Forests

21 pages, 3944 KiB

Open AccessArticle

Highlighting a New Morphospecies within the Dialium Genus Using Leaves and Wood Traits

by Robin Doucet, Gaël Bibang Bengono, Marius Ruwet, Isabelle Van De Vreken, Brieuc Lecart, Jean-Louis Doucet, Juan Antonio Fernandez Pierna, Philippe Lejeune, Benoit Jourez, Alain Souza and Aurore Richel

Forests 2022, 13(8), 1339; https://doi.org/10.3390/f13081339 - 22 Aug 2022

Cited by 2 | Viewed by 1913

Abstract

During inventories of lesser-known timber species in eastern Gabon, a new Dialium morphospecies was discovered. To discriminate it from the two other 2–5 leaflets Dialium species, 25 leaf traits were measured on 45 trees (16 Dialium pachyphyllum, 14 Dialium lopense, 15 [...] Read more.

During inventories of lesser-known timber species in eastern Gabon, a new Dialium morphospecies was discovered. To discriminate it from the two other 2–5 leaflets Dialium species, 25 leaf traits were measured on 45 trees (16 Dialium pachyphyllum, 14 Dialium lopense, 15 Dialium sp. nov.). Nine wood chemical traits, as well as infrared spectra, were also examined on harvestable trees (four Dialium pachyphyllum and four Dialium sp. nov.). This study revealed seven discriminant leaf traits that allowed to create a field identification key. Nine significant differences (five in sapwood and four in heartwood) in terms of wood composition were highlighted. The use of the PLS-DA technique on FT-IR wood spectra allowed to accurately identify the new morphospecies. These results provide strong support for describing a new species in this genus. Implications for sustainable management of its populations are also discussed. Full article

(This article belongs to the Special Issue The Diversity of Wood and Non-Wood Forest Products: Anatomical, Physical and Chemical Properties, and Potential Applications)

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31 pages, 3348 KiB

Open AccessReview

Secondary Metabolites Produced by Trees and Fungi: Achievements So Far and Challenges Remaining

by Katarzyna Nawrot-Chorabik, Małgorzata Sułkowska and Natalia Gumulak

Forests 2022, 13(8), 1338; https://doi.org/10.3390/f13081338 - 22 Aug 2022

Cited by 4 | Viewed by 4845

Abstract

Secondary metabolites are ubiquitous substances occurring naturally in trees and microorganisms. They are produced in various metabolic pathways which determine their structure and biochemical proprieties. However, the biological functions of many secondary metabolites remain undetermined. Usually, the amounts of secondary metabolites produced by [...] Read more.

Secondary metabolites are ubiquitous substances occurring naturally in trees and microorganisms. They are produced in various metabolic pathways which determine their structure and biochemical proprieties. However, the biological functions of many secondary metabolites remain undetermined. Usually, the amounts of secondary metabolites produced by trees under natural conditions are limited, which makes their mass production difficult and not cost-effective. Metabolites occurring naturally in plants, including gymnosperm and angiosperm trees, as well as in fungi, are important biologically active substances used by many industries and in modern medicine. The huge variability and potential of biological activity present in secondary metabolites make it possible to replace most of them with compounds of completely natural origin. The current breakdown of metabolites, together with the most important examples of compounds and their uses, are presented in this overview. The possibility of increasing the number of secondary metabolites in a specific environment through interaction with the most known biotic factors is discussed. The use of in vitro culture for the production of secondary metabolites and their extraction, as well as the possibility of subsequent analysis, are described. The current literature on the metabolites produced by individual species is presented. Full article

(This article belongs to the Special Issue Forest Plant Resources Bioactive Ingredients)

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17 pages, 3593 KiB

Open AccessArticle

Identification of Key Genes for Oleoresin Biosynthesis in High and Low Oleoresin-Yielding Slash Pine Based on Transcriptome Analysis

by Min Yi, Lu Zhang, Zishan Cheng, Rong Hu, Yuan Gao, Cangfu Jin, Shenggui Yuan, Shiwu Sun and Meng Lai

Forests 2022, 13(8), 1337; https://doi.org/10.3390/f13081337 - 22 Aug 2022

Cited by 4 | Viewed by 1544

Abstract

Slash pine (Pinus elliottii Engelmann) is a pine species widely cultivated for its high oleoresin production capacity. However, little is known about the underlying molecular mechanism of oleoresin biosynthesis between high and low oleoresin-yielding slash pines. In this study, the terpenoid compositions [...] Read more.

Slash pine (Pinus elliottii Engelmann) is a pine species widely cultivated for its high oleoresin production capacity. However, little is known about the underlying molecular mechanism of oleoresin biosynthesis between high and low oleoresin-yielding slash pines. In this study, the terpenoid compositions of oleoresin harvested from high- and low-yielding slash pines were identified using gas chromatography/mass spectrometry (GC-MS) analysis. The monoterpenes and diterpenes are the major constituents, of which the α- and β-pinenes are the overwhelming majority of turpentines, and abietic acid, levopimaric acid, and neoabietic acid are the most abundant in rosin. The transcriptomic analysis was also performed with secondary xylem tissues of high- and low-yielding slash pines. After functional annotation, the DEGs of RNA-seq data between high- and low-yielding pines in April, July, and October were screened, and many key enzyme genes were found to be implicated in terpenoid backbone biosynthesis. Moreover, weighted gene correlation network analysis (WGCNA) was carried out to uncover the gene modules highly related to α- and β-pinene biosynthesis in slash pine. Twenty-three modules were attained in this study. Focusing on the total oleoresin yield, the MEblue module exhibited the highest positive correlation, while the MEgreen module exhibited the highest negative correlation. A total of 20 TFs were identified in gene modules. Among these genes, the c215396.graph_c0 encoding an MYB TF is the key differentially expressed gene (DEG) between high- and low-yielding pines. The subsequent one-hybrid yeast assay verified that c215396.graph_c0 can activate the transcription of Apetala 2 (AP2) and 1-deoxy-d-xylulose 5-phosphate synthase (dxs), which are also two DEGs between high- and low-yielding pines. Thus, our study identified a set of key enzymes and TFs that are involved in regulating oleoresin and composition between high- and low-yielding slash pines and provided us a deep insight into oleoresin biosynthesis. Full article

(This article belongs to the Special Issue Molecular Mechanism of Secondary Metabolic Pathways in Forest Trees)

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15 pages, 2927 KiB

Open AccessArticle

Variation in Water Uptake Dynamics of Dominant Wood Plants of Pinus taiwanensis Hayata Communities Based on Stable Isotopes

by Linsheng Wen, Yun Peng, Wenping Deng, Yuanqiu Liu, Tianjun Bai, Qin Zou, Xiaojun Liu, Ling Zhang and Guodong Jia

Forests 2022, 13(8), 1336; https://doi.org/10.3390/f13081336 - 22 Aug 2022

Viewed by 1400

Abstract

Plant community formation is determined by plant competition, while the water uptake depth of vegetation is regarded as a critical factor in maintaining species coexistence under competition. However, the source variation of montane plant water uptake remains poorly understood, especially under the condition [...] Read more.

