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Forests, Volume 11, Issue 12 (December 2020) – 140 articles

Cover Story (view full-size image): In Northeast India, and many other parts of the world, shifting cultivation is an important land-use sustaining the livelihoods of large numbers of rural people. Despite this, there are concerns regarding shortened fallow length and forest recovery following cultivation. In this paper, we determine the important, but often ignored, below-ground components of ecosystem recovery focusing on roots and their interactions with soil nitrogen availability. We also show how there are strong seasonal patterns of root biomass, production, and nitrogen cycling in these montane forests that are on the very edge of the tropics at 23 degrees north. The picture here shows our natural forest reference site, the Reiek Community Forest. View this paper
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Article
Urban Green Corridors Analysis for a Rapid Urbanization City Exemplified in Gaoyou City, Jiangsu
Forests 2020, 11(12), 1374; https://doi.org/10.3390/f11121374 - 21 Dec 2020
Cited by 6 | Viewed by 1369
Abstract
The undergoing trend and development towards urbanization and the consequences of socio-ecological and climate change are increasing the pressure on cities worldwide. The planning of urban green and blue spaces is essential for sustainable urban development, especially for the conservation of urban ecosystems [...] Read more.
The undergoing trend and development towards urbanization and the consequences of socio-ecological and climate change are increasing the pressure on cities worldwide. The planning of urban green and blue spaces is essential for sustainable urban development, especially for the conservation of urban ecosystems in fast-growing cities. In this context, the spatial-explicit and ecological connectivity analyses of urban green infrastructure are helpful tools for planning and the evaluation of spatial patterns and their changes for the sustainability of urban development. The aim of this study is to understand the influence of urban expansion on the urban green corridors. In this paper, we present an analysis of ecological networks for green infrastructure planning at the city level, making the most out of morphological spatial pattern analysis (MSPA) techniques and social-ecological analysis methods. The findings reveal the changes of spatial patterns of urban green and blue areas in Gaoyou city and disclose its ecological corridors and connectivity from 1990 to 2012. The urban green corridors analysis method proposed here can be used in other cities and allow for the production of spatially detailed urban ecological connectivity assessment and monitoring. Recommendations to enhance and conserve green corridors and ecological networks such as reserving networks in the east of the example city have been concluded. The conclusion obtained using our spatial analysis method can be used in other municipalities to serve as spatial-explicit tools for urban green spaces and land use planning. Full article
(This article belongs to the Section Forest Ecology and Management)
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Article
Effect of Weathering on Surface Functional Groups of Charred Norway Spruce Cladding Panels
Forests 2020, 11(12), 1373; https://doi.org/10.3390/f11121373 - 21 Dec 2020
Cited by 7 | Viewed by 1009
Abstract
Norway spruce cladding panels were surface charred with a prototype device utilizing a hot plate method. The panels were used to construct a test wall that was exposed to natural weathering for a period of two years. The changes in functional groups were [...] Read more.
Norway spruce cladding panels were surface charred with a prototype device utilizing a hot plate method. The panels were used to construct a test wall that was exposed to natural weathering for a period of two years. The changes in functional groups were evaluated with photoacoustic FTIR spectroscopy. The analysis revealed degradation of the thermally modified lignin component, indicating poor stability in weathering. Improvements in the prototype device process conditions, such as increased surface pressure and slower feed speed, and future research needs regarding surface charred wood are discussed. Full article
(This article belongs to the Special Issue Wood Modification: Physical Properties and Biological Efficacy)
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Article
Molecular Cloning and Expression Analysis of the Endogenous Cellulase Gene MaCel1 in Monochamus alternatus
Forests 2020, 11(12), 1372; https://doi.org/10.3390/f11121372 - 21 Dec 2020
Cited by 1 | Viewed by 806
Abstract
The purpose of this study was to characterize the endogenous cellulase gene MaCel1 of Monochamus alternatus, which is an important vector of Bursaphelenchus xylophilus, a pine wood nematode, which causes pine wilt disease (PWD). In this study, MaCel1 was cloned by [...] Read more.
The purpose of this study was to characterize the endogenous cellulase gene MaCel1 of Monochamus alternatus, which is an important vector of Bursaphelenchus xylophilus, a pine wood nematode, which causes pine wilt disease (PWD). In this study, MaCel1 was cloned by rapid amplification of cDNA end (RACE), and its expression analyzed by RT-qPCR (real-time quantitative PCR detecting). A total of 1778 bp of cDNA was obtained. The encoding region of this gene was 1509 bp in length, encoding a protein containing 502 amino acids with a molecular weight of 58.66 kDa, and the isoelectric point of 5.46. Sequence similarity analysis showed that the amino acids sequence of MaCel1 had high similarity with the β-Glucosinolate of Anoplophoraglabripennis and slightly lower similarity with other insect cellulase genes (GH1). The β-D-Glucosidase activity of MaCel1 was 256.02 ± 43.14 U/L with no β-Glucosinolate activity. MaCel1 gene was widely expressed in the intestine of M. alternatus. The expression level of MaCel1 gene in male (3.46) and female (3.51) adults was significantly higher than that in other developmental stages, and the lowest was in pupal stage (0.15). The results will help reveal the digestive mechanism of M. alternatus and lay the foundation for controlling PWD by controlling M. alternatus. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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Article
Phenotypic Plasticity of Drought Tolerance Traits in a Widespread Eucalypt (Eucalyptus obliqua)
Forests 2020, 11(12), 1371; https://doi.org/10.3390/f11121371 - 21 Dec 2020
Cited by 5 | Viewed by 1114
Abstract
Long-term studies of tree responses to drought stress help us to understand the capacity of species to adapt to their environment. In this study, we investigated how Eucalyptus obliqua adjusts physiological and morphological traits in response to seasonal and multi-year droughts. We monitored [...] Read more.
Long-term studies of tree responses to drought stress help us to understand the capacity of species to adapt to their environment. In this study, we investigated how Eucalyptus obliqua adjusts physiological and morphological traits in response to seasonal and multi-year droughts. We monitored physiological and morphological traits over multiple years in undisturbed control and throughfall reduction plots in a eucalypt forest in south-eastern Australia. The throughfall reduction treatment did not induce significantly lower soil moisture in the throughfall reduction plots compared with the control plots. However, natural variability in precipitation and evaporative demand induced drought stress of varying intensity each summer in all plots. We observed a significant relationship between seasonal precipitation and leaf pre-dawn water potential (ΨPD), with less precipitation over summer, resulting in a decline in ΨPD and drought stress when ΨPD fell below −0.75 MPa. Eucalyptus obliqua responded to short-term summer drought through rapid leaf osmotic adjustment which lowered the leaf water potential at the turgor loss point beyond the minimum leaf water potential. Morphological adjustments, such as the reduction of leaf area to sapwood area (higher Huber Value) were moderate during the measurement period and only occurred under severe drought stress (pre-dawn water potential < −1.2 MPa). Overall, E. obliqua responded to short-term mild drought stress through physiological trait plasticity, while morphological adjustment only occurred under a more severe water deficit. Full article
(This article belongs to the Special Issue The Physiology of Tree Response to Drought)
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Article
Evaluating the Economic Incentives of Biomass Removal on Site Preparation for Different Harvesting Systems in Australia
Forests 2020, 11(12), 1370; https://doi.org/10.3390/f11121370 - 21 Dec 2020
Cited by 2 | Viewed by 777
Abstract
Research Highlights: This study evaluated the impacts of biomass recovery on site preparation costs while proposing a mathematical model and framework to catalogue the benefits depending on harvesting system. Background and Objectives: Biomass as a viable product depends on the requisite costs of [...] Read more.
