the primary determinant in stand-above-ground carbon dynamics under various management scenarios. Thus, the optimal rotation age/thinning treatment combinations differed between site classes. High productivity stands were estimated to sequester the most above-ground live carbon with 60-year rotations with a low-intensity thin at age 40. Moderately productive stands performed the best with 80-year rotations when two low-intensity thinning treatments were applied between harvests. For high and moderate productivity stands, estimates of gross carbon increased when two low or moderate-intensity thinning treatments were applied within 80- or 120-year rotations. High-intensity thinning treatments reduced total carbon sequestered over the 240-year projection timeframe for all productivity levels and rotation ages, except for low productivity stands under 120-year rotations. Full article
(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)
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13 pages, 2053 KiB  
Article
Ecophysiological Behavior of Fagus sylvatica L. Growing at Its Southern Distribution Limit: Insights for Understanding the Fate of the European Beech under Warmer and Dryer Growth Conditions
Forests 2023, 14(10), 2058; https://doi.org/10.3390/f14102058 - 15 Oct 2023
Viewed by 1042
Abstract
In the last 20 years, a significant mortality of Fagus sylvatica L. (European beech) has been documented in central and northern European forests. Surprisingly, no beech die off occurred at the southern limit. This fact leads us to hypothesize that European beech populations [...] Read more.
In the last 20 years, a significant mortality of Fagus sylvatica L. (European beech) has been documented in central and northern European forests. Surprisingly, no beech die off occurred at the southern limit. This fact leads us to hypothesize that European beech populations growing at the southern limit of the distribution might have a significant phenotypic plasticity to better cope with low water availability and rising temperatures. To check this hypothesis, we evaluated the ecophysiological behavior of F. sylvatica growing along an altitudinal transect in Calabria (Italy). We selected three study sites (750 m a.s.l., 976 m a.sl. m a.s.l., 1450 m a.s.l.) showing narrow ranges of temperature, rainfall and air humidity. Trees growing at 976 m a.s.l. showed the highest stomatal conductance values during the entire experimental period. The lowest gas exchange and highest leaf mass area were recorded in plants growing at 750 m a.s.l. In the European beech growing at 1450 m a.s.l., higher vessel density, lower mean vessel diameter and higher vessel grouping index values were recorded. Overall, our results highlighted that the measured populations show a considerable phenotypic plasticity leading them to adjust anatomical and physiological traits in response to narrow ranges of environmental parameters. Despite that, the distribution of F. sylvatica seems to be limited to areas with a growing season rainfall of at least 400 mm and vapor pressure deficit (VPD) values < 3 kPa, which may represent the main environmental thresholds which strongly limit the beech growth and, therefore, influence the ability of this species to cope with future environmental conditions. Full article
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18 pages, 6358 KiB  
Article
Barcoding Hymenoptera: 11 Malaise Traps in Three Thai Forests: The First 68 Trap Weeks and 15,338 Parasitoid Wasp Sequences
Forests 2023, 14(10), 1991; https://doi.org/10.3390/f14101991 - 03 Oct 2023
Cited by 1 | Viewed by 1383
Abstract
We report the results of DNA barcoding week-long Malaise trap catches from 11 sites in three Thai conservation areas, concentrating on the parasitoid Hymenoptera, particularly the superfamily Ichneumonoidea. From a total of 15,338 parasitoid wasp sequences, 13,473 were barcode compliant and could be [...] Read more.
We report the results of DNA barcoding week-long Malaise trap catches from 11 sites in three Thai conservation areas, concentrating on the parasitoid Hymenoptera, particularly the superfamily Ichneumonoidea. From a total of 15,338 parasitoid wasp sequences, 13,473 were barcode compliant and could be assigned to a family based on morphology and sequence data. These collectively represented 4917 unique BINs (putative species) in 46 families, with the Scelionidae, Ichneumonidae, Eulophidae, Braconidae and Platygastridae being, by far, the most abundant. Spatial proximity had a strong positive effect on the numbers of BINs shared between traps. Full article
(This article belongs to the Special Issue DNA Barcoding for Species Identification of Forest Organisms)
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17 pages, 6706 KiB  
Article
Land Suitability Analysis for Forests in Lebanon as a Tool for Informing Reforestation under Climate Change Conditions
Forests 2023, 14(9), 1893; https://doi.org/10.3390/f14091893 - 17 Sep 2023
Cited by 1 | Viewed by 1697
Abstract
Along with the concept of improving reforestation efforts in Lebanon, this study aimed to provide a land suitability analysis for forest species in Lebanon while considering the effect of climate change. Herein, the soil evaluation criteria developed by FAO (The Food and Agriculture [...] Read more.
Along with the concept of improving reforestation efforts in Lebanon, this study aimed to provide a land suitability analysis for forest species in Lebanon while considering the effect of climate change. Herein, the soil evaluation criteria developed by FAO (The Food and Agriculture Organization) for land suitability classification were implemented through the weighted overlay method to produce suitability maps based on natural variables (soil, climate, and topography) influencing the presence of the species on the land. Cedrus libani, Quercus calliprinos, Ceratonia siliqua, Eucalyptus globulus, and Pinus halepensis are the species considered in this study. The results of this study provide useful information to inform reforestation activities in Lebanon, considering the expected climate change projections for medium- (2050) and long-term (2070) periods, according to two different scenarios (RCP4.5 and RCP8.5) and three General Circulation Models: CCSM4, GFDL-CM3, and HadGEM2-ES. The suitability maps showed a generally critical situation for the spatial distribution of forest species under future climate change compared to the current situation (1970–2000). The distribution of thermophilic species, which tolerate high temperatures (over 20 °C), was projected to expand compared to the current situation. In contrast, the expansion of cold-adapted species may be limited by future climate change conditions. It is crucial to consider the expected effects of climate change to better select species for reforestation and, therefore, to maintain forest cover in Lebanon. Full article
(This article belongs to the Section Forest Meteorology and Climate Change)
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14 pages, 3427 KiB  
Article
Volatile Compound Chemistry and Insect Herbivory: Pinus edulis Engelm. (Pinaceae) Seed Cone Resin
Forests 2023, 14(9), 1862; https://doi.org/10.3390/f14091862 - 13 Sep 2023
Viewed by 1206
Abstract
Pinus edulis Engelm. (pinyon pine) is a tree in the Pinaceae family with wide geographic distribution throughout dry forests of western North America. Pinyon pine seed cones, which mature over a 2-year period before shedding seed, are often resinous. Conifer resin, which is [...] Read more.
Pinus edulis Engelm. (pinyon pine) is a tree in the Pinaceae family with wide geographic distribution throughout dry forests of western North America. Pinyon pine seed cones, which mature over a 2-year period before shedding seed, are often resinous. Conifer resin, which is a liquid-soluble mixture of volatile and non-volatile secondary metabolites, typically demonstrates significant ecological functions. In the current study, seed cones (n = 240) were collected monthly for a 1-year period from pinyon pine trees (n = 20) and separated equally into two groups, resinous and non-resinous cones, for research on the volatile compound chemistry and insect herbivory. Upon distillation, resinous cones yielded 41× more volatile oil and contained more viable seeds, compared to non-resinous cones. Chemical profiles of volatile oils were seemingly consistent between seasons but differed between cone groups. In resinous cone samples, volatile oils were largely composed of α-pinene (avg. 75.6%) and δ-3-carene (avg. 7.4%). In contrast, in non-resinous cone samples, the volatile oil profiles were not dominated by any single prominent compound. Cone inquiline insect communities varied with regard to the resinous status of the cones, the month of collection, and with overall volatile oil yield. Typically, with larger oil yields we saw more diverse and more abundant inquiline communities. Findings from this study suggest that the volatile oils, in addition to other components of cone resin and physical structures, play a significant ecological role in pinyon pine seed preservation from insect herbivory. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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12 pages, 1634 KiB  
Article
Identification of Candidate Genes Involved in Bud Growth in Pinus pinaster through Knowledge Transfer from Arabidopsis thaliana Models
Forests 2023, 14(9), 1765; https://doi.org/10.3390/f14091765 - 31 Aug 2023
Cited by 1 | Viewed by 1492
Abstract
Pinus pinaster is a plant species of great ecological and economic importance. Understanding the underlying molecular mechanisms that govern the growth and branching of P. pinaster is crucial for enhancing wood production and improving product quality. In this study, we describe a simple [...] Read more.
Pinus pinaster is a plant species of great ecological and economic importance. Understanding the underlying molecular mechanisms that govern the growth and branching of P. pinaster is crucial for enhancing wood production and improving product quality. In this study, we describe a simple methodology that enables the discovery of candidate genes in Pinus pinaster by transferring existing knowledge from model species like Arabidopsis thaliana and focusing on factors involved in plant growth, including hormonal and non-hormonal pathways. Through comparative analysis, we investigated the main genes associated with these growth-related factors in A. thaliana. Subsequently, we identified putative homologous sequences in P. pinaster and assessed the conservation of their functional domains. In this manner, we can exclude sequences that, despite displaying high homology, lack functional domains. Finally, we took an initial approach to their validation by examining the expression levels of these genes in P. pinaster trees exhibiting contrasting growth patterns. This methodology allowed the identification of 26 candidate genes in P. pinaster. Our findings revealed differential expression patterns of key genes, such as NCED3, NRT1.2, PIN1, PP2A, ARF7, MAX1, MAX2, GID1, AHK4, AHP1, and STP1, in relation to the different growth patterns analyzed. This study provides a methodological foundation for further exploration of these genes involved in the growth and branching processes of P. pinaster. This will contribute to the understanding of this important tree species and open new avenues for enhancing its utilization in sustainable forestry practices. Full article
(This article belongs to the Special Issue Application of Plant Biotechnology in Forestry)
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25 pages, 1477 KiB  
Article
The Wildfire Dataset: Enhancing Deep Learning-Based Forest Fire Detection with a Diverse Evolving Open-Source Dataset Focused on Data Representativeness and a Novel Multi-Task Learning Approach
Forests 2023, 14(9), 1697; https://doi.org/10.3390/f14091697 - 22 Aug 2023
Cited by 1 | Viewed by 3236
Abstract
This study explores the potential of RGB image data for forest fire detection using deep learning models, evaluating their advantages and limitations, and discussing potential integration within a multi-modal data context. The research introduces a uniquely comprehensive wildfire dataset, capturing a broad array [...] Read more.
