Forests

18 pages, 6130 KiB

Open AccessArticle

Comparative Transcriptome Analysis of Sophora japonica (L.) Roots Reveals Key Pathways and Genes in Response to PEG-Induced Drought Stress under Different Nitrogen Conditions

by Jing Tian, Yue Pang and Zhong Zhao

Forests 2021, 12(5), 650; https://doi.org/10.3390/f12050650 - 20 May 2021

Cited by 5 | Viewed by 3308

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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21 pages, 3649 KiB

Open AccessArticle

Classification of Tree Functional Types in a Megadiverse Tropical Mountain Forest from Leaf Optical Metrics and Functional Traits for Two Related Ecosystem Functions

by Oliver Limberger, Jürgen Homeier, Nina Farwig, Franz Pucha-Cofrep, Andreas Fries, Christoph Leuschner, Katja Trachte and Jörg Bendix

Forests 2021, 12(5), 649; https://doi.org/10.3390/f12050649 - 20 May 2021

Cited by 4 | Viewed by 3550

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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Figure 1
Plot locations at Bombuscaro (1000 m above sea level), San Francisco (2000 m above sea level.), and Cajanuma (3000 m above sea level). The DEM is based on SRTM data (USGS, 2006). The inlay shows the position of the research area in southern Ecuador. Full article ">Figure 2
Study workflow. The hyperspectral leaf data were pre-processed and converted to commonly used leaf optical metrics (<a href="#forests-12-00649-t001" class="html-table">Table 1</a>). A factor analysis was conducted to aggregate the optical metrics to optical traits indicators (OTIs), where the indication for the functional traits was documented by their correlation with species factor scores. A subsequent cluster analysis was used to assign the species to tree functional types (TFTs). Full article ">Figure 3
Correlations of species factor scores with functional leaf traits for the four factors. The color gradient indicates positive (green) to negative correlations (yellow). Weak correlations are depicted in lighter colors. Significant correlations are marked corresponding to the p-value: * < 0.05; ** < 0.01; *** < 0.001. Based on the correlation of the factor scores with leaf functional traits, F1 can be interpreted as the OTI (optical trait indicators) for resource acquisition and usage, F2 in terms of photosynthetic capacity and light use efficiency, F3 as photoprotection, and F4 in terms of leaf water effect on NIR albedo. Full article ">Figure 4
Relative deviation from the average median of dominating functional traits (relation > 0.5 with the OFIs F1 and F2) relevant to productivity for all P-TFTs. Average median values over all P-TFTs are: SLA = 81.5 cm2/g, leaf thickness = 0.32 mm, C = 478.9 mg/g, N = 17.3 mg/g, N/C = 29.7, and N/P = 20.2. Significant differences between the TFT traits and the average TFT median trait are marked corresponding to the p-value < 0.05: *; p-value < 0.01: **; p-value < 0.001: ***. The P-TFT 5 was not tested, as it was only comprised of a single species. Full article ">Figure 5
Deviations from average median VIS (blue, <700 nm) and NIR (red, >700 nm) albedos for the R-TFTs 1–8 related to different effects on solar radiation partitioning. Average median values over all R-TFTs were: VIS albedo = 7.4%, NIR albedo = 21.9%. Significant differences between the TFT albedos and the average TFT median albedo are marked corresponding to the p-value < 0.05: *; p-value < 0.01: **; p-value < 0.001: ***. The TFTs R1 and R3 were not tested, as they were only comprised of a single species. Full article ">Figure 6
Relative deviations from the average median of selected structural and biochemical functional traits (correlation > 0.5 with OFIs F1–4) relevant for solar radiation partitioning over all R-TFTs 1–8. Average median values over all R-TFTs were: SLA = 83.0 cm2/g, leaf thickness = 0.32 mm, N = 17.3 mg/g, and leaf water content (LWC) = 642.8 mg/g. Significant differences between the TFT traits and the average TFT median trait are marked corresponding to the p-value < 0.05: *; p-value < 0.01: **; p-value < 0.001: ***. The TFTs R1 and R3 were not tested, as they were only comprised of a single species. Full article ">

17 pages, 1366 KiB

Open AccessReview

The Potential Role of Cinnamon in Human Health

by Natalia Błaszczyk, Angelina Rosiak and Joanna Kałużna-Czaplińska

Forests 2021, 12(5), 648; https://doi.org/10.3390/f12050648 - 20 May 2021

Cited by 94 | Viewed by 23553

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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15 pages, 2682 KiB

Open AccessArticle

Identification of Extractives from Various Poplar Species

by Dominika Szadkowska, Janusz Zawadzki, Paweł Kozakiewicz and Andrzej Radomski

Forests 2021, 12(5), 647; https://doi.org/10.3390/f12050647 - 19 May 2021

Cited by 9 | Viewed by 3251

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

(This article belongs to the Special Issue Forest Sustainability: Wood Harvest, Supply and Procurement Chain, and Wood Raw Material Properties)