Research Highlights: This study evaluated the impacts of biomass recovery on site preparation costs while proposing a mathematical model and framework to catalogue the benefits depending on harvesting system. Background and Objectives: Biomass as a viable product depends on the requisite costs of production compared to the price paid by relative markets. The removal of biomass directly impacts site preparation costs, and the operational and economic ramifications of this should inform the feasibility of biomass harvesting and market viability. The relative incentives for biomass removal depend on the quantity, presentation, and location of the residues and are thus a result of the commercial sawlog harvesting system. This incentive also largely depends on the required work to prepare a site for replanting. Materials and Methods: This study developed a mathematical model to connect the concepts of site preparation, harvesting, and biomass costs and revenues to determine the maximum net revenue. This work also developed a framework for understanding and calculating the key model inputs related to site preparation and the relative economic site preparation incentive for biomass harvesting. The framework was then illustrated by using industry data from plantations in Queensland, Australia. Results and Conclusions: The analysis identified a potential reduction in site preparation costs due to biomass harvesting of USD 75–450 ha−1, with a greater incentive when using cut-to-length harvesting systems compared with whole-tree harvesting due to the greater volume of residues after cut-to-length harvesting. For example, a removal of 20 t ha−1 of recoverable biomass after cut-to-length harvesting may equate to an economic incentive of USD 22 t−1. Depending on the biomass market, this incentive may represent a significant percentage (or even exceed) the biomass market price. The combination of biomass market price plus site preparation economic incentive may make biomass an attractive market opportunity, even in challenging biomarkets. Full article
(This article belongs to the Section Forest Economics, Policy, and Social Science)
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Article
Parameter Optimization of the 3PG Model Based on Sensitivity Analysis and a Bayesian Method
Forests 2020, 11(12), 1369; https://doi.org/10.3390/f11121369 - 21 Dec 2020
Cited by 3 | Viewed by 692
Abstract
Sensitivity analysis and parameter optimization of stand models can improve their efficiency and accuracy, and increase their applicability. In this study, the sensitivity analysis, screening, and optimization of 63 model parameters of the Physiological Principles in Predicting Growth (3PG) model were performed by [...] Read more.
Sensitivity analysis and parameter optimization of stand models can improve their efficiency and accuracy, and increase their applicability. In this study, the sensitivity analysis, screening, and optimization of 63 model parameters of the Physiological Principles in Predicting Growth (3PG) model were performed by combining a sensitivity analysis method and the Markov chain Monte Carlo (MCMC) method of Bayesian posterior estimation theory. Additionally, a nine-year observational dataset of Chinese fir trees felled in the Shunchang Forest Farm, Nanping, was used to analyze, screen, and optimize the 63 model parameters of the 3PG model. The results showed the following: (1) The parameters that are most sensitive to stand stocking and diameter at breast height (DBH) are nWs(power in stem mass vs. diameter relationship), aWs(constant in stem mass vs. diameter relationship), alphaCx(maximum canopy quantum efficiency), k(extinction coefficient for PAR absorption by canopy), pRx(maximum fraction of NPP to roots), pRn(minimum fraction of NPP to roots), and CoeffCond(defines stomatal response to VPD); (2) MCMC can be used to optimize the parameters of the 3PG model, in which the posterior probability distributions of nWs, aWs, alphaCx, pRx, pRn, and CoeffCond conform to approximately normal or skewed distributions, and the peak value is prominent; and (3) compared with the accuracy before sensitivity analysis and a Bayesian method, the biomass simulation accuracy of the stand model was increased by 13.92%, and all indicators show that the accuracy of the improved model is superior. This method can be used to calibrate the parameters and analyze the uncertainty of multi-parameter complex stand growth models, which are important for the improvement of parameter estimation and simulation accuracy. Full article
(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)
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Article
Suitability Evaluation and Dominant Function Model for Multifunctional Forest Management
Forests 2020, 11(12), 1368; https://doi.org/10.3390/f11121368 - 21 Dec 2020
Viewed by 802
Abstract
Multifunctional forest management is a common topic and hotspot of forestry research in recent years. Evaluating the suitability of forest land for multifunctional management is the first and most important step for realizing sustainable and multifunctional forest management. This research aims to explore [...] Read more.
Multifunctional forest management is a common topic and hotspot of forestry research in recent years. Evaluating the suitability of forest land for multifunctional management is the first and most important step for realizing sustainable and multifunctional forest management. This research aims to explore the suitability and forest dominant function evaluation model for multifunctional forestry management in Guangxi Zhuang Autonomous Region of China. Using the model proposed in the paper, we expect to provide decision-making information for forest multifunctional management. The study incorporated the distance of the ridge lines extracted by the Digital Elevation Model (DEM) data into the evaluation index, and established the ecological status index (IE) and the forest productivity index (IF). Moreover, a nonlinear multifunctional site quality evaluation model (MSQEM) was constructed to evaluate the suitability of multifunctional forest management. A multifunctional management dominant function orientation model (MDFOM) was constructed by Principal Component Analysis, and divided each subcompartment into one of the four resource subgroups, such as timber production function, water conservation function, water and soil conservation function, and other functions. The MDFOM model was used for Rongshui County’s forest resource by 11 factors, which were selected because of their easy availability. The factors contain slope, soil thickness, altitude, average age, etc. The results showed that the number of small classes with multifunctional site index larger than 0.5 was 20,841 (56.87%), and the multifunctional suitable area was in clustered distribution, which was consistent with the reality. The result of subcompartment dominant function evaluated by MDFOM was compared with the planning forest species, the overall accuracy was 61%, and the accuracy rate of timber production function was 94.2%. The number of subcompartments with good and above multifunctional management status was 9174 (44.20%), with an area of 48,963.41 hm2 (51.24%). The multifunctional management status of subcompartments in the study area is at the middle and lower level. Thus, it is urgent to further improve the multi-functional management level of each subcompartment in this area and formulate scientific reasonable and multifunctional forestation measures. Full article
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Article
Metabolome and Transcriptome Association Analysis Reveals Regulation of Flavonoid Biosynthesis by Overexpression of LaMIR166a in Larix kaempferi (Lamb.) Carr
Forests 2020, 11(12), 1367; https://doi.org/10.3390/f11121367 - 21 Dec 2020
Cited by 3 | Viewed by 802
Abstract
Somatic embryogenesis is an ideal model process for studying early plant development. Embryonic cell lines of Larix kaempferi (Lamb.) Carr overexpressing LaMIR166a were obtained in our previous study. Here, a combination of de novo transcriptomics and extensively targeted metabolomics was used to study [...] Read more.
