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Forests, Volume 12, Issue 7 (July 2021) – 146 articles

Cover Story (view full-size image): The North American beaver (Castor canadensis Kuhl) and cottonwoods (Populus spp.) are foundation species, the interactions of which define a much larger community and affect a threatened riparian habitat type. Few studies have tested the effect of these interactions on plant chemistry and a diverse arthropod community. We experimentally examined the impact of beaver foraging on riparian communities by first investigating beaver food preferences for one cottonwood species, Fremont cottonwood (P. fremontii S. Watson), compared to other locally available woody species. View this paper
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13 pages, 3020 KiB  
Article
Growing Poplar in Acid Soils: Biomass Yield and Ash Behavior
by Cristina Eimil-Fraga, Nerea Oliveira, Luis Ortíz-Torres, Juan Luis Rodríguez-Somoza and Roque Rodríguez-Soalleiro
Forests 2021, 12(7), 960; https://doi.org/10.3390/f12070960 - 20 Jul 2021
Viewed by 1636
Abstract
Atlantic areas of southern Europe have low water restrictions but are also characterized by acid soils with low intrinsic fertility, so the selection of clones that have adapted to these characteristics is essential. In this study, biomass yield data for eight poplar clones [...] Read more.
Atlantic areas of southern Europe have low water restrictions but are also characterized by acid soils with low intrinsic fertility, so the selection of clones that have adapted to these characteristics is essential. In this study, biomass yield data for eight poplar clones established in two trials were evaluated after the first rotation. Both sites were representative of acid soils that had previously been used for agriculture and had low levels of alkali and alkaline earth elements. The first trial was used to determine which clones performed the best in terms of biomass and stem size, testing two Populus × euramericana (Dode) Guinier (I-214 and AF2), two P. × interamericana Van Brokehuizen × P. nigra L. (Monviso, AF6), three P. × interamericana (Unal, Beaupre and Raspalje), and one P. trichocarpa Torr & A. Gray (Trichobel) clone. The second trial explored the possibility of simultaneously growing biomass and timber, specifically considering the Raspalje and Trichobel balsam poplar clones. To complete a previous study on energy properties, nine biomass samples were obtained from each of the eight clones to evaluate the composition and behavior of the ash generated during combustion, particularly the sintering risk. Several indices of sintering risk were explored and compared with the actual sintering using the BioSlag test. The results show large differences in biomass yield between clones, with the balsam poplar derived clones (both hybrid or pure Populus trichocarpa) performing the best. Growth results for stems planted for wood and the cuttings planted in between these stems show that a mixed biomass–timber arrangement provides good results, at least during the first rotation. The relative proportion of oxides in the poplar ash followed the order CaO > K2O > MgO >> P2O5 >> SiO2 > Al2O3 > Na2O > Fe2O5 >> TiO2. Significant differences between clones were found for K2O and MgO. Risk indices showed moderate levels of sintering derived from alkali elements, with significant differences between clones. The actual slagging and the hardness of the slag particles were very low thus, denoting good ash behavior during combustion, particularly for the clones selected for biomass yield. No significant covariate effect of basal diameter was found for any of the analyzed variables. We conclude that growing site-undemanding poplar clones in acid soils can yield both reasonable levels of biomass yield and good quality chips for combustion in domestic thermal systems. Full article
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2 pages, 632 KiB  
Editorial
Modeling the Performance of Wood and Wood Products
by Christian Brischke
Forests 2021, 12(7), 959; https://doi.org/10.3390/f12070959 - 20 Jul 2021
Cited by 1 | Viewed by 1681
Abstract
Wood is an advantageous building material with respect to its material properties, its renewable character, its sustainable production, and its ability to store sequestered carbon [...] Full article
(This article belongs to the Special Issue Modeling the Performance of Wood and Wood Products)
16 pages, 2563 KiB  
Article
Modeling the Diameter Distribution of Mixed Uneven-Aged Stands in the South Western Carpathians in Romania
by Albert Ciceu, Diana Pitar and Ovidiu Badea
Forests 2021, 12(7), 958; https://doi.org/10.3390/f12070958 - 20 Jul 2021
Cited by 7 | Viewed by 2016
Abstract
Tree diameter measurements are repetitive, time-consuming, and laborious but necessary to obtain the diameter distribution of the stands. Tree diameter distribution provides much of the information necessary for sustainable management and can be predicted with high accuracy, thus saving time and financial resources. [...] Read more.
Tree diameter measurements are repetitive, time-consuming, and laborious but necessary to obtain the diameter distribution of the stands. Tree diameter distribution provides much of the information necessary for sustainable management and can be predicted with high accuracy, thus saving time and financial resources. Permanent sample plots that belong to a permanent sampling network located in a protected area in the South Western Carpathians in Romania were used in this study. We compared two theoretical distribution functions and predicted or recovered their parameters using parameter prediction and parameter recovery methods. Five modeling approaches based on maximum likelihood and the method of moments were used to predict the diameter distribution of unmanaged mixed uneven-aged stands. Parameter recovery methods outperformed parameter prediction methods while the left-truncated Weibull distribution outperformed the complete Weibull distribution. The accuracy obtained by the best modeling approach measured by the relative root mean squared error (%RMSE) reaches up to 12.6% when the sums of the diameters are raised to the third power and only 0.02% and 4.8% for the sums of the second powers and the sum of the diameters respectively. This research is the first of this kind in Romania and can serve as an example of alternative solutions to the yield tables in estimating the volume of mixed uneven-aged stands and can be easily implemented into forest growth models to predict the diameter distribution in the absence of tree lists. Full article
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19 pages, 3719 KiB  
Review
A Systematic Review of Best Practices for UAS Data Collection in Forestry-Related Applications
by Connor Cromwell, Jesse Giampaolo, Joseph Hupy, Zachary Miller and Aishwarya Chandrasekaran
Forests 2021, 12(7), 957; https://doi.org/10.3390/f12070957 - 20 Jul 2021
Cited by 12 | Viewed by 2605
Abstract
Recent advancements in unmanned aerial systems and GPS technology, allowing for centimeter precision without ground-based surveys, have been groundbreaking for applications in the field of forestry. As this technology becomes integrated into forest management approaches, it is important to consider the implementation of [...] Read more.