Plant community formation is determined by plant competition, while the water uptake depth of vegetation is regarded as a critical factor in maintaining species coexistence under competition. However, the source variation of montane plant water uptake remains poorly understood, especially under the condition of climate change. We introduced stable hydrogen and oxygen isotopes to investigate the water uptake pattern of the trees and shrubs in a Pinus taiwanensis Hayata community in subtropical mountains. The results showed that the main sources of water uptake in plants varied with soil water content, due to variations in annual precipitation distribution. In July and September, under extremely wet conditions, the evergreen conifer species P. taiwanensis and the shrub Eurya muricata mainly absorbed water from the deep soil layer (40–80 cm, more than 70%). By contrast, the deciduous shrub Rhododendron dilatatum largely relied on upper soil water (0–40 cm, 75.4%) in July but the same deep water source in September. In August and the non-growing season (January), when soil moisture content was low, plants preferred surface layer soil water (0–20 cm, above 50%). In October, the soil water in the middle (20–40 cm) and deep layers (40–80 cm) were the main water source of the three plants. However, the plant water sources showed great difference between P. taiwanensis and shrubs in November: P. taiwanensis absorbed more water from the soil surface layers (89.5%), while R. dilatatum mainly took up surface soil water (54.2%) and E. muricata predominantly obtained water from surface soil water (49.6%) and the deep soil layer (39.3%). These findings suggest that the water uptake of dominant woody plants in a P. taiwanensis community has great plasticity, and its water uptake depth varies with soil water content. In addition, these co-existing species generally absorbed water from similar soil layers in the P. taiwanensis community and exhibited a hydrological niche overlap, indicating a very possible competition between species in future water-limited conditions caused by climate change. Full article

(This article belongs to the Special Issue Assessments and Restoration Technique of Forest Land Development in Hilly Areas)

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18 pages, 2274 KiB

Open AccessArticle

Effect of Leptographium terebrantis on Foliage, New Root Dynamics, and Stemwood Growth in a Loblolly Pine (Pinus taeda L.) Plantation

by John K. Mensah, Mary Anne S. Sayer, Ryan L. Nadel, Shrijana Duwadi, Zhaofei Fan, Emily A. Carter and Lori G. Eckhardt

Forests 2022, 13(8), 1335; https://doi.org/10.3390/f13081335 - 21 Aug 2022

Viewed by 1600

Abstract

The course of the bark beetle-vectored fungus, Leptographium terebrantis S. J. Barras and T. J. Perry, in stemwood growth loss of declining pines in the southeastern United States was assessed in a 13-year-old loblolly pine (Pinus taeda L.) plantation near Eufaula, Alabama, [...] Read more.

The course of the bark beetle-vectored fungus, Leptographium terebrantis S. J. Barras and T. J. Perry, in stemwood growth loss of declining pines in the southeastern United States was assessed in a 13-year-old loblolly pine (Pinus taeda L.) plantation near Eufaula, Alabama, U.S.A. Using stem inoculation as a surrogate for root infection, we hypothesized that L. terebrantis infection impairs sapwood function and thus limits the tree leaf area (A_L), new root production, and stemwood growth. Sterile toothpicks colonized by L. terebrantis at varying inoculum densities was used to elicit host growth responses. In the third year after inoculation, the root pathogen reduced the foliage moisture content, whole-tree leaf area (A_L), the ratio of A_L to tree sapwood area (A_S), and stemwood growth in trees receiving the high inoculation treatment relative to those receiving the low or medium inoculation treatments, or the wound or control treatments after seven months of water deficit. The absence of a similar response to water deficit among trees that were noninoculated, wounded, or inoculated at the low or medium densities suggests that, in the loblolly pine–L. terebrantis pathosystem at our study site, the physiological stress caused by water deficit and the high inoculum density was required for the pathogen to elicit a stemwood growth loss. Thus, in loblolly pine forests of the southeastern United States, where climate and soil conditions yield prolonged periods of physiological stress, the presence of L. terebrantis has the potential to reduce stand volume and widen the gap between the predicted and actual stemwood production. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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12 pages, 1939 KiB

Open AccessArticle

The Habitat Type and Scale Dependences of Interspecific Associations in a Subtropical Evergreen Broad-Leaved Forest

by Changchun Jiang, Jiaqin Fu, Yunquan Wang, Pengtao Chai, Yidan Yang, Xiangcheng Mi, Mingjian Yu, Keping Ma and Jianhua Chen

Forests 2022, 13(8), 1334; https://doi.org/10.3390/f13081334 - 21 Aug 2022

Cited by 4 | Viewed by 1933

Abstract

“Interspecific associations” refers to the interrelationship among different species in a particular spatial distribution, which plays an important role in species distribution, community assembly, and responses to environmental changes. However, the strength and/or direction of interspecific associations may vary with environmental gradients and [...] Read more.

“Interspecific associations” refers to the interrelationship among different species in a particular spatial distribution, which plays an important role in species distribution, community assembly, and responses to environmental changes. However, the strength and/or direction of interspecific associations may vary with environmental gradients and scales. To understand the effects of habitat types and research scales on interspecific associations in subtropical forests, we modeled the interspecific associations for more than 15,000 individuals representing 74 co-occurring species from three habitat types and three scales by using the variance ratio and the Spearman rank correlation coefficient. We found that overall interspecific associations at a community level exhibited significant positive associations for most habitat types and scales. Moreover, interspecific associations of pairwise species have strong habitat dependence, and the association strengths decreased with the increase in elevation (change in habitat types). However, the scale dependence of pairwise interspecific associations varies with habitat types. The strength of interspecific associations increased with the increasing scales (10 m × 10 m, 20 m × 20 m, and 40 m × 40 m) at low-valleys and mid-hillside habitats, while the scale-dependent effect was not detected at high-ridges. In conclusion, our study highlights the importance of environmental gradients and research scales on interspecific associations in diverse subtropical forests, and environmental gradients and research scales should be considered in future studies. Full article

(This article belongs to the Special Issue Long-Term Monitoring of Forest Biodiversity and Dynamics in China)

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25 pages, 4495 KiB

Open AccessArticle

Morphophysiological Acclimation of Developed and Senescing Beech Leaves to Different Light Conditions

by Wojciech Kraj and Artur Ślepaczuk

Forests 2022, 13(8), 1333; https://doi.org/10.3390/f13081333 - 21 Aug 2022

Cited by 2 | Viewed by 1851

Abstract

Common beech is a shade-tolerant tree species that can adapt to varying light intensities at the level of whole plants, crown fragments, and individual leaves. The acclimation abilities of the morphological, physiological, and biochemical characteristics of beech leaves were experimentally determined in tree [...] Read more.

Common beech is a shade-tolerant tree species that can adapt to varying light intensities at the level of whole plants, crown fragments, and individual leaves. The acclimation abilities of the morphological, physiological, and biochemical characteristics of beech leaves were experimentally determined in tree crowns for different levels of light availability. About 24% higher length, width, and area and about 35% higher thickness were recorded in the sun leaves compared with shade leaves. Lower and earlier maximum leaf pigment levels, a faster degradation of leaf pigments during senescence, and a higher chlorophyll a/b ratio were observed in fully sun-grown leaves compared with leaves growing deeper in the canopy. Changes in the intensity of oxidative stress and the differential ability of developing and senescing leaves to defend against this effect under different light conditions were determined. This resulted in a higher redox imbalance and faster senescence in the outer parts of the tree crowns. Due to higher ascorbic acid and glutathione content and slower activity loss of antioxidative enzymes involved in superoxide anion and hydrogen peroxide decomposition, better control over the redox balance, oxidative stress, and senescence induction was noted in the sun leaves. Full article

(This article belongs to the Topic Plant Ecophysiology)

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15 pages, 6091 KiB

Open AccessEditor’s ChoiceArticle

A Small Target Forest Fire Detection Model Based on YOLOv5 Improvement

by Zhenyang Xue, Haifeng Lin and Fang Wang

Forests 2022, 13(8), 1332; https://doi.org/10.3390/f13081332 - 20 Aug 2022

Cited by 58 | Viewed by 6235

Abstract

Forest fires are highly unpredictable and extremely destructive. Traditional methods of manual inspection, sensor-based detection, satellite remote sensing and computer vision detection all have their obvious limitations. Deep learning techniques can learn and adaptively extract features of forest fires. However, the small size [...] Read more.