Somatic embryogenesis is an ideal model process for studying early plant development. Embryonic cell lines of Larix kaempferi (Lamb.) Carr overexpressing LaMIR166a were obtained in our previous study. Here, a combination of de novo transcriptomics and extensively targeted metabolomics was used to study the transcriptional profiles and metabolic changes in wild-type and LaMIR166a-overexpressed embryonic cell lines. A total of 459 metabolites were found in the wild-type and transgenic cell lines. Compared to those in the wild-type cell lines, transcripts and metabolites were significantly altered in the LaMIR166a-overexpressed cell lines. Among differentially expressed genes (DEGs), phenylalanine and flavonoid synthesis genes were significantly enriched, and among differentially accumulated metabolites (DAMs), phenolic acids and flavonoids accumulated in particularly high amounts. Thus, the flavonoid biosynthetic pathway seems to be the most abundant pathway in response to LaMIR166a overexpression. Based on the Kyoto Encyclopedia of Genes and Genomes database, the association analysis of metabolome and transcriptome data showed that flavonoid biosynthesis and plant hormone signal transduction processes were significantly changed in miR166a-overexpression lines, suggesting that miR166 might be involved in these processes. The present study identified a number of potential metabolites associated with LaMIR166a overexpression, providing a significant foundation for a better understanding of the regulatory mechanisms underlying miR166. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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Article
A New Method for Forest Canopy Hemispherical Photography Segmentation Based on Deep Learning
Forests 2020, 11(12), 1366; https://doi.org/10.3390/f11121366 - 19 Dec 2020
Cited by 4 | Viewed by 1124
Abstract
Research Highlights: This paper proposes a new method for hemispherical forest canopy image segmentation. The method is based on a deep learning methodology and provides a robust and fully automatic technique for the segmentation of forest canopy hemispherical photography (CHP) and gap fraction [...] Read more.
Research Highlights: This paper proposes a new method for hemispherical forest canopy image segmentation. The method is based on a deep learning methodology and provides a robust and fully automatic technique for the segmentation of forest canopy hemispherical photography (CHP) and gap fraction (GF) calculation. Background and Objectives: CHP is widely used to estimate structural forest variables. The GF is the most important parameter for calculating the leaf area index (LAI), and its calculation requires the binary segmentation result of the CHP. Materials and Methods: Our method consists of three modules, namely, northing correction, valid region extraction, and hemispherical image segmentation. In these steps, a core procedure is hemispherical canopy image segmentation based on the U-Net convolutional neural network. Our method is compared with traditional threshold methods (e.g., the Otsu and Ridler methods), a fuzzy clustering method (FCM), commercial professional software (WinSCANOPY), and the Habitat-Net network method. Results: The experimental results show that the method presented here achieves a Dice similarity coefficient (DSC) of 89.20% and an accuracy of 98.73%. Conclusions: The method presented here outperforms the Habitat-Net and WinSCANOPY methods, along with the FCM, and it is significantly better than the Otsu and Ridler threshold methods. The method takes the original canopy hemisphere image first and then automatically executes the three modules in sequence, and finally outputs the binary segmentation map. The method presented here is a pipelined, end-to-end method. Full article
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Article
Photosynthetic and Morphological Acclimation to High and Low Light Environments in Petasites japonicus subsp. giganteus
Forests 2020, 11(12), 1365; https://doi.org/10.3390/f11121365 - 19 Dec 2020
Cited by 9 | Viewed by 1482
Abstract
Within each species, leaf traits such as light-saturated photosynthetic rate or dark respiration rate acclimate to local light environment. Comparing only static physiological traits, however, may not be sufficient to evaluate the effects of such acclimation in the shade because the light environment [...] Read more.
Within each species, leaf traits such as light-saturated photosynthetic rate or dark respiration rate acclimate to local light environment. Comparing only static physiological traits, however, may not be sufficient to evaluate the effects of such acclimation in the shade because the light environment changes diurnally. We investigated leaf photosynthetic and morphological acclimation for a perennial herb, butterbur (Petasites japonicus (Siebold et Zucc.) Maxim. subsp. giganteus (G.Nicholson) Kitam.) (Asteraceae), in both a well-lit clearing and a shaded understory of a temperate forest. Diurnal changes in light intensity incident on the leaves were also measured on a sunny day and an overcast day. Leaves in the clearing were more folded and upright, whereas leaves in the understory were flatter. Leaf mass per area (LMA) was approximately twofold higher in the clearing than in the understory, while light-saturated photosynthetic rate and dark respiration rate per unit mass of leaf were similar between the sites. Consequently, both light-saturated photosynthetic rate and dark respiration rate per unit area of leaf were approximately twofold higher in the clearing than in the understory, consistent with previous studies on different species. Using this experimental dataset, we performed a simulation in which sun and shade leaves were hypothetically exchanged to investigate whether such plasticity increased carbon gain at each local environment. As expected, in the clearing, the locally acclimated sun leaves gained more carbon than the hypothetically transferred shade leaves. By contrast, in the understory, the daily net carbon gain was similar between the simulated sun and shade leaves on the sunny day due to the frequent sunflecks. Lower LMA and lower photosynthetic capacity in the understory reduced leaf construction cost per area rather than maximizing net daily carbon gain. These results indicate that information on static photosynthetic parameters may not be sufficient to evaluate shade acclimation in forest understories. Full article
(This article belongs to the Special Issue Relationship between Forest Ecophysiology and Environment)
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Review
Use of Remote Sensing Data to Improve the Efficiency of National Forest Inventories: A Case Study from the United States National Forest Inventory
Forests 2020, 11(12), 1364; https://doi.org/10.3390/f11121364 - 19 Dec 2020
Cited by 18 | Viewed by 1909
Abstract
Globally, forests are a crucial natural resource, and their sound management is critical for human and ecosystem health and well-being. Efforts to manage forests depend upon reliable data on the status of and trends in forest resources. When these data come from well-designed [...] Read more.
Globally, forests are a crucial natural resource, and their sound management is critical for human and ecosystem health and well-being. Efforts to manage forests depend upon reliable data on the status of and trends in forest resources. When these data come from well-designed natural resource monitoring (NRM) systems, decision makers can make science-informed decisions. National forest inventories (NFIs) are a cornerstone of NRM systems, but require capacity and skills to implement. Efficiencies can be gained by incorporating auxiliary information derived from remote sensing (RS) into ground-based forest inventories. However, it can be difficult for countries embarking on NFI development to choose among the various RS integration options, and to develop a harmonized vision of how NFI and RS data can work together to meet monitoring needs. The NFI of the United States, which has been conducted by the USDA Forest Service’s (USFS) Forest Inventory and Analysis (FIA) program for nearly a century, uses RS technology extensively. Here we review the history of the use of RS in FIA, beginning with general background on NFI, FIA, and sampling statistics, followed by a description of the evolution of RS technology usage, beginning with paper aerial photography and ending with present day applications and future directions. The goal of this review is to offer FIA’s experience with NFI-RS integration as a case study for other countries wishing to improve the efficiency of their NFI programs. Full article
(This article belongs to the Special Issue Mapping and Monitoring Forest Cover)
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Article
Molecular Cloning and Functional Characterization of the DELLA Gene Family in Liriodendron Hybrids
Forests 2020, 11(12), 1363; https://doi.org/10.3390/f11121363 - 18 Dec 2020
Viewed by 722
Abstract
DELLA proteins are key components of the gibberellins signal transduction pathway that play negative roles on promoting cell elongation and plant stature. However, the mechanisms underlying DELLA mediated growth inhibition in woody plant species are poorly understood. Here, we identified two LhDELLA genes [...] Read more.