Recent advancements in unmanned aerial systems and GPS technology, allowing for centimeter precision without ground-based surveys, have been groundbreaking for applications in the field of forestry. As this technology becomes integrated into forest management approaches, it is important to consider the implementation of proper safety and data collection strategies. The creation of such documentation is beneficial, because it allows for those aspiring to create a UAS program to learn from others’ experiences, without bearing the consequences of past blunders associated with the development of these practices. When establishing a UAS program, it is pertinent to deeply research the necessary equipment, create documentation that establishes operational norms, and develop standards for in-field operations. Regarding multispectral vs. RGB sensor payloads, the sensor selection should be based upon what type of information is desired from the imagery acquired. It is also important to consider the methods for obtaining the most precise geolocation linked to the aerial imagery collected by the sensor. While selecting the proper UAS platform and sensor are key to establishing a UAS operation, other logistical strategies, such as flight crew training and operational planning, are equally important. Following the acquisition of proper equipment, further preparations must be made in order to ensure safe and efficient operations. The creation of crew resource management and safety management system documentation is an integral part of any successful UAS program. Standard operating procedure documents for individual tasks and undertakings are also a necessity. Standardized practices for the scheduling, communication, and management of the UAS fleet must also be formulated. Once field operations are set in motion, the continuous improvement of the documentation and best practices is paramount. Full article
(This article belongs to the Special Issue Remote Sensing Applications in Forests Inventory and Management)
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13 pages, 1469 KiB  
Article
Macro- and Micronutrient Contents in Soils of a Chronosequence of Naturally Regenerated Birch Stands on Abandoned Agricultural Lands in Central Poland
by Tomasz Gawęda, Stanisław Małek, Ewa Błońska, Andrzej M. Jagodziński, Szymon Bijak and Michał Zasada
Forests 2021, 12(7), 956; https://doi.org/10.3390/f12070956 - 20 Jul 2021
Cited by 3 | Viewed by 1691
Abstract
Abandoned agricultural lands in Central and Northern Europe undergo a quite rapid secondary succession of woody species, especially silver birch (Betula pendula Roth.) as a pioneer tree species. Such a process is desirable both from natural and economic point of views, as [...] Read more.
Abandoned agricultural lands in Central and Northern Europe undergo a quite rapid secondary succession of woody species, especially silver birch (Betula pendula Roth.) as a pioneer tree species. Such a process is desirable both from natural and economic point of views, as afforestation involves a change to the entire ecosystem and, in particular, the transformation of anthropogenic habitats typical for agriculture into habitats similar to a natural forest. In the present study, we report the chemical properties of soils under birch stands that naturally regenerated on abandoned agricultural lands and answer the question of whether silver birch modifies the chemical properties of soils over a (relatively short—17 years) time and with depth in the soil profile. The research investigated the natural secondary succession of silver birch on 28 study plots established as a chronosequence in seven locations in Central Poland. The age of the stands ranged from 2 to 17 years. We analysed the contents of selected micro- and macroelements and heavy metals at three depths in the soil profile. The chemical properties of former agricultural soils covered with newly established silver birch stands, taking into account the depth in the soil profile, demonstrated tendencies to change over the time. In the first age class of birch stands, the stock of investigated nutrients in the soil was higher compared to the following age classes. Statistically significant differences were noted in the case of Cu and Cr. Along with the age of birch stands (age class IV), there was a tendency for stock of the analysed nutrients to grow, which can be associated with an increase in aboveground biomass and root system development. The changes in the contents of the macro- and microelements, as well as heavy metals, were characterised by a gradual increase of the elements analysed in the upper layer of the soil that, in the years following the birch influence on the soil, starts having an effect on the deeper layers. In the case of Cu, Pb, Cd, Ni and Cr, there was a statistically significant change in the depth of the soil. Longer chronosequences should be observed to see a clear trajectory in soil chemistry changes with birch stand ages. Full article
(This article belongs to the Section Forest Ecology and Management)
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33 pages, 7961 KiB  
Article
Stable Coexistence in a Field-Calibrated Individual-Based Model of Mangrove Forest Dynamics Caused by Inter-Specific Crown Plasticity
by Uwe Grueters, Mohd Rodila Ibrahim, Hartmut Schmidt, Katharina Tiebel, Hendrik Horn, Aor Pranchai, Alejandra G. Vovides, Juliane Vogt, Viviana Otero, Behara Satyanarayana and Farid Dahdouh-Guebas
Forests 2021, 12(7), 955; https://doi.org/10.3390/f12070955 - 20 Jul 2021
Cited by 3 | Viewed by 2360
Abstract
(1,2) In this theoretical study, we apply MesoFON, a field-calibrated individual-based model of mangrove forest dynamics, and its Lotka–Volterra interpretations to address two questions: (a) Do the dynamics of two identical red mangrove species that compete for light resources and avoid inter-specific competition [...] Read more.
(1,2) In this theoretical study, we apply MesoFON, a field-calibrated individual-based model of mangrove forest dynamics, and its Lotka–Volterra interpretations to address two questions: (a) Do the dynamics of two identical red mangrove species that compete for light resources and avoid inter-specific competition by lateral crown displacement follow the predictions of classical competition theory or resource competition theory? (b) Which mechanisms drive the dynamics in the presence of inter-specific crown plasticity when local competition is combined with global or with localized seed dispersal? (3) In qualitative support of classical competition theory, the two species can stably coexist within MesoFON. However, the total standing stock at equilibrium matched the carrying capacity of the single species. Therefore, a “non-overyielding” Lotka–Volterra model rather than the classic one approximated best the observed behavior. Mechanistically, inter-specific crown plasticity moved heterospecific trees apart and pushed conspecifics together. Despite local competition, the community exhibited mean-field dynamics with global dispersal. In comparison, localized dispersal slowed down the dynamics by diminishing the strength of intra-/inter-specific competition and their difference due to a restriction in the competitive race to the mean-field that prevails between conspecific clusters. (4) As the outcome in field-calibrated IBMs is mediated by the competition for resources, we conclude that classical competition mechanisms can override those of resource competition, and more species are likely to successfully coexist within communities. Full article
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15 pages, 4527 KiB  
Article
Models for the Evaluation of Productivity and Costs of Mechanized Felling on Poplar Short Rotation Coppice in Italy
by Giulio Sperandio, Andrea Acampora, Angelo Del Giudice and Vincenzo Civitarese
Forests 2021, 12(7), 954; https://doi.org/10.3390/f12070954 - 19 Jul 2021
Cited by 9 | Viewed by 1634
Abstract
The forest biomass, as a renewable energy source, can significantly contribute to the progressive replacement of fossil fuels in energy production, with a positive final balance in terms of greenhouse gas emissions. One of the different sources of woody biomass supply is represented [...] Read more.
The forest biomass, as a renewable energy source, can significantly contribute to the progressive replacement of fossil fuels in energy production, with a positive final balance in terms of greenhouse gas emissions. One of the different sources of woody biomass supply is represented by short rotation coppices (SRC) plantations, currently present in various European countries for a total of about fifty thousand hectares. In Italy, part of the SRC surface has been converted into other more profitable crops, both the low levels reached by the woodchips market price and the scarce availability of specific public incentives. In this study, the authors expose the results of the models for evaluating work time, productivity, and costs of the felling operation on SRC poplar plantations with 8- and 11-year-old trees. The aim is to evaluate the economic sustainability in the use of advanced mechanization on these plantations. The machine was a crawler excavator equipped with a shear head. In the 11-year-old plantation, the productivity estimation model returned a range of 1.09–18.93 Mg h−1 (average 5.56 ± 3.88 SD) when the weight variation of the trees was 20–491 kgw (average 100.41 ± 87.48 SD). In the 8-year-old poplar, the range was 1.02–11.60 Mg h−1 (average 3.80 ± 1.71 SD), for weight variation of 17–137 kgw (average 50.57 ± 18.82 SD). The consequent variation in unit cost was EUR 2.82–51.63 Mg−1 and EUR 4.05–49.65 Mg−1, corresponding to EUR 1252.17–3463.78 ha−1 and EUR 922.49–2545.11 ha−1 for 11- and 8-year-old trees, respectively. Full article
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17 pages, 2380 KiB  
Article
Evaluation of Long-Term Shortleaf Pine Progeny Tests in the Ouachita and Ozark National Forests, USA
by Shaik M. Hossain, Don C. Bragg, Virginia L. McDaniel, Carolyn C. Pike, Barbara S. Crane and C. Dana Nelson
Forests 2021, 12(7), 953; https://doi.org/10.3390/f12070953 - 19 Jul 2021
Viewed by 1371
Abstract
Between the late 1970s and the early 1990s, the USDA Forest Service installed 155 shortleaf pine (Pinus echinata Mill.) progeny tests in national forests across the Southern Region of the United States. Using control-pollinated crosses from the Mount Ida Seed Orchard, 84 [...] Read more.
