Journal Description
Forests
Forests
is a peer-reviewed, open access journal of forestry and forest ecology published monthly online by MDPI.
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Impact Factor:
2.634 (2020)
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5-Year Impact Factor:
2.804 (2020)
Latest Articles
Comparison of Variable Selection Methods among Dominant Tree Species in Different Regions on Forest Stock Volume Estimation
Forests 2022, 13(5), 787; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050787 - 18 May 2022
Abstract
The forest stock volume (FSV) is one of the crucial indicators to reflect the quality of forest resources. Variable selection methods are usually used for FSV estimated models. However, few studies have explored which variable selection methods can make the selected data set
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The forest stock volume (FSV) is one of the crucial indicators to reflect the quality of forest resources. Variable selection methods are usually used for FSV estimated models. However, few studies have explored which variable selection methods can make the selected data set have better explanatory and robustness for the same dominant tree species in different regions after the feature variables were filtered by the feature selection methods. In this study, we chose six dominant tree species from Lin’an District, Anji County, and a part of Longquan City. The tree species include broad-leaved, coniferous, Masson pine, Chinese fir, coniferous and broad-leaved mixed forest, and all tree species which include the above five groups of tree species. The last two tree species were represented by mixed and all, respectively. Then, the satellite images, terrain factors, and forest inventory data were selected by six variable selection methods (least absolute shrinkage and selection operator (LASSO), recursive feature elimination (RFE), stepwise regression (Step-Reg), permutation importance (PI), mean decrease impurity (MDI), and SelectFromModel based on LightGBM (SFM)), according to different dominant tree types in different regions. The selected variables were formed into a new dataset divided by different dominant trees. Besides, extreme gradient boosting (XGBoost) was used, combined with variable selection methods to estimate the FSV. The performed results are as follows: In the feature selection of coniferous, RFE performed better both in the average and in the separate regions. In the feature selection of Chinese fir and all, PI performed better both in the average and in the separate regions. In the feature selection of Masson pine, MDI performed better both in the average and in the separate regions. In the feature selection of mixed, MDI performed better in the average while RFE performed better in the separate regions comprehensively. The results showed that not only in separate regions, but the average result two factors, RFE, MDI, and PI all performed well to select variables to estimate the FSV. Furthermore, we selected the top five high feature-importance factors of different tree types, and the results showed that tree age and canopy density were both of great importance to the estimation of FSV. Besides, in the exhibited results of feature selection methods, compared with no variable selection, the research also found that variable selection can improve the performance of the model. Additionally, from the results of different tree types in different regions, we also found that small-scale and diversity of dominant tree types may lead to the instability and unreliability of experimental results. The study provides some insight into the application the optimal variable selection methods of the same dominant tree type in different regions. This study will help the development of variable selection methods to estimate FSV.
Full article
(This article belongs to the Special Issue Remote Sensing Application in Forest Biomass and Carbon Cycle)
Open AccessArticle
U.S. and Global Wood Energy Outlook under Alternative Shared Socioeconomic Pathways
Forests 2022, 13(5), 786; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050786 - 18 May 2022
Abstract
There has been a significant increase in the use of wood pellets for energy in the past decade due in large part to their climate mitigation potential. Because of this, the demand for wood pellets is largely driven by policy, as well as
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There has been a significant increase in the use of wood pellets for energy in the past decade due in large part to their climate mitigation potential. Because of this, the demand for wood pellets is largely driven by policy, as well as socioeconomic development, making projections of future wood energy markets highly uncertain. The aim of this study is to provide projections of future wood energy market trends under five distinct socioeconomic scenarios based on the assumed future evolution of gross domestic product, population, technological change, trade openness, and bioenergy preferences using the FOrest Resource Outlook Model. In four out of the five scenarios considered, it is projected that the use of roundwood and mill chips, particles, and residuals will rise in order to produce a growing output of wood pellets in the United States and globally. In terms of international markets, the global dominance of Europe’s demand for wood, to help that continent achieve its own climate goals, further explains the sustained and growing supply position of the U.S. South regions to meet that demand. Taken together, the projections suggest emerging bioenergy markets will drive increased competition for inputs with other manufacturers, particularly in the U.S. South regions.