Forest fires are highly unpredictable and extremely destructive. Traditional methods of manual inspection, sensor-based detection, satellite remote sensing and computer vision detection all have their obvious limitations. Deep learning techniques can learn and adaptively extract features of forest fires. However, the small size of the forest fire target in the long-range-captured forest fire images causes the model to fail to learn effective information. To solve this problem, we propose an improved forest fire small-target detection model based on YOLOv5. This model requires cameras as sensors for detecting forest fires in practical applications. First, we improved the Backbone layer of YOLOv5 and adjust the original Spatial Pyramid Pooling-Fast (SPPF) module of YOLOv5 to the Spatial Pyramid Pooling-Fast-Plus (SPPFP) module for a better focus on the global information of small forest fire targets. Then, we added the Convolutional Block Attention Module (CBAM) attention module to improve the identifiability of small forest fire targets. Second, the Neck layer of YOLOv5 was improved by adding a very-small-target detection layer and adjusting the Path Aggregation Network (PANet) to the Bi-directional Feature Pyramid Network (BiFPN). Finally, since the initial small-target forest fire dataset is a small sample dataset, a migration learning strategy was used for training. Experimental results on an initial small-target forest fire dataset produced by us show that the improved structure in this paper improves mAP@0.5 by 10.1%. This demonstrates that the performance of our proposed model has been effectively improved and has some application prospects. Full article

(This article belongs to the Special Issue Advances in Forest Fire and Other Detection Systems)

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16 pages, 5520 KiB

Open AccessArticle

Changes in Forest Conditions in a Siberian Larch Forest Induced by an Extreme Wet Event

by Aleksandr Nogovitcyn, Ruslan Shakhmatov, Tomoki Morozumi, Shunsuke Tei, Yumiko Miyamoto, Nagai Shin, Trofim C. Maximov and Atsuko Sugimoto

Forests 2022, 13(8), 1331; https://doi.org/10.3390/f13081331 - 20 Aug 2022

Cited by 2 | Viewed by 1916

Abstract

The taiga forest, a semi-arid and nitrogen-limited ecosystem on permafrost, has changed under extreme wet events. This study aims to understand the changes that occurred in a larch forest in Eastern Siberia after the wet event of 2006–2007. In the summer of 2018, [...] Read more.

The taiga forest, a semi-arid and nitrogen-limited ecosystem on permafrost, has changed under extreme wet events. This study aims to understand the changes that occurred in a larch forest in Eastern Siberia after the wet event of 2006–2007. In the summer of 2018, studies were conducted at the Spasskaya Pad Experimental Forest Station near Yakutsk, Russia, where a transect (60 m × 510 m) with 34 plots (30 m × 30 m) was set. It included intact sites and affected sites with different levels of forest damage, owing to the extreme wet event. We observed spatial variations in the normalized difference vegetation index (NDVI) calculated from Landsat satellite-observed data, and the foliar δ¹³C, δ¹⁵N, and C/N (carbon/nitrogen) ratio obtained from the needle samples of 105 mature larch trees. Our results reveal that the affected plots had a lower NDVI than the intact plots, resulting from a difference in tree stand density. In addition, the stand density is suggested to be a controlling factor in the spatial variations in the foliar C/N and δ¹³C values based on their significant relationships with the NDVI in June. We concluded that the larch trees from the regenerating forests in the affected areas have a higher nitrogen level and light availability (relatively low C/N and high δ¹³C) because of the slight competition for resources, owing to a low-stand density. This may lead to further succession of the larch forests after the extreme wet event. Full article

(This article belongs to the Section Forest Ecophysiology and Biology)

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11 pages, 1828 KiB

Open AccessArticle

Study on the Genetic Variation of Triadica sebifera (Linnaeus) Small Populations Based on SSR Markers

by Pengyan Zhou, Qi Zhou, Fengping Dong, Xin Shen and Yingang Li

Forests 2022, 13(8), 1330; https://doi.org/10.3390/f13081330 - 20 Aug 2022

Cited by 2 | Viewed by 1517

Abstract

Triadica sebifera (Linnaeus) Small is a tree species native to China. The seeds of T. sebifera are rich in oil and are widely used in industrial fields. To explore the genetic diversity and genetic differentiation of T. sebifera germplasm resources, 10 pairs of [...] Read more.

Triadica sebifera (Linnaeus) Small is a tree species native to China. The seeds of T. sebifera are rich in oil and are widely used in industrial fields. To explore the genetic diversity and genetic differentiation of T. sebifera germplasm resources, 10 pairs of microsatellite markers were applied to 203 samples collected from eight populations. Forty-three alleles were detected. The average expected heterozygosity (He = 0.491) revealed a low level of genetic diversity. The genetic differentiation among T. sebifera populations was low (Fst = 0.026), which might be related to high gene flow (average Nm = 11.151). Genetic distance and structure results further confirmed that the genetic compositions of the eight populations were quite similar. One of the possible reasons for this phenomenon is that the early introduction and cultivation of T. sebifera were common, so gene exchange was frequent among populations. However, UPGMA clustering results indicated that the eight T. sebifera populations could still be divided into three categories. The classification was related to their geographical location: the southwestern group (ZY), central group (HG and XY) and eastern group (LS, HS, LX, XZ and LY). The reason for this differentiation might be severe deforestation following the decline in T. sebifera economic status. In addition, the central XY population had the largest number of rare alleles (4). In conclusion, although T. sebifera germplasm resources had a low level of genetic diversity, several rare alleles were detected in the central populations, which are valuable for breeding. These resources should be conserved to maintain genetic diversity in the T. sebifera populations. Moreover, geographical distances were important reasons for the limited genetic variations among the populations. Full article

(This article belongs to the Special Issue Biodiversity and Conservation of Forests)

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11 pages, 2041 KiB

Open AccessArticle

The Long-Term Capital-Market Performance of the Forestry Sector: An Investors’ Perspective

by Karlo Beljan, Magdalena Brener and Denis Dolinar

Forests 2022, 13(8), 1329; https://doi.org/10.3390/f13081329 - 19 Aug 2022

Cited by 4 | Viewed by 2536

Abstract

High risk-adjusted returns, low correlation with financial asset classes and inflation hedging are investment characteristics that make forests a desirable investment opportunity. To examine returns on forestry investments (from 2011 to 2020), we focused solely on 48 forest companies (across the globe) that [...] Read more.

High risk-adjusted returns, low correlation with financial asset classes and inflation hedging are investment characteristics that make forests a desirable investment opportunity. To examine returns on forestry investments (from 2011 to 2020), we focused solely on 48 forest companies (across the globe) that were listed on stock exchanges. Results indicate the economic justification of investing in publicly traded forestry companies. The positive five-year beta coefficients (β) range from 0.21 to 3.46, amounting to 1.15 on average. Taking the last 10-year comparison of the world’s most common capital market benchmarks, the highest return was achieved by the S&P500 (13.8% on average) followed by forestry companies (9.1%), U.S. Treasury bonds (4.4%), and gold (3.0%). Forestry companies, along with their associated business activities (sawmilling, final products production, and paper production), show the best historical performance from an investor’s point of view (total return of 13.2%). Full article

(This article belongs to the Section Forest Economics, Policy, and Social Science)

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20 pages, 2787 KiB

Open AccessArticle

Effects of Excess Nitrogen (N) on Fine Root Growth in Tropical Forests of Contrasting N Status

by Feifei Zhu, Frank S. Gilliam, Jan Mulder, Muneoki Yoh, Jiangming Mo and Xiankai Lu

Forests 2022, 13(8), 1328; https://doi.org/10.3390/f13081328 - 19 Aug 2022

Cited by 2 | Viewed by 1608

Abstract

Elevated nitrogen (N) deposition may further acidify soils in tropical forests. Yet, we have limited evidence on this prediction and it remained unclear how this would affect fine root growth therein. Here, we report responses of fine root biomass, vitality, and chemistry, as [...] Read more.

