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Forests, Volume 12, Issue 5 (May 2021) – 137 articles

Cover Story (view full-size image): A total of 196 plots in the boreal forest of Quebec (Canada), either subject to whole-tree or stem-only harvesting, were resampled for soil and tree growth 30 years later. Soil C and N pools were smaller, and the C/N ratio was higher in whole-tree harvested sites in the two soil regions with coarse-textured soils but not in the other two soil regions with a finer texture. Tree growth in the regenerated stands was also lower in the affected soil regions. View this paper
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Article
Comparative Transcriptome Analysis of Sophora japonica (L.) Roots Reveals Key Pathways and Genes in Response to PEG-Induced Drought Stress under Different Nitrogen Conditions
Forests 2021, 12(5), 650; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050650 - 20 May 2021
Viewed by 593
Abstract
Sophora japonica is a native leguminous tree species in China. The high stress tolerance contributes to its long lifespan of thousands of years. The lack of genomic resources greatly limits genetic studies on the stress responses of S. japonica. In this study, [...] Read more.
Sophora japonica is a native leguminous tree species in China. The high stress tolerance contributes to its long lifespan of thousands of years. The lack of genomic resources greatly limits genetic studies on the stress responses of S. japonica. In this study, RNA-seq was conducted for S. japonica roots grown under short-term 20% polyethylene glycol (PEG) 6000-induced drought stress under normal N and N starvation conditions (1 and 0 mM NH4NO3, respectively). In each of the libraries, we generated more than 25 million clean reads, which were then de novo assembled to 46,852 unigenes with an average length of 1310.49 bp. In the differential expression analyses, more differentially expressed genes (DEGs) were found under drought with N starvation than under single stresses. The number of transcripts identified under N starvation and drought in S. japonica was nearly the same, but more upregulated genes were induced by drought, while more downregulated genes were induced by N starvation. Genes involved in “phenylpropanoid biosynthesis” and “biosynthesis of amino acids” pathways were upregulated according to KEGG enrichment analyses, irrespective of the stress treatments. Additionally, upregulated N metabolism genes were enriched upon drought, and downregulated photosynthesis genes were enriched under N starvation. We found 4,372 and 5,430 drought-responsive DEGs under normal N and N starvation conditions, respectively. N starvation may aggravate drought by downregulating transcripts in the “carbon metabolism”, “ribosome”, “arginine biosynthesis pathway”, “oxidative phosphorylation” and “aminoacyl-tRNA biosynthesis” pathways. We identified 78 genes related to N uptake and assimilation, 38 of which exhibited differential expression under stress. A total of 395 DEGs were categorized as transcription factors, of which AR2/ERF-ERF, WRKY, NAC, MYB, bHLH, C3H and C2C2-Dof families played key roles in drought and N starvation stresses. The transcriptome data obtained, and the genes identified facilitate our understanding of the mechanisms of S. japonica responses to drought and N starvation stresses and provide a molecular foundation for understanding the mechanisms of its long lifespan for breeding resistant varieties for greening. Full article
(This article belongs to the Special Issue Forest Genomics and Transcriptomics)
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Article
Classification of Tree Functional Types in a Megadiverse Tropical Mountain Forest from Leaf Optical Metrics and Functional Traits for Two Related Ecosystem Functions
Forests 2021, 12(5), 649; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050649 - 20 May 2021
Viewed by 614
Abstract
Few plant functional types (PFTs) with fixed average traits are used in land surface models (LSMs) to consider feedback between vegetation and the changing atmosphere. It is uncertain if highly diverse vegetation requires more local PFTs. Here, we analyzed how 52 tree species [...] Read more.
Few plant functional types (PFTs) with fixed average traits are used in land surface models (LSMs) to consider feedback between vegetation and the changing atmosphere. It is uncertain if highly diverse vegetation requires more local PFTs. Here, we analyzed how 52 tree species of a megadiverse mountain rain forest separate into local tree functional types (TFTs) for two functions: biomass production and solar radiation partitioning. We derived optical trait indicators (OTIs) by relating leaf optical metrics and functional traits through factor analysis. We distinguished four OTIs explaining 38%, 21%, 15%, and 12% of the variance, of which two were considered important for biomass production and four for solar radiation partitioning. The clustering of species-specific OTI values resulted in seven and eight TFTs for the two functions, respectively. The first TFT ensemble (P-TFTs) represented a transition from low to high productive types. The P-TFT were separated with a fair average silhouette width of 0.41 and differed markedly in their main trait related to productivity, Specific Leaf Area (SLA), in a range between 43.6 to 128.2 (cm2/g). The second delineates low and high reflective types (E-TFTs), were subdivided by different levels of visible (VIS) and near-infrared (NIR) albedo. The E-TFTs were separated with an average silhouette width of 0.28 and primarily defined by their VIS/NIR albedo. The eight TFT revealed an especially pronounced range in NIR reflectance of 5.9% (VIS 2.8%), which is important for ecosystem radiation partitioning. Both TFT sets were grouped along elevation, modified by local edaphic gradients and species-specific traits. The VIS and NIR albedo were related to altitude and structural leaf traits (SLA), with NIR albedo showing more complex associations with biochemical traits and leaf water. The TFTs will support LSM simulations used to analyze the functioning of mountain rainforests under climate change. Full article
(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)
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Review
The Potential Role of Cinnamon in Human Health
Forests 2021, 12(5), 648; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050648 - 20 May 2021
Viewed by 623
Abstract
Cinnamon is an unusual tropical plant belonging to the Lauraceae family. It has been used for hundreds of years as a flavor additive, but it has also been used in natural Eastern medicine. Cinnamon extracts are vital oils that contain biologically active compounds, [...] Read more.
Cinnamon is an unusual tropical plant belonging to the Lauraceae family. It has been used for hundreds of years as a flavor additive, but it has also been used in natural Eastern medicine. Cinnamon extracts are vital oils that contain biologically active compounds, such as cinnamon aldehyde, cinnamic alcohol, cinnamic acid, and cinnamate. It has antioxidant, anti-inflammatory, and antibacterial properties and is used to treat diseases such as diabetes and cardiovascular disease. In folk medicine, cinnamon species have been used as medicine for respiratory and digestive disorders. Their potential for prophylactic and therapeutic use in Parkinson’s and Alzheimer’s disease has also been discovered. This review summarizes the available isolation methods and analytical techniques used to identify biologically active compounds present in cinnamon bark and leaves and the influence of these compounds in the treatment of disorders. Full article
(This article belongs to the Special Issue Non-wood Forest Products)
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Article
Identification of Extractives from Various Poplar Species
Forests 2021, 12(5), 647; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050647 - 19 May 2021
Viewed by 569
Abstract
Fast-growing poplar trees from plantations are the source of inexpensive wood that is intended mainly for chemical processing in the pulp and paper industry. Their potential as raw material for biofuel manufacturing is widely discussed as well. The detailed chemical composition of this [...] Read more.