Full article
(This article belongs to the Special Issue Production, Trade and Consumption of Wood-Based Products)
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Open AccessArticle
The Potential of Ecological Restoration Programs to Increase Erosion-Induced Carbon Sinks in Response to Future Climate Change
Forests 2022, 13(5), 785; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050785 - 18 May 2022
Abstract
Erosion-induced carbon sinks are a wild card in the global carbon budget. Soil erosion results in aggregate carbon sequestration by reforming organic–inorganic complexes at depositional areas and plant reserves. The carbon sinks at the depositional sites are rarely considered in the prediction of
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Erosion-induced carbon sinks are a wild card in the global carbon budget. Soil erosion results in aggregate carbon sequestration by reforming organic–inorganic complexes at depositional areas and plant reserves. The carbon sinks at the depositional sites are rarely considered in the prediction of erosion-induced carbon sink dynamics. The effects of large-scale ecological restoration programs (ERPs) in subtropical regions on soil carbon sinks are still unclear. This study analyzed the potential effects of ERPs on erosion-induced carbon sinks in a red soil hilly region (RSHR) from 2030 to 2060. Based on a land use dataset and two climate scenarios of moderate (RCP4.5) and high emission paths (RCP8.5), three land use change (LUC) patterns were designed: an Ecological Restoration (ER) pattern; a Business-As-Usual (BAU) pattern; and a No LUC pattern. The results of the ER pattern and BAU pattern were compared with those of the No LUC pattern to reflect the role of ERPs in reducing erosion and increasing erosion-induced carbon sinks. The results indicated that the erosion-induced carbon sinks of forestland increased (58 kg km−2) in the BAU pattern under the RCP8.5 scenario and erosion-induced carbon sinks of cropland increased (39 kg km−2) in the ER pattern under the RCP8.5 scenario. In RCP4.5 and RCP8.5, the erosion-induced carbon sinks of the RSHR increased by 210 Tg and 85 Tg from 2030 to 2060, respectively (1 Tg = 1012 g). The average annual erosion-induced carbon sink accounted for 3.84% and 1.41% of the annual average carbon sequestration of terrestrial ecosystems, respectively. Neither the BAU pattern nor the ER pattern achieved the purpose of increasing grassland carbon sinks induced by soil erosion. Therefore, the focus of future ERP optimization should be to increase grassland carbon sinks. Our study provides new evidence for research into erosion-induced carbon sinks to mitigate global climate change and a scientific basis for increasing erosion-induced carbon sinks in croplands, forestlands and grasslands in the RSHR of southern China.
Full article
(This article belongs to the Section Forest Soil)
Open AccessArticle
Ecosystem Carbon Stocks and Their Annual Sequestration Rate in Mature Forest Stands on the Mineral Soils of Estonia
Forests 2022, 13(5), 784; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050784 - 18 May 2022
Abstract
Mature forest ecosystems are the most considerable reservoir of organic carbon (OC) among terrestrial ecosystems. The effect of soil type on aboveground OC stocks and their annual increases (AI) of overstorey tree, understorey tree and ground vegetation layers in Estonian forest phytocoenoses with
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Mature forest ecosystems are the most considerable reservoir of organic carbon (OC) among terrestrial ecosystems. The effect of soil type on aboveground OC stocks and their annual increases (AI) of overstorey tree, understorey tree and ground vegetation layers in Estonian forest phytocoenoses with mature stands on mineral soils were studied. The study enfolds nine mineral soil groups, which are characterized by their phytocoenoses composition, soil cover properties and tree stands’ taxation data. An assemblage of soil and plant cover or plant–soil system is the main focus point in explaining causal and quantitative sides of ecosystems functioning. Surface densities of OC stocks in aboveground phytomass of forests varied significantly in the range of 52–100 Mg OC ha−1. High AI or productivity (4.8–5.5 Mg OC ha−1 year−1) is a characteristic of forest ecosystems formed on leached, eluviated and pseudopodzolic soils. Forest ecosystem ground vegetation, which is an important ecological indicator, fulfils vacant ecological niches with herbs and/or mosses (up to 0.50 Mg OC ha−1). The variation of ecosystem OC stocks and their AI by soil type should be taken into account in regional OC stocks and its annual increase estimations.
Full article
(This article belongs to the Special Issue Soil Organic Matter and Nutrient Cycling in Forests)
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Open AccessArticle
Quality Assessment and Rehabilitation of Mountain Forest in the Chongli Winter Olympic Games Area, China
by
, , , , , , and
Forests 2022, 13(5), 783; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050783 - 18 May 2022
Abstract
Spurred by the degraded forest in the 2022 Chongli Winter Olympic Games area, the Chinese government initiated a national program for mountain forest rehabilitation. We developed a method to assess the quality of mountain forests using an index system composed of stand structure,
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Spurred by the degraded forest in the 2022 Chongli Winter Olympic Games area, the Chinese government initiated a national program for mountain forest rehabilitation. We developed a method to assess the quality of mountain forests using an index system composed of stand structure, site conditions, and landscape aesthetics at three criteria levels. The method involves index weights determined by the analytical hierarchy process (AHP) and entropy method. The results show that landscape aesthetics was the most important measure for the criterion layer. Slope aspect and naturalness were the most and second-most important indices, respectively, for the alternative layer. The quality of the mountain forest in the Chongli area was divided into four grades. The area had 7.8% with high quality, 46.7% with medium quality, 36.6% with low quality, and 8.9% with inferior quality. In total 76.6% of the damaged forest were distributed on sloping and steep sloping ground at 1700 to 2050 m altitude, and Betula platyphylla Sukaczev and Larix gmelinii var. principis-rupprechtii (Mayr) Pilg. were the predominating trees. The damaged forest was divided into over-dense, over-sparse, degraded, inappropriate tree species, and inferior landscape forest. For different types of damaged forest, corresponding modification measures were proposed. The methods developed in this study can be used for rehabilitation projects to improve the quality of degraded forests in mountainous temperate areas.