This study explores the potential of RGB image data for forest fire detection using deep learning models, evaluating their advantages and limitations, and discussing potential integration within a multi-modal data context. The research introduces a uniquely comprehensive wildfire dataset, capturing a broad array of environmental conditions, forest types, geographical regions, and confounding elements, aiming to reduce high false alarm rates in fire detection systems. To ensure integrity, only public domain images were included, and a detailed description of the dataset’s attributes, URL sources, and image resolutions is provided. The study also introduces a novel multi-task learning approach, integrating multi-class confounding elements within the framework. A pioneering strategy in the field of forest fire detection, this method aims to enhance the model’s discriminatory ability and decrease false positives. When tested against the wildfire dataset, the multi-task learning approach demonstrated significantly superior performance in key metrics and lower false alarm rates compared to traditional binary classification methods. This emphasizes the effectiveness of the proposed methodology and the potential to address confounding elements. Recognizing the need for practical solutions, the study stresses the importance of future work to increase the representativeness of training and testing datasets. The evolving and publicly available wildfire dataset is anticipated to inspire innovative solutions, marking a substantial contribution to the field. Full article
(This article belongs to the Special Issue Advances in Forest Fire and Other Detection Systems)
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27 pages, 9410 KiB  
Article
New Technologies for Expedited Forest Inventory Using Smartphone Applications
Forests 2023, 14(8), 1553; https://doi.org/10.3390/f14081553 - 29 Jul 2023
Cited by 2 | Viewed by 1501
Abstract
The forest inventory plays a crucial role in forest management planning, and it is the first step in planning actions for forest production. However, conducting an inventory can be expensive and complex. Forest inventory applications on smartphones have emerged as an alternative to [...] Read more.
The forest inventory plays a crucial role in forest management planning, and it is the first step in planning actions for forest production. However, conducting an inventory can be expensive and complex. Forest inventory applications on smartphones have emerged as an alternative to traditional methods and they aim to make field data collection more accessible to non-professionals while ensuring accuracy in determining the volume of wood in a given area. This study evaluates the effectiveness of the Katam, Arboreal, and Trestima applications compared to traditional data collection methods. The study focuses on assessing the stand density and diameter of sampled trees—two key variables that are assessed in forest inventories. Two species, maritime pine (Pinus pinaster Aiton) and Eucalyptus spp. (mainly Eucalyptus globulus and Eucalyptus nitens), were used to evaluate the performance of the methods, with assessments performed in the stands of diverse dendrometric characteristics, specifically those regarding the tree age, stand density, and topographic conditions (flat or sloping terrain). For the purpose of comparison, goodness-of-fit statistics (R2, RMSE, and BIAS) were calculated, and an analysis of the diameter distribution and comparison of the mean diameter, number of trees per hectare, and basal area were performed. In general, the applications were accurate, and the average basal area did not differ significantly from the traditional method. The diameter measurements showed good accuracy. The accuracy of the applications varied depending on the terrain and forest characteristics, with the applications performing better in areas with flat terrain, as well as with older forests that were regular and had low under-cover density. In contrast, the applications performed worse in younger, irregular forests with sloping terrain, high tree density, and those with a great deal of understory vegetation. The applications still need to evolve in evaluating other important variables (such as tree height or volume) as they are currently estimated from auxiliary variables through mathematical equations. Full article
(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)
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24 pages, 6892 KiB  
Article
Diversity of Phytophthora Species Involved in New Diseases of Mountain Vegetation in Europe with the Description of Phytophthora pseudogregata sp. nov.
Forests 2023, 14(8), 1515; https://doi.org/10.3390/f14081515 - 25 Jul 2023
Cited by 3 | Viewed by 1420
Abstract
New and emerging Phytophthora-related diseases in small trees, shrubs and herbaceous plants typical of subalpine vegetation have recently been observed in Italy and Slovenia. Diseased plants showed a complex symptomatology including foliar necrosis, fruit rot, shoot blight and branch bleeding cankers. Since [...] Read more.
New and emerging Phytophthora-related diseases in small trees, shrubs and herbaceous plants typical of subalpine vegetation have recently been observed in Italy and Slovenia. Diseased plants showed a complex symptomatology including foliar necrosis, fruit rot, shoot blight and branch bleeding cankers. Since little information is available about the aetiology of these aerial Phytophthora diseases, from 2019 to 2022, field surveys were conducted in 54 sites to define the occurrence, distribution and impact of the Phytophthora species on mountain vegetation. A total of 360 Phytophthora isolates were obtained from 397 samples collected from 33 herbaceous and woody host species. Based on phylogenetic analysis and morphometric data, 17 Phytophthora species were identified: P. pseudosyringae (201 isolates), P. plurivora (54), P. gonapodyides (21), P. ilicis (20), P. alpina (17), P. acerina (11), P. cactorum (7), P. pseudocryptogea (6), P. cambivora (5), P. idaei (4), P. psychrophila (3), P. bilorbang (2), P. chlamydospora (2), P. hedraiandra (1), P. kelmanii (1), P. rosacearum (1) and P. syringae (1). In addition, three isolates of a new putative Phytophthora species obtained from Alnus viridis, Juniperus communis and Rhododendron ferrugineum are described here as Phytophthora pseudogregata sp. nov. Overall, the results highlighted an unexpectedly high diversity of Phytophthora species in mountain areas, with many species able to cause aerial infections due to the production of caducous sporangia. Full article
(This article belongs to the Special Issue Forest Pathology and Entomology—Series II)
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15 pages, 5781 KiB  
Review
Recent Applications of Smart Technologies for Monitoring the Sustainability of Forest Operations
Forests 2023, 14(7), 1503; https://doi.org/10.3390/f14071503 - 23 Jul 2023
Cited by 2 | Viewed by 1517
Abstract
Precision forestry is a useful technique to help forest stakeholders with proper sustainable forest management. Modern sensors and technologies, with special reference to the sustainability of forest operations, can be applied on a variety of levels, including the monitoring of forest activities regarding [...] Read more.
Precision forestry is a useful technique to help forest stakeholders with proper sustainable forest management. Modern sensors and technologies, with special reference to the sustainability of forest operations, can be applied on a variety of levels, including the monitoring of forest activities regarding the three pillars (economy, environment, and society). In this review, we summarised the current level of knowledge regarding the use of precision forestry techniques for monitoring forest operations. We concentrated on recent data from the last five years (2019–2023). We demonstrated how an Industry 4.0 strategy for remote and proximal monitoring of working performance can be effective when using CAN-bus and StanForD data collected by modern forest machines. The same information can be effectively used to create maps of soil trafficability and to evaluate the patterns of skid tracks or strip roads built as a result of forest intervention. Similar information can be gathered in the case of small-scale forestry by using GNSS-RF (Global Navigation Satellite Systems—Radio Frequency) or even monitoring systems based on smartwatches or smartphones. LiDAR and Structure for Motion (SfM) photogrammetry are both useful tools for tracking soil rutting and disturbances caused by the passage of forest machinery. SfM offers denser point clouds and a more approachable method, whereas laser scanning can be considerably faster but needs a more experienced operator and better data-processing skills. Finally, in terms of the social component of sustainability, the use of location sharing technologies is strongly advised, based for instance on GNSS—RF to monitor the security of forest workers as they operate. Full article
(This article belongs to the Special Issue Forest Mechanization and Harvesting—Trends and Perspectives)
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13 pages, 3943 KiB  
Article
Organic Matter Content in Mangrove Soils from a Karstic Environment: Comparison between Thermogravimetric and Loss-on-Ignition Analytical Techniques
Forests 2023, 14(7), 1469; https://doi.org/10.3390/f14071469 - 18 Jul 2023
Viewed by 1311
Abstract
Mangroves represent one of the most important carbon sinks on the planet due to their ability to store a high organic matter (OM) concentration in their soils. Therefore, OM analysis is important for generating inventories that do not underestimate or overestimate carbon stocks [...] Read more.
Mangroves represent one of the most important carbon sinks on the planet due to their ability to store a high organic matter (OM) concentration in their soils. Therefore, OM analysis is important for generating inventories that do not underestimate or overestimate carbon stocks and for reducing uncertainties. Accordingly, we propose the use of thermogravimetric analysis (TGA) against the classical ignition method to determine the OM content in mangrove soils from a karstic region of the Yucatan Peninsula, Mexico. Therefore, fifty-five soil profiles from El Playón in the Sian Ka’an Biosphere Reserve were analyzed and divided according to the condition of the mangrove: conserved, under restoration, or degraded. TGA analysis of mangrove soils, which are in direct contact with water bodies, can be used to accurately identify the thermal decomposition of hydrated calcium sulfates, which cannot be detected using the loss-on-ignition (LOI) method. Using TGA, it was determined that the water content in the internal structure of hydrated calcium sulfates was between 8 and 16% in the preserved mangrove soils, between 2 and 5% in the mangrove soils under restoration, and between 0.5 and 1% in the degraded mangrove soils. The OM content obtained using both techniques was similar; however, using TGA, the amount of water evaporated from calcium sulfates could be measured, and this was not possible with the LOI method. Therefore, the TGA technique can be used as a proxy analysis to determine the OM content in soils, including the amount of water from hydrated calcium sulfates that are found naturally. Full article
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13 pages, 2642 KiB  
Article
Evaluation of Soundscape Perception in Urban Forests Using Acoustic Indices: A Case Study in Beijing
Forests 2023, 14(7), 1435; https://doi.org/10.3390/f14071435 - 12 Jul 2023
Cited by 2 | Viewed by 1450
Abstract
Soundscape is an essential component of urban forest landscapes, acoustic indices can be effectively used to monitor biodiversity, but whether they can be used for soundscape perception assessments needs to be further explored. In this study, soundscape recordings were collected in Beijing Eastern [...] Read more.