Fast-growing poplar trees from plantations are the source of inexpensive wood that is intended mainly for chemical processing in the pulp and paper industry. Their potential as raw material for biofuel manufacturing is widely discussed as well. The detailed chemical composition of this raw material is therefore an important question. Five species of poplars were investigated: Populus alba, P. maximowiczii, P. trichocarpa, P. nigra, and P. tremula. Wood is a material consisting mainly of lignocellulose, but there are also many extractives. In temperate zone climate they typically represent up to 5% of wood mass. Their identification is difficult, due to various classes of compounds and great number of individual ones. These compounds can affect the properties of wood—its resistance to biotic agents and suitability to enzymatic treatment towards biofuels. Gas chromatography coupled with mass spectrometer (GC-MS) was used to analysis of extractives in various species of poplar wood. Compounds from several classes were identified like phenols, fatty acids, and their derivatives, sterols. Their identification was discussed along with estimation of their content in wood of investigated species. Full article
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Article
Short-Rotation Coppice Managed According to Ecological Guidelines—What Are the Benefits for Phytodiversity?
Forests 2021, 12(5), 646; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050646 - 19 May 2021
Viewed by 565
Abstract
In recent years, the impact of short-rotation coppice (SRC) on biodiversity has been a regular subject of research and ecological guidelines have been developed to make biomass cultivation on SRC more compatible with biodiversity concerns. However, since these guidelines are only implemented voluntarily [...] Read more.
In recent years, the impact of short-rotation coppice (SRC) on biodiversity has been a regular subject of research and ecological guidelines have been developed to make biomass cultivation on SRC more compatible with biodiversity concerns. However, since these guidelines are only implemented voluntarily by farmers, there are barely any SRC that are managed according to ecological guidelines. Consequently, knowledge about their importance for farmland biodiversity and about the impact of different measures for increasing biodiversity remains scarce. Therefore, three experimental SRC, which are managed according to ecological guidelines and thus include stands of different tree species (varieties of poplar (Populus) and willow (Salix), rowan (Sorbus aucuparia), silver birch (Betula pendula)) and different growth-stages within the same site, were investigated with regard to their importance as habitat for vascular plants. Species numbers and species composition were compared with the following habitat types: afforestations (AFO), young (HE-Y) and old hedges (HE-O), field margins (FM) and arable land (AL). Furthermore, different stand types (i.e., stands with different tree species and growth-stages, headlands, clearings) within these SRC were surveyed and compared. Species numbers of SRC were similar to HE-Y, AFO and FM and significantly higher than in AL and HE-O. The composition of plant communities in SRC differed considerably from the other farmland habitats, especially from AL, HE-O and FM. Within the SRC, most stand types had similar species numbers. Only the non-harvested poplar stands were particularly species-poor. Harvesting led to increased species numbers. This increase was significant for the poplar stands but only moderate for the willow stands. With regard to their species composition, the different stand types differed considerably in many cases. We conclude that SRC, which are managed according to ecological guidelines, can be an additional measure to promote phytodiversity in agricultural landscapes as they contain relatively high species numbers (of mainly common and adaptable species) and support distinct plant communities that differ from other farmland habitats. Therefore, measures such as the cultivation of different tree species or sectional harvesting could be offered as agri-environmental schemes to further increase the ecological sustainability of biomass production on SRC. Full article
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Article
Resistance of Wood Treated with Iron Compounds against Wood-Destroying Decay and Mould Fungi
Forests 2021, 12(5), 645; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050645 - 19 May 2021
Viewed by 453
Abstract
Treatment of wood with various physical and chemical factors can change the number of wood parameters, which can also lead to changes in resistance to wood-destroying fungi. This study evaluates the effects of hydrothermal treatments (additives Fe2O3 or FeCl3 [...] Read more.
Treatment of wood with various physical and chemical factors can change the number of wood parameters, which can also lead to changes in resistance to wood-destroying fungi. This study evaluates the effects of hydrothermal treatments (additives Fe2O3 or FeCl3 with and without commercial tannins, also without additives and fresh wood) on decay and mould fungi resistance of modified wood of Scots pine (Pinus sylvestris), Norway spruce (Picea abies), Douglas fir (Pseudotsuga menziesii), walnut (Juglans regia), and Norway maple (Acer platanoides). For wood samples, the resistance against wood decay fungi Trametes versicolor (white rot) and Coniophora puteana (brown rot) and the resistance against mould fungi Aspergillus niger and Penicillium sp. were assessed. The study findings showed that wood modified with iron compounds could cause a higher resistance to wood-destroying fungi. The weight losses of the modified and control wood, caused by T. versicolor and C. puteana, differed for coniferous and deciduous: the average weight loss of treated pine, spruce, and fir wood caused by C. puteana was higher than that caused by T. versicolor, while these differences on maple and walnut wood were not significant. The wood hydrothermal treatment with Fe2Cl3 with and without tannins significantly reduced the weight loss caused by T. versicolor and C. puteana, and the treatment with Fe2O3 slightly improved the decay resistance. For the wood, hydrothermally modified with FeCl3 and FeCl3 + tannins, the mould area for both tested Aspergillus niger and Penicillium sp. was smallest for the wood of all tested tree species compared to other treatments. A different response was obtained for coniferous and deciduous tree species wood. The spruce wood, followed by fir wood, treated with FeCl3 with and without tannins, was the most resistant against the mould fungi. Relatively low resistance against the mould fungi was fixed for the maple wood treated by various iron compounds, except the treatment with Fe2O3 + tannins, which gave a very positive response against the Penicillium sp. Full article
(This article belongs to the Section Wood Science and Forest Products)
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Article
Effects of Underlay on Hill-Slope Surface Runoff Process of Cupressus funebris Endl. Plantations in Southwestern China
Forests 2021, 12(5), 644; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050644 - 19 May 2021
Viewed by 406
Abstract
Clarifying the impact of underlay (i.e., the combination of near-surface vegetation and surface micro-topography) on the surface runoff process would provide a significant theoretical basis for the adjustment of vegetation patterns and the control of soil erosion on steep slopes in mountainous areas [...] Read more.