Full article
(This article belongs to the Special Issue Ecological Forestry and Restoration)
Open AccessArticle
Computation of Strip Road Networks Based on Harvester Location Data
by
and
Forests 2022, 13(5), 782; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050782 - 18 May 2022
Abstract
The location information of strip roads in thinnings and the numerical variables of strip roads are one aspect of timber harvest quality information. The ideal of automatic quality management for mechanized logging is that the quality of the harvest is calculated and reported
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The location information of strip roads in thinnings and the numerical variables of strip roads are one aspect of timber harvest quality information. The ideal of automatic quality management for mechanized logging is that the quality of the harvest is calculated and reported based on data collected by forest machines. At present, quality data is collected by means of laborious, manual, field-based, post-harvest measurements. The aim of this study was to develop an automatic method to compute the strip roads of the harvested stands after harvesting, based on the stem-specific location data of the harvester. Subsequently, the strip road variables were computed from the strip road networks. The computed strip road networks were validated with 21 manually recorded field references. The method was also applied to operational stand data, including 544 harvested stands collected from Southern Finland. The results showed that the computation method produces well-located, stand-specific strip road networks from which strip road variables can be accurately determined, covering the whole stand. Thus, the method promotes the automation of quality management and reporting. The computed strip road networks can also support harvester operator work during the harvesting and, later, the automation of harvesting operations.
Full article
(This article belongs to the Special Issue Recent Advances in Wood Harvesting, Timber Logistics and Road Planning)
Open AccessArticle
Identification and Analysis of JAZ Gene Family in Ginkgo biloba Reveals Candidate Genes for Biosynthesis of Terpene Trilactones
Forests 2022, 13(5), 781; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050781 - 18 May 2022
Abstract
Terpene trilactones (TTLs) are the main secondary metabolites in Ginkgo biloba L. with efficacious pharmacological activity. Jasmonate ZIM-domain (JAZ) protein is a key regulatory factor of the JA signaling pathway, which regulates the biosynthesis of secondary metabolites such as terpenes, alkaloids, and flavonoids.
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Terpene trilactones (TTLs) are the main secondary metabolites in Ginkgo biloba L. with efficacious pharmacological activity. Jasmonate ZIM-domain (JAZ) protein is a key regulatory factor of the JA signaling pathway, which regulates the biosynthesis of secondary metabolites such as terpenes, alkaloids, and flavonoids. In this study, GbJAZ01~GbJAZ11 were identified from the genome data in G. biloba, which contained TIFY-, Jas-, and weakly conserved NT-domains, and the promoters in most of them contained light, hormone, and stress-responsive elements. Phylogenetic analysis divided all JAZ proteins of Arabidopsis thaliana, Oryza sativa, Picea sitchensis, Taxus chinensis, and G. biloba into nine groups, in which GbJAZs belong to Group VI-IX. GbJAZs have similar functional motifs to A. thaliana and O. sativa, but also contain three specific motifs of gymnosperms, indicating that, although gymnosperms and angiosperms have some conservative structures and functions, their evolutionary processes are independent. Expression pattern analysis showed that the expression levels of GbJAZs were significantly up-regulated by MeJA, but the change pattern and amplitude were different, indicating that the function of GbJAZs in response to a JA signal may be different. After ABA and SA treatment, the expression of GbJAZs was up-regulated or inhibited in varying degrees, and different GbJAZs may be involved in the synergistic or antagonistic effects between JA and other hormone signals. The MeJA significantly increased the content of TTLs in G. biloba leaves, which were significantly positively correlated with the expression levels of GbJAZ01, 02, 07, and 11, and negatively correlated with the expression of GbJAZ04. They may play an important role in JA signaling pathways and the interactions between JA and other hormone signals, and participate in the regulation of the biosynthesis of TTLs. Our results provide a reference for the discovery that GbJAZs are involved in JA signaling pathways, and lay a theoretical foundation for analyzing JA signaling pathways to regulate the synthesis of secondary metabolites.