DELLA proteins are key components of the gibberellins signal transduction pathway that play negative roles on promoting cell elongation and plant stature. However, the mechanisms underlying DELLA mediated growth inhibition in woody plant species are poorly understood. Here, we identified two LhDELLA genes including LhSLR-like (LhSLRL) and LhRGA from Liriodendron hybrids (Liriodendron chinense (Hemsl.) Sarg. × L. tulipifera L.), which is a horticultural tree with high-quality timber. Sequence analysis showed that LhSLRL and LhRGA possessed all typical conserved domains of DELLA proteins. Phylogenetic analysis showed that LhRGA was classified as the basal branch of DELLAs from species belonging to dicots. Interestingly, LhSLRL was a sister clade of DELLAs from the most ancient plant species such as bryophytes and ferns. Gene expression analysis showed that LhSLRL and LhRGA genes had the highest expression level in the stem. In addition, overexpression of LhSLRL decreased plant height and root length, increased branching and delayed flowering in Arabidopsis thaliana, while LhRGA overexpression enlarged leaves and reduced the number and length of roots. Overexpressing LhSLRL in tobacco caused a decreased plant height and the amount of root. Taken together, these results reveal that LhDELLA genes may play an important role in plant growth and development, especially in vegetative organs. Our results provide new insights into the function of DELLA genes in a woody plant, and contribute to a potential application of manipulating DELLA genetics. Full article
(This article belongs to the Section Forest Ecophysiology and Biology)
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Communication
Changes in Proline Levels during Seed Development of Orthodox and Recalcitrant Seeds of Genus Acer in a Climate Change Scenario
Forests 2020, 11(12), 1362; https://doi.org/10.3390/f11121362 - 18 Dec 2020
Cited by 3 | Viewed by 1287
Abstract
In the present study, we examined the utility of proline usage as a biochemical indicator of metabolic changes caused by climate change (mean temperature and precipitation) during seed development of two Acer species differing in desiccation tolerance: Norway maple (Acer platanoides L.—desiccation [...] Read more.
In the present study, we examined the utility of proline usage as a biochemical indicator of metabolic changes caused by climate change (mean temperature and precipitation) during seed development of two Acer species differing in desiccation tolerance: Norway maple (Acer platanoides L.—desiccation tolerant—orthodox) and sycamore (Acer pseudoplatanus L.—desiccation sensitive—recalcitrant). In plants, proline is an element of the antioxidant system, which has a role in response to water loss and high temperatures. Our study considered whether proline could be treated as an indicator of tree seed viability, crucial for genetic resources conservation. Proline content was measured biweekly in developing seeds (between 11 and 23 weeks after flowering) collected in consecutive years (2017, 2018, and 2019). We showed that proline concentrations in recalcitrant seeds were positively correlated with mean two-week temperature. In contrast, in orthodox seeds no such relationship was found. Proline content proved to be sensitive to thermal-moisture conditions changes, which makes it a promising biochemical marker of seed desiccation tolerance in different climatic conditions. Full article
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Article
Structure and Composition of Terra Firme and Seasonally Flooded Várzea Forests in the Western Brazilian Amazon
Forests 2020, 11(12), 1361; https://doi.org/10.3390/f11121361 - 18 Dec 2020
Cited by 6 | Viewed by 1359
Abstract
Research Highlights: Rare, or sparsely distributed, species drive the floristic diversity of upland, terra firme and seasonally flooded forests in the central Juruá—a remote and hitherto floristically poorly known area in the Brazilian Amazon. Background and Objectives: Floristic inventories are critical [...] Read more.
Research Highlights: Rare, or sparsely distributed, species drive the floristic diversity of upland, terra firme and seasonally flooded forests in the central Juruá—a remote and hitherto floristically poorly known area in the Brazilian Amazon. Background and Objectives: Floristic inventories are critical for modelling and understanding the role of Amazonian forests in climate regulation, for sustainable management of forest resources and efficient conservation planning. Yet, detailed information about the often complex spatial distributions of many Amazonian woody plants is limited. Here, we provide information about forest structure and species composition from a remote terra firme forest and an adjacent floodplain forest in the western Brazilian Amazon. More specifically, we ask (1) how floristically different are the terra firme and floodplain forests? and (2) how variable is species composition within the same forest type? Materials and Methods: Between September 2016 and October 2017, we inventoried 97 plots (each 0.1 ha; 100 × 10 m) placed at least 800 m apart, with 46 plots in terra firme forest and 51 in seasonally flooded forest. We included all trees, hemi-epiphytes and palms with diameter at breast height (dbh) > 10 cm and woody lianas > 5 cm dbh. We examine forest structure, family- and species-level floristic composition and species diversity within and between forest types using family and species importance values, rarefaction curves and dissimilarity matrices. Results: Terra firme forest and seasonally flooded forest woody plant communities differ both in structure and species composition, which was highly variable within forest types. Many species were shared between terra firme and seasonally flooded forests, but most species were forest type-specific. Whereas species richness was greatest in the terra firme forest, floodplain species richness was among the highest regionally. Conclusions: Floodplain forests are a crucial complement to terra firme forests in terms of Amazonian woody plant diversity. Full article
(This article belongs to the Special Issue Structure, Function, and Dynamics of Tropical Floodplain Forests)
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Commentary
Comparing the Environmental Integrity of Emission Reductions from REDD Programs with Renewable Energy Projects
Forests 2020, 11(12), 1360; https://doi.org/10.3390/f11121360 - 18 Dec 2020
Cited by 8 | Viewed by 1757
Abstract
Reducing deforestation and forest degradation presents a climate-change mitigation opportunity that is critical to meeting the Paris Agreement goals, and to achieving reductions in the atmospheric concentrations of greenhouse gases (GHGs). Reducing Emissions from Deforestation and Forest Degradation (REDD) provides developing countries with [...] Read more.