Clarifying the impact of underlay (i.e., the combination of near-surface vegetation and surface micro-topography) on the surface runoff process would provide a significant theoretical basis for the adjustment of vegetation patterns and the control of soil erosion on steep slopes in mountainous areas of southwestern China. In the current study, the runoff process under different rainfall characteristics was observed based on 10 natural runoff plots, and the correlation between the spatial pattern of cypress (Cupressus funebris), micro-topography, and runoff characteristic parameters was tested using the Pearson correlation coefficient method. The coupling effects of the spatial pattern of cypress and micro-topography on surface runoff also were analyzed using the Response Surface Method (RSM). The results showed that (1) under the conditions of long-duration moderate rainfall or long-duration rainstorm, topographic relief, surface roughness, runoff path density, contagion index of cypress, and stand density of cypress were the main reasons for the difference in the peak flow of each runoff plot, while under the condition of the short-duration rainstorm, the factors previously mentioned were no longer the dominant factors; (2) under the conditions of long-duration heavy rainfall or long-duration rainstorm, the common laws reflected by the response of the peak flow to the composite index of the spatial pattern of cypress and micro-topography were that (1) when the composite index of the spatial pattern of cypress (V) was below 21 and the composite index of micro-topography (U) was below 10.5, the peak flow would not be significantly affected; (2) when U > 10.5, increasing the composite index of the spatial pattern of cypress within a certain range would promote peak flow; (3) when U < 7.5 and V > 18, the increase of V value could significantly reduce the peak flow, and on this basis, adjusting the V value to 41, the reduction rate of peak flow could reach 84%. Full article
(This article belongs to the Section Forest Ecology and Management)
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Editorial
The Ecology of Fine Roots across Forest Biomes
Forests 2021, 12(5), 643; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050643 - 19 May 2021
Viewed by 436
Abstract
Fine root-soil interactions fundamentally affect the terrestrial carbon (C) cycle and thereby ecosystem feedbacks to climate change [...] Full article
(This article belongs to the Special Issue The Ecology of Fine Roots across Forest Biomes)
Article
Variations in Wood Density, Annual Ring Width and Vessel Properties of Quercus brantii Affected by Crown Dieback
Forests 2021, 12(5), 642; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050642 - 19 May 2021
Viewed by 425
Abstract
Tree decline due to climate change results in physiological weaknesses, attacks by harmful pests and pathogens and threats to forest ecosystem stability. In the work described here, the effects of drought on wood density, tree ring width and variations in vessel morphology are [...] Read more.
Tree decline due to climate change results in physiological weaknesses, attacks by harmful pests and pathogens and threats to forest ecosystem stability. In the work described here, the effects of drought on wood density, tree ring width and variations in vessel morphology are investigated in Persian oak (Quercus brantii) in the forest of the Zagros Mountains, Ilam Province, western Iran. Discs are cut from trunks of declined and healthy trees and woodblocks are cut radially from the sapwood near the bark, at a mid-point between the vascular cambium and the pith (middle) and from wood near the pith. Observations are made on transverse sections from the blocks using microscopy. In trees with decline symptoms, wood density is greater than in healthy trees. Furthermore, declining trees have the narrowest ring width, reduced vessel diameter and area and the highest numbers of vessels and tylose in pith towards the bark. It is concluded that changes in anatomical features are associated with the weakening of trees and are components of declining tree health. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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Article
Availability and Applicability of Wood and Crop Residues for the Production of Wood Composites
Forests 2021, 12(5), 641; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050641 - 19 May 2021
Viewed by 537
Abstract
Due to high levels of volatility in both the agricultural and the forestry commodity markets, specifically, of timber and agricultural crops, it is important to identify the risks associated with the stability of supplies necessary for the production of composite materials in the [...] Read more.
Due to high levels of volatility in both the agricultural and the forestry commodity markets, specifically, of timber and agricultural crops, it is important to identify the risks associated with the stability of supplies necessary for the production of composite materials in the Czech Republic. This study aims to accurately estimate the availability of selected raw materials that contain lignocellulose over the next 20 years. In addition, their suitability for the production of composite materials is assessed based on their physical properties. Furthermore, in the event of scarcity involving timber in the European Union, recycled wood and post-harvest residues could replace conventional raw materials in wood-based composites such as particleboards and chipboards. The viable potential of Czech forests is predicted to be between 740 and 750 million cubic meters of timber. For agricultural crops, it is estimated at 0.9 million hectares of wheat and 0.5 million hectares of canola under the current EU biofuel policy and at 0.4 million hectares if this policy is removed. According to moisture and fibre analyses carried out in our study, the most suitable candidate for wood-based composites production is soft wood. Full article
(This article belongs to the Section Wood Science and Forest Products)
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Article
Impact of Industrial Pollution on Radial Growth of Conifers in a Former Mining Area in the Eastern Carpathians (Northern Romania)
Forests 2021, 12(5), 640; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050640 - 19 May 2021
Viewed by 472
Abstract
The research aims to evaluate the impact of local industrial pollution on radial growth in affected Norway spruce (Picea abies (L.) Karst.) and silver fir (Abies alba Mill.) stands in the Tarnița study area in Suceava. For northeastern Romania, the Tarnița [...] Read more.
The research aims to evaluate the impact of local industrial pollution on radial growth in affected Norway spruce (Picea abies (L.) Karst.) and silver fir (Abies alba Mill.) stands in the Tarnița study area in Suceava. For northeastern Romania, the Tarnița mining operation constituted a hotspot of industrial pollution. The primary processing of non-ferrous ores containing heavy metals in the form of complex sulfides was the main cause of pollution in the Tarnița region from 1968 to 1990. Air pollution of Tarnița induced substantial tree growth reduction from 1978 to 1990, causing a decline in tree health and vitality. Growth decline in stands located over 6 km from the pollution source was weaker or absent. Spruce trees were much less affected by the phenomenon of local pollution than fir trees. We analyzed the dynamics of resilience indices and average radial growth indices and found that the period in which the trees suffered the most from local pollution was between 1978 and 1984. Growth recovery of the intensively polluted stand was observed after the 1990s when the environmental condition improved because of a significant reduction in air pollution. Full article
(This article belongs to the Special Issue Climate Change and Air Pollution Effects on Forest Ecosystems)
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Article
Influence of Chrysoporthe deuterocubensis Canker Disease on the Physical and Mechanical Properties of Eucalyptus urograndis
Forests 2021, 12(5), 639; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050639 - 19 May 2021
Viewed by 487
Abstract
Eucalyptus hybrid has been planted rigorously in wet tropical regions including Malaysia. Recently, there was a report on the occurrence of stem canker on these trees. However, the extent of the infections by this stem canker is unknown. The aim of this study [...] Read more.