Elevated nitrogen (N) deposition may further acidify soils in tropical forests. Yet, we have limited evidence on this prediction and it remained unclear how this would affect fine root growth therein. Here, we report responses of fine root biomass, vitality, and chemistry, as well as related soil parameters to eight years of N additions in three tropical forests different in initial soil N status, with one primary forest being N-saturated, and another two younger forests (one secondary forest and one planted forest) less N-rich. Results showed that in the primary forest, fine root biomass decreased and fine root necromass increased following N addition, resulting in lower live fine root proportion (fine root vitality). Declining fine root vitality was associated with fine root Fe accumulation and soil acidification indicated by regression analysis. These alterations of fine root growth and chemistry co-occurred with soil pH decline, soil exchangeable Fe³⁺ mobilization, exchangeable Ca²⁺, and Mg²⁺ depletion after N treatments in the primary forest. In contrast, N addition only elevated fine root K, Al, and Fe content in the secondary forest. In the planted forest, moderate but significant decreases in soil pH, soil exchangeable K⁺, and Mg²⁺ were found after N treatment, with fine root biomass negatively correlated with soil exchangeable Al³⁺ and Al³⁺/(Ca²⁺ + Mg²⁺) ratio. Our results suggested that long-term N fertilization may negatively affect fine root growth, via severed soil acidification, Fe mobilization, and base cation depletion in highly acidified, N-saturated primary tropical forests. Initial forest N status, influenced by different land-use history, mediates N deposition effects on fine root growth. Full article

(This article belongs to the Special Issue Nitrogen Biogeochemical Cycling in Forest Ecosystems)

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15 pages, 3926 KiB

Open AccessArticle

Roost Selection in Relation to a Patchy, Mosaic Management Burn by a Threatened Clutter-Adapted Bat

by Leroy Gonsalves, Brad Law, Traecey Brassil, Isobel Kerr and Christopher O’Loughlin

Forests 2022, 13(8), 1327; https://doi.org/10.3390/f13081327 - 19 Aug 2022

Cited by 1 | Viewed by 1672

Abstract

Fire is a major disturbance for forests and its impacts can be complex, influenced by a range of factors including fire severity and frequency. Changes to global climate have increased the frequency and lengthened the window for wildfires. Anthropogenic fires are now commonly [...] Read more.

Fire is a major disturbance for forests and its impacts can be complex, influenced by a range of factors including fire severity and frequency. Changes to global climate have increased the frequency and lengthened the window for wildfires. Anthropogenic fires are now commonly used to try to mitigate the risk and spread of wildfires or for ecological purposes, yet it is unclear how many flora and fauna species respond to this lower severity and more patchily distributed treatment. We assessed day-roost selection by a threatened narrow space bat, Nyctophilus corbeni, after a management burn left a mosaic of unburnt forest, low severity (ground scorch) burnt and higher severity (midstorey to crown scorch) burnt forest. Radio-tracking was used to identify day-roosts of 11 individuals (8 lactating females and 3 males) during the maternity season. Characteristics of day-roost trees (n = 42 trees) were similar for males and lactating females and were comparable to other day-roosts used elsewhere in the broader study area, with bats selecting moderately sized (23–24 cm dbhob) dead buloke (Allocasuarina luehmannii) with hollows. However, roost selection at the scale of the neighborhood varied by sex and was random for lactating females. Selection of the post-burn mosaic by males was non-random at all scales of assessment greater than a 100 m neighborhood, with bats selecting areas burnt by low-severity fire at these scales, but avoiding areas of higher severity fire. Locally, there were ~14 more hollow trees per ha surrounding roosts in areas burnt by low severity fire than in the unburnt forest, whereas forest burnt by higher severity fire had on average ~8 fewer hollow trees per hectare. Our study confirmed that dead buloke with hollows is a key resource for N. corbeni that should be prioritized for retention, particularly when identifying areas to offset habitat loss. Patchy management fires appear to be compatible with roosting habits of breeding N. corbeni, provided hollow resources are not impacted by fire. Management burns may promote roosting habitat for male bats, but areas of higher severity burns need to be minimized. Further research is needed to assess the use of the post-burn mosaic for nightly movements, including foraging. The effects of repeated burning on hollow availability and roost selection by N. corbeni should be investigated to identify suitable intervals between fires for this threatened species. Full article

(This article belongs to the Special Issue Effects of Forest Management Practices on Bat Habitat and Community Structure)

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24 pages, 2363 KiB

Open AccessArticle

Getting Flow: The Place of Production Forests in the Rise of Mountain Biking

by Karen M. Bayne, Matthew B. Scott and Richard T. Yao

Forests 2022, 13(8), 1326; https://doi.org/10.3390/f13081326 - 19 Aug 2022

Cited by 2 | Viewed by 3530

Abstract

Mountain biking has increased in popularity in many countries over recent decades. Production forests provide not only an outstanding space for mountain bike riding, but also specific characteristics conducive to purpose-built track building. With recreational access to production forests, managers must balance commercial [...] Read more.

Mountain biking has increased in popularity in many countries over recent decades. Production forests provide not only an outstanding space for mountain bike riding, but also specific characteristics conducive to purpose-built track building. With recreational access to production forests, managers must balance commercial operations and industry environmental obligations with the interests and actions of riders. Production forests in New Zealand have accommodated mountain biking activities for decades. The trend from 1991 to 2022 showed overall increasing opportunities for mountain biking in production forests, particularly in smaller commercial peri-urban plantations and forest parks maintained as dedicated mountain bike parks. Over the same period, public mountain biking access to larger (>1500 ha) forests peaked in 2008. These recreational changes within forests, and the impact these changes have pressed onto forest managers, have not been well documented. This paper explores the rise in popularity of mountain biking in New Zealand’s production plantation forests, and the response of forest owners and managers to increased mountain biking activities in their commercial forest estates. The paper discusses implications for forest planning to accommodate active recreational sports such as mountain biking in production forests, suggesting policies and procedures to help protect commercial interests and forest ecology, while allowing for a contemporary mix of recreational activities. Full article

(This article belongs to the Special Issue Forest Recreation and Landscape Protection)

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13 pages, 2877 KiB

Open AccessArticle

Effects of the Ball Milling Process on the Particle Size of Graphene Oxide and Its Application in Enhancing the Thermal Conductivity of Wood

by Na Zhang, Yiqun Mao, Shuangshuang Wu and Wei Xu

Forests 2022, 13(8), 1325; https://doi.org/10.3390/f13081325 - 19 Aug 2022

Cited by 16 | Viewed by 2547

Abstract

To improve the dispersion of graphene oxide particles in wood for better thermal conductivity, this paper proposes the feasibility of obtaining graphene oxide with a smaller particle size using ball milling and its application in melamine resin-modified poplar veneer. The median diameter of [...] Read more.

To improve the dispersion of graphene oxide particles in wood for better thermal conductivity, this paper proposes the feasibility of obtaining graphene oxide with a smaller particle size using ball milling and its application in melamine resin-modified poplar veneer. The median diameter of multilayer graphene oxide was measured to learn the effects of different ball milling conditions on the particle size of graphene oxide, and the optimum ball milling process was chosen. In addition, the microscopic characterization of graphene oxide under the optimum ball milling process was carried out to investigate the microstructural changes in multilayer graphene after ball milling. Furthermore, the thermal conductivity of the graphene oxide/melamine resin-impregnated mixture modified veneer with the optimum ball milling process was also tested. The results show that, under the optimum ball milling process conditions of SDS wet ball milling with a vibration frequency of 30 Hz for 60 min, the particle size of the multilayer graphene was the smallest, and the median diameter could be reduced to 124 nm. Simultaneously, the thermal conductivity of the melamine resin-modified poplar veneer enhanced by the ball-milled graphene reached 0.405 W·m⁻¹·K⁻¹. In addition, it revealed that the number of graphene oxide layers was reduced to four after ball milling. However, the multilayer graphene was partially oxidized, the lamellar structure was destroyed and the crystallinity was reduced. Full article

(This article belongs to the Section Wood Science and Forest Products)

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18 pages, 1994 KiB

Open AccessArticle

The Spatial Pattern and Spillover Effect of the Eco-Efficiency of Regional Tourism from the Perspective of Green Development: An Empirical Study in China

by Sidi Li, Teng Ren, Binbin Jia and Yongde Zhong

Forests 2022, 13(8), 1324; https://doi.org/10.3390/f13081324 - 19 Aug 2022

Cited by 12 | Viewed by 1815

Abstract

Scientifically analyzing the spatial pattern and spillover effect of the eco-efficiency of regional tourism embodies the green development theory. In addition, it is also of important significance for realizing the sustainable development of regional tourism and promoting regional ecological civilization. This study incorporates [...] Read more.