Between the late 1970s and the early 1990s, the USDA Forest Service installed 155 shortleaf pine (Pinus echinata Mill.) progeny tests in national forests across the Southern Region of the United States. Using control-pollinated crosses from the Mount Ida Seed Orchard, 84 of these progeny tests were established in the Ouachita and Ozark-St. Francis National Forests in Arkansas and Oklahoma. Each of these 84 test locations had, on average, 33 full-sibling families representing three local geographic seed sources (East Ouachita, West Ouachita, and Ozark). Though largely abandoned years ago, the progeny tests that remain provided an opportunity to determine if significant genetic and genetic × environment variance exists for performance traits (d.b.h., tree height, and survival) decades after installation. In 2018 and 2019, we remeasured d.b.h. and height and determined survival in 15 fully stocked progeny tests. Family variances were significant (p < 0.01) for both d.b.h. and height but not for survival (p > 0.05). Seed sources differed significantly (p < 0.05) for d.b.h., with more pronounced latitudinal differences. Additionally, we determined that individual tree and full-sibling family mean heritabilities were moderate (0.15 and 0.72, respectively, for d.b.h and 0.09 and 0.41, for height), suggesting relatively high genetic to environmental variation and good potential for genetic improvement. We also found that shortleaf pine families were broadly adapted in this region since family-by-test variances were non-significant (p > 0.05). Full article
(This article belongs to the Section Genetics and Molecular Biology)
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15 pages, 1857 KiB  
Article
Seasonal Changes and the Interaction between the Horse Chestnut Leaf Miner Cameraria ohridella and Horse Chestnut Leaf Blotch Disease Caused by Guignardia aesculi
by Michal Kopačka, Gösta Nachman and Rostislav Zemek
Forests 2021, 12(7), 952; https://doi.org/10.3390/f12070952 - 19 Jul 2021
Cited by 7 | Viewed by 2292
Abstract
The horse chestnut leaf miner Cameraria ohridella (Lepidoptera: Gracillariidae) is an invasive pest of horse chestnut Aesculus hippocastanum (Sapindales: Sapindaceae) and has spread through Europe since 1985. Horse chestnut leaf blotch is a fungal disease caused by Guignardia aesculi (Botryosphaeriales: Botryosphaeriaceae) that also [...] Read more.
The horse chestnut leaf miner Cameraria ohridella (Lepidoptera: Gracillariidae) is an invasive pest of horse chestnut Aesculus hippocastanum (Sapindales: Sapindaceae) and has spread through Europe since 1985. Horse chestnut leaf blotch is a fungal disease caused by Guignardia aesculi (Botryosphaeriales: Botryosphaeriaceae) that also seriously damages horse chestnut trees in Europe. The interaction between the leaf miner and the fungus has not yet been sufficiently described. Therefore, the aim of the present study was to assess leaf damage inflicted to horse chestnut by both C. ohridella and G. aesculi during the vegetation season and to model their interaction. The damage to leaf area was measured monthly from May to September 2013 in České Budějovice, the Czech Republic using digital image analysis of sampled leaves. A simple phenomenological model describing the expected dynamics of the two species was developed. The study revealed that the damage caused by both the pests and the fungus varied significantly among sampling sites within the city. The overall leaf damage exceeded 50% in no-raking sites in August. The mathematical model indicates that infestation by C. ohridella is more affected by G. aesculi than vice versa. Guignardia aesculi is thus the superior competitor of the two species. Our findings highlight the delicate interplay between insect pests and fungal pathogens and the spatiotemporal dynamics influencing them, calling for more research in this understudied area. Full article
(This article belongs to the Special Issue Pests and Pathogens of Urban Trees)
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18 pages, 3853 KiB  
Article
Bioclimatic Suitability of Actual and Potential Cultivation Areas for Jacaranda mimosifolia in Chinese Cities
by Chunping Xie, Guowu Zhang, Chiyung Jim, Xuefeng Liu, Peijian Zhang, Jianhuang Qiu and Dawei Liu
Forests 2021, 12(7), 951; https://doi.org/10.3390/f12070951 - 19 Jul 2021
Cited by 8 | Viewed by 2495
Abstract
Jacaranda mimosifolia is regarded as a prized ornamental tree in the urban landscape with attractive, abundant and long-lasting violet-colored flowers and graceful tree form. It has been widely cultivated in recent years in many Chinese cities. However, the lack of scientific and practical [...] Read more.
Jacaranda mimosifolia is regarded as a prized ornamental tree in the urban landscape with attractive, abundant and long-lasting violet-colored flowers and graceful tree form. It has been widely cultivated in recent years in many Chinese cities. However, the lack of scientific and practical guidance to cultivate the exotic species has brought about planting failures in some areas, incurring substantial economic losses and landscape decline. A comprehensive understanding of the current spatial pattern and climatic conditions of J. mimosifolia in China can inform species choice, planting and management. We collected data on the geographical coordinates of 257 planting cities and acquired additional information from the literature and field surveys. The limiting factors for cultivation were investigated using principal component analysis (PCA) of 19 bioclimatic parameters of the sampled sites. The potentially suitable habitats were predicted by BIOCLIM modeling using eight selected ecological-important climatic parameters. We found that the present cultivated areas were focused in the low-altitude parts of the subtropical zone, mainly covering the provinces of Yunnan, Sichuan, Guangxi, Guangdong and Fujian. The PCA results indicated that temperature was the clinching determinant of the current cultivation patterns, especially annual mean temperature, the minimum temperature of the coldest month and the mean temperature of the warmest quarter. Moisture was a necessary but not critical secondary factor. The predicting model for potential habitats was graded as “excellent” by objective validation measures. The findings can provide science-based evidence to plan the expansion of the biogeographical range of cultivation into hitherto unplanted cities and rationalize urban tree introduction and management practices. Full article
(This article belongs to the Section Urban Forestry)
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7 pages, 992 KiB  
Article
Native or Invasive? The Red-Haired Pine Bark Beetle Hylurgus ligniperda (Fabricius) (Curculionidae: Scolytinae) in East Asia
by Wei Lin, Sangwook Park, Zi-Ru Jiang, Ying-Chao Ji, Andris Simon Ernstsons, Jun-Jun Li, You Li and Jiri Hulcr
Forests 2021, 12(7), 950; https://doi.org/10.3390/f12070950 - 19 Jul 2021
Cited by 8 | Viewed by 3088
Abstract
The red-haired pine bark beetle, Hylurgus ligniperda (Fabricius), is one of the most rapidly spreading invasive forest insects. Originally from Eurasia, it has subsequently been introduced to Oceania, North, and South America. Yet, the status of H. ligniperda in East Asia is ambiguous. [...] Read more.