Reducing deforestation and forest degradation presents a climate-change mitigation opportunity that is critical to meeting the Paris Agreement goals, and to achieving reductions in the atmospheric concentrations of greenhouse gases (GHGs). Reducing Emissions from Deforestation and Forest Degradation (REDD) provides developing countries with results-based financial incentives for reducing deforestation and forest degradation through either non-market payments (payments without generation of carbon credits), or market-based mechanisms (carbon credits). REDD credits have been recently accepted to be used in offsetting programs (e.g., CORSIA) and are being considered under Article 6. However, various publications have questioned whether carbon credits from REDD should be accepted under market-based mechanisms, and have identified issues regarding their environmental integrity and their ability to offset emissions from other sectors. In recent years, REDD implementation has moved from the project level to the national or subnational (jurisdictional) level, and is addressing some of the concerns that have been raised for project-level interventions regarding the robustness of baselines and leakage, for example. In this paper we compare the environmental integrity of credits from REDD programs with that from on-grid renewable energy projects by examining aspects related to permanence, additionality, baselines, uncertainty, and leakage. We show that the environmental integrity of emission reductions sourced from REDD programs has unique strengths, and that those sourced from renewable energy projects have weaknesses of their own. Probably due to a lack of understanding of the respective weaknesses and strengths of these two sources of credits, the emission reductions from REDD programs have been historically questioned and subjected to a level of scrutiny that has not been made with emission reductions from other sectors, such as renewable energy projects. Recognizing the strengths and weaknesses of emission reductions from both types should help decision makers and carbon standards recognize the high quality of emission reductions from REDD programs, and rationalize the current requirements or restrictions imposed. Full article
(This article belongs to the Special Issue REDD+: Protecting Climate, Forests and Livelihoods)
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Article
Stomatal and Leaf Morphology Response of European Beech (Fagus sylvatica L.) Provenances Transferred to Contrasting Climatic Conditions
Forests 2020, 11(12), 1359; https://doi.org/10.3390/f11121359 - 18 Dec 2020
Cited by 10 | Viewed by 1131
Abstract
Climate change-induced elevated temperatures and drought are considered to be serious threats to forest ecosystems worldwide, negatively affecting tree growth and viability. We studied nine European beech (Fagus sylvatica L.) provenances located in two provenance trial plots with contrasting climates in Central [...] Read more.
Climate change-induced elevated temperatures and drought are considered to be serious threats to forest ecosystems worldwide, negatively affecting tree growth and viability. We studied nine European beech (Fagus sylvatica L.) provenances located in two provenance trial plots with contrasting climates in Central Europe. Stomata play a vital role in the water balance of plants by regulating gaseous exchanges between plants and the atmosphere. Therefore, to explain the possible adaptation and acclimation of provenances to climate conditions, stomatal (stomatal density, the length of guard cells, and the potential conductance index) and leaf morphological traits (leaf size, leaf dry weight and specific leaf area) were assessed. The phenotypic plasticity index was calculated from the variability of provenances’ stomatal and leaf traits between the provenance plots. We assessed the impact of various climatic characteristics and derived indices (e.g., ecodistance) on intraspecific differences in stomatal and leaf traits. Provenances transferred to drier and warmer conditions acclimated through a decrease in stomatal density, the length of guard cells, potential conductance index, leaf size and leaf dry weight. The reduction in stomatal density and the potential conductance index was proportional to the degree of aridity difference between the climate of origin and conditions of the new site. Moreover, we found that the climate heterogeneity and latitude of the original provenance sites influence the phenotypic plasticity of provenances. Provenances from lower latitudes and less heterogeneous climates showed higher values of phenotypic plasticity. Furthermore, we observed a positive correlation between phenotypic plasticity and mortality in the arid plot but not in the more humid plot. Based on these impacts of the climate on stomatal and leaf traits of transferred provenances, we can improve the predictions of provenance reactions for future scenarios of global climate change. Full article
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Article
Changes in Community Composition of Tropical Evergreen Forests during Succession in Ta Dung National Park, Central Highlands of Vietnam
Forests 2020, 11(12), 1358; https://doi.org/10.3390/f11121358 - 18 Dec 2020
Viewed by 937
Abstract
Degradation of tropical forests is a major driver of the global extinction crisis. A key question is understanding the role of evolution history during forest succession in the context of forest restoration for maintaining ecosystem function and stability. This study was conducted in [...] Read more.
Degradation of tropical forests is a major driver of the global extinction crisis. A key question is understanding the role of evolution history during forest succession in the context of forest restoration for maintaining ecosystem function and stability. This study was conducted in a fragmented forest landscape in the central highlands of Vietnam. We sampled living trees with diameters at breast height of ≥6.0 cm in nineteen 0.25 ha plots to evaluate forest community structure changes over two early successional stages (<10 years and 10–20 years old) after abandonment and old-growth. We used both statistically metric and nonmetric analyses to examine correlations of community composition during successional stages and along elevational gradients. We found that (i) significant differences existed in the structural compositions between early successional forests and old-growth forests, but did not exist within early successional forests; (ii) the phylogenetic structure shifted from overdispersion to clustering with increasing successional ages; and (iii) above-ground biomass (AGB), representing ecosystem functioning, significantly increased from early-to-late successional stages, but did not correlate with phylogenetic diversity or elevation. Our results revealed that the forest community structure was strongly affected by degradation, particularly AGB and phylogenetic structure. These findings have clear implications for sustaining biodiversity persistence and ecosystem functioning in human-modified landscapes in the study region. Full article
(This article belongs to the Special Issue Modelling of Forests Structure and Biomass Distribution)
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Article
Feature-Level Fusion between Gaofen-5 and Sentinel-1A Data for Tea Plantation Mapping
Forests 2020, 11(12), 1357; https://doi.org/10.3390/f11121357 - 18 Dec 2020
Cited by 2 | Viewed by 846
Abstract
The accurate mapping of tea plantations is significant for government decision-making and environmental protection of tea-producing regions. Hyperspectral and Synthetic Aperture Radar (SAR) data have recently been widely used in land cover classification, but effective integration of these data for tea plantation mapping [...] Read more.
The accurate mapping of tea plantations is significant for government decision-making and environmental protection of tea-producing regions. Hyperspectral and Synthetic Aperture Radar (SAR) data have recently been widely used in land cover classification, but effective integration of these data for tea plantation mapping requires further study. This study developed a new feature-level image fusion method called LPPSubFus that combines locality preserving projection and subspace fusion (SubFus) to map tea plantations. Based on hyperspectral and SAR data, we first extracted spectral indexes, textures, and backscattering information. Second, this study applied LPPSubFus to tea plantation mapping with different classification algorithms. Finally, we compared the performance of LPPSubFus, SubFus, and pixel-level image fusion in tea plantation mapping. Feature-level image fusion performed better than pixel-level image fusion. An improvement of about 3% was achieved using feature-level image fusion compared to hyperspectral data alone. Regarding feature-level image fusion, LPPSubFus improved the overall accuracy by more than 3% compared to SubFus. In particular, LPPSubFus using neural network algorithms achieved the highest overall accuracy (95%) and over 90% producer and user accuracy for tea plantations and forests. In addition, LPPSubFus was more compatible with different classification algorithms than SubFus. Based on these findings, it is concluded that LPPSubFus has better and more stable performance in tea plantation mapping than pixel-level image fusion and SubFus. This study demonstrates the potential of integrating hyperspectral and SAR data via LPPSubFus for mapping tea plantations. Our work offers a promising tea plantation mapping method and contributes to the understanding of hyperspectral and SAR data fusion. Full article
(This article belongs to the Special Issue Remote Sensing Applications in Forests Inventory and Management)
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Article
Quantitative Genetic Variation in Bark Stripping of Pinus radiata
Forests 2020, 11(12), 1356; https://doi.org/10.3390/f11121356 - 18 Dec 2020
Cited by 7 | Viewed by 1656
Abstract
Bark stripping by mammals is a major problem for conifer forestry worldwide. In Australia, bark stripping in the exotic plantations of Pinus radiata is mainly caused by native marsupials. As a sustainable management option, we explored the extent to which natural variation in [...] Read more.