Scientifically analyzing the spatial pattern and spillover effect of the eco-efficiency of regional tourism embodies the green development theory. In addition, it is also of important significance for realizing the sustainable development of regional tourism and promoting regional ecological civilization. This study incorporates energy consumption and CO₂ emissions of tourism into the efficiency evaluation index system. On this basis, the slacks-based measure–data envelopment analysis (SBM-DEA) with undesirable output, the spatial autocorrelation (SAC) model and the spatial Durbin model (SDM) are used to study the spatial pattern and spillover effect of the eco-efficiency of provincial tourism in China from 2008 to 2017. Results show that the following: (1) The average eco-efficiency of national tourism is 0.534, which is at the medium development level as a whole. Among the decomposed efficiencies of eco-efficiency, the scale efficiency drives the optimal development of eco-efficiency in tourism. (2) The eco-efficiency of tourism shows a spatial differentiation pattern on the regional scale as follows: it is the highest in the central region, moderate in the western region, and lowest in the eastern region. (3) The degree of clustering of the eco-efficiency of tourism first increases and then decreases. The SAC-based cluster pattern is dominated by a low-low (LL) cluster, followed successively by a high-high (HH) cluster and a low-high (LH) outlier, while a high-low (HL) outlier is the least significant (4). Among the influencing factors, the technical level shows spatial spillover effects on both the eco-efficiency and pure technical efficiency of tourism; the economic development level and traffic accessibility mainly have spatial spillover effects on the pure technical efficiency and scale efficiency of tourism; the industrial structure and environmental regulation separately have a spatial spillover effect only on the pure technical efficiency and the scale efficiency of tourism. Full article

(This article belongs to the Special Issue Nature-Based Tourism and Nature Conservation Activation by Tourism)

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17 pages, 3004 KiB

Open AccessArticle

Multiscale Regulation of Leaf Traits in Woody Plants as an Adaptation to a Post-Earthquake Environment in Broadleaved Forests of Southwestern China

by Di Kang, Caijia Yin, Shiqi Liu, Li Chen, Shuzhen Zou and Dahai Zhu

Forests 2022, 13(8), 1323; https://doi.org/10.3390/f13081323 - 18 Aug 2022

Viewed by 1350

Abstract

Functional traits are important indicators for examining ecological processes and after-effects of plant community restoration after large-scale geological disturbance. Sample sites with and without landslides in typical forest ecosystems within the region that experienced the highest intensity of the Wenchuan 8.0 earthquake in [...] Read more.

Functional traits are important indicators for examining ecological processes and after-effects of plant community restoration after large-scale geological disturbance. Sample sites with and without landslides in typical forest ecosystems within the region that experienced the highest intensity of the Wenchuan 8.0 earthquake in China were selected in this study, and the characteristics, variations, relationships and influencing factors of woody plant traits at the species, individual and functional type scales were studied. The total interspecific and intraspecific variation of woody plant functional traits was 62.02% and 14.86%, respectively. Differences in woody plant traits were observed at multiple ecological scales on landslides compared with those on nonlandslides. The differentiation of functional traits of recovering communities significantly decreased among woody plant functional types (WFTs) on landslides after the earthquake, indicating disruption and reorganization of the original functional structure. Woody plants on landslides adapted to the new environment by adjusting their leaf traits to improve light use efficiency and adopting rapid ecological strategies. In contrast, woody plants on nonlandslides were more inclined to accumulate material and support structures. Leaf thickness was sensitive to earthquakes. Leaf traits showed a high degree of synergy in their environmental response. Full article

(This article belongs to the Special Issue Plant Functional Traits in Forests: Variation and Linkages with Function)

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15 pages, 3100 KiB

Open AccessArticle

Detection of Eucalyptus Leaf Disease with UAV Multispectral Imagery

by Kuo Liao, Fan Yang, Haofei Dang, Yunzhong Wu, Kunfa Luo and Guiying Li

Forests 2022, 13(8), 1322; https://doi.org/10.3390/f13081322 - 18 Aug 2022

Cited by 2 | Viewed by 2688

Abstract

Forest disease is one of the most important factors affecting tree growth and product quality, reducing economic values of forest ecosystem goods and services. In order to prevent and control forest diseases, accurate detection in a timely manner is essential. Unmanned aerial vehicles [...] Read more.

Forest disease is one of the most important factors affecting tree growth and product quality, reducing economic values of forest ecosystem goods and services. In order to prevent and control forest diseases, accurate detection in a timely manner is essential. Unmanned aerial vehicles (UAVs) are becoming an important tool for acquiring multispectral imagery, but have not been extensively used for detection of forest diseases. This research project selected a eucalyptus forest as a case study to explore the performance of leaf disease detection using high spatial resolution multispectral imagery that had been acquired by UAVs. The key variables sensitive to eucalyptus leaf diseases, including spectral bands and vegetation indices, were identified by using a mutual information–based feature selection method, then distinguishing disease levels using random forest and spectral angle mapper approaches. The results show that green, red edge, and near-infrared wavelengths, nitrogen reflectance index, and greenness index are sensitive to forest diseases. The random forest classifier, based on a combination of sensitive spectral bands (green, red edge, and near-infrared wavelengths) and a nitrogen reflectance index, provided the best differentiation results for healthy and three disease severity levels (mild, moderate, and severe) with overall accuracy of 90.1% and kappa coefficient of 0.87. This research provides a new way to detect eucalyptus leaf diseases, and the proposed method may be suitable for other forest types. Full article

(This article belongs to the Topic Challenges, Development and Frontiers of Smart Agriculture and Forestry)

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20 pages, 5812 KiB

Open AccessArticle

Drivers of Native Species Regeneration in the Process of Restoring a Dry Evergreen Forest from Exotic Tree Plantations in Northeastern Thailand

by Duriya Staporn, Dokrak Marod, Jetsada Wongprom and Sapit Diloksumpun

Forests 2022, 13(8), 1321; https://doi.org/10.3390/f13081321 - 18 Aug 2022

Cited by 4 | Viewed by 1672

Abstract

Establishment of exotic plantations is one of the most effective ways to induce natural regeneration for the restoration of degraded lands, as it has the potential to improve soil properties and creates favorable microclimates. This study aims to determine the effects of stand [...] Read more.