Eucalyptus hybrid has been planted rigorously in wet tropical regions including Malaysia. Recently, there was a report on the occurrence of stem canker on these trees. However, the extent of the infections by this stem canker is unknown. The aim of this study was to evaluate the influence of stem canker disease, Chrysoporthe deuterocubensis, on the physical and mechanical properties of 11-year-old E. urophylla × E. grandis or also known as E. urograndis. The samples were taken from infected and healthy trees that were segregated into different classes based on the severity of the attack, i.e., healthy (class 1), moderately infected (class 2), severely infected (class 3) and very severely infected (class 4). A total of 1440 samples from four infection classes were used in this study. The physical and mechanical properties were determined according to the standard test procedures specified by the International Organization for Standardization (ISO) 13061:2014 (Parts 1 to 4, 13, 14 and 17) and British Standard (BS 373: 1957). From the result, a significant effect by the infection classes was observed on physical and mechanical properties of E. urograndis. All infected wood experienced less shrinkage compared to that of a healthy one, particularly the volumetric (Volsh) and radial shrinkage (Rsh). Wood from class 2 and class 3 was less affected by the infection while the majority of wood from class 4 had significantly lower density and poorer strength. Based on the strength data, wood from infection class 2 can be considered to be used for non-structural applications such as furniture, interior finishing, window frames and doors since reduction in mechanical properties was observed. Wood from class 3 would need further investigation to examine its suitability for structural applications. Full article
(This article belongs to the Special Issue Tree Improvement for Promising New Forest Products and Applications)
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Article
Uncovering the Hidden Numbers of Nature in the Standard Accounts of Society: Application to a Case Study of Oak Woodland dehesa and Conifer Forest Farms in Andalusia-Spain
Forests 2021, 12(5), 638; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050638 - 18 May 2021
Viewed by 480
Abstract
The standard System of National Accounts (SNA) does not estimate the margins of the products without market prices consumed because it assumes that the cost prices of the final products consumed correspond to the consumer marginal willingness to pay (MWTP). Valuations of products [...] Read more.
The standard System of National Accounts (SNA) does not estimate the margins of the products without market prices consumed because it assumes that the cost prices of the final products consumed correspond to the consumer marginal willingness to pay (MWTP). Valuations of products consumed without market prices at their cost prices may not coincide with their simulated exchange values (SEV) that would be paid by consumers. This inconsistent SNA valuation can be avoided by simulating stated or revealed market prices based on consumers’ demands. Our Agroforestry Accounting System (AAS) methodology estimates the margins of the individual products without market prices based on the consumer MWTP. The SEV of private owners and public consumers MWTP for these non-market products are estimated in this study by applying stated and revealed preference valuation methods. The objectives of this study are to compare the environmental incomes, ecosystem services and profitability rates obtained by applying the AAS and the refined SNA (rSNA) methodologies to the case-study oak woodland dehesa and conifer forest farms in Andalusia, Spain. The 41 farms comprise 26 large oak woodland dehesa farms in which trees of the Quercus genus predominate, and 15 conifer forest farms where Pinus species predominate. In the studied farms, 20 individual activities have been identified which 19 are common to both the AAS and rSNA approaches, along with the additional activity of carbon which is registered in the AAS. Ownership rights of 13 private activities correspond to the farmer and 7 public activities to the government. In 2010, the case-study results show that livestock and game species consume grazed fodder which represents 50% and 95%, respectively, of their total forage units consumed in the period 2010. Livestock farming accounts for 31% of the labour compensation in the private oak woodland dehesa farms and 1% in the public conifer forest farms for the farm activities as a whole. The ecosystem services measured by the AAS in the privately-owned oak woodland dehesa and publicly-owned conifer forest farms are 2.7 and 4.6 times greater, respectively, than those estimated by the rSNA. The environmental incomes measured by the AAS for the privately-owned oak woodland dehesa and publicly-owned conifer forest farms account for 61% and 53%, respectively, of their total incomes. Full article
(This article belongs to the Special Issue Environmental Valuation and Sustainable Management of Forests)
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Article
Mangrove Forest Landcover Changes in Coastal Vietnam: A Case Study from 1973 to 2020 in Thanh Hoa and Nghe An Provinces
Forests 2021, 12(5), 637; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050637 - 18 May 2021
Viewed by 533
Abstract
Mangrove forests can ameliorate the impacts of typhoons and storms, but their extent is threatened by coastal development. The northern coast of Vietnam is especially vulnerable as typhoons frequently hit it during the monsoon season. However, temporal change information in mangrove cover distribution [...] Read more.
Mangrove forests can ameliorate the impacts of typhoons and storms, but their extent is threatened by coastal development. The northern coast of Vietnam is especially vulnerable as typhoons frequently hit it during the monsoon season. However, temporal change information in mangrove cover distribution in this region is incomplete. Therefore, this study was undertaken to detect change in the spatial distribution of mangroves in Thanh Hoa and Nghe An provinces and identify reasons for the cover change. Landsat satellite images from 1973 to 2020 were analyzed using the NDVI method combined with visual interpretation to detect mangrove area change. Six LULC classes were categorized: mangrove forest, other forests, aquaculture, other land use, mudflat, and water. The mangrove cover in Nghe An province was estimated to be 66.5 ha in 1973 and increased to 323.0 ha in 2020. Mangrove cover in Thanh Hoa province was 366.1 ha in 1973, decreased to 61.7 ha in 1995, and rose to 791.1 ha in 2020. Aquaculture was the main reason for the loss of mangroves in both provinces. Overall, the percentage of mangrove loss from aquaculture was 42.5% for Nghe An province and 60.1% for Thanh Hoa province. Mangrove restoration efforts have contributed significantly to mangrove cover, with more than 1300 ha being planted by 2020. This study reveals that improving mangrove restoration success remains a challenge for these provinces, and further refinement of engineering techniques is needed to improve restoration outcomes. Full article
(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)
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Article
Biochemical and Gene Expression Analyses in Different Poplar Clones: The Selection Tools for Afforestation of Halomorphic Environments
Forests 2021, 12(5), 636; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050636 - 18 May 2021
Viewed by 446
Abstract
Halomorphic soils cover a significant area in the Vojvodina region and represent ecological and economic challenges for agricultural and forestry sectors. In this study, four economically important Serbian poplar clones were compared according to their biochemical and transcriptomic responses towards mild and severe [...] Read more.
Halomorphic soils cover a significant area in the Vojvodina region and represent ecological and economic challenges for agricultural and forestry sectors. In this study, four economically important Serbian poplar clones were compared according to their biochemical and transcriptomic responses towards mild and severe salt stress to select the most tolerant clones for afforestation of halomorphic soils. Three prospective clones of Populus deltoides (Bora-B229, Antonije-182/81 and PE19/66) and one of hybrid genetic background P. nigraxP. deltoides, e.g., P. x euramericana (Pannonia-M1) were hydroponically subjected to NaCl as a salt stress agent in a concentration range from 150 mM to 450 mM. Plant responses were measured at different time periods in the leaves. Biochemical response of poplar clones to salt stress was estimated by tracking several parameters such as different radical scavenging capacities (estimated by DPPH, FRAP and ABTS assays), accumulation of total phenolic content and flavonoids. Furthermore, accumulation of two osmolytes, glycine betaine and proline, were quantified. The genetic difference of those clones has been already shown by single nucleotide polymorphisms (SNPs) but this paper emphasized their differences regarding biochemical and transcriptomic salt stress responses. Five candidate genes, two putative poplar homologues of GRAS family TFs (PtGRAS17 and PtGRAS16), PtDREB2 of DREB family TFs and two abiotic stress-inducible genes (PtP5SC1, PtSOS1), were examined for their expression profiles. Results show that most salt stress-responsive genes were induced in clones M1 and PE19/66, thus showing they can tolerate salt environments with high concentrations and could be efficient in phytoremediation of salt environments. Clone M1 and PE19/66 has ABA-dependent mechanisms expressing the PtP5CS1 gene while clone 182/81 could regulate the expression of the same gene by ABA-independent pathway. To improve salt tolerance in poplar, two putative GRAS/SCL TFs and PtDREB2 gene seem to be promising candidates for genetic engineering of salt-tolerant poplar clones. Full article
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Article
Calibration of Electrical Resistance to Moisture Content for Beech Laminated Veneer Lumber “BauBuche S” and “BauBuche Q”
Forests 2021, 12(5), 635; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050635 - 17 May 2021
Viewed by 549
Abstract
Electrical resistance measurements are often employed for the purpose of nondestructive long-term monitoring of wood moisture content (MC) in timber structures. As a structural material for high-performance load-bearing applications in such structures, beech laminated veneer lumber (LVL) enjoys a growing popularity. However, due [...] Read more.