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(This article belongs to the Section Genetics and Molecular Biology)
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Open AccessEditorial
Abiotic and Biotic Stress Cascades in the Era of Climate Change Pose a Challenge to Genetic Improvements in Plants
Forests 2022, 13(5), 780; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050780 - 18 May 2022
Abstract
Forest ecosystems are vast, second in expanse only to marine ecosystems [...]
Full article
(This article belongs to the Special Issue Forest-Tree Gene Regulation in Response to Abiotic and Biotic Stress)
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Open AccessArticle
Extractives of Tree Biomass of Scots Pine (Pinus sylvestris L.) for Biorefining in Four Climatic Regions in Finland—Lipophilic Compounds, Stilbenes, and Lignans
by
, , , , , , and
Forests 2022, 13(5), 779; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050779 - 18 May 2022
Abstract
The aim of the study was to quantify total extractive contents and lipophilic compounds, stilbenes, and lignans in Scots pine stem wood, stem bark, branch biomass, and sawmill residues in four climatic regions of Finland to evaluate the most optimal sources of extractives
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The aim of the study was to quantify total extractive contents and lipophilic compounds, stilbenes, and lignans in Scots pine stem wood, stem bark, branch biomass, and sawmill residues in four climatic regions of Finland to evaluate the most optimal sources of extractives for bio-based chemical biorefining and bioenergy products. Data were derived from 78 chip samples from the before-mentioned raw materials, the samples being pooled by tree height position from the sample trees of 42 experimental forest stands, and sawdust lots from 10 log stands. Accelerated solvent extraction (ASE) was employed to determine total extractive contents, followed by gas chromatography with flame ionization detection (GC–FID) to quantify extractive groups and gas chromatography-mass spectrometry (GC–MS) to analyse individual extractive compounds. Resin acids and triglycerides followed by fatty acids were the dominant extractive groups. Resin acids were most abundant in stem wood from final fellings and in sawdust, fatty acids in bark and branch biomass, and triglycerides also in stem wood from thinnings and the top parts of trees. Of the minor extractive groups, stilbenes were the most abundant in stem wood from final fellings and in sawdust, and steryl esters, sterols, and lignans in bark and branch biomass, the two last groups almost missing from other biomass components. Regional differences in the contents of extractive groups were generally small, 1.0−1.5 percentage points at the maximum, but factor analysis distinguished northern and southern regions into their own groups. Bark was the most potential source of fatty acids and sterols in southern Finland, and triglycerides and steryl esters in northern Finland. In stem wood, steryl esters, triglycerides, and lignans decreased and stilbenes increased from north to south. Certain fatty acids and resin acids were more frequent in the north. The results highlighted the importance of focused procurement and efficient sorting of raw materials, purity, unique properties, and feasible isolation techniques for competitive ability as well as large raw material volumes or well-defined value-added products.
Full article
(This article belongs to the Special Issue Wood Extracts and By-Products: Formation, Significance, and Technological and Biological Applications)
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Open AccessArticle
How to Improve Forest Carbon Sequestration Output Performance: An Evidence from State-Owned Forest Farms in China
Forests 2022, 13(5), 778; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050778 - 18 May 2022
Abstract
China’s state-owned forest farms are the basic sectors of forestry production, and their carbon cycle functions, such as timber processing and forest carbon sequestration, are of great significance to the national emission reduction strategy. By three-stage DEA and Tobit models, this paper measures
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China’s state-owned forest farms are the basic sectors of forestry production, and their carbon cycle functions, such as timber processing and forest carbon sequestration, are of great significance to the national emission reduction strategy. By three-stage DEA and Tobit models, this paper measures the carbon sequestration output efficiency of 3706 state-owned forest farms involved in China’s National Forestry and Grassland Administration’s 2008–2018 survey. We figure out how the mechanism on the carbon sequestration impacts output efficiency of these forest farms and analyze the temporal trends and spatial distributions of their outputs in various regions. Our results indicate that the overall output efficiency of state-owned forest farms in China is relatively low compared with the international advanced level and show that distinctive north-south regional differences exist. Specifically, the carbon storage of the state-owned forest farms in Northeast China and Inner Mongolia occupies more than half of the carbon storage of total amounts, but their output efficiency is unsatisfactory. Conversely, the forest farms in Southwest China have a medium amount of carbon storage and the highest output efficiency. After improving the external environments of these farms, the efficiency value in each province appears as a significant increment. Moreover, the effects of afforestation, timber harvests, the under-forest economy, and other operating behaviors exhibit regional heterogeneity to some extent. Therefore, this paper advocates reforming the current forest cultivation strategy that emphasizes afforestation and neglects management, and relevant government departments are supposed to adjust operations according to local conditions to promote sustainable forest management.