The red-haired pine bark beetle, Hylurgus ligniperda (Fabricius), is one of the most rapidly spreading invasive forest insects. Originally from Eurasia, it has subsequently been introduced to Oceania, North, and South America. Yet, the status of H. ligniperda in East Asia is ambiguous. Here, investigation and analysis were conducted on the beetle in China, South Korea, and Japan. New occurrences in China and South Korea were recorded by field surveys and the expansion of H. ligniperda spreading in East Asia was analyzed. The results show that H. ligniperda is likely an invasive species in East Asia, initially invading Japan, then South Korea. Now it has invaded and successfully colonized Shandong province, China. Furthermore, the species has spread rapidly and it is now widely distributed in South Korea and Japan. Full article
(This article belongs to the Special Issue Diversity and Distribution of Forest Insects)
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5 pages, 654 KiB  
Editorial
Recent Advances in Nondestructive Evaluation of Wood: In-Forest Wood Quality Assessments
by Xiping Wang
Forests 2021, 12(7), 949; https://doi.org/10.3390/f12070949 - 19 Jul 2021
Cited by 5 | Viewed by 1845
Abstract
Efficient wood production and utilization requires knowing the wood quality attributes of forest resources relevant to various end uses, prescribing appropriate silvicultural treatments that positively influence wood quality, and then, at the time of harvesting, sorting and allocating standing timbers to the most [...] Read more.
Efficient wood production and utilization requires knowing the wood quality attributes of forest resources relevant to various end uses, prescribing appropriate silvicultural treatments that positively influence wood quality, and then, at the time of harvesting, sorting and allocating standing timbers to the most appropriate markets [...] Full article
14 pages, 2538 KiB  
Article
Phenotypic Variability and Differences in the Drought Response of Norway Spruce Pendula and Pyramidalis Half-Sib Families
by Marius Budeanu, Ecaterina Nicoleta Apostol, Emanuel Besliu, Vlad Emil Crișan and Any Mary Petritan
Forests 2021, 12(7), 947; https://doi.org/10.3390/f12070947 - 19 Jul 2021
Cited by 5 | Viewed by 1874
Abstract
In a changing climate, forest managers need to select productive and climate-change-resilient tree species and provenances. Therefore, assessing the growth response of provenances growing in field trials to climate provides useful information for identifying the more appropriate provenance or variety. To determine the [...] Read more.
In a changing climate, forest managers need to select productive and climate-change-resilient tree species and provenances. Therefore, assessing the growth response of provenances growing in field trials to climate provides useful information for identifying the more appropriate provenance or variety. To determine the genetic gain through selection of the most productive and resilient families and to decipher the role of crown forms of Norway spruces (Picea abies (L.) Karst.), we used 24 families with a classical crown (pyramidalis) and 24 with a narrow crown (pendula) from eight provenances, growing in a 25-year-old comparative trial. The annual wood characteristics (ring width and early- and latewood), the wood resistance (expressed by latewood proportion (LWP)), and the growth response to climate of the two spruce crown forms were investigated. No significant differences between the two spruce forms were found regarding the ring width characteristics. However, three pendula families of Stâna de Vale I provenance exhibited the highest LWP and could be included in a future selection strategy, the respective trait having also high heritability. Radial growth was positively and significantly correlated with previous September and current July precipitation and negatively with current June temperature. Both spruce forms showed good recovery capacity after a drought event. Full article
(This article belongs to the Section Genetics and Molecular Biology)
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13 pages, 1633 KiB  
Review
The Erythrina Gall Wasp Quadrastichus erythrinae (Insecta: Hymenoptera: Eulophidae): Invasion History, Ecology, Infestation and Management
by Sheng-Feng Lin, Gene-Sheng Tung and Man-Miao Yang
Forests 2021, 12(7), 948; https://doi.org/10.3390/f12070948 - 18 Jul 2021
Cited by 7 | Viewed by 3015
Abstract
The Erythrina gall wasp Quadrastichus erythrinae Kim (Hymenoptera: Eulophidae) is an invasive insect that induces galls on coral trees (species of Erythrina, Fabaceae) in urban and suburban landscapes. Weakening and death of the tree were both observed after the infestation by this [...] Read more.
The Erythrina gall wasp Quadrastichus erythrinae Kim (Hymenoptera: Eulophidae) is an invasive insect that induces galls on coral trees (species of Erythrina, Fabaceae) in urban and suburban landscapes. Weakening and death of the tree were both observed after the infestation by this insect, wherein feeding and consequent draining of nutrients by a large population of Q. erythrinae could be playing a key role. In this article, we consolidate and summarize the information on the distribution, invasion route, ecology, infestation level, and management of Q. erythrinae populations in the last two decades and analyze the challenges in their management. Full article
(This article belongs to the Special Issue Pests and Pathogens of Urban Trees)
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19 pages, 4229 KiB  
Article
Professionals’ Feedback on the PEFC Fair Supply Chain Project Activated in Italy after the “Vaia” Windstorm
by Francesco Negro, Omar Espinoza, Antonio Brunori, Corrado Cremonini and Roberto Zanuttini
Forests 2021, 12(7), 946; https://doi.org/10.3390/f12070946 - 17 Jul 2021
Cited by 3 | Viewed by 1738
Abstract
In the fall of 2018, the “Vaia” windstorm grounded around 8.5 million m3 of timber in northeastern Italy. Soon after, the Programme for the Endorsement of Forest Certification (PEFC) Italy activated a project called “fair supply chain” to promote the purchase of [...] Read more.
In the fall of 2018, the “Vaia” windstorm grounded around 8.5 million m3 of timber in northeastern Italy. Soon after, the Programme for the Endorsement of Forest Certification (PEFC) Italy activated a project called “fair supply chain” to promote the purchase of timber from the damaged areas at a reasonable price. The initiative was addressed at forest owners, forest and processing enterprises, retailers, and supporting organizations. This study reports the results of a survey performed to assess the effectiveness of the project two years after its launch. The survey, in the form of a questionnaire submitted to all adhering organizations, investigated different aspects such as motivations for adherence to the project, satisfaction with the project, sale of the labeled material, and promotion of the specific label. The results provide a detailed outline of the above aspects. Through the various findings, the project is perceived as effective in supporting the region, enhancing an organizations’ image, and limiting price fall. Yet, further efforts should be aimed at increasing networking and business opportunities. Some recommendations are also offered for similar projects in the future, as forest disturbances are increasing worldwide in frequency and intensity due to climate change. Full article
(This article belongs to the Special Issue Wood Production and Promotion)
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16 pages, 2373 KiB  
Article
Antagonistic Potential of Native Trichoderma spp. against Phytophthora cinnamomi in the Control of Holm Oak Decline in Dehesas Ecosystems
by Francisco J. Ruiz-Gómez and Cristina Miguel-Rojas
Forests 2021, 12(7), 945; https://doi.org/10.3390/f12070945 - 17 Jul 2021
Cited by 7 | Viewed by 3313
Abstract
Phytophthora root rot caused by the pathogen Phytophthora cinnamomi is one of the main causes of oak mortality in Mediterranean open woodlands, the so-called dehesas. Disease control is challenging; therefore, new alternative measures are needed. This study focused on searching for natural biocontrol [...] Read more.