Electrical resistance measurements are often employed for the purpose of nondestructive long-term monitoring of wood moisture content (MC) in timber structures. As a structural material for high-performance load-bearing applications in such structures, beech laminated veneer lumber (LVL) enjoys a growing popularity. However, due to the processing of beech LVL affecting physical properties, calibration curves for bulk beech wood cannot be used. In this study, resistance was measured on 160 beech LVL samples equilibrated in four different relative humidity (RH) climates. The results show a difference not only between the beech LVL products “BauBuche S” and “BauBuche Q”, but also between measurements at two different depths. For each data set, parameters for calibration models using two and using three model parameters were determined by regression analysis to MC determined by the gravimetric method. Full article
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Article
Impact of Tree Age and Size on Selected Properties of Black Locust (Robinia pseudoacacia L.) Wood
Forests 2021, 12(5), 634; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050634 - 17 May 2021
Viewed by 398
Abstract
Black locust (Robinia pseudoacacia L.) is a non-native tree species that occupies a remarkable area in the forests of western Poland. It is mainly cultivated for the bee-keeping purposes as well as for its high quality wood. We investigated the impact of [...] Read more.
Black locust (Robinia pseudoacacia L.) is a non-native tree species that occupies a remarkable area in the forests of western Poland. It is mainly cultivated for the bee-keeping purposes as well as for its high quality wood. We investigated the impact of tree age and diameter on the selected structural, physical and mechanical attributes of wood of black locust that grows in conditions of mesic oligotrophic site. We analysed 200 samples originating from 18 trees that varied with age (38, 60 and 71 years old) and diameter (thin, medium and thick specimen selected according to Hartig’s method). Individual wood properties were determined along with corresponding European or Polish standards. Structural and mechanical attributes were determined for moisture of 12%. We found significant impact of tree age on tree-ring width, latewood proportion, density, oven-dry density, basic density, share of woody substance, porosity, as well as radial, tangential, longitudinal and volumetric shrinkage, compression strength parallel to grain, static bending, coefficient of compression strength parallel to grain and coefficient of static bending. The older the trees, the higher values of individual attributes were observed. In turn, the effect of tree diameter was less profound and no significant impact of that feature was found for latewood proportion, anisotropy and almost all of the shrinkage parameters. Thin trees exhibited the lowest values of the analysed parameters, while medium ones—the highest. In general, the highest technical quality of the investigated wood can be found in the youngest trees, whose wood characterises with the properties significantly exceeding native Polish tree species such as oak or beech. Full article
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Article
Spatial Distribution and Structural Characteristics for Haloxylon ammodendron Plantation on the Southwestern Edge of the Gurbantünggüt Desert
Forests 2021, 12(5), 633; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050633 - 17 May 2021
Viewed by 459
Abstract
Haloxylon ammodendron (C.A.Mey.) Bge. is crucially important for stabilizing sand dunes in the desert area of the Junggar Basin and has thus been widely planted in the oasis–desert ecotone for windbreak and sand fixation purposes since the 1980s. The spatial distribution and structural [...] Read more.
Haloxylon ammodendron (C.A.Mey.) Bge. is crucially important for stabilizing sand dunes in the desert area of the Junggar Basin and has thus been widely planted in the oasis–desert ecotone for windbreak and sand fixation purposes since the 1980s. The spatial distribution and structural characteristics of Haloxylon ammodendron plantations of three different ages—planted in 1983 (36a), 1997 (22a), and 2004 (15a)—on the southwestern edge of the Gurbantünggüt Desert were studied. The results showed that the spatial distribution patterns for the different stages of growth showed a trend of cluster that was random during the transformation from seedlings to juvenile and mature trees. Forest density for the 15a, 22a, and 36a plantations was, respectively, 1110, 1189, and 1933 plants ha−1; the base stem diameter for the main forest layer was 5.85, 8.77, and 6.17 cm, respectively, and the tree height was concentrated in the range of 1.5–3.0 m, 2.0–3.5 m, and 1.5–2.5 m. In the regeneration layers, the proportion of seedlings was the largest in all three stand ages, followed by juvenile trees, and mature trees only appeared in the 22a plantation. The proportion of deadwood in the 36a forest was the highest, and there were no mature trees in the regeneration layer. These results indicate that the three Haloxylon ammodendron plantation stages were in the period of rising at 15a, stable and degenerate with increasing age at 22a, and at 36a the regeneration ability was very weak and presented degradation due to species competition for soil moisture, because of too many seedlings and mature plants. In this case, measures such as thinning could be taken to prevent rapid degradation and to accelerate regeneration when the stand age exceeds 20 years. Considering the sand fixation effect, the pressure of competition for water resources, and forest capacity for renewal and sustainability, the most suitable forest density in the Haloxylon ammodendron plantation would be 8.5–9 m2 per plant. Full article
(This article belongs to the Section Forest Ecology and Management)
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Article
Comparison of Soil Properties, Understory Vegetation Species Diversities and Soil Microbial Diversities between Chinese Fir Plantation and Close-to-Natural Forest
Forests 2021, 12(5), 632; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050632 - 17 May 2021
Viewed by 511
Abstract
With the continuous increase in plantation areas, the reduction of natural forest areas, and the unreasonable management of plantations by human beings, the service function of forest ecosystems has gradually reduced. Therefore, close-to-natural forestry has become important for the sustainable development of modern [...] Read more.