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(This article belongs to the Special Issue Circular Bioeconomy in Forest-Based Sector: Governance and Policy)
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Open AccessArticle
Surface Roughness of Varnished Wood Pre-Treated Using Sanding and Thermal Compression
Forests 2022, 13(5), 777; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050777 - 17 May 2022
Abstract
Surface roughness is an important factor during the processes of wood gluing and finishing. This study proposed a new approach for the preparation of wood veneer surfaces before varnishing through the use of thermal compression instead of sanding. The quality of the pre-treated
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Surface roughness is an important factor during the processes of wood gluing and finishing. This study proposed a new approach for the preparation of wood veneer surfaces before varnishing through the use of thermal compression instead of sanding. The quality of the pre-treated surface was examined using surface roughness measurements. In the experiment, a wood veneer of black alder and birch, before varnishing, was subjected to sanding with a sandpaper of 180 grit size, and thermal compression at temperatures of 180 and 210 °C. Three different types of commercially manufactured varnishes (water-based (WB), polyurethane (PUR) and UV-cured (UV)) were applied to the prepared veneer surfaces with various numbers of varnish layers. Seven roughness parameters such as Ra, Rz, Rq, Rp, Rv, Rsk, and Rku were determined for the sanded and thermally densified unvarnished and varnished surfaces. The profile surface was recorded with a portable surface roughness tester along and across the wood fibers. It was found that there was no difference between the surface roughnesses of the surfaces that had been sanded and the surface roughnesses of those that had been thermally densified at a temperature of 210 °C. The research suggests that thermal compression at a temperature of 210 °C is enough to obtain smoother surfaces with a UV varnish system, and this process can be recommended as a replacement for sanding before varnishing as the most labor-intensive and expensive operations in woodworking industry. Applying two layers of varnish along with intermediate sanding was also sufficient to obtain a satisfactory finish.
Full article
(This article belongs to the Special Issue The Role of Wood Gluing and Finishing Technologies in a Sustainable World)
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Open AccessArticle
Assimilation Efficiencies and Gas Exchange Responses of Four Salix Species in Elevated CO2 under Soil Moisture Stress and Fertilization Treatments
Forests 2022, 13(5), 776; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050776 - 17 May 2022
Abstract
Assimilation to the internal CO2 (ACi) response curve and gas exchange parameters were quantified for four North American willows ((Salix cordata (COR), S. discolor (DIS), S. eriocephala (ERI), and S. interior (INT)) grown in a 2 × 2 factorial
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Assimilation to the internal CO2 (ACi) response curve and gas exchange parameters were quantified for four North American willows ((Salix cordata (COR), S. discolor (DIS), S. eriocephala (ERI), and S. interior (INT)) grown in a 2 × 2 factorial of atmospheric CO2 and soil moisture treatments to see how they would respond to climate change factors. After the first year of greenhouse growth under said treatments, we saw no difference in the aboveground stem biomass between CO2 treatments. Thus, in the second year, a second experiment on a subset of well-watered, coppiced willows was conducted in a 2 × 2 factorial of atmospheric CO2 and soil fertilization (FERT) treatments. In both experiments, the maximum rate of carboxylation (Vcmax) significantly declined for all four species in response to elevated CO2 (eCO2). In response to a drought treatment (DRT), Vcmax declined, except for INT, which increased Vcmax. In both experiments, INT had the greatest Vcmax, maximum rate of electron transport (Jmax), and triose phosphate utilization, followed by COR and ERI, with DIS having the lowest values. FERT resulted in a strong increase in assimilation (A) and stomatal conductance (Gwv) by 92 and 119%, respectively. Gwv is the primary driver and A is a minor driver of water use efficiency (WUE) under DRT. FERT mitigated the Vcmax and A downregulation in eCO2, but eCO2 did not mitigate the DRT downregulation effect. Differences between INT and the other three willows in a number of adaptive traits and responses related to drought may reflect the evolutionary origins of INT and the taxonomic group Longifoliae in the arid southwest USA and Mexico.