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Origin (place of harvest) of poplar trees (<a href="https://www.bdl.lasy.gov.pl/" target="_blank">https://www.bdl.lasy.gov.pl/</a>, accessed on 1 April 2021). Full article ">Figure 2
Raw chromatograms of individual poplar samples (black—P. alba L., pink—P. tremula L., blue—P. nigra L., brown—P. trichocarpa Torr. and A. Gray ex. Hook., green—P. maksimowiczi Henry. Full article ">Figure 3
European aspen chromatogram (P. tremula L.) with peak identification. Full article ">Figure 4
Mass spectrum of a compound identified as sinapyl alcohol. Full article ">Figure 5
Presumed fragmentationof sinapyl alcohol. Full article ">Figure 6
Mass spectrum of the compound identified as probably syringic acid acetate. Full article ">Figure 7
Mass spectrum of the initial unidentified peak fragment on the chromatogram of P.tremula extract with a retention time of 26.82. Full article ">Figure 8
Mass spectrum of the final unidentified peak fragment on the chromatogram of P.tremula extract with a retention time of 26.82. Full article ">

20 pages, 5456 KiB

Open AccessArticle

Short-Rotation Coppice Managed According to Ecological Guidelines—What Are the Benefits for Phytodiversity?

by Felix Zitzmann and Michael Rode

Forests 2021, 12(5), 646; https://doi.org/10.3390/f12050646 - 19 May 2021

Cited by 4 | Viewed by 3520

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

(This article belongs to the Special Issue Fast-Growing Trees Species—Opportunities and Risks for Sustainable Agricultural and Forest Land Use Systems)

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15 pages, 10356 KiB

Open AccessArticle

Resistance of Wood Treated with Iron Compounds against Wood-Destroying Decay and Mould Fungi

by Marius Aleinikovas, Iveta Varnagirytė-Kabašinskienė, Aistė Povilaitienė, Benas Šilinskas, Mindaugas Škėma and Lina Beniušienė

Forests 2021, 12(5), 645; https://doi.org/10.3390/f12050645 - 19 May 2021

Cited by 13 | Viewed by 3839

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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Mean weight loss of wood samples from pine, spruce, fir, maple, and walnut exposed to decay fungi T. versicolor and C. puteana for 12 weeks. Bars show standard error of the mean. Full article ">Figure 2
Examples of spruce wood samples exposed to brown rot fungus C. puteana after treatment with FeCl3 (A) and on fresh wood Control 2 (B) after 12 weeks (Photos: Aistė Povilaitienė). Full article ">Figure 3
Examples of maple wood samples exposed to white rot fungus T. versicolor after treatment with FeCl3 (A) and on fresh wood Control 2 (B) after 12 weeks (Photos: Aistė Povilaitienė). Full article ">Figure 4
Growth activity of moulds Aspergillus niger and Penicillium sp. on pine and maple wood samples from the 7th to 28th day (n = 8). Note: the wood samples were exposed to the suspension made from a mixture containing the two fungi. Full article ">Figure 5
Examples of mould growth on pine (A), spruce (B), and maple (C) wood samples after the treatments with Fe2O3, FeCl3, and Fe2O3 + tannins, respectively, and Control 1 (A,B) and Control 2 (C) exposed in each Petri dish for 28 days after inoculation. Note: the wood samples were exposed to the suspension made from a mixture containing the two fungi. Full article ">

19 pages, 27524 KiB

Open AccessArticle

Effects of Underlay on Hill-Slope Surface Runoff Process of Cupressus funebris Endl. Plantations in Southwestern China

by Bingchen Wu and Shi Qi

Forests 2021, 12(5), 644; https://doi.org/10.3390/f12050644 - 19 May 2021

Cited by 9 | Viewed by 2399

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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2 pages, 624 KiB

Open AccessEditorial

The Ecology of Fine Roots across Forest Biomes

by Antonino Di Iorio and Agostino Sorgonà

Forests 2021, 12(5), 643; https://doi.org/10.3390/f12050643 - 19 May 2021

Viewed by 1820

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)

13 pages, 8191 KiB

Open AccessArticle

Variations in Wood Density, Annual Ring Width and Vessel Properties of Quercus brantii Affected by Crown Dieback

by Forough Soheili, Stephen Woodward, Isaac Almasi, Hazandy Abdul-Hamid and Hamid Reza Naji