Bark stripping by mammals is a major problem for conifer forestry worldwide. In Australia, bark stripping in the exotic plantations of Pinus radiata is mainly caused by native marsupials. As a sustainable management option, we explored the extent to which natural variation in the susceptibility of P. radiata is under genetic control and is thus amenable to genetic improvement. Bark stripping was assessed at ages four and five years in two sister trials comprising 101 and 138 open-pollinated half-sib families. A third younger trial comprising 74 full-sib control-pollinated families was assessed at two and three years after planting. Significant additive genetic variation in bark stripping was demonstrated in all trials, with narrow-sense heritability estimates between 0.06 and 0.14. Within sites, the amount of additive genetic variation detected increased with the level of bark stripping. When strongly expressed across the two sister trials, the genetic signal was stable (i.e., there was little genotype × environment interaction). No significant non-additive effect (specific combining ability effect) on bark stripping was detected in the full-sib family trial, where it was estimated that up to 22.1% reduction in bark stripping might be achieved by selecting 20% of the less susceptible families. Physical traits that were genetically correlated, and likely influenced the amount of bark removed from the trees by the marsupials, appeared to depend upon tree age. In the older trials, these traits included bark features (presence of rough bark, rough bark height, and bark thickness), whereas in the younger trial where rough bark was not developed, it was the presence of obstructive branches or needles on the stem. In the younger trial, a positive genetic correlation between prior height and bark stripping was detected, suggesting that initially faster growing trees exhibit more bark stripping than slower growing trees but later develop rough bark faster and became less susceptible. While the presence of unexplained genetic variation after accounting for these physical factors suggests that other explanatory plant traits may be involved, such as chemical traits, overall the results indicate that selection for reduced susceptibility is possible, with potential genetic gains for deployment and breeding. Full article
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Erratum
Erratum: Perry, K.I., et al. Responses of Ground-Dwelling Invertebrates to Gap Formation and Accumulation of Woody Debris from Invasive Species, Wind, and Salvage Logging Running Title: Perry and Herms: Responses of Ground-Dwelling Invertebrates. Forests 2017, 8, 174
Forests 2020, 11(12), 1355; https://doi.org/10.3390/f11121355 - 18 Dec 2020
Viewed by 544
Abstract
There is an error in the title of this paper [...] Full article
Article
Low Population Differentiation but High Phenotypic Plasticity of European Beech in Germany
Forests 2020, 11(12), 1354; https://doi.org/10.3390/f11121354 - 18 Dec 2020
Cited by 4 | Viewed by 1010
Abstract
Drought is increasingly impairing the vitality of European beech (Fagus sylvatica L.) in several regions of its distribution range. In times of climate change, adaptive traits such as plant phenology and frost tolerance are also becoming more important. Adaptive patterns of European [...] Read more.
Drought is increasingly impairing the vitality of European beech (Fagus sylvatica L.) in several regions of its distribution range. In times of climate change, adaptive traits such as plant phenology and frost tolerance are also becoming more important. Adaptive patterns of European beech seem to be complex, as contrasting results regarding the relative effect of phenotypic plasticity and genetic variation in trait variation have been reported. Here, we used a large translocation experiment comprising more than 15,500 seedlings in three regions of Germany to investigate local adaptation and phenotypic plasticity in beech. We found low population differentiation regarding plant survival, and plant height increment, but high phenotypic plasticity for these traits. Survival showed a positive correlation with temperature variables and a less pronounced and negative correlation with precipitation-related variables. This suggests a predominant effect of temperature and growing degree days on the survival of beech seedlings under moderate drought stress. The high phenotypic plasticity may help beech to cope with changing environmental conditions, albeit increasing drought stress may make adaptive changes necessary in the long term. Full article
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Correction
Correction: Branca, G., et al. Forest Protection Unifies, Silviculture Divides: A Sociological Analysis of Local Stakeholders’ Voices after Coppicing in the Marganai Forest (Sardinia, Italy). Forests 2020, 11, 708
Forests 2020, 11(12), 1353; https://doi.org/10.3390/f11121353 - 17 Dec 2020
Viewed by 693
Abstract
We have recently been made aware by the Forests Editorial Offices of some errors and omissions in the Introduction Section 1 [...] Full article
Review
Poplar Short Rotation Coppice Plantations under Mediterranean Conditions: The Case of Spain
Forests 2020, 11(12), 1352; https://doi.org/10.3390/f11121352 - 17 Dec 2020
Cited by 14 | Viewed by 1367
Abstract
Developing a circular bioeconomy based on the sustainable use of biological resources, such as biomass, seems to be the best way of responding to the challenges associated with global change. Among the many sources, short rotation forest crops are an essential instrument for [...] Read more.
Developing a circular bioeconomy based on the sustainable use of biological resources, such as biomass, seems to be the best way of responding to the challenges associated with global change. Among the many sources, short rotation forest crops are an essential instrument for obtaining quality biomass with a predictable periodicity and yield, according to the areas of cultivation. This review aims to provide an overview of available knowledge on short rotation coppice Populus spp. plantations under Mediterranean conditions and specifically in Spain, in order to identify not only the status, but also the future prospects, for this type of biomass production. The analysis of available information was conducted by taking into consideration the following aspects: Genetic plant material; plantation design, including densities, rotation lengths and the number of rotations, and mixtures; management activities, including irrigation, fertilization, and weed control; yield prediction; biomass characterization; and finally, an evaluation of the sustainability of the plantation and ecosystem services provided. Despite advances, there is still much to be done if these plantations are to become a commercial reality in some Mediterranean areas. To achieve this aim, different aspects need to be reconsidered, such as irrigation, bearing in mind that water restrictions represent a real threat; the specific adaptation of genetic material to these conditions, in order to obtain a greater efficiency in resource use, as well as a greater resistance to pests and diseases or tolerance to abiotic stresses such as drought and salinity; rationalizing fertilization; quantifying and valuing the ecosystem services; the advance of more reliable predictive models based on ecophysiology; the specific characterization of biomass for its final use (bioenergy/bioproducts); technological improvements in management and harvesting; and finally, improving the critical aspects detected in environmental, energy, and economic analyses to achieve profitable and sustainable plantations under Mediterranean conditions. Full article
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Article
Uranium Vertical and Lateral Distribution in a German Forested Catchment
Forests 2020, 11(12), 1351; https://doi.org/10.3390/f11121351 - 17 Dec 2020
Cited by 1 | Viewed by 714
Abstract
The natural measurements of uranium (U) are important for establishing natural baseline levels of U in soil. The relations between U and other elements are important to determine the extent of geological origin of soil U. The present study was aimed at providing [...] Read more.