With the continuous increase in plantation areas, the reduction of natural forest areas, and the unreasonable management of plantations by human beings, the service function of forest ecosystems has gradually reduced. Therefore, close-to-natural forestry has become important for the sustainable development of modern forestry. However, the differences in soil properties, enzyme activities, microbial diversities, and undergrowth vegetation species diversities have not been systematically explained for Chinese fir (Cunninghamia lanceolata). How do these indicators interact? The purpose of this paper was to study the difference in soil properties and biodiversity in different aged Chinese fir plantations and close-to-natural forests to explore their interactions and to provide direction for close-to-nature management. The results showed that the above indicators were significantly different in different aged Chinese fir plantations, soil pH, organic matter, total nitrogen, total phosphorus, total potassium, alkali-hydrolyzed nitrogen, available phosphorus concentrations, and urease activities in close-to-natural forests were significantly higher than plantations. It is worth mentioning that the richness of undergrowth vegetation species diversity (especially shrubs) and soil microbial diversities (especially fungi) in the close-to-natural forests were obviously higher than those in plantations. The correlation analysis results showed that the diversity of shrub species with respect to soil properties presented a higher correlation than herb species, the diversity of fungi with respect to soil properties presented a higher correlation than that observed for bacteria, and the diversity of fungi were significantly correlated with the diversity of undergrowth vegetation species diversities, but the correlation between bacteria and undergrowth vegetation species diversities was not significant. Our results suggest that the above factors are fundamental factors for the transformation of Chinese fir plantations to close-to-natural forests. To realize close-to-natural forestry, we must change the tree structure, combine the difference of those factors in different aged plantations, restore undergrowth vegetation species diversity, and thus improve microbial diversity and increase decomposition, transformation, and improvement of soil properties. Full article
(This article belongs to the Special Issue Patterns of Tree Species Diversity and Forest Structure)
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Communication
Short Communication: IPC Salix Cultivar Database Proof-of-Concept
Forests 2021, 12(5), 631; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050631 - 17 May 2021
Viewed by 457
Abstract
A variety of Salix L. (Willow) tree and shrub cultivars provide resources for significant commercial markets such as bioenergy, environmental applications, basket manufacturing, and ornamental selections. The International Poplar Commission of the Food and Agriculture Organization (IPC FAO) has maintained the Checklist for [...] Read more.
A variety of Salix L. (Willow) tree and shrub cultivars provide resources for significant commercial markets such as bioenergy, environmental applications, basket manufacturing, and ornamental selections. The International Poplar Commission of the Food and Agriculture Organization (IPC FAO) has maintained the Checklist for Cultivars of Salix L. (Willow) since 2015 and now lists 968 epithet records in a Microsoft Excel spreadsheet format. This Proof-of-Concept (POC) investigates using an SQL database to store existing IPC Salix cultivar information and provide users with a format to compare and submit new Salix cultivar entries. The original IPC data were divided into three separate tables: Epithet, Species, and Family. Then, the data were viewed from three different model perspectives: the original Salix IPC spreadsheet data, the Canadian (PWCC), and the Open4st database. Requirements for this process need to balance database integrity rules with the ease of adding new Salix cultivar entries. An integrated approach from all three models proposed three tables: Epithet, Family, and Pedigree. The Epithet and Family tables also included Species data with a reference to a website link for accepted species names and details. The integrated process provides a more robust method to store and report data, but would require dedicated IT personnel to implement and maintain long-term. A potential use case scenario could involve users submitting their Checklist entries to the Salix administrator for review; the entries are then entered into a test environment by IT resources for final review and promotion to a production online environment. Perhaps the most beneficial outcome of this study is the investigation of various strategies and standards for Epithet and Family recording processes, which may benefit the entire Populus and Salix communities. Full article
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Editorial
Influence of Climate Change on Tree Growth and Forest Ecosystems: More Than Just Temperature
Forests 2021, 12(5), 630; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050630 - 16 May 2021
Viewed by 558
Abstract
Recent research has shown that climate change is already altering tree species ranges, mortality and growth rates [...] Full article
(This article belongs to the Special Issue Influence of Climate Change on Tree Growth and Forest Ecosystems)
Article
Exploring Pattern of Green Spaces (GSs) and Their Impact on Climatic Change Mitigation and Adaptation Strategies: Evidence from a Saudi Arabian City
Forests 2021, 12(5), 629; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050629 - 16 May 2021
Viewed by 766
Abstract
Green spaces (GSs) are significant, nature-based solutions to climate change and have immense potential to reduce vulnerability to heat waves while enhancing the resilience of urban areas in the light of climate change. However, in the Saudi context, the availability of GSs across [...] Read more.
Green spaces (GSs) are significant, nature-based solutions to climate change and have immense potential to reduce vulnerability to heat waves while enhancing the resilience of urban areas in the light of climate change. However, in the Saudi context, the availability of GSs across cities and their perceived role in climate change mitigations and adaptation strategies remain unexplored. This study aimed to examine the per capita availability of GSs in the Jeddah megacity in Saudi Arabia, and their role in climate change mitigation and adaptation strategies. This study assessed the per capita availability of GS in Jeddah city using GIS techniques, and a questionnaire survey (online and an onsite) was conducted to assess the GSs users’ perception of the role of GSs on climate change mitigation and adaptation strategies. Non-parametric tests were also used to find differences in roles based on socio-demographic attributes. The findings of the study revealed that: (i) the per capita availability of GS in Jeddah is relatively low in comparison to international organization recommendations (such as World Health Organization and European Union). As per the survey result, it was reported that GSs play crucial role for climate change mitigation such as temperature regulation, reduction in heat stress, enhancement outdoor thermal comfort, and the maintenance of air quality. More than 85% of the total respondents agreed with the very high importance of GSs for climate change mitigation. More than 80% of respondents in the city highly agreed with climate change adaptation strategies such as the enhancement of accessibility to GSs, ecosystem-based protection of GSs, and the improvement of per capita availability of GSs. The findings of the study will be very helpful to planners and policymakers in implementing nature-based solutions to reduce vulnerability to climate change in Jeddah city, and particularly other cities in a desert environment. Full article
(This article belongs to the Special Issue Landscape and Urban Planning-Sustainable Forest Development)
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Article
Induction of Defense Responses in Pinus sylvestris Seedlings by Methyl Jasmonate and Response to Heterobasidion annosum and Lophodermium seditiosum Inoculation
Forests 2021, 12(5), 628; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050628 - 14 May 2021
Viewed by 476
Abstract
The induction of defense responses in Pinus sylvestris L. seedlings by methyl jasmonate (MeJA) was investigated in three experiments. Two different MeJA application methods were tested, and induction of defense responses was assayed by seedling inoculation with Heterobasidion annosum (Fr.) Bref. and Lophodermium [...] Read more.