Establishment of exotic plantations is one of the most effective ways to induce natural regeneration for the restoration of degraded lands, as it has the potential to improve soil properties and creates favorable microclimates. This study aims to determine the effects of stand structure and composition as well as environmental factors under the canopies of three exotic plantations in northeastern Thailand on the regeneration of native species. For each plantation, we conducted three 10 m × 150 m transect lines with fifteen 10 m × 10 m subplots along a forest remnant gradient. The canonical correspondence analysis (CCA) was used to identify the environmental factors responsible for the differences in natural regeneration among these stands. Three exotic plantations had different stand structure in terms of number of tree species, basal area, and tree density but similar dominant native tree species. Across all stands, 74 native tree species, 60 genera, and 30 families were observed. Some physical and chemical properties in the topsoil were significantly different between species but similar among stands within a species. On the other hand, differences in environmental factors such as RLI were significant among species and stands within a species. The CCA ordination identified that the soil particles, soil pH, and light intensity were key factors influencing the native species composition, which could be categorized into three groups: drought-tolerant pioneer species; light-demanding pioneer species; and shade-tolerant climax species. However, most of the climax species were incapable of regenerating and maturing along the forest edge gradient to plantation stands. To accelerate the restoration process by converting these old exotic plantations to a dry evergreen forest, further research is required to determine the appropriate canopy management and/or dominant climax species for planting beneath their canopies. Full article

(This article belongs to the Special Issue Ecological and Anthropogenic Drivers of Forest Regeneration and Afforestation)

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14 pages, 3039 KiB

Open AccessArticle

Genetic Diversity of Nanmu (Phoebe zhennan S. Lee. et F. N. Wei) Breeding Population and Extraction of Core Collection Using nSSR, cpSSR and Phenotypic Markers

by Yan Zhu, Wenna An, Jian Peng, Jinwu Li, Yunjie Gu, Bo Jiang, Lianghua Chen, Peng Zhu and Hanbo Yang

Forests 2022, 13(8), 1320; https://doi.org/10.3390/f13081320 - 18 Aug 2022

Cited by 5 | Viewed by 2369

Abstract

Genetic characterization is vital for tree germplasm utilization and conservation. Nanmu (Phoebe zhennan S. Lee. et F. N. Wei) is an extremely valuable tree species that can provide logs for many industrial products. This study aimed to assess the genetic diversity of [...] Read more.

Genetic characterization is vital for tree germplasm utilization and conservation. Nanmu (Phoebe zhennan S. Lee. et F. N. Wei) is an extremely valuable tree species that can provide logs for many industrial products. This study aimed to assess the genetic diversity of a Nanmu breeding population using nine nSSR, five newly-developed cpSSR markers, and nine phenotypic traits, and extract a core collection. In general, the Na, Ne, and PIC for each nSSR/cpSSR were 2–37/2–3, 1.160–11.276/1.020–1.940, and 0.306–0.934/0.109–0.384, respectively. Fifteen chlorotype haplotypes were detected in 102 germplasms. The breeding population exhibited a relatively high level of genetic diversity for both nSSR (I = 1.768), cpSSR (I = 0.440, h = 0.286), and phenotypic traits (H′ = 1.98). Bayesian and cluster analysis clustered these germplasms into three groups. The germplasms revealed a high level of admixture between clusters, which indicated a relatively high level of gene exchange between germplasms. The F value (0.124) also showed a moderate genetic differentiation in the breeding population. A core collection consisting of 64 germplasms (62.7% of the whole germplasm) was extracted from phenotypic and molecular data, and the diversity parameters were not significantly different from those of the whole germplasm. Thereafter, a molecular identity was made up for each core germplasm. These results may contribute to germplasm management and conservation in the Nanmu breeding program, as well as genetics estimation and core collection extraction in other wood production rare species. Full article

(This article belongs to the Special Issue Genetic Diversity and Conservation of Forest Species)

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9 pages, 2291 KiB

Open AccessCommunication

Firefighting: Challenges of Smart PPE

by Gilda Santos, Rita Marques, João Ribeiro, Adriana Moreira, Patricia Fernandes, Margarida Silva, André Fonseca, João M. Miranda, João B. L. M. Campos and Soraia F. Neves

Forests 2022, 13(8), 1319; https://doi.org/10.3390/f13081319 - 18 Aug 2022

Cited by 7 | Viewed by 2604

Abstract

The continuous research and development regarding firefighters’ personal protective equipment (PPE) has led to significant improvements in recent decades. Despite the evolution of firefighters’ PPE, every year an undesirable number of firefighters are seriously burned during firefighting operations, with some of them eventually [...] Read more.

The continuous research and development regarding firefighters’ personal protective equipment (PPE) has led to significant improvements in recent decades. Despite the evolution of firefighters’ PPE, every year an undesirable number of firefighters are seriously burned during firefighting operations, with some of them eventually losing their lives. The protection given by firefighters’ PPE can be further increased with the incorporation of smart textiles in the personal protective equipment, namely, wearable electronics (i.e., integrated sensors to monitor diverse parameters: heart rate, oxygen saturation, carbon dioxide detector, and setting real-time communication with a command post) and advanced materials such as phase change materials (PCMs). The evolution of firefighters’ PPE has been followed by an evolution and update in the international and national standards that specify performance requirements for firefighters’ protective clothing for structural and wildland firefighting as well as technical rescue. This study will focus on the analysis of firefighters protective clothing evolution regarding the use and integration of advanced smart materials, namely, phase change materials, taking into consideration the evolution and requirements of international and European standards as well as national legislation for firefighters’ protective clothing. Full article

(This article belongs to the Topic Recent Breakthroughs in Forest Fire Research)

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11 pages, 1886 KiB

Open AccessFeature PaperArticle

Effects of Neighborhood Competition and Stand Structure on the Productivity of Pure and Mixed Larix principis-rupprechtii Forests

by Jing Zhang, Jinman Zhao, Ruiming Cheng, Zhaoxuan Ge and Zhidong Zhang

Forests 2022, 13(8), 1318; https://doi.org/10.3390/f13081318 - 18 Aug 2022

Cited by 5 | Viewed by 1656

Abstract

Understanding the factors influencing tree productivity is central to forest ecology. However, the relative contributions of neighborhood interactions, tree species diversity, and tree size to larch (Larix principis-rupprechtii) productivity require further study. Three plots in the Guandi Mountains, Shanxi Province, were [...] Read more.

Understanding the factors influencing tree productivity is central to forest ecology. However, the relative contributions of neighborhood interactions, tree species diversity, and tree size to larch (Larix principis-rupprechtii) productivity require further study. Three plots in the Guandi Mountains, Shanxi Province, were set up for each of the following forest types: natural pure larch forest (PL), mixed larch and birch (Betula platyphylla) forest (LB), and mixed larch and spruce (Picea asperata) forest (LS). Based on the tree size-stratified sampling method, a total of 318 tree core samples were collected. A linear mixed model was used to analyze the effects of tree size, dominance, mixing, and neighborhood competition on larch productivity. Birch and spruce promoted larch growth at the stand and individual tree levels, and birch exhibited a more significant facilitating effect. Intraspecific competition was the main factor affecting larch growth. When the intensity of competition among trees was low, the basal area increment (BAI) of larch in the mixed forests was higher than that in the pure forest. However, with increasing competition, the BAI of larch was lower in the mixed forests than in the pure forest. Factors including tree size, dominance, and mingling were positively correlated with the BAI of larch. With increasing tree size, the BAI of larch was higher in the mixed forests than in the pure forest and higher in LB than in LS. When the dominance was less than 0.5, the BAI of larch was higher in the pure forest than in the mixed forests and higher in LS than in LB. With increasing dominance, the BAI of larch was higher in the mixed forests than in the pure forest. The BAI of larch increased with an increasing mixing degree in the mixed forests, and the increasing trend of BAI was larger in LB than in LS. Larch productivity was influenced mainly by neighborhood interactions and stand structure. Improving neighborhood tree diversity and increasing the large tree proportion and dominance of larch will be helpful for improving larch productivity in mixed forests. Full article

(This article belongs to the Section Forest Ecology and Management)

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15 pages, 3947 KiB

Open AccessArticle

Operating Characteristics of a Timber Trailer with a Hybrid Drive

by Tomáš Zemánek, Petr Procházka, Ivo Pazdera, Jindřich Neruda, Václav Mergl, Ondřej Vítek, Radomír Ulrich and Luboš Staněk

Forests 2022, 13(8), 1317; https://doi.org/10.3390/f13081317 - 17 Aug 2022

Viewed by 1966

Abstract

This paper deals with the design and operational evaluation of a timber tractor-trailer unit with a hybrid trailer drive. The source of electrical energy for the two induction motors driving the front wheels of the tandem trailer axle is a battery, which is [...] Read more.