Phytophthora root rot caused by the pathogen Phytophthora cinnamomi is one of the main causes of oak mortality in Mediterranean open woodlands, the so-called dehesas. Disease control is challenging; therefore, new alternative measures are needed. This study focused on searching for natural biocontrol agents with the aim of developing integrated pest management (IPM) strategies in dehesas as a part of adaptive forest management (AFM) strategies. Native Trichoderma spp. were selectively isolated from healthy trees growing in damaged areas by P. cinnamomi root rot, using Rose Bengal selective medium. All Trichoderma (n = 95) isolates were evaluated against P. cinnamomi by mycelial growth inhibition (MGI). Forty-three isolates presented an MGI higher than 60%. Twenty-one isolates belonging to the highest categories of MGI were molecularly identified as T. gamsii, T. viridarium, T. hamatum, T. olivascens, T. virens, T. paraviridescens, T. linzhiense, T. hirsutum, T. samuelsii, and T. harzianum. Amongst the identified strains, 10 outstanding Trichoderma isolates were tested for mycoparasitism, showing values on a scale ranging from 3 to 4. As far as we know, this is the first report referring to the antagonistic activity of native Trichoderma spp. over P. cinnamomi strains cohabiting in the same infected dehesas. The analysis of the tree health status and MGI suggest that the presence of Trichoderma spp. might diminish or even avoid the development of P. cinnamomi, protecting trees from the worst effects of P. cinnamomi root rot. Full article
(This article belongs to the Special Issue Adaptive Forest Management to Climatic Change)
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16 pages, 3342 KiB  
Article
Growing Stock Volume Retrieval from Single and Multi-Frequency Radar Backscatter
by Mihai A. Tanase, Ignacio Borlaf-Mena, Maurizio Santoro, Cristina Aponte, Gheorghe Marin, Bogdan Apostol and Ovidiu Badea
Forests 2021, 12(7), 944; https://doi.org/10.3390/f12070944 - 17 Jul 2021
Cited by 4 | Viewed by 2285
Abstract
While products generated at global levels provide easy access to information on forest growing stock volume (GSV), their use at regional to national levels is limited by temporal frequency, spatial resolution, or unknown local errors that may be overcome through locally calibrated products. [...] Read more.
While products generated at global levels provide easy access to information on forest growing stock volume (GSV), their use at regional to national levels is limited by temporal frequency, spatial resolution, or unknown local errors that may be overcome through locally calibrated products. This study assessed the need, and utility, of developing locally calibrated GSV products for the Romanian forests. To this end, we used national forest inventory (NFI) permanent sampling plots with largely concurrent SAR datasets acquired at C- and L-bands to train and validate a machine learning algorithm. Different configurations of independent variables were evaluated to assess potential synergies between C- and L-band. The results show that GSV estimation errors at C- and L-band were rather similar, relative root mean squared errors (RelRMSE) around 55% for forests averaging over 450 m3 ha−1, while synergies between the two wavelengths were limited. Locally calibrated models improved GSV estimation by 14% when compared to values obtained from global datasets. However, even the locally calibrated models showed particularly large errors over low GSV intervals. Aggregating the results over larger areas considerably reduced (down to 25%) the relative estimation errors. Full article
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40 pages, 5697 KiB  
Review
Decision Support System Development of Wildland Fire: A Systematic Mapping
by Felipe Vásquez, Ania Cravero, Manuel Castro and Patricio Acevedo
Forests 2021, 12(7), 943; https://doi.org/10.3390/f12070943 - 17 Jul 2021
Cited by 10 | Viewed by 3294
Abstract
Wildland fires have been a rising problem on the worldwide level, generating ecological and economic losses. Specifically, between wildland fire types, uncontrolled fires are critical due to the potential damage to the ecosystem and their effects on the soil, and, in the last [...] Read more.
Wildland fires have been a rising problem on the worldwide level, generating ecological and economic losses. Specifically, between wildland fire types, uncontrolled fires are critical due to the potential damage to the ecosystem and their effects on the soil, and, in the last decade, different technologies have been applied to fight them. Selecting a specific technology and Decision Support Systems (DSS) is fundamental, since the results and validity of this could drastically oscillate according to the different environmental and geographic factors of the terrain to be studied. Given the above, a systematic mapping was realized, with the purpose of recognizing the most-used DSS and context where they have been applied. One hundred and eighty-three studies were found that used different types of DSS to solve problems of detection, prediction, prevention, monitoring, simulation, administration, and access to routes. The concepts key to the type of solution are related to the use or development of systems or Information and Communication Technologies (ICT) in the computer science area. Although the use of BA and Big Data has increased in recent years, there are still many challenges to face, such as staff training, the friendly environment of DSS, and real-time decision-making. Full article
(This article belongs to the Special Issue Decision Support System Development of Wildland Fire)
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12 pages, 1901 KiB  
Article
Marked Differences in Butterfly Assemblage Composition between Forest Types in Central Amazonia, Brazil
by Isabela Freitas Oliveira, Fabricio Beggiato Baccaro, Fernanda P. Werneck, Thamara Zacca and Torbjørn Haugaasen
Forests 2021, 12(7), 942; https://doi.org/10.3390/f12070942 - 17 Jul 2021
Cited by 7 | Viewed by 2231
Abstract
Amazonia comprises a mosaic of contrasting habitats, with wide environmental heterogeneity at local and regional scales. In central Amazonia, upland forest (terra firme) is the predominant forest type and seasonally flooded forests inundated by white- and black-water rivers (várzea and [...] Read more.
Amazonia comprises a mosaic of contrasting habitats, with wide environmental heterogeneity at local and regional scales. In central Amazonia, upland forest (terra firme) is the predominant forest type and seasonally flooded forests inundated by white- and black-water rivers (várzea and igapó, respectively) represent around 20% of the forested areas. In this work, we took advantage of a natural spatial arrangement of the main vegetation types in central Amazonia to investigate butterfly assemblage structure in terra firme, várzea and igapó forests at the local scale. We sampled in the low- and high-water seasons, combining active and passive sampling with traps placed in both the understory and canopy. Terra firme supported the highest number of butterfly species, whereas várzea forest provided the highest number of butterfly captures. The high species richness in terra firme may reflect that this forest type is floristically richer than várzea and igapó. Várzea is a very productive environment and may thus support a higher number of butterfly individuals than terra firme and igapó. Most butterfly species (80.2%) were unique to a single forest type and 17 can be considered forest type indicator species in this landscape. Floodplain forest environments are therefore an important complement to terra firme in terms of butterfly species richness and conservation in Amazonia. Full article
(This article belongs to the Special Issue Structure, Function, and Dynamics of Tropical Floodplain Forests)
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11 pages, 1223 KiB  
Article
Felled and Lure Trap Trees with Uncut Branches Are Only Weakly Attractive to the Double-Spined Bark Beetle, Ips duplicatus
by Vojtěch Šotola, Jaroslav Holuša, Karel Kuželka and Emanuel Kula
Forests 2021, 12(7), 941; https://doi.org/10.3390/f12070941 - 17 Jul 2021
Cited by 5 | Viewed by 1784
Abstract
Bark beetles are the most important forest pests in the Northern Hemisphere. The range of Ips duplicatus, an invasive bark beetle in central Europe, has been steadily expanding, and it is now responsible for a high proportion of the spruce wood infested [...] Read more.