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(This article belongs to the Section Forest Soil)
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Open AccessFeature PaperArticle
Inherent Water-Use Efficiency of Different Forest Ecosystems and Its Relations to Climatic Variables
Forests 2022, 13(5), 775; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050775 - 17 May 2022
Abstract
Inherent water-use efficiency (IWUE) is a vital parameter connecting the carbon and water cycles. However, the factors influencing the IWUE in different forest ecosystems are still a subject of debate. In this work, FLUXNET platform measurements of 67 forest sites were used to
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Inherent water-use efficiency (IWUE) is a vital parameter connecting the carbon and water cycles. However, the factors influencing the IWUE in different forest ecosystems are still a subject of debate. In this work, FLUXNET platform measurements of 67 forest sites were used to detect trends of the IWUE of four forest ecosystems, namely deciduous broadleaf forests (DBF), evergreen broadleaf forests (EBF), needle-leaf forests (ENF), and mixed forests (MF). The IWUE differed significantly among different forest ecosystems and positively correlated with temperature and solar radiation. The IWUE of EBF was the highest at 32.02 g·C·Kg·H2O−1. The values of DBF and MF were similar and higher than that of ENF. With increasing latitude, the IWUE increased first and then decreased, with a maximum of 35° N. The IWUE of EBF was negatively correlated with precipitation and leaf area index. Temperature and solar radiation were the main factors controlling the IWUE of forest ecosystems, whereas precipitation was the major factor controlling the inter-annual variation in the ΔIWUE of forest ecosystems. Our results provide a scientific basis for the study of forest carbon sinks, forest eco-hydrological processes, and forest ecosystem responses to global climatic changes.
Full article
(This article belongs to the Special Issue Altitudinal Gradients and Forest Response: Climate, Hydrology, and Isotope Variability of Temperate Forest Ecosystems)
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Open AccessArticle
Compatible Biomass Model of Moso Bamboo with Measurement Error
Forests 2022, 13(5), 774; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050774 - 17 May 2022
Abstract
Moso bamboo is characterized by its fast growth and high yield and is important as a carbon sink species. Therefore, understanding the biomass distribution of its components is crucial. Based on the measured individual biomass data of 66 Phyllostachys heterocycla cv. Pubescens plants
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Moso bamboo is characterized by its fast growth and high yield and is important as a carbon sink species. Therefore, understanding the biomass distribution of its components is crucial. Based on the measured individual biomass data of 66 Phyllostachys heterocycla cv. Pubescens plants in the Yixing state-owned forest in Jiangsu Province, nonlinear simultaneous equations with measurement errors were constructed using nonlinear error-in-variable models (NEIVM) (one step, two step) and nonlinear seemingly unrelated regression (NSUR). Variables affecting biomass were evaluated, including diameter at breast height (DBH), bamboo height (H), height to crown base (HCB), node length at DBH (NL), base diameter (BD), and bamboo age (A). DBH, H, and HCB had significant effects on the biomass of each component. They were used to construct a one-predictor system using DBH, a two-predictor system using DBH and H, and a three-predictor system using DBH, H, and HCB. Regardless of the number of variables used, the fitting accuracy of the NEIVM one-step method exceeded that of the two-step method, and that of NEIVM exceeded that of NSUR estimation. As a system using three predictive variables is better than other systems, we recommend using the one-step NEIVM method for Moso bamboo biomass estimation.
Full article
(This article belongs to the Special Issue Advances in Forest Growth and Site Productivity Modeling)
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Open AccessArticle
Cryopreservation of Fraxinus mandshurica Rupr. by Using the Slow Cooling Method
by
, , , , , and
Forests 2022, 13(5), 773; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050773 - 17 May 2022
Abstract
Cryopreservation is an important method for the excellent long-term preservation of plant germplasm. This study explores an optimal cryopreservation technology for the embryogenic callus of Fraxinus mandshurica to effectively maintain its genetic stability and morphogenesis potential. The optimal cryopreservation conditions were assessed using
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Cryopreservation is an important method for the excellent long-term preservation of plant germplasm. This study explores an optimal cryopreservation technology for the embryogenic callus of Fraxinus mandshurica to effectively maintain its genetic stability and morphogenesis potential. The optimal cryopreservation conditions were assessed using the embryogenic callus of F. mandshurica as the material, and the slow cooling method was optimized for its cryopreservation. The results indicated that the preculture of embryogenic callus in 0.4 mol·L−1 sorbitol solution for 20 h at room temperature, followed by its cryoprotection in 7.5% dimethyl sulfoxide solution at 0 °C for 90 min, constituted the optimal material treatment method. The freezing tube was placed in a −80 °C refrigerator for 2 h and then quickly put into liquid nitrogen for frozen storage. During thawing, the cryopreservation tube was taken out from liquid nitrogen, directly placed in a water bath at 40 °C for 2 min, and used for culturing on the woody plant media + 0.1 mg·L−1 6-benzyladenine + 0.15 mg·L−1 2, 4-dichlorophenoxyacetic acid. After cryopreservation using the slow cooling method, the highest survival rate of callus cells was 80.82%. The fresh weight reached 1.93 g after 60-day recovery culture. The regeneration rate and the proliferation coefficient of the callus were 100% and 2.79, respectively. The differentiation rate was 56.83%, and the emergence rate was 23.59%. The results provide a scientific basis for the long-term preservation of F. mandshurica germplasm resources.