Soundscape is an essential component of urban forest landscapes, acoustic indices can be effectively used to monitor biodiversity, but whether they can be used for soundscape perception assessments needs to be further explored. In this study, soundscape recordings were collected in Beijing Eastern Suburban Forest Park, and acoustic indices were used to explore the relationship between the acoustic environment and soundscape perception, as well as the possible effects of temporal changes. To achieve this, audio recordings collected in spring and summer were divided, and a total of 90 audio segments were extracted from three time periods—morning, afternoon, and evening—to calculate the acoustic index and complete a questionnaire survey. The urban forest soundscape was evaluated according to the eight perceptual attribute quality indicators of ISO 12913, and generalized linear models were constructed to quantify the relationships between the acoustic indices and perception. The results showed that the temporal variation of the soundscape influenced the subjective evaluation, with the highest overall evaluation relating to the morning soundscape. The combination of acoustic indices explained the soundscape pleasantness (R2 = 0.58) better than the soundscape eventfulness (R2 = 0.54), demonstrating the utility of these indices in soundscape assessment. Linking acoustic indices to human perception generates innovative ideas and theoretical support for soundscape enhancement, contributing to a more pleasant acoustic environment and maximizing the social value of urban forests. Full article
(This article belongs to the Special Issue Urban Forestry and Sustainable Cities)
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13 pages, 1698 KiB  
Review
The Utilization of European Beech Wood (Fagus sylvatica L.) in Europe
Forests 2023, 14(7), 1419; https://doi.org/10.3390/f14071419 - 11 Jul 2023
Cited by 3 | Viewed by 1297
Abstract
European beech is one of the dominating wood species in central Europe and the most abundant hardwood species in Austrian, German and Swiss forests. Today, it is predominantly used for the provision of energy and in the furniture industry. With the increasing demand [...] Read more.
European beech is one of the dominating wood species in central Europe and the most abundant hardwood species in Austrian, German and Swiss forests. Today, it is predominantly used for the provision of energy and in the furniture industry. With the increasing demand on forests to provide sustainable raw materials for energy as well as products, the importance of lesser-used wood species like European beech has continuously increased over the last decade. The application in load-bearing products has gained significant interest. In order to connect the current and historical state of knowledge about this wood species, this review provides an overview of the past and present utilization of European beech wood. On the basis of the historical literature, technical approvals and standards of established products, it aims to summarize the extensive state of the art of this wood species and provide an overview of recent scientific publications in the field of wood material science. Based on the reviewed literature, current research efforts deal with different engineered wood products like glued laminated timber, cross-laminated timber and laminated veneer lumber. Furthermore, strength grading, adhesive technology as well as improving dimensional stability is of particular interest. Full article
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23 pages, 811 KiB  
Article
Alignment of National Forest Policy Frameworks with the EU Timber Regulation Requirements: Insights from Montenegro and the Republic of Srpska (Bosnia and Herzegovina)
Forests 2023, 14(6), 1157; https://doi.org/10.3390/f14061157 - 04 Jun 2023
Viewed by 1446
Abstract
The Western Balkans represent a priority area for improving forest legality monitoring systems in line with the European Union Timber Regulation (EUTR). However, research on EUTR implementation in Western Balkan countries is still sporadic with a limited geographical scope; therefore, the preparedness of [...] Read more.
The Western Balkans represent a priority area for improving forest legality monitoring systems in line with the European Union Timber Regulation (EUTR). However, research on EUTR implementation in Western Balkan countries is still sporadic with a limited geographical scope; therefore, the preparedness of forestry sector actors for the EUTR in the region is largely unknown. The main objective of this study is to determine to what extent the forest policy frameworks of Montenegro and the Republic of Srpska (Bosnia and Herzegovina) are aligned with the EUTR requirements. To achieve this aim, we applied a qualitative content analysis of policy documents identified via an expert-based approach. Our results show that both countries have well-developed policy frameworks addressing illegal logging and preventing illegal activities in forestry, especially through dedicated action plans. Key actors in both countries are public, including the ministries responsible for forestry, public forest enterprises, and forestry inspectorates. The forestry sector in Montenegro is facing significant changes due to the termination of forest concessions and the reorganization of the management of state forests, including forest certification. The Republic of Srpska has relatively well-established institutional bodies for EUTR implementation but, in some cases, insufficient exchange of information and cooperation among them. Our findings indicate that the forestry sectors in Montenegro and the Republic of Srpska (as well as in Serbia, Croatia, and Slovenia, as per previous research) are dynamic, undergoing various changes, so there is room for improvement in terms of capacities (e.g., human, technological, infrastructural), legal responsibilities, and information access and availability. With an increasing focus on “deforestation-free” commodities within the EU and global policy arena, a new, more demanding, and broader regulation is expected at the EU level, replacing the EUTR. The incoming regulation will expand existing EUTR requirements, likely posing severe challenges to many EU member countries. This could be even more challenging for countries with less developed or advanced systems to enforce legality requirements, including Western Balkan countries. Full article
(This article belongs to the Section Forest Economics, Policy, and Social Science)
20 pages, 3596 KiB  
Article
Long-Term Simulated Nitrogen Deposition Has Moderate Impacts on Soil Microbial Communities across Three Bioclimatic Domains of the Eastern Canadian Forest
Forests 2023, 14(6), 1124; https://doi.org/10.3390/f14061124 - 30 May 2023
Viewed by 1248
Abstract
The soil microbiome plays major roles in the below-ground processes and productivity of forest ecosystems. Atmospheric nitrogen (N) deposition is predicted to increase globally and might create disturbances in soil microbial communities, essentially by modifying soil chemistry. However, the impacts of higher N [...] Read more.
The soil microbiome plays major roles in the below-ground processes and productivity of forest ecosystems. Atmospheric nitrogen (N) deposition is predicted to increase globally and might create disturbances in soil microbial communities, essentially by modifying soil chemistry. However, the impacts of higher N deposition on the soil microbiome in N-limited northern forests are still unclear. For 16 years, we simulated N deposition by adding ammonium nitrate at rates of 3 and 10 times the ambient N deposition directly into soils located in three bioclimatic domains of the eastern Canadian forest (i.e., sugar maple–yellow birch, balsam fir–white birch, and black spruce–feather moss). We identified changes in the microbial communities by isolating the DNA of the L, F, and H soil horizons, as well as by sequencing amplicons of the bacterial 16S rRNA gene and the fungal ITS region. We found that long-term increased N deposition had no effect on soil microbial diversity, but had moderate impacts on the composition of the bacterial and fungal communities. The most noticeable change was the increase in ectomycorrhizal fungi ASV abundance, potentially due to increased tree root growth on fertilized plots. Our work suggests that, in N-limited northern forests, extra N is rapidly mobilized by vegetation, thus minimizing impacts on the soil microbiome. Full article
(This article belongs to the Section Forest Soil)
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32 pages, 5012 KiB  
Article
Temperature and Tree Size Explain the Mean Time to Fall of Dead Standing Trees across Large Scales
Forests 2023, 14(5), 1017; https://doi.org/10.3390/f14051017 - 15 May 2023
Cited by 2 | Viewed by 1778
Abstract
Dead standing trees (DSTs) generally decompose slower than wood in contact with the forest floor. In many regions, DSTs are being created at an increasing rate due to accelerating tree mortality caused by climate change. Therefore, factors determining DST fall are crucial for [...] Read more.
Dead standing trees (DSTs) generally decompose slower than wood in contact with the forest floor. In many regions, DSTs are being created at an increasing rate due to accelerating tree mortality caused by climate change. Therefore, factors determining DST fall are crucial for predicting dead wood turnover time but remain poorly constrained. Here, we conduct a re-analysis of published DST fall data to provide standardized information on the mean time to fall (MTF) of DSTs across biomes. We used multiple linear regression to test covariates considered important for DST fall, while controlling for mortality and management effects. DSTs of species killed by fire, insects and other causes stood on average for 48, 13 and 19 years, but MTF calculations were sensitive to how tree size was accounted for. Species’ MTFs differed significantly between DSTs killed by fire and other causes, between coniferous and broadleaved plant functional types (PFTs) and between managed and unmanaged sites, but management did not explain MTFs when we distinguished by mortality cause. Mean annual temperature (MAT) negatively affected MTFs, whereas larger tree size or being coniferous caused DSTs to stand longer. The most important explanatory variables were MAT and tree size, with minor contributions of management and plant functional type depending on mortality cause. Our results provide a basis to improve the representation of dead wood decomposition in carbon cycle assessments. Full article
(This article belongs to the Section Forest Ecology and Management)
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11 pages, 2093 KiB  
Article
Defective or Just Different? Observed Storm Failure in Four Urban Tree Growth Patterns
Forests 2023, 14(5), 988; https://doi.org/10.3390/f14050988 - 11 May 2023
Cited by 1 | Viewed by 2258
Abstract
Practitioners who assess the risk associated with urban trees often factor in the presence or absence of visual tree defects when determining whether a tree may fail. Although these defects are a main fixture in many tree risk assessment systems and best-management practices, [...] Read more.