Forests 2021, 12(5), 642; https://doi.org/10.3390/f12050642 - 19 May 2021

Cited by 5 | Viewed by 2674

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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Location of the forest sampled in the Ilam Province in western Iran. Full article ">Figure 2
Wood density of declined (D1–D3) and healthy trees (H1–H3) of Quercus brantii in three areas of the Iranian forest: Dareh shahr, Sheshdar and Chavar. Density was measured in the wood samples from near-pith towards near-bark. H: Healthy trees; D: Declined trees; 1: Area A; 2: Area B; 3: Area C; P: Near-pith; M: Middle; B: Near-bark. Full article ">Figure 3
Time series of annual ring width of Quercus brantii for declined (D1–D3) and healthy trees (H1–H3). Full article ">Figure 4
Mean diameter of earlywood vessels in declined and healthy trees of Quercus brantii. H: Healthy trees; D: Declined trees; 1: Area A; 2: Area B; 3: Area C; P: Near-pith; M: Middle; B: Near-bark. The bar on each column represents the SE (standard error). Columns with no letters on them indicate insignificance. Full article ">Figure 5
Comparisons of mean area of earlywood vessels in declined and healthy trees of Quercus brantii. H: Healthy trees; D: Declined trees; 1: Area A; 2: Area B; 3: Area C; P: Near-pith; M: Middle; B: Near-bark. The bar on each column represents the SE (standard error). Full article ">Figure 6
Mean number of vessels in declined and healthy trees of Quercus brantii. H: Healthy trees; D: Declined trees; 1: Area A; 2: Area B; 3: Area C; P: Near-pith; M: Middle; B: Near-bark. The bar on each column represents the SE (standard error). Columns with no letters on them indicate insignificance. Full article ">Figure 7
Mean number of tyloses in xylem vessels of Quercus brantii. H: Healthy trees; D: Declined trees; 1: Area A; 2: Area B; 3: Area C; P: Near-pith; M: Middle; B: Near-bark. The bar on each column represents the SE (standard error). Columns with no letters on them indicate insignificance. Full article ">Figure 8
Tyloses (T) occluding vessel lumen in transverse section of a declined tree from near-bark tissues. Full article ">

15 pages, 2087 KiB

Open AccessArticle

Availability and Applicability of Wood and Crop Residues for the Production of Wood Composites

by Petr Procházka, Vladimír Honig, Jiří Bouček, Kateřina Hájková, Lukáš Trakal, Jana Soukupová and Hynek Roubík

Forests 2021, 12(5), 641; https://doi.org/10.3390/f12050641 - 19 May 2021

Cited by 6 | Viewed by 3123

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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11 pages, 2497 KiB

Open AccessArticle

Impact of Industrial Pollution on Radial Growth of Conifers in a Former Mining Area in the Eastern Carpathians (Northern Romania)

by Cristian Gheorghe Sidor, Radu Vlad, Ionel Popa, Anca Semeniuc, Ecaterina Apostol and Ovidiu Badea

Forests 2021, 12(5), 640; https://doi.org/10.3390/f12050640 - 19 May 2021

Cited by 13 | Viewed by 3548

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 Tarni?a study area in Suceava. For northeastern Romania, the Tarni?a [...] 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 Tarni?a study area in Suceava. For northeastern Romania, the Tarni?a 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 Tarni?a region from 1968 to 1990. Air pollution of Tarni?a 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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Study location: (a) Silver fir from Tarnița region; (b) Norway spruce from Tarnița region (the red arrow indicates the source of pollution and the predominant direction of airmasses in the area is NE–SW, according to the valley orientation). Full article ">Figure 2
The average series of radial growth indices developed for each of the 3 categories of stands studied (the dotted circle represents the time interval in which the trees were most affected by air pollution); (A) silver fir; (B) Norway spruce. Full article ">Figure 3
Resilience indices of the average radial growth series of silver fir (A) and Norway spruce (B). Full article ">Figure 3 Cont.
Resilience indices of the average radial growth series of silver fir (A) and Norway spruce (B). Full article ">Figure 4
Average resilience indices for each of the 3 categories of silver fir (A) and Norway spruce (B) stands in the Tarnița area (the dotted circle represents the time interval in which the trees were most affected by the influence of pollution). Full article ">Figure 5
Radial growth losses recorded by the trees ((A) silver fir; (B) Norway spruce) in the Tarnița area affected by moderate and intensive air pollution. Full article ">

17 pages, 8618 KiB

Open AccessArticle

Influence of Chrysoporthe deuterocubensis Canker Disease on the Physical and Mechanical Properties of Eucalyptus urograndis

by Rasdianah Dahali, Paridah Md. Tahir, Adlin Sabrina Muhammad Roseley, Lee Seng Hua, Edi Suhaimi Bakar, Zaidon Ashaari, Mohd Redzuan Abdul Rauf, Nur Aziera Zainuddin and Noor Syazwani Mansoor