The natural measurements of uranium (U) are important for establishing natural baseline levels of U in soil. The relations between U and other elements are important to determine the extent of geological origin of soil U. The present study was aimed at providing a three-dimensional view of soil U distribution in a forested catchment (ca. 38.5 ha) in western Germany. The evaluated data, containing 155 sampled points, each with four major soil horizons (L/Of, Oh, A, and B), were collected from two existing datasets. The vertical U distribution, the lateral pattern of U in the catchment, and the occurrence of correlations between U and three groups of elements (nutrient elements, heavy metals, and rare earth elements) were examined. The results showed the median U concentration increased sevenfold from the top horizon L/Of (0.14 mg kg−1) to the B horizon (1.01 mg kg−1), suggesting a geogenic origin of soil U. Overall, soil U concentration was found to be negatively correlated with some plant macronutrients (C, N, K, S, Ca) but positively with others (P, Mg, Cu, Zn, Fe, Mn, Mo). The negative correlations between U and some macronutrients indicated a limited accumulation of plant-derived U in soil, possibly due to low phytoavailability of U. Positive correlations were also found between U concentration and heavy metals (Cr, Co, Ni, Ga, As, Cd, Hg, Pb) or rare earth elements, which further pointed to a geogenic origin of soil U in this forested catchment. Full article
(This article belongs to the Section Forest Ecology and Management)
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Review
Results Based Payments for REDD+ under the Green Climate Fund: Lessons Learned on Social, Environmental and Governance Safeguards
Forests 2020, 11(12), 1350; https://doi.org/10.3390/f11121350 - 17 Dec 2020
Cited by 3 | Viewed by 1639
Abstract
United Nations Framework Convention on Climate Change (UNFCCC) Decisions for reducing emissions from deforestation and forest degradation in developing countries (REDD+) recognize its role in poverty alleviation, enhancing social and environmental resilience and ensuring linkages between mitigation and adaptation. Similarly, the UNFCCC recognizes [...] Read more.
United Nations Framework Convention on Climate Change (UNFCCC) Decisions for reducing emissions from deforestation and forest degradation in developing countries (REDD+) recognize its role in poverty alleviation, enhancing social and environmental resilience and ensuring linkages between mitigation and adaptation. Similarly, the UNFCCC recognizes the diversity of potential environmental and social risks and benefits that could result from REDD+ implementation. As a result, the UNFCCC adopted a set of social, environmental and governance safeguards, commonly known as “Cancun Safeguards.” Cancun Safeguards should be addressed and respected throughout REDD+ implementation regardless of the source and type of funding and play a key role in accessing results-based finance. The UNFCCC provides guidance regarding an information system as well as up-to-date reports as information and reporting tools on how all Cancun Safeguards have been addressed and respected. However, the UNFCCC does not offer any guidance on how to consider, assess and/or verify reported information. Given the key role that the Green Climate Fund (GCF) plays in channeling REDD+ results-based finance, this research paper examines early lessons from the GCF’s pilot programme for REDD-plus results-based payments (RBPs). It assesses the extent to which REDD+ activities have been implemented in consistency with the Cancun Safeguards. This paper examines the assessment and verification procedures of the GCF’s pilot programme. Key informant interviews have been a key source of information. We conclude that assessing the extent to which REDD+ results-based activities have in fact been consistent with Cancun Safeguards is a complex endeavor. Such complexity requires a qualitative approach as well as a dedicated verification procedure. This in turn has not been fully captured in the GCF’s pilot programme. Additionally, we conclude that by requiring countries to demonstrate conformance with its interim safeguards in the context of REDD+ results-based finance, the GCF’s pilot programme poses a significant burden to countries’ abilities to access results-based financing. Full article
(This article belongs to the Special Issue REDD+: Protecting Climate, Forests and Livelihoods)
Article
Investigation of the Factors Affecting Artificial Seed Sowing Success and Seedling Survival in Pinus brutia Natural Stands in Middle Elevations of Central Cyprus
Forests 2020, 11(12), 1349; https://doi.org/10.3390/f11121349 - 17 Dec 2020
Cited by 2 | Viewed by 904
Abstract
The aim of this study was to analyze the germination of Pinus brutia Ten. seeds, in the field, in relation to factors such as period of sowing, light environment, and watering, in sites of different productivity in the middle elevations in central Cyprus. [...] Read more.
The aim of this study was to analyze the germination of Pinus brutia Ten. seeds, in the field, in relation to factors such as period of sowing, light environment, and watering, in sites of different productivity in the middle elevations in central Cyprus. Two sowing experiments were conducted in three sites of different productivity. In the first experiment P. brutia seed sowing took place in February 2009 in two sowing environments which were gap and under canopy environments. The shade conditions in those environments were determined using hemispherical photographs. Also, the influence of watering on the seed germination was checked. In the second experiment, which was established in the same areas as in the first experiment, the seed sowing took place in December 2009. However, in this case, no watering was applied during the germination period. Moreover, the survival of the seedlings from both sowing periods were monitored up to the end of 2010. During the period of monitoring, the influence of watering was checked. The germination rates of seeds from the February sowing were very low. On the contrary, from the December sowing, the germination rates of seeds were very high in both sowing environments in all studied sites. In the case of seedling survival from the February and December sowing, mortality rates were relatively high in all sites except from the under-canopy sowing environment where watering was applied in the medium productivity site. From the December sowing, from a practical point of view, the number of survived seedlings, in all the plots of the three sites can be considered adequate for the successful regeneration of P. brutia. Full article
(This article belongs to the Special Issue Application of Innovative Silvicultural Treatments in Pine Forests)
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Article
Potassium-Solubilizing Activity of Bacillus aryabhattai SK1-7 and Its Growth-Promoting Effect on Populus alba L.
Forests 2020, 11(12), 1348; https://doi.org/10.3390/f11121348 - 17 Dec 2020
Cited by 8 | Viewed by 962
Abstract
In the present study, the potassium-solubilizing characteristics of Bacillus aryabhattai SK1-7 and its growth-promoting effect on plants were evaluated to determine the biotechnological potential of this bacterium in alleviating soil potassium deficiency. The potassium-solubilizing activity of SK1-7 was determined by fermentation. Additionally, the [...] Read more.
In the present study, the potassium-solubilizing characteristics of Bacillus aryabhattai SK1-7 and its growth-promoting effect on plants were evaluated to determine the biotechnological potential of this bacterium in alleviating soil potassium deficiency. The potassium-solubilizing activity of SK1-7 was determined by fermentation. Additionally, the fermentation broth was determined by flame spectrophotometry. The aluminum and silicon ion contents in SK1-7 fermentation broth were determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) after digestion with nitric acid hydrogen peroxide hydrofluoric acid. Scanning electron microscopy (SEM)-based observations were performed to assess the morphological changes in potassium feldspar surfaces digested by potassium-solubilizing bacteria. In addition, the effects of SK1-7 on plant growth and soil physical and chemical properties were analyzed. After incubation for 7 days in a potassium-solubilizing medium, the concentration of potassium dissolved reached 10.8 μg/mL and the percentage of potassium released was 32.6%. The pH rapidly decreased from 7.2 to 4.321 within the first day and then further decreased to 3.90 after 7 days. After 7 days, the concentrations of aluminum and silicon in the fermentation broth were 1.01 and 24.19 μg/mL, respectively. The growth promotion assay results showed that SK1-7 has good growth-promoting effects on poplar and can effectively improve the available potassium content in poplar rhizosphere soil. The SK1-7 strain can effectively dissolve insoluble potassium to release soluble potassium ions and clearly promotes the growth of poplar after being applied to soil. Thus, the SK1-7 strain is a potassium-solubilizing microorganism with good application prospects. Full article
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Article
Evaluating Street Greenery by Multiple Indicators Using Street-Level Imagery and Satellite Images: A Case Study in Nanjing, China
Forests 2020, 11(12), 1347; https://doi.org/10.3390/f11121347 - 17 Dec 2020
Cited by 6 | Viewed by 1095
Abstract
Street greenery plays an essential role in improving the street environment and residents’ health. The evaluation of street greenery is of great value to establish environmentally friendly streets. The evaluation indicators of present studies evaluating street greenery were relatively single, either the Green [...] Read more.