Practitioners who assess the risk associated with urban trees often factor in the presence or absence of visual tree defects when determining whether a tree may fail. Although these defects are a main fixture in many tree risk assessment systems and best-management practices, the research supporting their usefulness in predicting tree failure during storms is limited. When looking at past research involving populations of storm-damaged trees, several defects have never predicted failure (or have been associated with reduced rates of failure). In this study, we took a closer look at four such defects: codominant branches; branch unions with included bark; multiple stems originating from the same point; and overextended branches. After Hurricane Ian, we revisited 1518 risk-assessed trees where one of these four defects was identified as the primary condition of concern. Fourteen of these trees experienced branch failure during the storm (which hit the study area as a downgraded tropical storm). Upon closer inspection, none of these failures occurred at the defect of concern. Our findings indicate that none of the defects assessed appeared to increase the likelihood of tree failure in the species tested. Our results are in line with past research on these defects derived from post-storm assessments and analysis. Full article
(This article belongs to the Special Issue Prediction and Management of Urban Forest Storm Damage)
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11 pages, 2079 KiB  
Article
Suitability of a Historical, Novel, and Occasional Host for Mountain Pine Beetle (Coleoptera: Curculionidae)
Forests 2023, 14(5), 989; https://doi.org/10.3390/f14050989 - 11 May 2023
Viewed by 1166
Abstract
The mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), recently underwent a notable range-expansion event in western Canada, resulting in access to the novel host jack pine, Pinus banksiana Lamb. We assessed the suitability of jack pine for mountain pine beetle, as well [...] Read more.
The mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae), recently underwent a notable range-expansion event in western Canada, resulting in access to the novel host jack pine, Pinus banksiana Lamb. We assessed the suitability of jack pine for mountain pine beetle, as well as the historic host lodgepole pine, Pinus contorta Dougl. var. latifolia Engelm., and the non-Pinus host white spruce, Picea glauca (Moench) Voss, to help inform an assessment of the risk of future spread into Canada’s boreal forest and to further our understanding of host use in bark beetles. Several performance traits we measured were similar between lodgepole pine and jack pine, but gallery length and productivity indicated that lodgepole pine was the more suitable host. Development appeared to be faster in jack pine; however, in contrast to previous studies, we attribute it to oviposition arresting earlier in the novel host compared to the other hosts and not a difference in development rate. Initial productivity was surprisingly high in spruce, but we found evidence of a delayed negative effect that manifested as reduced cold tolerance, delayed development, and high mortality of late-instar larvae. Although jack pine is a suitable host for the mountain pine beetle, our results indicate that the beetle’s eruptive potential could be lower in jack pine compared to lodgepole pine, given all other factors are equal. Other factors that may also affect mountain pine beetle population dynamics require additional research and include the composition and structure of jack pine forests, environmental conditions, and biotic interactions. Full article
(This article belongs to the Special Issue Forest Health: Forest Insect Population Dynamics)
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32 pages, 10275 KiB  
Article
Tree Species Classification in a Complex Brazilian Tropical Forest Using Hyperspectral and LiDAR Data
Forests 2023, 14(5), 945; https://doi.org/10.3390/f14050945 - 04 May 2023
Cited by 1 | Viewed by 3071
Abstract
This study experiments with different combinations of UAV hyperspectral data and LiDAR metrics for classifying eight tree species found in a Brazilian Atlantic Forest remnant, the most degraded Brazilian biome with high fragmentation but with huge structural complexity. The selection of the species [...] Read more.
This study experiments with different combinations of UAV hyperspectral data and LiDAR metrics for classifying eight tree species found in a Brazilian Atlantic Forest remnant, the most degraded Brazilian biome with high fragmentation but with huge structural complexity. The selection of the species was done based on the number of tree samples, which exist in the plot data and in the fact the UAV imagery does not acquire information below the forest canopy. Due to the complexity of the forest, only species that exist in the upper canopy of the remnant were included in the classification. A combination of hyperspectral UAV images and LiDAR point clouds were in the experiment. The hyperspectral images were photogrammetric and radiometric processed to obtain orthomosaics with reflectance factor values. Raw spectra were extracted from the trees, and vegetation indices (VIs) were calculated. Regarding the LiDAR data, both the point cloud—referred to as Peak Returns (PR)—and the full-waveform (FWF) LiDAR were included in this study. The point clouds were processed to normalize the intensities and heights, and different metrics for each data type (PR and FWF) were extracted. Segmentation was preformed semi-automatically using the superpixel algorithm, followed with manual correction to ensure precise tree crown delineation before tree species classification. Thirteen different classification scenarios were tested. The scenarios included spectral features and LiDAR metrics either combined or not. The best result was obtained with all features transformed with principal component analysis with an accuracy of 76%, which did not differ significantly from the scenarios using the raw spectra or VIs with PR or FWF LiDAR metrics. The combination of spectral data with geometric information from LiDAR improved the classification of tree species in a complex tropical forest, and these results can serve to inform management and conservation practices of these forest remnants. Full article
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22 pages, 4279 KiB  
Article
Microevolutionary Processes in a Foundation Tree Inform Macrosystem Patterns of Community Biodiversity and Structure
Forests 2023, 14(5), 943; https://doi.org/10.3390/f14050943 - 03 May 2023
Cited by 1 | Viewed by 1961
Abstract
Despite an increased focus on multiscale relationships and interdisciplinary integration, few macroecological studies consider the contribution of genetic-based processes to landscape-scale patterns. We test the hypothesis that tree genetics, climate, and geography jointly drive continental-scale patterns of community structure, using genome-wide SNP data [...] Read more.
Despite an increased focus on multiscale relationships and interdisciplinary integration, few macroecological studies consider the contribution of genetic-based processes to landscape-scale patterns. We test the hypothesis that tree genetics, climate, and geography jointly drive continental-scale patterns of community structure, using genome-wide SNP data from a broadly distributed foundation tree species (Populus fremontii S. Watson) and two dependent communities (leaf-modifying arthropods and fungal endophytes) spanning southwestern North America. Four key findings emerged: (1) Tree genetic structure was a significant predictor for both communities; however, the strength of influence was both scale- and community-dependent. (2) Tree genetics was the primary driver for endophytes, explaining 17% of variation in continental-scale community structure, whereas (3) climate was the strongest predictor of arthropod structure (24%). (4) Power to detect tree genotype—community phenotype associations changed with scale of genetic organization, increasing from individuals to populations to ecotypes, emphasizing the need to consider nonstationarity (i.e., changes in the effects of factors on ecological processes across scales) when inferring macrosystem properties. Our findings highlight the role of foundation tree species as drivers of macroscale community structure and provide macrosystems ecology with a theoretical framework for linking fine- and intermediate-scale genetic processes to landscape-scale patterns. Management of the genetic diversity harbored within foundation species is a critical consideration for conserving and sustaining regional biodiversity. Full article
(This article belongs to the Special Issue Global Change and Forest Plant Community Dynamics)
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21 pages, 2046 KiB  
Article
A Multi-Country Study Assessing the Mechanisms of Natural Elements and Sociodemographics behind the Impact of Forest Bathing on Well-Being
Forests 2023, 14(5), 904; https://doi.org/10.3390/f14050904 - 27 Apr 2023
Cited by 3 | Viewed by 3304
Abstract
Interventions such as forest bathing (slow, mindful nature walks) have been shown to increase our connection to nature and be an effective intervention for improving health and well-being. However, there is variation in the activities delivered during forest bathing and the guidance given. [...] Read more.
Interventions such as forest bathing (slow, mindful nature walks) have been shown to increase our connection to nature and be an effective intervention for improving health and well-being. However, there is variation in the activities delivered during forest bathing and the guidance given. Few researchers have evaluated which activities, elements of nature, and senses are responsible for improvements in well-being. The current evaluation addresses this gap and also monitors the emotional state and nature connection following guided forest bathing walks. Participants (N = 1142) across 35 countries completed post-walk evaluation surveys online. Results suggest that well-being and nature connection were rated very highly following forest bathing activities. Experiencing happy feelings and trusting emotions were especially highly rated. The natural elements perceived as contributing the most to well-being were sound-related elements. In terms of sociodemographics, women had higher well-being and nature connection ratings than men; ratings were higher in specialised nature resort areas, with little difference between natural and urban park areas; higher scores were seen in the southern hemisphere and during hot or long-day seasons. This has implications for forest bathing, forest therapy, and nature-based training organisations and their guides who want to improve their method of intervention delivery, maximise well-being, and enhance nature connection. Full article
(This article belongs to the Special Issue Forest Bathing and Forests for Public Health)
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17 pages, 4996 KiB  
Article
Exploring the Potential of Portable Spectroscopic Techniques for the Biochemical Characterization of Roots in Shallow Landslides
Forests 2023, 14(4), 825; https://doi.org/10.3390/f14040825 - 18 Apr 2023
Cited by 1 | Viewed by 1788
Abstract
In the present work, Raman, Fourier Transform Infrared (FTIR) and elemental Laser-Induced Breakdown Spectroscopy (LIBS) spectroscopic techniques were used for the assessment of the influence of plant root composition towards shallow landslide occurrence. For this purpose, analyses were directly carried out on root [...] Read more.