Forests 2021, 12(5), 639; https://doi.org/10.3390/f12050639 - 19 May 2021

Cited by 9 | Viewed by 3266

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 (Vol_sh) and radial shrinkage (R_sh). 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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Symptoms of Cryphonectria deuterocubensis on E. urograndis; (a) healthy tree, absence of any symptom; (b) swollen/callus, the reaction from the infected trees can be observed by the form of callus around the site of infection, leading to the bulging of the outer layer of bark; (c) cracking, by the shredding of outer layer bark, and these swollen/callus may coalesce to form a larger crack; (d) fruiting structure, stromata harbouring the fruiting bodies of C. deuterocubensis may develop in the bark and cambium of the cankers which are a clear sign of a E. urograndis infection; (e,h) kino pocket, due to injury of the cambium which resulting in the formation of kino pocket under the bark of infected stem; (g) canker, C. deuterocubensis causes perennial necrotic lesions (cankers) on the bark of stems are orange to reddish-brown on the surface; (f,i) fresh and dried kino/gummosis, as a defense response by the tree to infection of fungal disease, leads to abundant kino exudation produced from the secretory cells in the tree; (j) sunken, when the cambium is killed, the bark sinks inwards, giving the canker a characteristic sunken appearance; (k) rotten, decayed and brittle texture near the canker area due to repeated infections for a long period of time; (l) epicormic shoots, observed below the canker area as trees regrow after coppicing or pollarding. Full article ">Figure 2
Cutting of infected logs by using live sawing technique. The numbering of 1R, 2R, 3R, 1L, 2L, 3L indicate the number and position (right (R) and left (L)) of boards obtained during sawing. The number of boards obtained depends on the diameter size of the log. Full article ">Figure 3
Some of the defects found on the surface of lumbers cut from different infection classes: Class 1, no apparent defect except for tight knots; Class 2, arrow showing a kino pocket; Class 3, arrow showing kino pocket filled with kino/gummosis; Class 4, area in the rectangular showing signs of decay. Full article ">Figure 4
Types and percentage of occurrence of failure (in static bending) of Eucalyptus urograndis. Full article ">Figure 5
Average modulus of rupture (MOR) of Eucalyptus urograndis wood corresponding to types of failure. Full article ">Figure 6
Average modulus of elasticity (MOE) of Eucalyptus urograndis wood corresponding to types of failure. Full article ">Figure 7
Percentage of failure modes according to infection class. Full article ">

39 pages, 1214 KiB

Open AccessArticle

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

by Pablo Campos, Bruno Mesa and Alejandro Álvarez

Forests 2021, 12(5), 638; https://doi.org/10.3390/f12050638 - 18 May 2021

Cited by 3 | Viewed by 2355

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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20 pages, 3081 KiB

Open AccessArticle

Mangrove Forest Landcover Changes in Coastal Vietnam: A Case Study from 1973 to 2020 in Thanh Hoa and Nghe An Provinces

by Huong Thi Thuy Nguyen, Giles E. S. Hardy, Tuat Van Le, Huy Quoc Nguyen, Hoang Huy Nguyen, Thinh Van Nguyen and Bernard Dell

Forests 2021, 12(5), 637; https://doi.org/10.3390/f12050637 - 18 May 2021

Cited by 23 | Viewed by 6432

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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Location map of the study areas showing the distribution of the mangroves in green in 2020 (1—Hau Loc district; 2—Nga Son district; 3, 4—Hoang Hoa district; 5, 6—Tinh Gia district; 7, 8—Quynh Luu district; 9—Vinh city; 10, 11—Nghi Loc district; and 12—Dien Chau district); the coast is highlighted in grey. Full article ">Figure 2
Chart of the methodology used for mapping mangrove extent and land cover. Full article ">Figure 3
Land use and land cover classification map of the river mouth in Hau Loc district in Thanh Hoa province obtained from Landsat 1 for 1973 (a), Landsat 5 for 1988 (b), 1995 (c), 2005 (d), 2010 (e), and Landsat 8 for 2015 (f) and 2020 (g). Panel (h) provides the LULC (ha) for panels (a–g). Full article ">Figure 4
Mangrove restoration programs in Nga Son district. (a) Google Earth image of 2014 overlaid with mangrove extent obtained from Landsat images from 1973 to 2020; (b) Landsat image from 24/8/2020 showing boundaries for mangrove distribution in 2016 (light blue) and 2020 (yellow) obtained by NDVI; (c) Google Earth image of 26/7/2020 showing the extent of mangrove restoration projects planted in 2015 and 2017, and the planned area for mangrove planting from 2019 to 2021 sourced from [<a href="#B85-forests-12-00637" class="html-bibr">85</a>]. Imagery in (a,c) copyright of Google Earth. Full article ">

21 pages, 3502 KiB

Open AccessArticle

Biochemical and Gene Expression Analyses in Different Poplar Clones: The Selection Tools for Afforestation of Halomorphic Environments

by Vladislava Galović, Marko Kebert, Boris M. Popović, Branislav Kovačević, Verica Vasić, Mary Prathiba Joseph, Saša Orlović and László Szabados

Forests 2021, 12(5), 636; https://doi.org/10.3390/f12050636 - 18 May 2021

Cited by 5 | Viewed by 3061

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

(This article belongs to the Special Issue Growth and Development of Short Rotation Woody Crops for Rural and Urban Applications)