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(This article belongs to the Section Forest Ecophysiology and Biology)
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Open AccessArticle
Effects of Nitrogen and Phosphorus Additions on Soil N2O Emissions and CH4 Uptake in a Phosphorus-Limited Subtropical Chinese Fir Plantation
Forests 2022, 13(5), 772; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050772 - 17 May 2022
Abstract
Increased nitrogen (N) inputs in subtropical forest ecosystems were widely reported. Extra N additions were reported to cause nutrient imbalance and phosphorus (P) limitation in many tropical and subtropical forests, and further result in changes in soil nitrous oxide (N2O) and
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Increased nitrogen (N) inputs in subtropical forest ecosystems were widely reported. Extra N additions were reported to cause nutrient imbalance and phosphorus (P) limitation in many tropical and subtropical forests, and further result in changes in soil nitrous oxide (N2O) and methane (CH4) fluxes. Here, we conducted experiments with N (high N addition: 15 g N/m2, HN), P (low: 5 g P/m2, LP; high: 15 g P/m2, HP) and their interactive (HNLP and HNHP) treatments to investigate how N and P additions affected CH4 and N2O exchanges in an N-rich Chinese fir plantation (Cunninghamia lanceolata), and further explored the underlying mechanisms through the structural equation model (SEM) analysis. The results indicated that N addition alone (HN) significantly (p < 0.05) increased the soil N2O emissions by 30.15% and 80.47% over annual and 4-month periods, mainly owing to the elevated NH4+-N content. P addition alone (LP and HP) did not significantly affect the soil N2O emissions as compared with the control. The SEM analysis indicated that increased N2O emissions under N addition were primarily explained by the increase in available N and contributed more to the stimulated NH4+-N contents. N and P interactive additions slightly (not significant) stimulated the N2O emissions as compared with that under the N addition alone treatment. High-dose P addition significantly increased the soil CH4 uptake by 15.80% and 16.23% under the HP and HNHP treatments, respectively, while N addition alone and low P addition (LP and HNLP) did not significantly affect CH4 uptake as compared with the control. The increased water-soluble organic carbon and microbial biomass carbon explained the increased CH4 uptake under high P addition. The fertilization effects on N2O emissions and CH4 uptake mainly occurred in the first 4 months and diminished after that. Our results suggested that the direction, magnitude and timing of the N and P addition effects on N2O emissions and CH4 uptake would depend on the soil nutrient status and plant–microbial competition for N and P in subtropical forests.
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(This article belongs to the Special Issue Responses of Soil Carbon and Nitrogen Dynamics and GHG Fluxes in Forest Ecosystems to Climate Change and Human Activity)
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Open AccessArticle
Biomass Assessment and Carbon Sequestration in Post-Fire Shrublands by Means of Sentinel-2 and Gaussian Processes
by
, , , , and
Forests 2022, 13(5), 771; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050771 - 17 May 2022
Abstract
In this contribution, we assessed the biomass and carbon stock of a post-fire area covered by a young oak coppice of Quercus pyrenaica Willd. associated with shrubs, mainly of Cistus laurifolius L. This area was burned during the fire event of Chequilla (Guadalajara,
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In this contribution, we assessed the biomass and carbon stock of a post-fire area covered by a young oak coppice of Quercus pyrenaica Willd. associated with shrubs, mainly of Cistus laurifolius L. This area was burned during the fire event of Chequilla (Guadalajara, Spain) in 2012. Sentinel-2 imagery was used together with our own forest inventories in 2020 and machine learning methods to assess the total biomass of the area. The inventory includes plots of total dry weight ranging between 6 and 14 Mg·ha−1 with individuals up to 8 years old. Nonlinear, nonparametric Gaussian process regression methods were applied to link reflectance values from Sentinel-2 imagery with total shrub biomass. With a reduced inventory of only 32 plots covering 136 ha, the total biomass could be assessed with a root-mean-square error of 1.36 Mg·ha−1 and a bias of −0.04 Mg·ha−1, getting a relative error between 9.8% and 20.4% for the gathered biomass. This is a rather good estimation considering the little effort and time invested; thus, the suggested methodology is very suitable for forest monitoring and management.