In the present work, Raman, Fourier Transform Infrared (FTIR) and elemental Laser-Induced Breakdown Spectroscopy (LIBS) spectroscopic techniques were used for the assessment of the influence of plant root composition towards shallow landslide occurrence. For this purpose, analyses were directly carried out on root samples collected from chestnut forests of the Garfagnana basin (northern Apennines, Italy) in different areas devoid and affected by shallow landslides due to frequent heavy rain events. Results have highlighted a correlation between the biochemical constituents of wooden roots and the sampling areas. In particular, different content of lignin/cellulose, as well as minerals nutrients, have been detected in roots collected where shallow landslides occurred, with respect to more stable areas. The results achieved are in line with the scientific literature which has demonstrated the link between the chemical composition of roots with their mechanical properties and, in particular, tensile strength and cohesion. Finally, portable spectroscopic instrumentations were employed without the need for either any sample preparation for Raman and LIBS spectroscopy or minimal preparation for FTIR spectroscopy. This novel and fast approach has allowed achieving information on the content of the major constituents of the root cell, such as cellulose and lignin, as well as their mineral nutrients. This approach could be reasonably included among the vegetation protection actions towards instability, as well as for the evaluation of shallow landslide susceptibility, combining geological, vegetational and biochemical parameters with sustainability. Full article
(This article belongs to the Section Natural Hazards and Risk Management)
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14 pages, 2227 KiB  
Review
An Overview of Oak Species in Pakistan: Past, Present, and Future Research Perspectives
Forests 2023, 14(4), 777; https://doi.org/10.3390/f14040777 - 10 Apr 2023
Cited by 2 | Viewed by 3869
Abstract
Quercus spp. have formed broad-leaved evergreen forests in the Hindu Kush and Himalayan regions of Pakistan. Seven species of the genus Quercus (Q. baloot Griff., Q. dilatata Royle., Q. glauca Thunb., Q. incana Roxb., Q. robur Linn., Q. semecarpifolia Smith., and Q. [...] Read more.
Quercus spp. have formed broad-leaved evergreen forests in the Hindu Kush and Himalayan regions of Pakistan. Seven species of the genus Quercus (Q. baloot Griff., Q. dilatata Royle., Q. glauca Thunb., Q. incana Roxb., Q. robur Linn., Q. semecarpifolia Smith., and Q. leucotrichophora A. Camus.) have been identified. These species have received little attention compared with other economically valuable plant species in Pakistan, which has been mainly linked to traditional medicine and the identification of phytonutrients to evaluate their bioactivities and toxicological effects. Quercus spp. are promising for commercial applications, so government policy should encourage their management and conservation. However, they are currently threatened by severe human activities and climate change. The goal of this review is to highlight the relevance of these forgotten species, describing overall aspects related to their distribution, morphology, traditional uses, phytochemical constituents, and threats. To date, no proper and comprehensive molecular studies on the populations of these species found in Pakistan have been conducted, which is a critical gap as molecular studies are essential for conservation and management strategies. Finally, we discuss future directions in molecular approaches for Quercus that follow the strategies that are being used for other species of the genus Quercus that are not found in Pakistan. Full article
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23 pages, 3095 KiB  
Review
Carbon Sequestration Potential of Commercial Agroforestry Systems in Indo-Gangetic Plains of India: Poplar and Eucalyptus-Based Agroforestry Systems
Forests 2023, 14(3), 559; https://doi.org/10.3390/f14030559 - 12 Mar 2023
Cited by 5 | Viewed by 4965
Abstract
Climate change, land degradation, and desertification lead to the loss of carbon present in the soil and plants. The carbon dioxide (CO2) concentration in the atmosphere has reached 412 ppm. This is a rise of 47% since the start of the [...] Read more.
Climate change, land degradation, and desertification lead to the loss of carbon present in the soil and plants. The carbon dioxide (CO2) concentration in the atmosphere has reached 412 ppm. This is a rise of 47% since the start of the industrial period, when the concentration was close to 280 ppm. Therefore, the sequestration of carbon from the atmosphere to earth is the need of the hour. Many scientists have suggested agroforestry as a potent instrument for climate change mitigation as well as to fetch lucrative benefits. The Indian government is also promulgating tree-based systems for increasing tree cover up to 33% of the total geographical area to mitigate climate change. Therefore, the expansion of the commercial agroforestry system of fast-growing tree species producing higher biomass could be a sustainable and ecologically benign technique to sequester carbon, increase green cover, and improve the financial status of farmers. This review highlights the commercial agroforestry systems, biomass and carbon sequestration potential, and case studies of poplar and eucalyptus. The species such as poplar (Populus deltoides), nilgiri (Eucalyptus spp.), subabul (Leucaena leucocephala), tree of heaven (Ailanthus excelsa), willow (Salix spp.), malabar neem (Melia dubia), cadamba (Neolamarckia cadamba), and white teak (Gmelina arborea) are the suitable tree species for carbon sequestration under agroforestry. Among these species, poplar and eucalyptus are major agroforestry tree species that have been adopted by millions of farmers in India since the 1990s. Indo-Gangetic plains are considered the birthplace of commercial or industrial agroforestry, as poplar and eucalyptus are widely planted. This review reports that poplar and eucalyptus have the potential to sequester carbon stock of 212.7 Mg C ha−1 and 237.2 Mg C ha−1, respectively. Further, the net carbon sequestration rate in poplar and eucalyptus was 10.3 and 12.7 Mg C ha−1 yr−1, respectively. In conclusion, the commercial agroforestry system was very successful in the Indo-Gangetic regions of the country but needs further expansion with suitable compatible crops in different parts of the country. Full article
(This article belongs to the Special Issue Pollution, Heavy Metal, and Emerging Threats in Forest Soil)
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14 pages, 2520 KiB  
Article
Biocultural Importance of the Chiuri Tree [Diploknema butyracea (Roxb.) H. J. Lam] for the Chepang Communities of Central Nepal
Forests 2023, 14(3), 479; https://doi.org/10.3390/f14030479 - 27 Feb 2023
Cited by 1 | Viewed by 4283
Abstract
Major socio-economic changes over the last few decades have reduced Indigenous peoples’ engagement in cultural practices, such as harvesting of forest resources. Nevertheless, some species remain important for culture, subsistence and livelihood, such as the chiuri tree (Diploknema butyracea (Roxb.) H. J. [...] Read more.
Major socio-economic changes over the last few decades have reduced Indigenous peoples’ engagement in cultural practices, such as harvesting of forest resources. Nevertheless, some species remain important for culture, subsistence and livelihood, such as the chiuri tree (Diploknema butyracea (Roxb.) H. J. Lam) to the Chepang people of Central Nepal. Using the cultural keystone species framework, we conducted interviews within Chepang communities to assess the biocultural importance of the chiuri tree. It is central to the Chepang culture, and no other species could provide the same benefits. It also provides food and habitat for a number of wildlife species, including bats, which are themselves culturally important. Strictly observed tree ownership rules, as well as a cultural ban on tree cutting and branch lopping, have so far contributed to chiuri conservation. However, these rules are increasingly less adhered to. Other threats to chiuri sustainability are excessive flower foraging by bees (reducing pollen production) and bat hunting (reducing pollen transport). Further studies are needed to quantify these threats and to adjust forest and wildlife management practices so that the cultural landscape continues to provide multiple benefits to the Chepang people. Our study of the chiuri case attests to the usefulness of the cultural keystone species framework in landscape assessment for management and conservation. Full article
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14 pages, 4824 KiB  
Article
Modeling Climate Change Effects on the Distribution of Oak Forests with Machine Learning
Forests 2023, 14(3), 469; https://doi.org/10.3390/f14030469 - 24 Feb 2023
Cited by 3 | Viewed by 2146
Abstract
The present study models the effect of climate change on the distribution of Persian oak (Quercus brantii Lindl.) in the Zagros forests, located in the west of Iran. The modeling is conducted under the current and future climatic conditions by fitting the [...] Read more.
The present study models the effect of climate change on the distribution of Persian oak (Quercus brantii Lindl.) in the Zagros forests, located in the west of Iran. The modeling is conducted under the current and future climatic conditions by fitting the machine learning method of the Bayesian additive regression tree (BART). For the anticipation of the potential habitats for the Persian oak, two general circulation models (GCMs) of CCSM4 and HADGEM2-ES under the representative concentration pathways (RCPs) of 2.6 and 8.5 for 2050 and 2070 are used. The mean temperature (MT) of the wettest quarter (bio8), solar radiation, slope and precipitation of the wettest month (bio13) are respectively reported as the most important variables in the modeling. The results indicate that the suitable habitat of Persian oak will significantly decrease in the future under both climate change scenarios as much as 75.06% by 2070. The proposed study brings insight into the current condition and further projects the future conditions of the local forests for proper management and protection of endangered ecosystems. Full article
(This article belongs to the Special Issue Forest Resilience and Resistance to Climate Change)
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23 pages, 2180 KiB  
Article
Modelling Climatically Suitable Areas for Mahogany (Swietenia macrophylla King) and Their Shifts across Neotropics: The Role of Protected Areas
Forests 2023, 14(2), 385; https://doi.org/10.3390/f14020385 - 14 Feb 2023
Cited by 5 | Viewed by 2735
Abstract
Mahogany (Swietenia macrophylla King) is a species with great economic interest worldwide and is classified as vulnerable to extinction by the IUCN. Deforestation and climate change are the main hazards to this species. Therefore, it is vital to describe possible changes in [...] Read more.
Mahogany (Swietenia macrophylla King) is a species with great economic interest worldwide and is classified as vulnerable to extinction by the IUCN. Deforestation and climate change are the main hazards to this species. Therefore, it is vital to describe possible changes in distribution patterns under current and future climatic conditions, as they are important for their monitoring, conservation, and use. In the current study, we predict, for the very first time, the potential distribution of Mahogany based on data that reflect the total distribution of the species, climatic and edaphic variables, and a consensus model that combines the results of three statistical techniques. The obtained model was projected to future climatic conditions considering two general circulation models (GCM), under two shared socioeconomic pathways (SSP245 and SSP585) for 2070. Predictions under current climatic conditions indicated wide adequate areas in Central American countries such as Mexico and demonstrated a coverage of up to 28.5% within the limits of the protected areas. Under future scenarios, drastic reductions were observed in different regions, particularly in Venezuela, Perú, and Ecuador, with losses of up to 56.0%. On the other hand, an increase in suitable areas for the species within protected areas was also detected. The results of this study are certainly useful for identifying currently unrecorded populations of Mahogany, as well as for identifying locations that are likely to be suitable both now and in the future for conservation management planning. The methodology proposed in this work is able to be used for other forest species in tropical zones as a tool for conducting dynamic conservation and restoration strategies that consider the effects of climate change. Full article
(This article belongs to the Special Issue Biodiversity and Conservation of Forests)
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15 pages, 772 KiB  
Review
A Review of Research on Forest Ecosystem Quality Assessment and Prediction Methods
Forests 2023, 14(2), 317; https://doi.org/10.3390/f14020317 - 06 Feb 2023
Cited by 2 | Viewed by 5131
Abstract
The accurate assessment and prediction of forest ecosystem quality is an important basis for evaluating the effectiveness of regional ecological protection and restoration, establishing a positive feedback mechanism for forest quality improvement and restoration policies, and promoting the construction of an ecological civilization [...] Read more.