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11 pages, 1661 KiB

Open AccessArticle

Calibration of Electrical Resistance to Moisture Content for Beech Laminated Veneer Lumber “BauBuche S” and “BauBuche Q”

by Philippe Grönquist, Gianna Weibel, Claude Leyder and Andrea Frangi

Forests 2021, 12(5), 635; https://doi.org/10.3390/f12050635 - 17 May 2021

Cited by 9 | Viewed by 2917

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

(This article belongs to the Special Issue Nondestructive Evaluation of Forest Biomaterials: A Global Perspective)

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12 pages, 1034 KiB

Open AccessArticle

Impact of Tree Age and Size on Selected Properties of Black Locust (Robinia pseudoacacia L.) Wood

by Szymon Bijak and Hubert Lachowicz

Forests 2021, 12(5), 634; https://doi.org/10.3390/f12050634 - 17 May 2021

Cited by 11 | Viewed by 2988

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

(This article belongs to the Special Issue Forest Sustainability: Wood Harvest, Supply and Procurement Chain, and Wood Raw Material Properties)

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15 pages, 3305 KiB

Open AccessArticle

Spatial Distribution and Structural Characteristics for Haloxylon ammodendron Plantation on the Southwestern Edge of the Gurbantünggüt Desert

by Chunwu Song, Congjuan Li, Ümüt Halik, Xinwen Xu, Jiaqiang Lei, Zhibin Zhou and Jinglong Fan

Forests 2021, 12(5), 633; https://doi.org/10.3390/f12050633 - 17 May 2021

Cited by 11 | Viewed by 2851

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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Location of the study sites in the Mosuowan reclamation area. Full article ">Figure 2
Annual precipitation at the study sites in the Mosuowan reclamation area. Full article ">Figure 3
Semi-variograms for height (a,e,i), crown width (b,f,j), diameter of base stem (c,g,k), and deadwood proportion (d,h,l) of Haloxylon ammodendron plantations of different stand stages at 15a, 22a, and 36a, respectively. Full article ">Figure 4
Basal stem diameter and tree height characteristics of the main stand layer of Haloxylon ammodendron plantations of different stand ages: Basal stem diameter class (a, 15a; b, 22a; and c, 36a), tree height class (d, 15a; e, 22a; and f, 36a). Full article ">Figure 5
The deadwood proportion of the main forest layer in Haloxylon ammodendron plantations of different stand ages: (a), 15a; (b), 22a; and (c), 36a. Different colors represent the deadwood proportion of individual trees. Full article ">Figure 6
Basal stem diameter structure of the regeneration layer in Haloxylon ammodendron plantations at different stand ages. Stand age: (a) for mature >6.5 cm; (b) for juvenile >1.2 cm and <6.5 cm; (c) for seedling <1.2 cm. Full article ">Figure 7
Stem maps (a, 15a; b, 22a; and c, 36a) and spatial patterns (d, 15a; e, 22a; f, 36a) of Haloxylon ammodendron at three stages of development. Full article ">

17 pages, 23051 KiB

Open AccessFeature PaperArticle

Comparison of Soil Properties, Understory Vegetation Species Diversities and Soil Microbial Diversities between Chinese Fir Plantation and Close-to-Natural Forest

by Lingyu Hou, Yongqiang Zhang, Zhichao Li, Guodong Shao, Liguo Song and Qiwu Sun