Bark beetles are the most important forest pests in the Northern Hemisphere. The range of Ips duplicatus, an invasive bark beetle in central Europe, has been steadily expanding, and it is now responsible for a high proportion of the spruce wood infested by bark beetles. Apart from searching for and eliminating infested trees, there is no effective control method. The aim of this study was to determine whether trap trees with a pheromone evaporator can be used to capture I. duplicatus. Felled trap trees with branches and with pheromone lures (ID Ecolure®) were infested by I. duplicatus, at a median density of 1 nuptial chambers per 0.1 m2 (median); similar trees without lures and lying at a distance of 1, 5, or 10 m from the lure trees were rarely infested by I. duplicatus. The entire surface of the lure trees could capture <400 beetles per tree. The results indicate that lure trap trees (felled and with branches attached) could only be used in a limited number of situations; one such situation would involve forests that suffered wind damage and contained very high numbers of I. duplicatus. Full article
(This article belongs to the Special Issue Insect Pest Management in Forest Ecosystems)
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13 pages, 7645 KiB  
Article
Climate Connectivity of European Forests for Species Range Shifts
by Qiyao Han, Greg Keeffe and Sean Cullen
Forests 2021, 12(7), 940; https://doi.org/10.3390/f12070940 - 17 Jul 2021
Cited by 2 | Viewed by 2255
Abstract
Forest connectivity is important for the range shifts and long-term persistence of forest-dependent species, especially in the context of climate change. This study assessed the climate connectivity of European forests for species to track suitable climate conditions as the climate warms. Here, climate [...] Read more.
Forest connectivity is important for the range shifts and long-term persistence of forest-dependent species, especially in the context of climate change. This study assessed the climate connectivity of European forests for species to track suitable climate conditions as the climate warms. Here, climate connectivity was calculated as the temperature difference between each forest patch and the coolest patch that can be reached along temperature gradients. We found that, overall, about 36% of the total forested area in Europe has achieved successful climate connectivity under the moderate emission scenario (SSP245), whereby species range shifts could circumvent the impact of climate warming. The percentage is much lower under the highest emission scenario (SSP585), which is only 12%. To identify forest areas of high importance for climate connectivity, we further evaluated the potential of each forest patch to serve as a stepping stone for species range shifts. Our results showed that about 94% of the European forested area is expected to experience species range shifts. Our study identified sites of high conservation value for improving and sustaining forest connectivity to facilitate climate-driven range shifts and thus could provide information for climate-smart management of European forests. Full article
(This article belongs to the Section Forest Ecology and Management)
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14 pages, 4456 KiB  
Article
Effects of Elevated CO2 and Nitrogen Loading on the Defensive Traits of Three Successional Deciduous Broad-Leaved Tree Seedlings
by Yoko Watanabe, Kiyomi Hinata, Laiye Qu, Satoshi Kitaoka, Makoto Watanabe, Mitsutoshi Kitao and Takayoshi Koike
Forests 2021, 12(7), 939; https://doi.org/10.3390/f12070939 - 16 Jul 2021
Cited by 6 | Viewed by 1894
Abstract
To elucidate changes in the defensive traits of tree seedlings under global environmental changes, we evaluated foliar defensive traits of the seedlings of successional trees, such as beech, oak, and magnolia grown in a natural-light phytotron. Potted seedlings were grown under the combination [...] Read more.
To elucidate changes in the defensive traits of tree seedlings under global environmental changes, we evaluated foliar defensive traits of the seedlings of successional trees, such as beech, oak, and magnolia grown in a natural-light phytotron. Potted seedlings were grown under the combination of two CO2 concentrations (360 vs. 720 ppm) and two nitrogen (N) treatments (4 vs. 15 kg N ha−1 yr−1) for two growing seasons using quantitative chemical analyses and anatomical method. We hypothesized that the effects of CO2 and N depend on the successional type, with late successional species providing greater defense of their leaves against herbivores, as this species exhibits determinate growth. Beech, a late successional species, responded the most to both elevated CO2 concentration (eCO2) and high N treatment. eCO2 and low N supply enhanced the defensive traits, such as the high leaf mass per area (LMA), high carbon to N ratio (C/N ratio), and increase in the concentrations of total phenolic and condensed tannin in agreement with the carbon–nutrient balance (CNB) hypothesis. High N supply decreased the C/N ratio due to the high N uptake in beech leaves. Oak, a mid–late successional species, exhibited different responses from beech: eCO2 enhanced the LMA, C/N ratio, and concentration of total phenolics of oak leaves, but only condensed tannin increased under high N supply. Magnolia did not respond to all treatments. No interactive effects were observed between CO2 and N supply in all species, except for the concentration of total phenolics in oak. Although the amounts of phenolic compounds in beech and oak varied under eCO2 and high N treatments, the distribution of these compounds did not change. Our results indicate that the changes in the defensive traits of forest tree species under eCO2 with N loading are related to the successional type. Full article
(This article belongs to the Special Issue Ecophysiology of Forest Succession under Changing Environment)
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16 pages, 2423 KiB  
Article
The Role of Canopy Cover Dynamics over a Decade of Changes in the Understory of an Atlantic Beech-Oak Forest
by Mercedes Valerio, Ricardo Ibáñez and Antonio Gazol
Forests 2021, 12(7), 938; https://doi.org/10.3390/f12070938 - 16 Jul 2021
Cited by 9 | Viewed by 2535 | Correction
Abstract
The understory of temperate forests harbour most of the plant species diversity present in these ecosystems. The maintenance of this diversity is strongly dependent on canopy gap formation, a disturbance naturally happening in non-managed forests, which promotes spatiotemporal heterogeneity in understory conditions. This, [...] Read more.
The understory of temperate forests harbour most of the plant species diversity present in these ecosystems. The maintenance of this diversity is strongly dependent on canopy gap formation, a disturbance naturally happening in non-managed forests, which promotes spatiotemporal heterogeneity in understory conditions. This, in turn, favours regeneration dynamics, functioning and structural complexity by allowing changes in light, moisture and nutrient availability. Our aim is to study how gap dynamics influence the stability of understory plant communities over a decade, particularly in their structure and function. The study was carried out in 102 permanent plots (sampled in 2006 and revisited in 2016) distributed throughout a 132 ha basin located in a non-managed temperate beech-oak forest (Bertiz Natural Park, Spain). We related changes in the taxonomical and functional composition and diversity of the understory vegetation to changes in canopy coverage. We found that gap dynamics influenced the species composition and richness of the understory through changes in light availability and leaf litter cover. Species with different strategies related to shade tolerance and dispersion established in the understory following the temporal evolution of gaps. However, changes in understory species composition in response to canopy dynamics occur at a slow speed in old-growth temperate forests, needing more than a decade to really be significant. The presence of gaps persisting more than ten years is essential for maintaining the heterogeneity and stability of understory vegetation in old-growth temperate forests. Full article
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15 pages, 4117 KiB  
Article
A Novel Multi-Scale Attention PFE-UNet for Forest Image Segmentation
by Boyang Zhang, Hongbo Mu, Mingyu Gao, Haiming Ni, Jianfeng Chen, Hong Yang and Dawei Qi
Forests 2021, 12(7), 937; https://doi.org/10.3390/f12070937 - 16 Jul 2021
Cited by 5 | Viewed by 2047
Abstract
The precise segmentation of forest areas is essential for monitoring tasks related to forest exploration, extraction, and statistics. However, the effective and accurate segmentation of forest images will be affected by factors such as blurring and discontinuity of forest boundaries. Therefore, a Pyramid [...] Read more.