The accurate assessment and prediction of forest ecosystem quality is an important basis for evaluating the effectiveness of regional ecological protection and restoration, establishing a positive feedback mechanism for forest quality improvement and restoration policies, and promoting the construction of an ecological civilization in China. Based on the existing studies at home and abroad, this paper mainly analyzes and summarizes the connotation of forest ecosystem quality, assessment index systems, assessment and prediction methods, and outlooks on the existing problems of imperfect forest ecological quality assessment index systems, preliminary assessment and prediction capabilities, and unknown dynamic responses of forest ecological quality to climate change, etc. Efforts should be made to develop a scientific and standardized assessment index system, produce high-quality forest ecological data products, develop localization of assessment model parameters, and explore forest quality–climate change response mechanisms to provide references for in-depth research to realize the transformation of forest ecosystem quality assessments from historical and status quo assessments to future predictions, and to support the construction of a national ecological civilization. Full article
28 pages, 7986 KiB  
Review
Adhesive-and Metal-Free Assembly Techniques for Prefabricated Multi-Layer Engineered Wood Products: A Review on Wooden Connectors
Forests 2023, 14(2), 311; https://doi.org/10.3390/f14020311 - 05 Feb 2023
Cited by 7 | Viewed by 4686
Abstract
Engineered wood products (EWPs) are being increasingly used as construction materials. EWPs are currently being made using synthetic adhesives or metal fasteners, which lead to poor recyclability and reusability. Therefore, this review paper focused on emerging adhesive- and metal-free assembling techniques including wood [...] Read more.
Engineered wood products (EWPs) are being increasingly used as construction materials. EWPs are currently being made using synthetic adhesives or metal fasteners, which lead to poor recyclability and reusability. Therefore, this review paper focused on emerging adhesive- and metal-free assembling techniques including wood dowels, rotary-dowel welding, wooden nails, and dovetail joining as alternative ways of making prefabricated EWPs. This will contribute towards green construction and optimising the building process to minimise its negative impact on the environment and its inhabitants, while maximising the positive aspects of the finished structure. The respective advantages and shortcomings will be compared with those of equivalent EWPs. In general, the dowel-laminated timber (DLT) provides sufficient load-bearing capacity and even better ductility than EWPs of equivalent size, but its relatively low stiffness under a bending load limits its application as a structural element. Optimised manufacturing parameters such as dowel species, dowel spacing, dowel diameter, dowel insertion angle, dowel shape, etc. could be studied to improve the stiffness. The improved mechanical properties and tight fitting due to set-recovery of densified wood support its use as sustainable alternatives to hardwood dowels in DLT to overcome problems such as the loosening of connections over time and dimensional instability. The rotary welding technology could also enhance the strength and long-term performance of dowel-type joints, but its poor water resistance needs further investigation. The main obstacles to implementing DLT products in the market are missing technical information and design guidelines based on national codes. Full article
(This article belongs to the Special Issue Frontiers in Modification of Wood and Wood-Based Composites)
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22 pages, 5336 KiB  
Review
Distinct Responses of European Beech (Fagus sylvatica L.) to Drought Intensity and Length—A Review of the Impacts of the 2003 and 2018–2019 Drought Events in Central Europe
Forests 2023, 14(2), 248; https://doi.org/10.3390/f14020248 - 28 Jan 2023
Cited by 7 | Viewed by 2867
Abstract
A combined severe heatwave and drought, starting in 2018 and lasting for several months, restarted the discussion on the resistance of European beech to climatic changes, with severe growth reductions, early leaf senescence, leaf browning, and diebacks reported across Central Europe. These responses [...] Read more.
A combined severe heatwave and drought, starting in 2018 and lasting for several months, restarted the discussion on the resistance of European beech to climatic changes, with severe growth reductions, early leaf senescence, leaf browning, and diebacks reported across Central Europe. These responses may result in long-term impacts such as reduced vitality of beech, especially under potential future drought periods. While the 2003 drought caused severe crown damage and defoliation and a loss in vitality, resulting in insect and fungal infestations and subsequent dieback, the drought in 2018 was even more severe in terms of geographical scale, duration, and intensity with reports of complete diebacks and severe mortality across Central Europe. These impacts were exacerbated in some regions by the consecutive drought in 2019 and secondary attacks from pathogens, as well as a further loss in vitality. Such enhanced drought exposure of beech trees could push them beyond their hydraulic safety margins. Moreover, growth legacy effects due to past droughts may lead to lower recovery over time, potentially leading to subsequent tree death. In order to better predict the future of beech growth and vitality in Central Europe, both short- and long-term legacy effects of defoliation and their influence on post-drought growth should be explored, and adaptive forest management strategies evaluated. Moreover, synergistic or additive interactions of legacy effects with drought, as well as with biotic disturbances, require further investigation. Long-term forest monitoring data facilitates investigations of drought responses of beech. Full article
(This article belongs to the Section Forest Ecology and Management)
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12 pages, 12366 KiB  
Article
The Differences in Water Repellency in Root Mat (Biomat) and Soil Horizons of Thinned and Non-thinned Chamaecyparis obtusa (Siebold et Zucc.) Endl. Plantations
Forests 2023, 14(2), 210; https://doi.org/10.3390/f14020210 - 21 Jan 2023
Cited by 1 | Viewed by 1401
Abstract
Water repellency (WR) is one cause of root mat (biomat) flow and soil surface runoff in dense Chamaecyparis obutsa (Siebold et Zucc.) Endl. plantations. However, the changes in WR of biomat and soil horizons are unclear in the thinned C. obtusa plantations. This [...] Read more.
Water repellency (WR) is one cause of root mat (biomat) flow and soil surface runoff in dense Chamaecyparis obutsa (Siebold et Zucc.) Endl. plantations. However, the changes in WR of biomat and soil horizons are unclear in the thinned C. obtusa plantations. This study compares the WR of biomat and soil horizons in the thinned and non-thinned C. obtusa plantations by considering the water content and surface temperature of biomat and soil from July 2021 to June 2022. We selected one plot in each thinned and non-thinned area in a catchment at Obora Experimental Forest in Japan. Our results showed that the 40% thinned plot lacked a biomat horizon, whereas the non-thinned plot had a ca. 3 cm depth of biomat. The biomat WR of the non-thinned plot (none to very strong) was higher than the soil WR of the thinned plot (none to strong). There was no relationship between WR and both water content and surface temperature of biomat and/or soil in either thinned or non-thinned plots. Our findings show that the biomat horizon had an essential role in the severity of WR in C. obtusa plantations. The lack of biomat after thinning could substantially impact soil surface hydrology. Full article
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17 pages, 16803 KiB  
Article
A Small-Target Forest Fire Smoke Detection Model Based on Deformable Transformer for End-to-End Object Detection
Forests 2023, 14(1), 162; https://doi.org/10.3390/f14010162 - 16 Jan 2023
Cited by 12 | Viewed by 2865
Abstract
Forest fires have continually endangered personal safety and social property. To reduce the occurrences of forest fires, it is essential to detect forest fire smoke accurately and quickly. Traditional forest fire smoke detection based on convolutional neural networks (CNNs) needs many hand-designed components [...] Read more.
Forest fires have continually endangered personal safety and social property. To reduce the occurrences of forest fires, it is essential to detect forest fire smoke accurately and quickly. Traditional forest fire smoke detection based on convolutional neural networks (CNNs) needs many hand-designed components and shows poor ability to detect small and inconspicuous smoke in complex forest scenes. Therefore, we propose an improved early forest fire smoke detection model based on deformable transformer for end-to-end object detection (deformable DETR). We use deformable DETR as a baseline containing the best sparse spatial sampling for smoke with deformable convolution and relation modeling capability of the transformer. We integrate a Multi-scale Context Contrasted Local Feature module (MCCL) and a Dense Pyramid Pooling module (DPPM) into the feature extraction module for perceiving features of small or inconspicuous smoke. To improve detection accuracy and reduce false and missed detections, we propose an iterative bounding box combination method to generate precise bounding boxes which can cover the entire smoke object. In addition, we evaluate the proposed approach using a quantitative and qualitative self-made forest fire smoke dataset, which includes forest fire smoke images of different scales. Extensive experiments show that our improved model’s forest fire smoke detection accuracy is significantly higher than that of the mainstream models. Compared with deformable DETR, our model shows better performance with improvement of mAP (mean average precision) by 4.2%, APS (AP for small objects) by 5.1%, and other metrics by 2% to 3%. Our model is adequate for early forest fire smoke detection with high detection accuracy of different-scale smoke objects. Full article
(This article belongs to the Special Issue Advances in Forest Fire and Other Detection Systems)
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18 pages, 2701 KiB  
Article
Effects of Wild Forest Fires on Genetic Diversity and Population Structure of a Boreal Conifer, White Spruce (Picea glauca (Moench) Voss): Implications for Genetic Resource Management and Adaptive Potential under Climate Change
Forests 2023, 14(1), 157; https://doi.org/10.3390/f14010157 - 14 Jan 2023
Cited by 3 | Viewed by 2679
Abstract
Climate change is predicted to increase forest fires in boreal forests, which can threaten the sustainability of forest genetic resources. Wildfires can potentially impact genetic diversity and population structure in forest trees by creating population bottlenecks, and influencing demography, effective population size ( [...] Read more.