Street greenery plays an essential role in improving the street environment and residents’ health. The evaluation of street greenery is of great value to establish environmentally friendly streets. The evaluation indicators of present studies evaluating street greenery were relatively single, either the Green View Index (GVI) or Normalized Difference Vegetation Index (NDVI), which cannot describe the greenery condition in its entirety. The objective of this study is to assess the street greenery using multiple indicators, including GVI, NDVI, and Vegetation Structural Diversity (VSD). We combined street view images with a semantic segmentation method to extract the GVI and VSD and used satellite images to calculate the NDVI in the urban area of Nanjing, China. We found correlations and discrepancies of these indicators using statistical analyses in different urban districts, functional areas, and road levels. The results indicate that: (1) the GVI and NDVI are strongly correlated in open spaces, whereas weakly correlated in residential and industrial lands, (2) the areas with higher VSD are mainly located in the new city, whereas the VSD in the old city is lower, and a weak negative correlation exists between the GVI and VSD in the research area, and (3) the old city has a higher GVI level compared to the new city on the main road, whereas the new city has a higher GVI level than the old city on the branch road. Compared with the GVI, the trend of VSD in the old city and the new city is relatively consistent. Our findings suggest that considering multiple indicators of street greenery evaluation can provide a comprehensive reference for building more human-friendly and diversified street green belts. Full article
(This article belongs to the Section Forest Inventory, Modeling and Remote Sensing)
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Article
Dynamics in Stoichiometric Traits and Carbon, Nitrogen, and Phosphorus Pools across Three Different-Aged Picea asperata Mast. Plantations on the Eastern Tibet Plateau
Forests 2020, 11(12), 1346; https://doi.org/10.3390/f11121346 - 17 Dec 2020
Cited by 3 | Viewed by 994
Abstract
Understanding the variations in soil and plants with stand aging is important for improving management measures to promote the sustainable development of plantations. However, few studies have been conducted on the dynamics of stoichiometric traits and carbon (C), nitrogen (N), and phosphorus (P) [...] Read more.
Understanding the variations in soil and plants with stand aging is important for improving management measures to promote the sustainable development of plantations. However, few studies have been conducted on the dynamics of stoichiometric traits and carbon (C), nitrogen (N), and phosphorus (P) pools across Picea asperata Mast plantations of different ages in subalpine regions. In the present study, we examined the stoichiometric traits and C, N, and P stocks in different components of three different aged (22-, 32-, and 42-year-old) P. asperata plantations by plot-level inventories. We hypothesized that the stoichiometric traits in mineral soil could shape the corresponding stoichiometric traits in soil microbes, tree roots and foliage, and the C, N, and P stocks of the total P. asperata plantation ecosystem would increase with increasing stand age. Our results show that the N:P ratio in mineral soil was significantly correlated with that in tree foliage and herbs. Additionally, the C:N ratio and C:P ratio in mineral soil only correlated with the corresponding stoichiometric traits in soil microbes and forest floor, respectively. Both the fractions of microbial biomass C in soil organic C and microbial biomass N in soil total N decreased with increasing stand age. The C, N, and P stocks of the total ecosystem did not continuously increase across stand development. In particular, the P stock of the total ecosystem exhibited a trend of increasing first and then decreasing. The aboveground tree biomass C accounted for more than 55% of the total ecosystem C stock regardless of stand age. In contrast, mineral soil and forest floor were the major contributors to the total ecosystem N and P stocks in all stands. This study suggested that all three different stands were N limited, and the stoichiometric homeostasis in the roots of P. asperata was more stable than that in the foliage. In addition, the soil microbial community assembly may change with increasing stand age for P. asperata plantations in the subalpine region. Full article
(This article belongs to the Section Forest Ecology and Management)
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Article
Post-Fire Recovery of Vegetation and Diversity Patterns in Semiarid Pinus halepensis Mill. Habitats after Salvage Logging
Forests 2020, 11(12), 1345; https://doi.org/10.3390/f11121345 - 17 Dec 2020
Cited by 6 | Viewed by 1159
Abstract
After wildfires, emergency actions and post-fire management are implemented to mitigate fire damage. Salvage logging is a tool often applied to burned stands, but despite being a post-fire forest management tool to restore ecosystem functions, its ecological effects remain poorly understood. In the [...] Read more.
After wildfires, emergency actions and post-fire management are implemented to mitigate fire damage. Salvage logging is a tool often applied to burned stands, but despite being a post-fire forest management tool to restore ecosystem functions, its ecological effects remain poorly understood. In the Mediterranean Basin, where land use and land-use change are bringing about changes in drought periods and fire regimes, optimal treatments should be included in adaptive management in order to increase resilience and reduce vulnerability. In July 2012, a mid- to high-burn severity fire burned almost 7000 ha of an Aleppo pine forest (Pinus halepensis Mill.) in southeastern Spain. Five years later (late spring 2017), we designed an experimental study to monitor four stand categories on a burn severity basis (unburned mature stands, low-burn severity stands, and high-burn severity stands) and a salvage logging operation carried out 6 months after the fire in high-burn severity areas. We set 60 circular plots (15 in each treatment scenario) and 180 linear transects (3 per plot, 45 per scenario) to check the ecological facilitation of pine trees and snags (canopy size and/or perch effect). We estimated plant alpha diversity (floristic richness, abundance and dominance indices) and post-fire plant recovery (pine recruitment and adaptive traits). Fire depleted the system’s diversity, but in low-severity burning areas some basic functions remained intact (e.g., soil protection). We found that high-burn severity very negatively impacted ecosystem functions through the removal of duff and litter leaving unprotected soil. Collecting wood reduced pine regeneration and growth, which was considerable in the areas that suffered high-burn severity. The burned snags did not appear to act as perches resulting in seed dispersal. Obligate seeders were determined to be an efficient strategy for facing high-severity fires, whereas resprouters response showed no clear burn severity pattern despite being present in all the scenarios. Therefore, salvage logging did not affect the recovery of some ecosystem properties/features (such as plant total cover or litter cover), although retaining dead pines facilitated pine regeneration. Thus, leaving snags in areas affected by high-burn severity in ecosystems mainly modelled by fires is proposed. However, the ecosystem response could be widely variable and influenced by local abiotic factors, so restoration might not be as effective as in the current proposal. Full article
(This article belongs to the Special Issue Forest Fires and Biodiversity in the Anthropocene)
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