The induction of defense responses in Pinus sylvestris L. seedlings by methyl jasmonate (MeJA) was investigated in three experiments. Two different MeJA application methods were tested, and induction of defense responses was assayed by seedling inoculation with Heterobasidion annosum (Fr.) Bref. and Lophodermium seditiosum Minter, Staley and Millar. In the first experiment, five-year-old P. sylvestris ramets of one clone were directly treated with MeJA, followed by inoculation with H. annosum. In the second experiment, open-pollinated Scots pine seedlings were treated with MeJA by direct spraying and vaporization, and inoculation with H. annosum was done using a slightly modified protocol. In the third experiment, open-pollinated Scots pine seedlings were treated with MeJA by vaporization and inoculated with L. seditiosum. Direct application of MeJA induced seedling mortality, and in some cases, decreased resistance to inoculation with H. annosum. Application of MeJA by vaporization was less stressful for seedlings, and resulted in increased resistance to both H. annosum and L. seditiosum. In addition, an unforeseen Neodiprion sertifer (Geoffroy) and Hylobius abietis L. infestation provided anecdotal evidence of the efficacy of MeJA in inducing resistance to insect pests as well. Further studies are required on the induction of resistance to additional diseases and pests. Induced resistance could be used as a possible protective mechanism for Scots pine seedlings prior to planting during reforestation of stands to increase vitality and survival. Full article
(This article belongs to the Section Genetics and Molecular Biology)
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Article
Asynchrony and Time-Lag between Primary and Secondary Growth of Norway Spruce Growing in Different Elevations
Forests 2021, 12(5), 627; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050627 - 14 May 2021
Viewed by 527
Abstract
Norway spruce is one of the most economically important coniferous species in Europe, but it has faced high mortality rates in the last few decades due to the increasing frequency of extreme weather events. Primary and secondary growth development may be affected by [...] Read more.
Norway spruce is one of the most economically important coniferous species in Europe, but it has faced high mortality rates in the last few decades due to the increasing frequency of extreme weather events. Primary and secondary growth development may be affected by these non-optimal conditions. In this study, we aimed to analyze the timing, possible asynchrony and time-lag between the growth processes of Norway spruce. We used a novel methodological approach of primary (based on phenocamera picture evaluation) and secondary (dendrometers) growth detection. The combination of these novel approaches allowed us to compare these growth process in high temporal resolution. Measurements were performed in two experimental plots with contrasting climatic conditions (middle and higher elevations) in the years 2016–2019, during the presence of extreme climatic conditions. We demonstrated a significant elongation of the growing season, with a more pronounced effect at higher elevation. Compared to the long-term mean, we observed an additional 50 days with a temperature above 15 °C at the higher elevation plot. There were no found patterns in the time-shift of both growth processes between plots. On the other hand we observed asynchrony of radial growth and meristems growth. Radial growth began earlier than the phenology of apical meristems growth. The onset, end and duration of meristem growth differed between studied plots and years as well. The onset of radial growth did not follow the gradient of microclimatic parameters; however, the differences in climatic conditions between plots did cause a shift in the onset of meristem growth. The process of the radial growth was twice as long as for apical meristem development. On average, radial growth requires 71 days more than meristem phenology to reach full process completion. Our data confirmed that these growth processes are strongly affected by external weather conditions and the duration of the growing season. More advanced and detailed monitoring of these processes can provide more accurate data of the health status of trees in the forest. Full article
(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)
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Article
Periurban Areas in the Design of Supra-Municipal Strategies for Urban Green Infrastructures
Forests 2021, 12(5), 626; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050626 - 14 May 2021
Viewed by 622
Abstract
Nowadays, an increasing number of large cities, districts, and towns have tools for the Planning and Management of Green Infrastructures. All such tools seek a progression towards a future city model that is more resilient on an environmental, economic, and social level. To [...] Read more.
Nowadays, an increasing number of large cities, districts, and towns have tools for the Planning and Management of Green Infrastructures. All such tools seek a progression towards a future city model that is more resilient on an environmental, economic, and social level. To achieve this, emphasis is placed on the creation of a green infrastructure and, particularly, on improving urban biodiversity, urban forests, the value of natural areas in the urban environment, periurban agriculture, ecological connectivity, and accessibility. Moreover, the recent COVID19 health crisis has further highlighted that the city dweller’s relationship with the environment requires a reconciliation with nature and rural life that goes beyond typical compartmentalization. The objective must be to emphasize the need to establish creative processes which, through micro-scale activities (landscaping), generate the articulation of visible actions on a territorial scale (landscape planning) in both the natural environment (environmental landscape planning) and the urban environment (town planning based on the landscape). This article analyzes the issue of the large towns in south-west Madrid, where there is a dramatic divide on the border between the city landscape and the surrounding natural or agricultural landscape, and where there is an increasing need to establish landscapes with a certain uniqueness and to classify them as protected periurban areas, nature reserves, or land for which use and management is regulated. It is therefore important to develop environmental quality standards to assess Green Infrastructures as a whole: the administrative processes, their design, construction, maintenance, and resilience. This research focuses upon how this change in the planning and management of green periurban areas improves the multifunctionality of periurban spaces along with the intrinsic quality of the landscape, and promotes the city’s sustainability and resilience and improves governance. From the conclusions drawn, it should be noted that analysis, design, and action should be built on premises of sustainability and multifunctionality, and comply with the criteria for characterizing elements as green infrastructure. In the field of study, the characterization of the periurban area, and its subsequent assessment as a green infrastructure, provide the guidelines for action for devising an Open Space Strategy. This strategy constitutes a cross-disciplinary planning tool for local authorities when reading the landscape. Full article
(This article belongs to the Special Issue Landscape and Urban Planning-Sustainable Forest Development)
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Article
Ants as Bioindicators of Riparian Ecological Health in Catalonian Rivers
Forests 2021, 12(5), 625; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050625 - 14 May 2021
Viewed by 597
Abstract
In this study, we assess the potential of ants as bioindicators of riparian ecological health in two river types (upland and lowland type) located in the Catalonian region. We proposed to understand to what extent do metrics based on ant responses provide useful [...] Read more.
In this study, we assess the potential of ants as bioindicators of riparian ecological health in two river types (upland and lowland type) located in the Catalonian region. We proposed to understand to what extent do metrics based on ant responses provide useful information that cannot be presented by traditional biophysical assessments while attempting an approach to creating an ant-based multimetric index (ant-based MMI) of the riparian ecological health. A total of 22 ant species were identified, and 42 metrics related to ant foraging activity, species richness, and functional traits were evaluated as potential core metrics of the index. Riparian features and proximal land use land cover (LULC) were used to distinguish disturbed from less disturbed sites. We found that ant communities strongly responded to human disturbance. When compared with an exclusively physical-based index for the assessment of the riparian health, the ant-based MMI was more sensitive to human disturbance, by also reacting to the effects of the surrounding LULC pressure. This study provides a preliminary approach for an ant-based assessment tool to evaluate the health of riparian corridors although additional research is required to include other river types and a wider stressor gradient before a wider application. Full article
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Article
Temperature Sensitivity of CO2 and CH4 Fluxes from Coarse Woody Debris in Northern Boreal Forests
Forests 2021, 12(5), 624; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050624 - 14 May 2021
Viewed by 543
Abstract
Carbon dioxide (CO2) and methane (CH4) are recognized as the main greenhouse gases causing climate warming. In forest ecosystems, the death of trees leads to the formation of coarse woody debris (CWD) that is one of the sources of [...] Read more.