Climate change is predicted to increase forest fires in boreal forests, which can threaten the sustainability of forest genetic resources. Wildfires can potentially impact genetic diversity and population structure in forest trees by creating population bottlenecks, and influencing demography, effective population size (Ne) and various evolutionary processes. We have investigated this critical issue in a widely-distributed, transcontinental, ecologically and economically important and fire-intolerant boreal conifer, white spruce (Picea glauca (Moench) Voss). We tested the hypothesis that in a predominantly outcrossing species with long distance gene flow, such as white spruce, located in primary undisturbed forests, normal forest fires do not adversely affect genetic diversity and population structure. We used 10 nuclear genic and genomic microsatellite loci to examine genetic diversity and population structure of post-fire pristine old-growth (PF-OG) and adjacent post-fire naturally regenerated young (PF-YR) stands. The genetic diversity, inbreeding and genetic differentiation levels, Bayesian population structure, Ne and latent genetic potential were statistically similar between the PF-OG and PF-YR populations. None of the microsatellites showed any signature of selection. Our study demonstrates that normal wild forest fires do not adversely affect genetic diversity, differentiation, and population genetic structure in white spruce. The results should have wide significance for sustainable forest management. Full article
(This article belongs to the Section Genetics and Molecular Biology)
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17 pages, 3562 KiB  
Article
The Role of Provenance for the Projected Growth of Juvenile European Beech under Climate Change
Forests 2023, 14(1), 26; https://doi.org/10.3390/f14010026 - 23 Dec 2022
Cited by 5 | Viewed by 2539
Abstract
European beech is one of the most common tree species in Europe and is generally suggested to play even more of a prominent role in forestry in the future. It seems to have the potential to partially replace Norway spruce, as it is [...] Read more.
European beech is one of the most common tree species in Europe and is generally suggested to play even more of a prominent role in forestry in the future. It seems to have the potential to partially replace Norway spruce, as it is less sensitive to expected warmer and drier conditions. It is, however, not well known in which regions these new plantings would be particularly favourable and if specific provenances may be better adapted to the new conditions than others. Therefore, we estimated the potential early height growth under climate conditions in 2040–2060 for 20 beech provenances across a region covering the Czech Republic and Slovakia. This Central European region is expected to experience considerably drier and warmer conditions in the future. For this exercise, we implemented a new neural network model developed from height growth information obtained from the open-access BeechCOSTe52 database. The simulations are driven by past and future climate data obtained from the WorldClim database of historical climate data and future climate projections. Simulations revealed that provenances originating from drier regions performed on average significantly better than those from regions with good water supply. Moreover, provenances originating from drier regions had a particularly large advantage in the relatively arid regions of Central Czechia and Southern Slovakia. We can also confirm that all provenances showed a high phenotypic plasticity of height growth across the whole investigated region. Full article
(This article belongs to the Special Issue Impact of Climate Change on Tree Growth)
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30 pages, 3691 KiB  
Review
Water in Wood: A Review of Current Understanding and Knowledge Gaps
Forests 2022, 13(12), 2051; https://doi.org/10.3390/f13122051 - 02 Dec 2022
Cited by 10 | Viewed by 9183
Abstract
Wood-water interactions are central to the utilization of wood in our society since water affects many important characteristics of wood. This topic has been investigated for more than a century, but new knowledge continues to be generated as a result of improved experimental [...] Read more.
Wood-water interactions are central to the utilization of wood in our society since water affects many important characteristics of wood. This topic has been investigated for more than a century, but new knowledge continues to be generated as a result of improved experimental and computational methods. This review summarizes our current understanding of the fundamentals of water in wood and highlights significant knowledge gaps. Thus, the focus is not only on what is currently known but equally important, what is yet unknown. The review covers locations of water in wood; phase changes and equilibrium states of water in wood; thermodynamics of sorption; terminology including cell wall water (bound water), capillary water (free water), fiber saturation point, and maximum cell wall moisture content; shrinkage and swelling; sorption hysteresis; transport of water in wood; and kinetics of water vapor sorption in the cell wall. Full article
(This article belongs to the Special Issue Reviews on Structure and Physical and Mechanical Properties of Wood)
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19 pages, 4741 KiB  
Article
Contribution of Dry Forests and Forest Products to Climate Change Adaptation in Tigray Region, Ethiopia
Forests 2022, 13(12), 2026; https://doi.org/10.3390/f13122026 - 29 Nov 2022
Viewed by 2932
Abstract
Despite their ecological importance, dry forests’ contribution to climate change adaptation is often neglected. Hence, this study was initiated to assess the socioeconomic contribution of dry forests to climate change adaptation in Tigray Region, Ethiopia. A mixed quantitative and qualitative research design was [...] Read more.
Despite their ecological importance, dry forests’ contribution to climate change adaptation is often neglected. Hence, this study was initiated to assess the socioeconomic contribution of dry forests to climate change adaptation in Tigray Region, Ethiopia. A mixed quantitative and qualitative research design was used to examine the role of dry forests in climate change adaptation. Household questionnaire survey, key informants, and a focus group discussion were used to collect data. The results indicated that 94% of all households visited a dry forest at least once a month to access the forest and forest products. While the dry forest income level varied significantly (p < 0.05), the overall dry forest income level contributed to 16.8% of the total household income. Dry forest income enabled the reduction of the area between the line of equality and the Lorenz curve by 21% in dry evergreen Afromontane Forest users, by 3.02% in Combretum–Terminalia woodland users, and by 3% in Acacia–Commiphora woodland users. Gender, occupation, wealth status, and distance from the forest to their homes are all factors that significantly affected Combretum–Terminalia woodland users’ income level. Among Acacia–Commiphora woodland users, the respondents’ age influenced the dry forest income level, whereas, among dry evergreen Afromontane Forest users, the family size of the household influenced the dry forest income level. The findings of this study could help policy makers understand the crucial role of dry forest income in the livelihood of the community and in climate change adaptation. Policymakers could reduce the pressure on dry forests by introducing policies that recognize the role of dry forest income in reducing poverty and income inequality and by establishing farmer cooperation in commercializing the non-timber forest products which support the long-term coping and adaptation strategy. Further research is needed to understand the increasing role of dry forest products in climate change adaptation over time and its contribution to the national economy at large. Full article
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21 pages, 1741 KiB  
Review
Toward the Genetic Improvement of Drought Tolerance in Conifers: An Integrated Approach
Forests 2022, 13(12), 2016; https://doi.org/10.3390/f13122016 - 29 Nov 2022
Cited by 4 | Viewed by 2859
Abstract
The constant rise in the global temperature and unpredictable shifts in precipitation patterns are two of the main effects of climate change. Therefore, there is an increasing amount of interest in the identification of tree species, provenances and genotypes capable of withstanding more [...] Read more.
The constant rise in the global temperature and unpredictable shifts in precipitation patterns are two of the main effects of climate change. Therefore, there is an increasing amount of interest in the identification of tree species, provenances and genotypes capable of withstanding more arid conditions and tolerating drought stress. In the present review, we focus our attention on generally more susceptible conifers and describe the different strategies that plants adopt to respond to drought stress. We describe the main approaches taken in studies of conifer adaptations to low water availability, the advantages and limitations of each, and the main results obtained with each of these approaches in the recent years. Then we discuss how the increasing amount of morphological, physiological and genetic data may find practical applications in forest management, and in particular in next-generation breeding programs. Finally, we provide some recommendations for future research. In particular, we suggest extending future studies to a broader selection of species and genera, increasing the number of studies on adult plants, in particular those on gene expression, and distinguishing between the different types of drought stress that a tree can withstand during its life cycle. The integration of data coming from different disciplines and approaches will be a key factor to increasing our knowledge about a trait as complex as drought resistance. Full article
(This article belongs to the Special Issue Tree Genetics: Molecular and Functional Characterization of Genes)
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25 pages, 3558 KiB  
Article
The Macroeconomic Implications of the Transition of the Forestry Industry towards Bioeconomy
Forests 2022, 13(11), 1961; https://doi.org/10.3390/f13111961 - 21 Nov 2022
Cited by 1 | Viewed by 1973
Abstract
In a global economic system where essential resources are limited, demand is increasing and environmental degradation is more pronounced, the only viable option to ensure sustainable development is to create an environmentally friendly and efficient economy in order to produce more economic value [...] Read more.
In a global economic system where essential resources are limited, demand is increasing and environmental degradation is more pronounced, the only viable option to ensure sustainable development is to create an environmentally friendly and efficient economy in order to produce more economic value with the same or fewer resources. The aim of this paper is to provide insight into the macroeconomic implications determined by the transition to a forest bioeconomy, with a focus on the impact on the national gross value added. More specifically, this analysis assesses the relationship between the potential of the macroeconomic value creation on the forestry industry and the measures of progress on the transition towards sustainable forest management and long-term economic growth. The analysis refers to a period between 2013 and 2019, summing-up 133 observations, data that were reported by Eurostat for 23 European Union members. We propose a model that describes a construct of the potential of the value creation that can be generated by each country included in our sample, translated into an efficiency score determined using the Data Envelopment Analysis(DEA)methodology. The results highlighted that the evolution of economic, social, and environmental (ESG) context positively impacted the efficiency score. This positive evolution in time was mainly driven by the higher awareness of governments, companies, and people on the need for a transition to sustainable economic growth and sustainable forest management. Furthermore, this study highlights that the transition to sustainable economic growth implies negative changes to the cost structure of the economies, which lead to higher operational costs and lower gross value added. Moreover, our study provides more insight, from an econometric methodology perspective, regarding the synergy effect as determined by the transformation of business models in the forestry sector towards sustainable forest management. Full article
(This article belongs to the Section Forest Economics, Policy, and Social Science)
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11 pages, 2362 KiB  
Article
A Dynamical Model Based on the Chapman–Richards Growth Equation for Fitting Growth Curves for Four Pine Species in Northern Mexico
Forests 2022, 13(11), 1866; https://doi.org/10.3390/f13111866 - 08 Nov 2022
Cited by 1 | Viewed by 2559
Abstract
Tree growth models describe the growth and development of forest ecosystems by considering how the dimensions of each simulated tree change within a certain time. These models have commonly used three growth parameters that describe various biological processes and behaviours, considering a sigmoid [...] Read more.