The precise segmentation of forest areas is essential for monitoring tasks related to forest exploration, extraction, and statistics. However, the effective and accurate segmentation of forest images will be affected by factors such as blurring and discontinuity of forest boundaries. Therefore, a Pyramid Feature Extraction-UNet network (PFE-UNet) based on traditional UNet is proposed to be applied to end-to-end forest image segmentation. Among them, the Pyramid Feature Extraction module (PFE) is introduced in the network transition layer, which obtains multi-scale forest image information through different receptive fields. The spatial attention module (SA) and the channel-wise attention module (CA) are applied to low-level feature maps and PFE feature maps, respectively, to highlight specific segmentation task features while fusing context information and suppressing irrelevant regions. The standard convolution block is replaced by a novel depthwise separable convolutional unit (DSC Unit), which not only reduces the computational cost but also prevents overfitting. This paper presents an extensive evaluation with the DeepGlobe dataset and a comparative analysis with several state-of-the-art networks. The experimental results show that the PFE-UNet network obtains an accuracy of 94.23% in handling the real-time forest image segmentation, which is significantly higher than other advanced networks. This means that the proposed PFE-UNet also provides a valuable reference for the precise segmentation of forest images. Full article
(This article belongs to the Special Issue Applications of Satellite Data for Forest Monitoring and Management)
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5 pages, 994 KiB  
Communication
Invasive vs. Invasive, Parthenium hysterophorus as a Bio-Control Agent against Invasive Mealybugs
by Taswar Ahsan, Bingxue Li and Yuanhua Wu
Forests 2021, 12(7), 936; https://doi.org/10.3390/f12070936 - 16 Jul 2021
Cited by 1 | Viewed by 1572
Abstract
Parthenium hysterophorus has an antagonistic potential against mealybugs, which are hosted on wild Dalbergia sissoo. In the current study, an aqueous extract of Parthenium was evaluated against mealybugs on Dalbergia sissoo. A serial dose of 12.5, 25, 50, 100, 200, and [...] Read more.
Parthenium hysterophorus has an antagonistic potential against mealybugs, which are hosted on wild Dalbergia sissoo. In the current study, an aqueous extract of Parthenium was evaluated against mealybugs on Dalbergia sissoo. A serial dose of 12.5, 25, 50, 100, 200, and 500 µg/mL of aqueous extract was prepared from all parts of the Parthenium plant. After 72 h at high doses, 200 µg/mL and 500 µg/mL aqueous extracts had high mortality of 76.67% and 73.33% via the residual method, respectively. Meanwhile at same dose after 72 h, the contact method had higher mortality percentages of 80% and 80% at 200 µg/mL and 500 µg/mL, respectively. After 48 h at a high dose (200 µg/mL and 500 µg/mL), the mortality of the mealybugs was highest via the contact method. The results show a mortality of 73.33% with both doses. Meanwhile the same doses, via the contact method, after 48 h had a 63.33% mortality rate. After 24 h via the contact method, at 200 µg/mL and 500 µg/mL the mortality of mealybug was 70% with both doses, whereas via the mortality rate via the residual method at 200 µg/mL and 500 µg/mL doses was 56.67% and 66.67%, respectively. These results indicate that Parthenium is a strong bio-control agent against mealybugs. Aqueous extracts could lead to a cost effective and environmentally friendly insecticidal for sustainable use in large scale forestry. Full article
(This article belongs to the Special Issue Biological Control in Forests Protection)
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17 pages, 1783 KiB  
Article
Competition Effects on Growth and Crown Dimensions of Shortleaf and Loblolly Pine in Mature, Natural-Origin, Pine–Hardwood Mixtures of the Upper West Gulf Coastal Plain of Arkansas, USA: A Neighborhood Analysis
by Mohammad Bataineh and Ethan Childs
Forests 2021, 12(7), 935; https://doi.org/10.3390/f12070935 - 16 Jul 2021
Cited by 2 | Viewed by 1540
Abstract
The need for a comprehensive and mechanistic understanding of competition has never been more important as plants adapt to a changing environment and as forest management evolves to focus on maintaining and enhancing complexity. With the recent decline in shortleaf pine (Pinus [...] Read more.
The need for a comprehensive and mechanistic understanding of competition has never been more important as plants adapt to a changing environment and as forest management evolves to focus on maintaining and enhancing complexity. With the recent decline in shortleaf pine (Pinus echinata Mill.) land area, it is critical to determine the effects of competition on shortleaf pine and its performance against loblolly pine (Pinus taeda L.), the preferred planted replacement. We evaluate differences in shortleaf and loblolly pine 10 year mean basal area increment (BAI) and crown dimensions across a gradient of neighborhoods. Linear mixed-effects regression models were developed using BAI and several crown metrics as responses and crowding, competitor species abundance and identity, and initial size and species identity of focal tree as predictors. Crowding of focal trees negatively impacted BAI and crown size (p < 0.001, respectively). Although loblolly pine had three times higher BAI as compared to shortleaf pine within similar neighborhoods, BAI was variable, and the crowding effect did not differ between shortleaf and loblolly pine (p ranged from 0.51–0.99). Competitive impacts on focal trees did not differ by competitor identity (p ranged from 0.07–0.70). Distance-independent competition indices better explained the variation in BAI and horizontal crown metrics, while distance-dependent size ratios were more effective at evaluating vertical crown metrics. These findings highlight shortleaf pine competitive potential in mature, natural-origin stands and provide support for the restoration of pine–hardwood and hardwood–pine stratified mixtures as well as management of shortleaf pine at long rotations. Full article
(This article belongs to the Section Forest Health)
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20 pages, 5208 KiB  
Article
Hazards of Risk: Identifying Plausible Community Wildfire Disasters in Low-Frequency Fire Regimes
by Andy McEvoy, Becky K. Kerns and John B. Kim
Forests 2021, 12(7), 934; https://doi.org/10.3390/f12070934 - 16 Jul 2021
Cited by 12 | Viewed by 3349
Abstract
Optimized wildfire risk reduction strategies are generally not resilient in the event of unanticipated, or very rare events, presenting a hazard in risk assessments which otherwise rely on actuarial, mean-based statistics to characterize risk. This hazard of actuarial approaches to wildfire risk is [...] Read more.