Forests 2021, 12(5), 632; https://doi.org/10.3390/f12050632 - 17 May 2021

Cited by 24 | Viewed by 3676

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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Soil chemical characteristics. General soil properties at the Experimental Center of Subtropical Forest, China. Properties are average values measured for soil samples (the experiment was repeated three times for each sample) taken from each replicate plot in 2018 (n = 9). p-values within each column were determined by ANOVA. Different lowercase letters and different uppercase letters represent significant differences between the same soil depth of different stand ages and between different soil depths (0–20 cm and 20–40 cm) of the same stand age (p < 0.05), respectively, as determined by Tukey’s HSD test (α = 0.05). The same below. (A) pH values, (B) soil organic matter (SOM) concentrations, (C) soil total nitrogen (STN) concentrations, (D) soil total phosphorus (STP) concentrations, (E) soil total potassium (STK) concentrations, (F) soil alkali-hydrolyzable nitrogen (SAN) concentrations, (G) soil available phosphorus (AP) concentrations, (H) soil available potassium (SAK) concentrations in different stand ages and different soil depths. Full article ">Figure 1 Cont.
Soil chemical characteristics. General soil properties at the Experimental Center of Subtropical Forest, China. Properties are average values measured for soil samples (the experiment was repeated three times for each sample) taken from each replicate plot in 2018 (n = 9). p-values within each column were determined by ANOVA. Different lowercase letters and different uppercase letters represent significant differences between the same soil depth of different stand ages and between different soil depths (0–20 cm and 20–40 cm) of the same stand age (p < 0.05), respectively, as determined by Tukey’s HSD test (α = 0.05). The same below. (A) pH values, (B) soil organic matter (SOM) concentrations, (C) soil total nitrogen (STN) concentrations, (D) soil total phosphorus (STP) concentrations, (E) soil total potassium (STK) concentrations, (F) soil alkali-hydrolyzable nitrogen (SAN) concentrations, (G) soil available phosphorus (AP) concentrations, (H) soil available potassium (SAK) concentrations in different stand ages and different soil depths. Full article ">Figure 2
Soil enzyme activities at different stand ages. Different lowercase letters and different uppercase letters represent significant differences between the same soil depth of different stand ages and between different soil depths of the same stand ages (p < 0.05), respectively. (A) polyphenol oxidase activity, (B) urease activity, (C) cellulase activity, and (D) acid phosphatase activity. Full article ">Figure 2 Cont.
Soil enzyme activities at different stand ages. Different lowercase letters and different uppercase letters represent significant differences between the same soil depth of different stand ages and between different soil depths of the same stand ages (p < 0.05), respectively. (A) polyphenol oxidase activity, (B) urease activity, (C) cellulase activity, and (D) acid phosphatase activity. Full article ">Figure 3
Diversity indices of shrub and grass calculated from plant investigation. (A) Richness index (S) and Margalef index (Dm), (B) Shannon diversity index (H) and Simpson index (Ds), (C) McIntosh evenness index (Jsi) and Shannon evenness index (Jsw). p-values within each column were determined by ANOVA. Different lowercase letters between different stand ages in the same soil layer indicate significant differences as determined by Tukey’s HSD test (α = 0.05). Full article ">Figure 4
Changes of AWCD of soil microbial communities that utilized carbon sources in 323 different aged stands over time. AWCD is the average well color development. Full article ">Figure 5
Stacked vertical bars depicting the relative abundance of the taxa present at different stands. Colors in the stacked vertical bars correspond to the phylum level classification of each taxon; taxa accounting for less than 1% of the total number of sequences are depicted in “others”. (A) fungi, (B) bacteria. Full article ">

8 pages, 2219 KiB

Open AccessCommunication

Short Communication: IPC Salix Cultivar Database Proof-of-Concept

by Patrick N. McGovern, Yulia A. Kuzovkina and Raju Y. Soolanayakanahally

Forests 2021, 12(5), 631; https://doi.org/10.3390/f12050631 - 17 May 2021

Cited by 1 | Viewed by 2694

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

(This article belongs to the Special Issue Growth and Development of Short Rotation Woody Crops for Rural and Urban Applications)

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4 pages, 665 KiB

Open AccessEditorial

Influence of Climate Change on Tree Growth and Forest Ecosystems: More Than Just Temperature

by Juan A. Blanco, Ester González de Andrés and Yueh-Hsin Lo

Forests 2021, 12(5), 630; https://doi.org/10.3390/f12050630 - 16 May 2021

Cited by 5 | Viewed by 2952

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)

16 pages, 4054 KiB

Open AccessArticle

Exploring Pattern of Green Spaces (GSs) and Their Impact on Climatic Change Mitigation and Adaptation Strategies: Evidence from a Saudi Arabian City

by Ahmad Maghrabi, Abdulelah Alyamani and Abdullah Addas

Forests 2021, 12(5), 629; https://doi.org/10.3390/f12050629 - 16 May 2021

Cited by 15 | Viewed by 4824

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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18 pages, 10615 KiB

Open AccessArticle

Induction of Defense Responses in Pinus sylvestris Seedlings by Methyl Jasmonate and Response to Heterobasidion annosum and Lophodermium seditiosum Inoculation

by Ilze Šņepste, Baiba Krivmane, Vilnis Šķipars, Astra Zaluma and Dainis E. Ruņģis

Forests 2021, 12(5), 628; https://doi.org/10.3390/f12050628 - 14 May 2021

Cited by 9 | Viewed by 3094

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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Two different inoculation techniques utilized: (a–c) Inoculation of P. sylvestris ramets with H. annosum in experiment 1. (a) Pine sapwood pieces (0.3 × 0.8 cm) with H. annosum mycelium; (b) circular drill wound and sapwood piece inserted into stem; (c) inoculation point covered with gardening wax. (d–f) Inoculation experiment of P. sylvestris seedlings in experiment 2. (d) Pine sapwood chips (0.05 × 0.5 cm) with H. annosum mycelium; (e) cut in the stem made by grafting knife for inoculation; (f) inoculation point covered with PVC electrical insulation tape. Full article ">Figure 2
(a,b) Stem discs of MeJA-treated P. sylvestris ramets with resin on their surface; (c) Stem disc of a control ramet with Heterobasidion spp. conidiophores. Full article ">Figure 3
Comparison of the sensitivity of Taq and FIREPol DNA polymerases in detecting H. annosum in DNA extracted from stem discs of two seedlings. Circles indicate DNA samples from stem discs at the inoculation points, lanes to the left and right contain PCR products from DNA samples extracted from discs below and above the inoculation point, respectively. Full article ">Figure 4
(a) PCR products from the control seedling; (b) cut stem disks from the same seedling. N—necrosis, circle—inoculation point, blue numbers—discs above inoculation point (sequential direction to the stem apex), red numbers—discs below inoculation point (sequential direction to the roots). Full article ">Figure 5
European pine sawfly (N. sertifer) larvae and their caused damage on the control seedlings. Full article ">