This paper deals with the design and operational evaluation of a timber tractor-trailer unit with a hybrid trailer drive. The source of electrical energy for the two induction motors driving the front wheels of the tandem trailer axle is a battery, which is recharged by an induction machine operating as a generator during periods of a lower demand for power from the tractor diesel engine. An electric drive was designed for the defined working cycle of the tractor-trailer unit, and its loading characteristics were tested in the laboratory. The parameters measured on the field tests during timber forwarding were battery voltage and power, and the energy balance. Three adjustment levels of the potentiometer controlling the trailer hybrid drive (50, 75 and 100%) were tested at three different forwarding distances of 100, 500 and 1000 m. Additionally, any slippage of the prime mover wheels and trailer was measured. The maximum peak power taken from the battery was ca. 33 kW during the field tests, whilst the drive was able to deliver a peak output of up to 72 kW for 10 s and permanently up to ca. 50 kW. Even in harsh terrain conditions, the electric drive assisted the combustion engine only when the loaded tractor-trailer unit was travelling uphill. The hybrid drive operation was sustainable for the whole working shift, without the need for recharging when the potentiometer was set to 50%. This appropriate setting of the potentiometer controlling the trailer’s hybrid drive reduced the slipping of the driven wheels of the tractor-trailer unit whilst travelling uphill. Full article

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13 pages, 1706 KiB

Open AccessArticle

Developing a Yield Table and Analyzing the Economic Feasibility for Acacia Hybrid Plantations in Achieving Carbon Neutrality in Southern Vietnam

by Sang-Hyun Lee, Dong-Hyuk Kim, Jin-Heon Jeong, Seung-Hyun Han, Seongjun Kim, Hee-Jung Park and Hyun-Jun Kim

Forests 2022, 13(8), 1316; https://doi.org/10.3390/f13081316 - 17 Aug 2022

Cited by 1 | Viewed by 1661

Abstract

To achieve the goal of carbon neutrality, overseas plantation projects have been conducted in several countries, including Vietnam. In the present study, stand growth models and a yield table were developed and used to analyze the economic feasibility of Acacia hybrid plantations in [...] Read more.

To achieve the goal of carbon neutrality, overseas plantation projects have been conducted in several countries, including Vietnam. In the present study, stand growth models and a yield table were developed and used to analyze the economic feasibility of Acacia hybrid plantations in southern Vietnam. Diameter at breast height, tree height, and number of trees were determined in the field; basal area, mean height, dominant tree height, stand density, and stand volume were estimated using in situ data. The initial number of trees increased for five years and reached 4947 trees ha⁻¹; tree numbers then decreased to 1987 trees ha⁻¹ until the stands reached ten years of age. The highest current annual increment of stand volume was shown to be 46.23 m³ ha⁻¹ yr⁻¹ when stands were 7 years old. For 7 years of stand age, the net present value was USD 1566/ha, and the internal rate of return was 13%, exceeding the market interest rate (4%). Therefore, an A. hybrid plantation is a reasonable proposition for an overseas plantation project in southern Vietnam and the growth models will be useful for the management of an A. hybrid plantation. Full article

(This article belongs to the Special Issue Effects of Environmental Changes on Forest Growth and Stability)

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27 pages, 7576 KiB

Open AccessArticle

The Climate-Growth Relationship between Picea smithiana (Wall.) Boiss. and Abies pindrow (Royle ex D.Don) Royle along the Latitudinal Gradient in Northern Pakistan

by Habib Ullah, Xiaochun Wang, Quaid Hussain, Abdullah Khan, Naveed Ahmad, Nizar Ali, Muhammad Waheed Riaz and Izhar Hussain

Forests 2022, 13(8), 1315; https://doi.org/10.3390/f13081315 - 17 Aug 2022

Cited by 2 | Viewed by 2076

Abstract

A changing climate and global warming have adversely affected Pakistan’s moist and dry temperate vegetation. Abies pindrow (fir) (Royle ex D.Don) Royle and Picea smithiana (spruce) Wall.) Boiss are the two major representative species of the moist and dry temperate forests in Northern [...] Read more.

A changing climate and global warming have adversely affected Pakistan’s moist and dry temperate vegetation. Abies pindrow (fir) (Royle ex D.Don) Royle and Picea smithiana (spruce) Wall.) Boiss are the two major representative species of the moist and dry temperate forests in Northern Pakistan. The dendroclimatic study of both species is crucial for the assessment of climate variability at various spatial and temporal scales. This study examined the dendroclimatology of fir and spruce, and analyzed the growth–climate relationship along the latitudinal gradient. Two hundred and nineteen samples (ring cores) of the two species were collected from five different sites (Shogran (SHG), Upper Dir (UDS), Bahrain Swat (BSG), Astore Gilgit (NPKA), and Sharan Kaghan (SHA)) in Northern Pakistan. The cores were cross-dated, and chronologies were generated for the species and climatic data (precipitation, temperature, and Palmer Drought Severity Index (PDSI)) correlated with radial growth. The interspecies correlations for fir were calculated as 0.54, 0.49, 0.52, 0.60, and 0.48 for SHG, UDS, BSG, NPKA, and SHA, respectively, whereas in the case of spruce, the interspecies correlations were 0.44 for SHG, 0.55 for UDS, and 0.49 for BSG. Climate variability was observed in the samples of both species, which showed significant drought and humid years at specific intervals. With respect to the correlation between tree-ring width and climatic factors, a positive correlation was observed between fir growth and summer season precipitation, mean temperature, and PDSI in the spring, summer, and autumn seasons. Similarly, the growth of spruce was positively correlated with precipitation (in February, September, and May) and PDSI (in the summer and autumn seasons); however, no correlation was observed between monthly temperature and spruce growth. The relationship of fir and spruce growth with seasonal precipitation and PDSI showed a change from a negative to a positive correlation after 1980, following rapid warming. During the winter and spring, the correlation coefficient between fir radial growth and seasonal temperature showed an initial upward trend followed by a progressive decrease along with increasing latitude. Seasonal variations were observed regarding the correlation coefficient between spruce radial growth and increasing latitude (increasing in winter; a decreasing trend in spring and summer; an initial increase and then a decrease in autumn). In the same way, the correlation of seasonal temperature and PDSI with the radial growth of both species showed increasing trends with increasing latitude, except in the autumn season. Full article

(This article belongs to the Special Issue Impact of Climate Change on Tree Growth)

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11 pages, 717 KiB

Open AccessArticle

Parents’ Perceptions of UK Forest School: Descriptive and Evaluative Aspects

by Alexios Arvanitis, Anna K. Touloumakos and Alexia Barrable

Forests 2022, 13(8), 1314; https://doi.org/10.3390/f13081314 - 17 Aug 2022

Cited by 2 | Viewed by 2353

Abstract

Parental support for children’s Forest School (FS) education is likely connected to the parents’ own views about FS. We investigated parents’ perceptions of FS by performing a qualitative study on parents’ views, as expressed in an online forum for parents (Mumsnet). Findings were [...] Read more.

Parental support for children’s Forest School (FS) education is likely connected to the parents’ own views about FS. We investigated parents’ perceptions of FS by performing a qualitative study on parents’ views, as expressed in an online forum for parents (Mumsnet). Findings were grouped into two main categories, descriptive (what FS is) and evaluative (FS is good or bad). Thematic analysis revealed five dimensions of evaluation: skills and knowledge, nature connectedness and physical/mental health, structure, inclusivity and enjoyment. Along these dimensions we uncovered tensions between opposing views. We also identified two strategies for dealing with these tensions, dismissal and balance. This is the first study that identifies dimensions of evaluation for FS and potential parent satisfaction. The implications are discussed. Full article

(This article belongs to the Special Issue Efficacy of Nature-Based Learning and Global Outlook on Outdoor Education)

17 pages, 779 KiB

Open AccessArticle

The Impact of Forest Certification on the Ternary Margins of China’s Forest Product Export

by Jinzhu Zhang, Ziyue Zhao, Wenqi Zhao, Chenlu Tao and Baodong Cheng

Forests 2022, 13(8), 1313; https://doi.org/10.3390/f13081313 - 17 Aug 2022

Cited by 2 | Viewed by 1453

Abstract

Forest certification as a typical green trade measure has been gradually adopted by developed countries. Although it can promote the upgrading of forest products’ trade structure, it also threatens the stability of export growth. However, most studies have focused on the impact of [...] Read more.