Optimized wildfire risk reduction strategies are generally not resilient in the event of unanticipated, or very rare events, presenting a hazard in risk assessments which otherwise rely on actuarial, mean-based statistics to characterize risk. This hazard of actuarial approaches to wildfire risk is perhaps particularly evident for infrequent fire regimes such as those in the temperate forests west of the Cascade Range crest in Oregon and Washington, USA (“Westside”), where fire return intervals often exceed 200 years but where fires can be extremely intense and devastating. In this study, we used wildfire simulations and building location data to evaluate community wildfire exposure and identify plausible disasters that are not based on typical mean-based statistical approaches. We compared the location and magnitude of simulated disasters to historical disasters (1984–2020) in order to characterize plausible surprises which could inform future wildfire risk reduction planning. Results indicate that nearly half of communities are vulnerable to a future disaster, that the magnitude of plausible disasters exceeds any recent historical events, and that ignitions on private land are most likely to result in very high community exposure. Our methods, in combination with more typical actuarial characterizations, provide a way to support investment in and communication with communities exposed to low-probability, high-consequence wildfires. Full article
(This article belongs to the Special Issue Decision Support System Development of Wildland Fire)
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14 pages, 4067 KiB  
Article
A Physics-Guided Deep Learning Model for 10-h Dead Fuel Moisture Content Estimation
by Chunquan Fan and Binbin He
Forests 2021, 12(7), 933; https://doi.org/10.3390/f12070933 - 16 Jul 2021
Cited by 13 | Viewed by 2977
Abstract
Dead fuel moisture content (DFMC) is a key driver for fire occurrence and is often an important input to many fire simulation models. There are two main approaches to estimating DFMC: empirical and process-based models. The former mainly relies on empirical methods to [...] Read more.
Dead fuel moisture content (DFMC) is a key driver for fire occurrence and is often an important input to many fire simulation models. There are two main approaches to estimating DFMC: empirical and process-based models. The former mainly relies on empirical methods to build relationships between the input drivers (weather, fuel and site characteristics) and observed DFMC. The latter attempts to simulate the processes that occur in the fuel with energy and water balance conservation equations. However, empirical models lack explanations for physical processes, and process-based models may provide an incomplete representation of DFMC. To combine the benefits of empirical and process-based models, here we introduced the Long Short-Term Memory (LSTM) network and its combination with an effective physics process-based model fuel stick moisture model (FSMM) to estimate DFMC. The LSTM network showed its powerful ability in describing the temporal dynamic changes of DFMC with high R2 (0.91), low RMSE (3.24%) and MAE (1.97%). When combined with a FSMM model, the physics-guided model FSMM-LSTM showed betterperformance (R2 = 0.96, RMSE = 2.21% and MAE = 1.41%) compared with the other models. Therefore, the combination of the physics process and deep learning estimated 10-h DFMC more accurately, allowing the improvement of wildfire risk assessments and fire simulating. Full article
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17 pages, 5543 KiB  
Article
Taxonomy and Molecular Phylogeny of Phellodon (Thelephorales) with Descriptions of Four New Species from Southwest China
by Chang-Ge Song, Xing Ji, Shun Liu, Xiao-Lan He and Bao-Kai Cui
Forests 2021, 12(7), 932; https://doi.org/10.3390/f12070932 - 16 Jul 2021
Cited by 4 | Viewed by 2119
Abstract
Phellodon is a genus of ectomycorrhizal fungi belonging to the group known as the stipitate hydnoids. It is associated with coniferous trees in forest ecosystems and is widely distributed in the northern hemisphere. Phellodon, together with Hydnellum, and Sarcodon, is classified in [...] Read more.
Phellodon is a genus of ectomycorrhizal fungi belonging to the group known as the stipitate hydnoids. It is associated with coniferous trees in forest ecosystems and is widely distributed in the northern hemisphere. Phellodon, together with Hydnellum, and Sarcodon, is classified in the Bankeraceae, members of which are generally considered as symbiotic fungi. Ectomycorrhizal fungi can help plant roots fix nitrogen and improve the absorption capacity of soil nutrients by trees, so they play an important role in ecosystem protection. Taxonomic and phylogenetic studies of Chinese Phellodon collections were carried out. Four new Phellodon species were discovered from southwestern China based on a combination of morphological characters and molecular data. Phellodon atroardesiacus is characterized by the blackish blue to dark grey pileus, dark grey to ash grey spines, and presence of clamp connections in spines. Phellodon cinereofuscus is distinguished by a cottony tomentose pileal margin, long spines which become clay-buff when dry, and echinulate basidiospores. Phellodon stramineus is characterized by a depressed and tomentose pileus, straw buff-colored pileal surface, and dark grey to ash grey spines. Phellodon yunnanensis is distinguished by a clay-pink to brown pileus, pale brown to white spines, and the presence of clamp connections in the outer layer of stipe. Detailed descriptions, illustrations, and ecological traits for the new taxa are provided. Phylogenetic analyses inferred from the internal transcribed spacer (ITS) regions confirmed that the four new species are distinct within Phellodon. Full article
(This article belongs to the Special Issue Fungal Diversity in Forest Ecosystems)
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18 pages, 3677 KiB  
Article
Population Demographic History of a Rare and Endangered Tree Magnolia sprengeri Pamp. in East Asia Revealed by Molecular Data and Ecological Niche Analysis
by Tong Zhou, Xiao-Juan Huang, Shou-Zhou Zhang, Yuan Wang, Ying-Juan Wang, Wen-Zhe Liu, Ya-Ling Wang, Jia-Bin Zou and Zhong-Hu Li
Forests 2021, 12(7), 931; https://doi.org/10.3390/f12070931 - 16 Jul 2021
Cited by 2 | Viewed by 2083
Abstract
Quaternary climate and environment oscillations have profoundly shaped the population dynamic history and geographic distributions of current plants. However, how the endangered and rare tree species respond to the climatic and environmental fluctuations in the subtropical regions of China in East Asia still [...] Read more.
Quaternary climate and environment oscillations have profoundly shaped the population dynamic history and geographic distributions of current plants. However, how the endangered and rare tree species respond to the climatic and environmental fluctuations in the subtropical regions of China in East Asia still needs elucidation. In this study, we collected 36 natural populations of an endangered and rare tree species Magnolia sprengeri Pamp. in subtropical China to determine the demographic history, and modeled the changes of geographic distributions of this species in East Asia based on the MaxEnt ecological niche analyses. In addition, we sequenced three maternally inherited chloroplast DNA fragments (matK, trnH-psbA, and rbcL) for all the natural populations which covered the whole geographic distributions of M. sprengeri. Population genetic analysis showed that the endangered tree species have a low level of chloroplast DNA diversity. However, the genetic variation contribution within populations was greater than that among populations (FST = 0.276), which demonstrated a high level of genetic differentiation. Interestingly, some unique chloroplast DNA haplotypes and higher genetic variations were identified in the Qinling-Daba Mountains, Central China, and Tianmu Mountains of Zhejiang province, East of China in East Asia. Combining with the species distribution modeling, we speculated that these areas might be the potential glacial refugia for the endangered plant M. sprengeri. Phylogeographic analysis demonstrated that the geographic factors (e.g., mountains, rivers, and other isolation barriers) had little effect on the genetic divergence among populations. Ecological niche modeling further revealed that the natural populations of M. sprengeri did not experience significant geographic distribution changes from the last glacial maximum to the present time. These findings are in line with the analysis results of the multimodal mismatch patterns of the chloroplast DNA variations. To protect the endangered species M. sprengeri, in situ and ex situ conservation strategies should be formulated for the natural populations with higher genetic variations. Full article
(This article belongs to the Section Genetics and Molecular Biology)
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