Carbon dioxide (CO2) and methane (CH4) are recognized as the main greenhouse gases causing climate warming. In forest ecosystems, the death of trees leads to the formation of coarse woody debris (CWD) that is one of the sources of greenhouse gas emissions due to wood decomposition. We quantified the CO2 and CH4 fluxes from CWD of larch (Larix gmelinii (Rupr.)) and birch (Betula tortuosa Ledeb.) collected in the northern boreal forests of Central Siberia. The CWD samples were incubated at +5, +15 and +25 °C. The CO2 and CH4 fluxes showed strong correlations with temperature, moisture, decomposition stage and the type of wood’s rot. The temperature coefficient Q10 indicated higher temperature sensitivity of CO2 flux within the temperature interval from +5 to +15 °C than from +15 to +25 °C. Methane flux had higher temperature sensitivity within the interval from +15 to +25 °C. It was found that, in boreal forests, CWD of early decay stage can serve as a source of methane to the atmosphere when air temperatures increased above +15 °C. Strong positive correlation between CH4 production and CO2 emission indicated a biological source and supported findings on aerobic origin of the main process contributing to the CH4 flux from decomposing CWD. Full article
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Article
Economic Modelling of Poplar Short Rotation Coppice Plantations in Hungary
Forests 2021, 12(5), 623; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050623 - 14 May 2021
Viewed by 390
Abstract
No study has been previously completed on the range of sites, potential yield, and financial characteristics of poplar short rotation coppice plantations (SRC) in Hungary. This paper conducts a literature survey to reveal the biomass production potential of such plantations and presents a [...] Read more.
No study has been previously completed on the range of sites, potential yield, and financial characteristics of poplar short rotation coppice plantations (SRC) in Hungary. This paper conducts a literature survey to reveal the biomass production potential of such plantations and presents a model that is used to analyze their financial performance. The results indicate that the break-even-point of production is between 6 and 8 oven-dry tons per hectare per year once a minimum cost level and wood chip price within a 10% range of the 2020 value are considered. The higher the wood chip price, the lower the break-even-point. Since the model excluded the administrative costs that depend on the type and size of the management organization, the break-even-points can be significantly higher in reality, which suggests that short rotation energy plantations can be a financially reasonable land-use option in above average or even superior poplar-growing sites. The rotation period of industrial poplar plantations that produce high quality veneer logs ranges from 12 to 25 years. Though such sites can provide higher returns on investment, short rotation plantations have the advantage of providing a more evenly distributed cash flow. To facilitate the wider application of poplar SRC, the related policies need to apply specific subsidies and allow the rotation cycle to be extended up to 20–25 years, which is currently limited to 15 years. Full article
Article
Mid-Scale Drivers of Variability in Dry Mixed-Conifer Forests of the Mogollon Rim, Arizona
Forests 2021, 12(5), 622; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050622 - 14 May 2021
Viewed by 503
Abstract
The structure and composition of southwestern dry mixed-conifer forests have changed significantly, decreasing forest resiliency to uncharacteristic disturbances which also threaten ecosystem services. Restoration of these forests can be informed by historical conditions; however, managers and researchers still lack a full understanding of [...] Read more.
The structure and composition of southwestern dry mixed-conifer forests have changed significantly, decreasing forest resiliency to uncharacteristic disturbances which also threaten ecosystem services. Restoration of these forests can be informed by historical conditions; however, managers and researchers still lack a full understanding of how environmental factors influence forest conditions. We investigated historical and contemporary variability in dry mixed-conifer forests in northern Arizona and identified important environmental drivers. We utilized forest sample plots and dendrochronological reconstruction modelling to describe forest conditions in 1879 and 2014, respectively. We used correlogram analysis to compare spatial autocorrelation of average diameter, basal area and tree density, and structural equation modeling to partition the causal pathways between forest structure, forest composition, and a suite of environmental factors reflecting climate, topography, and soil. Historical (1879) reconstructed forests had significantly fewer trees, lower basal area, and higher average diameter than contemporarily (2014). Composition has shifted from ponderosa pine dominance towards a more mixed-species composition. Historically, forest structure did not exhibit strong spatial autocorrelation, but contemporary tree density and diameter were strongly autocorrelated. Environmental factors described little variation in historical forest conditions but are more important for contemporary conditions. Managers can utilize this increased understanding of variation to tailor silvicultural prescriptions to environmental templates. Full article
(This article belongs to the Section Forest Ecology and Management)
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Article
Stratification, Scarification and Application of Phytohormones Promote Dormancy Breaking and Germination of Pelleted Scots Pine (Pinus sylvestris L.) Seeds
Forests 2021, 12(5), 621; https://0-doi-org.brum.beds.ac.uk/10.3390/f12050621 - 14 May 2021
Viewed by 440
Abstract
Seed quality is an important issue in forestry as it is an essential parameter in the production of high quality planting material. Many factors may hinder the harvesting of high quality seeds, including an insufficient number of sunny days, external conditions in temperate [...] Read more.
Seed quality is an important issue in forestry as it is an essential parameter in the production of high quality planting material. Many factors may hinder the harvesting of high quality seeds, including an insufficient number of sunny days, external conditions in temperate climate zones, and fungal pathogens affecting development of seedlings. We undertook to develop a procedure maximizing seed protection and promoting the optimum physiological development of seedlings by examination of the impact of seed pelleting (a general seed protection method) on germination rates and seedling development of Scots pine (Pinus sylvestris L.). Germination of pelleted seeds was examined in relation to substrate (water vs. soil) and LED light spectrum (white vs. red-blue). Several dormancy breaking treatments were applied: stratification/scarification, and growth regulator treatments including gibberellic acid (GA3), indole-3-acetic acid (IAA) and 1-naphthaleneacetic acid (NAA), to stimulate seed germination. Experiments included independent tests for each treatment (stratification/scarification and plant growth regulators), and combinations of both stratification/scarification and phytohormone treatments. The impacts of these treatments and various controlled germination conditions on the fluorescence of chlorophyll were analyzed using the maximum efficiency of photosystem II photochemistry parameter (Fv/Fm). In addition, chlorophyll a and b content in Scots pine seedlings germinated from pelleted seeds, were quantified using high-performance liquid chromatography (HPLC). The combined stratification/scarification and growth regulator treatment was the most effective germination promoting method for pelleted Scots pine seeds. Scots pine seeds are highly likely to be photoblastic. The best germination rate, while maintaining optimal physiological parameters, was achieved in acidic soil (pH 5.0) with white LED light. Full article
(This article belongs to the Special Issue Forest Plant Resources Bioactive Ingredients)
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