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(This article belongs to the Special Issue Using Remote Sensing to Monitor Forest Fire Behavior and Forest Landscape)
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Open AccessArticle
Landowner Acceptability of Silvicultural Treatments to Restore an Open Forest Landscape
by
, , , , and
Forests 2022, 13(5), 770; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050770 - 17 May 2022
Abstract
This study examined the acceptability of different silvicultural treatments to restore pine barrens, an open, fire-dependent forest landscape type globally imperiled across the northern Great Lakes region of the United States and Canada. In an online survey, we asked family-forest owners (N
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This study examined the acceptability of different silvicultural treatments to restore pine barrens, an open, fire-dependent forest landscape type globally imperiled across the northern Great Lakes region of the United States and Canada. In an online survey, we asked family-forest owners (N = 466) in Northeastern Wisconsin about the acceptability of pine barrens restoration treatments through ratings of both verbal descriptions and visual scenarios. An informational statement about pine barrens restoration purposes and goals preceded ratings for half the sample. Across the entire sample, acceptability ratings for eleven verbally-described treatments generally declined as treatments became more intensive, creating greater openness on the landscape. Information recipients found two groups of treatments identified by factor analysis (selective openings, fire) more acceptable than non-recipients, and cluster analysis identified four respondent subgroups, each with varying levels of acceptability. The respondents also rated the acceptability of visual scenarios, with treatment attribute combinations portraying a range of likely restoration alternatives. While we generally found correspondence between verbal and visual acceptability ratings across the entire sample, the groups distinguished by their verbal acceptability ratings did not substantially differ in how they rated the acceptability of the visual scenarios. Implications are discussed for designing and communicating the purpose and value of restoration treatments to stakeholder groups.
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(This article belongs to the Section Forest Economics, Policy, and Social Science)
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The Effect of Tree-Uprooting on the Soil Spatial Complexity in an Old-Growth Temperate Forest, Central Europe
Forests 2022, 13(5), 769; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050769 - 17 May 2022
Abstract
The formation of spatial pedocomplexity in forested landscapes is an issue that has not yet been comprehensively resolved. This study analysed the effects of tree disturbances on the spatial variability of soil chemical properties in order to explain the spatial pedocomplexity in one
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The formation of spatial pedocomplexity in forested landscapes is an issue that has not yet been comprehensively resolved. This study analysed the effects of tree disturbances on the spatial variability of soil chemical properties in order to explain the spatial pedocomplexity in one of the oldest forest reserves in Europe. A total of 1545 sites over an area of 74 ha were assessed in terms of soil taxonomy, morphology, and profiles. We quantified the spatial autocorrelation of soil chemical properties and analysed the effects of soil disturbance regimes on soil chemical properties in both the surface and subsurface layers using geostatistics and redundancy analysis, respectively. A paired difference test revealed that the factors involved in the soil formation of the two layers are different. The neoformation of the surface layer proceeds rapidly after soil disturbance and, therefore, some formerly disturbed surface layers become mature above immature subsurface layers. The effect of tree disturbances on soil chemical properties was significant for totally decomposed treethrows. Treethrow density partially explained the variation in soil chemical properties in both layers, but even more so in the subsurface layer. This study further elucidates the impact of treethrows on soils and shows that they are an important driver of soil spatial pedocomplexity.
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(This article belongs to the Section Forest Soil)
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Threshold Responses of Canopy Cover and Tree Growth to Drought and Siberian silk Moth Outbreak in Southern Taiga Picea obovata Forests
Forests 2022, 13(5), 768; https://0-doi-org.brum.beds.ac.uk/10.3390/f13050768 - 16 May 2022
Abstract
The consecutive occurrence of drought and insect outbreaks could lead to cumulative, negative impacts on boreal forest productivity. To disentangle how both stressors affected productivity, we compared changes in tree canopy cover and radial growth after a severe outbreak in Siberian spruce (
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The consecutive occurrence of drought and insect outbreaks could lead to cumulative, negative impacts on boreal forest productivity. To disentangle how both stressors affected productivity, we compared changes in tree canopy cover and radial growth after a severe outbreak in Siberian spruce (Picea obovata) southern taiga forests. Specifically, we studied the impacts of the 2012 severe drought followed by a Siberian silk moth (Dendrolimus sibiricus, hereafter SSM) outbreak, which started in 2016, on spruce forests by comparing one non-defoliated site and two, nearby fully defoliated sites, using remote sensing and tree-ring data. The SSM outbreak caused total defoliation and death of trees in the infested stands. We found a sharp drop (–32%) in the normalized difference infrared index and reduced radial growth in the defoliated sites in 2018. The growth reduction due to the 2012 drought was –37%, whereas it dropped to 4% of pre-outbreak growth in 2018. Tree growth was constrained by warm and dry conditions from June to July, but such a negative effect of summer water shortage was more pronounced in the defoliated sites than in the non-defoliated site. This suggests a predisposition of sites where trees show a higher growth responsivity to drought to SSM-outbreak defoliation. Insect defoliation and drought differently impacted taiga forest productivity since tree cover dropped due to the SSM outbreak, whereas tree growth was reduced either by summer drought or by the SSM outbreak. The impacts of abiotic and biotic stressors on boreal forests could be disentangled by combining measures or proxies of canopy cover and radial growth which also allow the investigation of drought sensitivity predisposes to insect damage.
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(This article belongs to the Special Issue Structural and Anatomical Adjustments of Woody Species to Environmental Changes)
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