15 pages, 3276 KiB

Open AccessArticle

Asynchrony and Time-Lag between Primary and Secondary Growth of Norway Spruce Growing in Different Elevations

by Ondřej Nezval, Jan Krejza, Michal Bellan and Jan Světlík

Forests 2021, 12(5), 627; https://doi.org/10.3390/f12050627 - 14 May 2021

Cited by 4 | Viewed by 2687

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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Geographical location of the two experimental study plots in the Czech Republic. Full article ">Figure 2
The PhenoCam EMS 800 (EMS Brno, the Czech Republic) placed on the top of the meteorological tower (A) and the example of photos (B) at the ESP Rajec, which were used for evaluation of Pgrowth; tree rectangles represent views of different focal length (frames). Full article ">Figure 3
The seasonal course of monthly mean air temperature Ta (°C), monthly sum of precipitation P (mm) and monthly mean of vapor pressure deficit VPD (kPa) at the ESP Bily Kriz and Rajec in the years 2016–2019. Red lines represent long-term measurements (1961–2010). Vertical bars represent standard deviation. Full article ">Figure 4
Time series of cumulative daily primary growth (Pgrowth) in % (left) and time series of daily rate (right) in % day−1 at the ESP Bily Kriz (A) and Rajec (B) in 2016–2019. Vertical bars represent standard deviation. Full article ">Figure 5
Time series of cumulative daily secondary growth expressed by stem radial increment (SRI) in µm (left) and time series of daily rate of SRI in µm day−1 (at the studied plots Bily Kriz (A) and Rajec (B) in 2016–2019. Vertical bars represent standard deviation. Full article ">Figure 6
Mean value of daily rate of Sgrowth (brown line; SRI) and Pgrowth (green line; Pgrowth) calculated for all study years (2016–2019) at the ESP Rajec (A) and Bily Kriz (B). Vertical bars represent standard deviation. Full article ">Figure 7
Correlation between onset (A) of primary (Pgrowth) and secondary growth (Sgrowth) and end of Pgrowth and Sgrowth (B) at the ESP Bily Kriz (black circles) and Rajec (red circles) in 2016–2019. The 1:1 red line is drawn for reference. Vertical and horizontal bars represent standard deviation. Full article ">Figure 8
Timing and time lag of primary (Pgrowth) and secondary growth (Sgrowth) at the ESP Bily Kriz (A) and Rajec (B) in 2016–2019. Time lag between seasonal dynamics of primary growth and secondary growth, both processes are expressed in relative values (percentage of completion). Full article ">

14 pages, 35686 KiB

Open AccessArticle

Periurban Areas in the Design of Supra-Municipal Strategies for Urban Green Infrastructures

by Eva Fernández-Pablos, Amparo Verdú-Vázquez, Óscar López-Zaldívar and Rafael V. Lozano-Diez

Forests 2021, 12(5), 626; https://doi.org/10.3390/f12050626 - 14 May 2021

Cited by 15 | Viewed by 3703

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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18 pages, 3013 KiB

Open AccessArticle

Ants as Bioindicators of Riparian Ecological Health in Catalonian Rivers

by Vera Zina, Marc Ordeix, José Carlos Franco, Maria Teresa Ferreira and Maria Rosário Fernandes

Forests 2021, 12(5), 625; https://doi.org/10.3390/f12050625 - 14 May 2021

Cited by 6 | Viewed by 3807

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

(This article belongs to the Special Issue Riparian Forest Dynamics: Ecological Relations and Species Interactions)

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Geographical location and aerial photo of the nine sampling sites at the Catalonian river corridors. Red and green points indicate disturbed and less disturbed sites, respectively. Full article ">Figure 2
Aerial photo of a sampling site, showing details of the pitfall traps arrangement, riparian vegetation cover delimitation and the riverbank line that worked as a support to create the 200 m half-size buffer radius used to calculate relative measurements of LULC anthropogenic pressures. Full article ">Figure 3
Box plots of: (a) Riparian vegetation cover; (b) Average width of riparian cover; (c) Urban LULC; (d) Cropland and intensive grassland LULC; (e) Shrublands and natural woodlands LULC, at disturbed and less disturbed sites in the upland and lowland river types. Boxes show interquartile ranges (25th and 75th percentiles), middle lines are medians, and whiskers are non-outlier ranges beyond the boxes. Full article ">Figure 4
Boundary values for the five classes of ecological quality of the Ant-based MMI expressed in Ecological Quality Ratios (EQR) for the Lowland and Upland river types. Boxes show interquartile ranges (25th and 75th percentiles), middle lines are medians, and whiskers are non-outlier ranges beyond the boxes. Full article ">Figure 5
Scatter plot and correspondent regression line (in black) with 95% confidence interval (shaded area) representing the relationship between the Ant-based MMI and the QBR index. Spearman’s ρ correlation test revealed a significant positive correlation between the two indices. Full article ">