Forest certification as a typical green trade measure has been gradually adopted by developed countries. Although it can promote the upgrading of forest products’ trade structure, it also threatens the stability of export growth. However, most studies have focused on the impact of forest certification on the total volume of forest product exports, but less on the impact on the growth structure. This study used the cross-country panel data and an extended gravity model to empirically analyze the impact of forest certification on the ternary margins of China’s forest products export to 39 countries that have introduced green trade measures from 2006 to 2019. The results show that the growth of China’s export of forest products is primarily driven by the quantitative margin, followed by the price margin. Forest certification in the trading partner countries has a significant positive impact on the price margin and a significant negative effect on the quantitative margin of China’s forest products. Furthermore, the effect on the quantitative margin is greater than that on the price margin, while the impact on the extensive margin is not significant. The study provides a scientific basis for responding to the forest certification measures, deepening cooperation with trading countries on forest products, and strengthening the mutual recognition and coordination of forest certification systems. Full article

(This article belongs to the Special Issue Production, Trade and Consumption of Wood-Based Products)

19 pages, 3470 KiB

Open AccessFeature PaperArticle

Site Quality Classification Models of Cunninghamia Lanceolata Plantations Using Rough Set and Random Forest West of Zhejiang Province, China

by Chen Dong, Yuling Chen, Xiongwei Lou, Zhiqiang Min and Jieyong Bao

Forests 2022, 13(8), 1312; https://doi.org/10.3390/f13081312 - 17 Aug 2022

Cited by 1 | Viewed by 1284

Abstract

The site quality evaluation of plantations has consistently been the focus in matching tree species with sites. This paper studied the site quality of Chinese fir (Cunninghamia lanceolata) plantations in Lin’an District, Zhejiang Province, China. The site quality model was constructed [...] Read more.

The site quality evaluation of plantations has consistently been the focus in matching tree species with sites. This paper studied the site quality of Chinese fir (Cunninghamia lanceolata) plantations in Lin’an District, Zhejiang Province, China. The site quality model was constructed using the algebraic difference approach (ADA) to classify the site quality grades. The rough set algorithm was used to screen out the key site factors affecting the site rank of Chinese fir plantations. Site quality classification models based on random forest were established, and the importance of key site factors was evaluated. The results are as follows. The random forest model based on the rough set algorithm had small scale and low complexity, and the training and testing accuracies of the model were 92.47% and 78.46%, respectively, which were better than the model without attribute reduction. The most important factors affecting Chinese fir growth in the study area were the slope aspect, slope grade, and canopy closure. The least important factors were the humus layer thickness, soil layer thickness, naturalness, and stand origin. The attribute reduction method proposed in this study overcame the subjectivity of traditional site factor selection, and the site quality classification model constructed improved the model accuracy and reduced the complexity of the algorithm. The methods used in this study can be extended to other tree species to provide a basis for matching tree species with sites and to improve the level of forest management in the future. Full article

(This article belongs to the Section Forest Ecology and Management)

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16 pages, 2634 KiB

Open AccessArticle

Evidence of a Climate-Change-Induced Shift in European Beech Distribution: An Unequal Response in the Elevation, Temperature and Precipitation Gradients

by Matija Klopčič, Andrej Rozman and Andrej Bončina

Forests 2022, 13(8), 1311; https://doi.org/10.3390/f13081311 - 17 Aug 2022

Cited by 2 | Viewed by 1590

Abstract

Climate is a strong predictor of the geographic distribution of tree species, and thus climate change may trigger shifts in the distribution of a tree species and/or its demographic structure. In the study, we aim to comprehensively compare the distributions of four life [...] Read more.

Climate is a strong predictor of the geographic distribution of tree species, and thus climate change may trigger shifts in the distribution of a tree species and/or its demographic structure. In the study, we aim to comprehensively compare the distributions of four life stages of European beech (Fagus sylvatica) (i.e., regeneration, recruitment, young trees and mature trees) in forests in Slovenia, Central Europe, which are characterized by strong gradients of elevation (ELV), temperature (TEMP) and precipitation (PREC) to detect possible shifts in distribution and demography. Beech life stages were surveyed on 3366 plots. To depict disparities between ELV, TEMP and PREC distributions of beech life stages, we applied several non-parametric methods: basic statistical tests to study differences in medians, means, and 1st and 9th deciles; generalized additive models to study shifts in the optimum; and extreme value analysis to study shifts at the trailing and leading edges. A substantial shift in juvenile beech stages upward and toward colder sites was detected. However, the shift was not uniform along the distributions; the most significant shift was detected at the leading edge of ELV (+73 m) and TEMP (−2.6 °C), but surprisingly there was no beech movement identified at the trailing edge. The observed shift may be a result of the interplay between climate change, high spatial variability in microclimate, unexceptional droughts in the recent past, changes in forest use and possible limitations in the migration ability of beech and its adaptation capacity. Full article

(This article belongs to the Special Issue Climate Change Effect on Mixed-Species Forest Management)

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13 pages, 3863 KiB

Open AccessArticle

Tree Cover Improved the Species Diversity of Understory Spontaneous Herbs in a Small City

by Yimin Ren, Min Guo, Fangyuan Yin, Ming-Juan Zhang and Jiaxing Wei

Forests 2022, 13(8), 1310; https://doi.org/10.3390/f13081310 - 17 Aug 2022

Cited by 5 | Viewed by 1988

Abstract

A large number of trees have been planted in built-up areas to improve the urban environment, but the effects of tree cover on spontaneous understory herbs are not yet well understood. This study surveyed spontaneous herbs in two kinds of habitats (habitats with [...] Read more.

A large number of trees have been planted in built-up areas to improve the urban environment, but the effects of tree cover on spontaneous understory herbs are not yet well understood. This study surveyed spontaneous herbs in two kinds of habitats (habitats with and without tree cover) in the built-up area of the small city Junlian in Sichuan Province, China. A total of 222 species of spontaneous herbaceous plants in 180 genera of 71 families were recorded, including a vulnerable species and six species endemic to China. Although the overall species richness values were similar in the two kinds of habitat, the average species richness per quadrat of all plants, perennials, plants with the dwarf growth form, and animal-dispersed plants was significantly higher in the habitats with tree cover than in those without tree cover. The overall species association was significantly positive in the habitats with tree cover (VR = 1.51, p < 0.05) and neural (VR = 0.86) in the habitats without tree cover. Among the top 25 frequently recorded species in each kind of habitat, the species association of plants with the same trait combination type differed greatly in the two kinds of habitats. For the species association between annuals, only 13.33% of species pairs were significantly associated in the habitats with tree cover, while 22.22% of the species pairs were significantly negatively associated in the habitats without tree cover. For the species association between plants with tall growth forms, the proportion of significant positive associations in the habitats with tree cover was approximately twice than in the habitats without tree cover. For the species association between plants with the dwarf growth form, the proportion of negative associations in the habitats without tree cover was approximately twice that in the habitats with tree cover. Species with the same dispersal mode generally had a very low proportion of negative interspecific associations or a high proportion of positive interspecific associations in habitats unfavorable to their establishment. Our findings suggest that tree cover can improve the species richness of the spontaneous herbaceous species beneath them and profoundly influence interspecific coexistence relationships in a built-up area. Full article

(This article belongs to the Special Issue Urban Forests and Landscape Ecology—Series II)

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Forests, Volume 13, Issue 8 (August 2022) – 186 articles

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