Tree growth models describe the growth and development of forest ecosystems by considering how the dimensions of each simulated tree change within a certain time. These models have commonly used three growth parameters that describe various biological processes and behaviours, considering a sigmoid growth function: (i) the upper asymptote (θ1), which is the maximal yield indicated by a final dimension (such as the maximal stem diameter); (ii) the maximum specific growth rate (θ2), defined as the slope of the tangent at the inflexion point; and (iii) the time elapsed (θ3), defined by the intercept of this tangent with the abscissas. To the best of our knowledge, however, associations between the three parameters have not been documented for tree species. Using diameter growth data from pine trees located in typical mixed and uneven-aged pine-oak forests in the Sierra Madre Occidental, Mexico, our study aims were: (i) to quantify the putative associations between the three growth parameters and (ii) to test the accuracy of a proposed Hybrid Chapman-Richards growth model based on associations between the three growth parameters, but including only one single parameter, relative to the widely used Generalized Algebraic Difference Approach (GADA) based on the Chapman-Richards, Lundqvist and Hossfeld models and the Hybrid Weibull Model. For statistical comparison of the quality of the models, we used the mean relative percentage error, root mean square error, coefficient of determination and Akaike information criterion to assess the quality of the fit. Although the quality of the five growth models studied was similar, from a practical point of view, the proposed Hybrid Chapman-Richards Model (CR-H) is easier to apply than the other models and has a lower data collection and computational cost. The parameter of CR-H can be easily obtained, by measuring just the dominant trees, especially in coniferous forests with irregular ages. Moreover, in contrast to the Chapman-Richards-GADA factor χ0, when θ2 is assumed to be site-specific, the CR-H has always a closed-form solution. Full article
(This article belongs to the Special Issue Spatial Distribution and Growth Dynamics of Tree Species)
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16 pages, 2496 KiB  
Article
Linking Bacterial Rhizosphere Communities of Two Pioneer Species, Brachystegia boehmii and B. spiciformis, to the Ecological Processes of Miombo Woodlands
Forests 2022, 13(11), 1840; https://doi.org/10.3390/f13111840 - 04 Nov 2022
Cited by 1 | Viewed by 1736
Abstract
Miombo is the most extensive ecosystem in southern Africa, being strongly driven by fire, climate, herbivory, and human activity. Soils are major regulating and supporting services, sequestering nearly 50% of the overall carbon and comprising a set of yet unexploited functions. In this [...] Read more.
Miombo is the most extensive ecosystem in southern Africa, being strongly driven by fire, climate, herbivory, and human activity. Soils are major regulating and supporting services, sequestering nearly 50% of the overall carbon and comprising a set of yet unexploited functions. In this study, we used next-generation Illumina sequencing to assess the patterns of bacterial soil diversity in two pioneer Miombo species, Brachystegia boehmii and Brachystegia spiciformis, along a fire gradient, in ferric lixisol and cambic arenosol soils. In total, 21 phyla, 51 classes, 98 orders, 193 families, and 520 genera were found, revealing a considerably high and multifunctional diversity with a strong potential for the production of bioactive compounds and nutrient mobilization. Four abundant genera characterized the core microbiome among plant species, type of soils, or fire regime: Streptomyces, Gaiella, Chthoniobacter, and Bacillus. Nevertheless, bacterial networks revealed a higher potential for mutualistic interactions and transmission of chemical signals among phylotypes from low fire frequency sites than those from high fire frequency sites. Ecological networks also revealed the negative effects of frequent fires on the complexity of microbial communities. Functional predictions revealed the core “house-keeping” metabolisms contributing to the high bacterial diversity found, suggesting its importance to the functionality of this ecosystem. Full article
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20 pages, 4767 KiB  
Article
Water Retention Characteristics of Mineral Forest Soils in Finland: Impacts for Modeling Soil Moisture
Forests 2022, 13(11), 1797; https://doi.org/10.3390/f13111797 - 29 Oct 2022
Cited by 1 | Viewed by 2278
Abstract
Soil hydraulic properties are central for soil quality and affect forest productivity and the impacts of climate change on forests. The water retention characteristics (WRC) of mineral forest soils in Finland are not well known, and practical tools to predict them for hydrological, [...] Read more.
Soil hydraulic properties are central for soil quality and affect forest productivity and the impacts of climate change on forests. The water retention characteristics (WRC) of mineral forest soils in Finland are not well known, and practical tools to predict them for hydrological, biogeochemical and forest models are lacking. We statistically analyzed mineral forest soils WRC from over 130 sites in Finland, focusing on the humus layer and main root zone (0–19 cm depth). We showed that mineral forest soils can be grouped into five WRC classes that are well predictable from soil bulk density, organic matter content and clay fraction. However, the majority of the forest soils are hydrologically rather similar. We found that neither topsoil maps nor any combination of open geospatial data were able to predict WRC. Thus, in the absence of site-specific soil data, parameterizing WRC as a function of forest site fertility type was proposed. We demonstrated the approach in soil moisture modeling at a small forest headwater catchment and showed that the soil moisture response to weather conditions is jointly affected by WRC, stand attributes and topography. We showed that drought risks are highest for dense mature forests at nutrient-poor, coarse-textured sites and lower for young stands on peatlands and lowland herb-rich sites with groundwater influence. The results improve hydrological predictions for Finnish forests, and the open dataset can contribute to the larger synthesis and development of boreal forest soil pedo-transfer functions. Full article
(This article belongs to the Special Issue Forest Management, Hydrology and Biogeochemistry Modelling)
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11 pages, 4930 KiB  
Article
Forest Management, Barred Owls, and Wildfire in Northern Spotted Owl Territories
Forests 2022, 13(10), 1730; https://doi.org/10.3390/f13101730 - 20 Oct 2022
Cited by 2 | Viewed by 2535
Abstract
The Northern Spotted Owl (Strix occidentalis caurina) (NSO) was listed as federally threatened in 1992 due to widespread logging of its old-growth forest habitat. The NSO recovery plan in 2011 elevated competition with Barred Owls (Strix varia) (BO) and [...] Read more.
The Northern Spotted Owl (Strix occidentalis caurina) (NSO) was listed as federally threatened in 1992 due to widespread logging of its old-growth forest habitat. The NSO recovery plan in 2011 elevated competition with Barred Owls (Strix varia) (BO) and wildfires as primary NSO threats based partly on the assumption that severely burned forests were no longer NSO nesting and roosting habitat. We quantified amount of logging before and/or after wildfire and opportunistic detections of BOs within two home range scales (0.8 and 2.09 km) at 105 NSO sites that experienced severe wildfire from 2000–2017. Logging affected 87% of severely burned NSO sites, with BO recorded at 22% of burned-and-logged sites. Most (60%) severely burned NSO sites had evidence of logging both before and after fires while only 12% of severely burned sites had no logging or BO detections, indicating rarity of NSO territories subjected to severe fire without the compounding stressors of logging and invasive BOs. We recommend changes to NSO habitat modeling that assume nesting and roosting habitat is no longer viable if severely burned, and to the U.S. Fish and Wildlife Service’s practice of granting incidental take permits for NSOs in logging operations within severely burned owl sites. Full article
(This article belongs to the Special Issue The Extinction Crisis: How Bad, What Can Be Done?)
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25 pages, 3125 KiB  
Article
Critical Aspects of People’s Participation in Community-Based Forest Management from the Case of Van Panchayat in Indian Himalaya
Forests 2022, 13(10), 1667; https://doi.org/10.3390/f13101667 - 11 Oct 2022
Cited by 1 | Viewed by 2147
Abstract
The importance of community-based forest management (hereafter, CBFM) is drawing attention to forest policies in finding solutions for deforestation and importantly to also understand the basis of people’s involvement. Focusing on the latter, the study presented here targets a regional CBFM (Van (forest) [...] Read more.
The importance of community-based forest management (hereafter, CBFM) is drawing attention to forest policies in finding solutions for deforestation and importantly to also understand the basis of people’s involvement. Focusing on the latter, the study presented here targets a regional CBFM (Van (forest) Panchayat; hereafter, VP) at the village level in Uttarakhand, India and looks into characteristics and critical aspect of people’s participation. Participatory observations were conducted in four selected villages, followed by structured interviews with 113 of a total of 131 households and semi-structured interviews with additional 28 female villagers. Some specific findings were (a) the VP members were mostly involved in forest-related activities, e.g., plantation, forest patrols, (b) a greater use of firewood by the management committee (hereafter, MC) where most members were from the higher-caste, and (c) most of the VP forest users were women; however, few women members were involved in decision-making, as they were mostly fixed members and they had not voluntarily chosen their positions. In the above context, it implied a limited participation of women in the decision-making process, i.e., no or little involvement in the management plan by the main VP forest users. Results concluded three stages of local peoples’ participation in forest management: “participation in activities”, “participation in decision-making” and “participation in management plan creation”. In summary, what our study shows is that participation by the VP members in CBFM activities was easy. The most difficult aspect related to the participation of female members was the decision-making process in each VPMC investigated. Full article
(This article belongs to the Section Forest Ecology and Management)
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