25 pages, 2679 KiB

Open AccessArticle

Temperature Sensitivity of CO₂ and CH₄ Fluxes from Coarse Woody Debris in Northern Boreal Forests

by Liudmila Mukhortova, Natalia Pashenova, Maria Meteleva, Leonid Krivobokov and Georg Guggenberger

Forests 2021, 12(5), 624; https://doi.org/10.3390/f12050624 - 14 May 2021

Cited by 13 | Viewed by 3147

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

(This article belongs to the Special Issue Cool Forests at risk? The Critical Role of Boreal and Mountain Ecosystems for People, Bioeconomy, and Climate)

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The rate of CO2 emission during decomposition of larch (Larch) and birch (Birch) wood, shown as box plots (box is an interquartile range (from 25th percentile to 75th percentile), horizontal line is a median value, vertical lines are a range between minimum and maximum values, dots are an outliers): DC I–DC III—decomposition classes I–III; DC IIIw—separately, larch wood of DC III decomposed by white rot fungi; DC IIIb—separately, larch wood of DC III decomposed by brown rot. Full article ">Figure 2
The rate of CH4 flux (a), CH4 production (b) and CH4 consumption (c) during decomposition of larch (Larch) and birch (Birch) wood shown as box plots: DC I–DC III—decomposition classes I–III; DC IIIw—separately larch wood of DC III decomposed by white rot fungi; DC IIIb—separately larch wood of DC III decomposed by brown rot. CH4 consumption (c) was calculated as a difference between CH4 production (b) and CH4 flux (a). Full article ">Figure 3
The relationship between 12CH4 ([12CH4], ppm) and 13CH4 ([13CH4], ppm) content during incubation of larch and birch CWD: DC I–DC III—decomposition Classes; DC IIIb—CWD of Decomposition Class III decomposed by brown rot fungi; DC IIIw—CWD of Decomposition Class III decomposed by white rot fungi. Dotted line indicates reference ratio between 13CH4 and 12CH4 if to assume that δ13C in the produced methane is similar to that in the substrate (decomposing wood). Full article ">Figure 4
Box plots of temperature response of the CO2 flux during decomposition of larch and birch CWD at different decomposition classes: TI 1—temperature interval from +5 to +15 °C; TI 2—temperature interval from +15 to +25 °C; DC I–DC III—decomposition classes; DC IIIb and DC IIIw—wood of Decomposition Class III decomposed by brown rot and white rot fungi, respectively. Full article ">Figure 5
The relationship between CO2 and CH4 fluxes and water content of larch (a) and birch (b) CWD samples at different temperatures. Superscript * indicates significance at p < 0.05. Full article ">Figure 6
The relationship between CO2 emission and CH4 fluxes during decomposition of birch and larch CWD samples: MP—methane production, MC—methane consumption. Shadowed area indicates the 95% confidence interval of the trend line. Full article ">Figure 7
The relationship between bulk density and water content in the decomposed larch and birch wood. Shadowed area indicates the 95% confidence interval of the smooth line. Full article ">Figure 8
Temperature response of the CH4 fluxes during decomposition of larch and birch CWD at different decomposition classes: MP—methane production; MC—methane consumption; TI 1—temperature interval from +5 to +15 °C; TI 2—temperature interval from +15 to +25 °C; DC I—DC III—decomposition classes; DC IIIb and DC IIIw—wood of Decomposition Class III decomposed by brown rot and white rot fungi, respectively. Full article ">

12 pages, 724 KiB

Open AccessArticle

Economic Modelling of Poplar Short Rotation Coppice Plantations in Hungary

by Endre Schiberna, Attila Borovics and Attila Benke

Forests 2021, 12(5), 623; https://doi.org/10.3390/f12050623 - 14 May 2021

Cited by 19 | Viewed by 2996

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

(This article belongs to the Special Issue Growth and Development of Short Rotation Woody Crops for Rural and Urban Applications)

29 pages, 4997 KiB

Open AccessArticle

Mid-Scale Drivers of Variability in Dry Mixed-Conifer Forests of the Mogollon Rim, Arizona

by Matthew Jaquette, Andrew J. Sánchez Meador, David W. Huffman and Matthew A. Bowker

Forests 2021, 12(5), 622; https://doi.org/10.3390/f12050622 - 14 May 2021

Cited by 3 | Viewed by 2523

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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14 pages, 1362 KiB

Open AccessArticle

Stratification, Scarification and Application of Phytohormones Promote Dormancy Breaking and Germination of Pelleted Scots Pine (Pinus sylvestris L.) Seeds

by Katarzyna Nawrot-Chorabik, Małgorzata Osmenda, Krzysztof Słowiński, Dariusz Latowski, Sylwester Tabor and Stephen Woodward

Forests 2021, 12(5), 621; https://doi.org/10.3390/f12050621 - 14 May 2021

Cited by 10 | Viewed by 3658

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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