Forests doi: 10.3390/f15040615
Authors: Minmin Xu Zhihui Wang Zhenrui Li Zhenbing Sun Lili Shang Genlin Tian Jianfeng Ma Xing’e Liu
The objective of this study is to investigate the impacts of steam heat treatment parameters (e.g., temperature, time, and pressure) on the impact toughness of rattan (Calamus simplicifolius). The Box–Behnken design response surface analysis was employed to optimize the steam heat treatment parameters. Impact toughness was selected as the evaluation index, with single-factor tests conducted as a baseline for comparison. Changes in chemical composition, cellulose crystallinity, and pyrolysis properties were analyzed using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, Thermogravimetry–Fourier transform infrared (TG-FTIR) spectra, and wet-chemistry methods for both untreated control samples and the heat-treated samples. The results show that a 1 h steam heat treatment at 160 °C under 0.1 MPa pressure has the optimal process parameters for the rattan. The achieved impact toughness value closely matches the predicted value at 71.29 kJ/m2. After the steam heat treatment, hemicellulose and cellulose contents decrease, whereas relative lignin content increases significantly, leading to improved toughness characteristics in Calamus simplicifolius samples. The TG results indicate that maximum weight loss occurs at temperatures of 352 °C, 354 °C, and 361 °C, respectively, for three different samples. This suggests that the thermal stability is enhanced as a result of the heat treatment. These findings will help optimize the heat treatments of the rattan material.
]]>Forests doi: 10.3390/f15040614
Authors: Kun Yang Bo-Hui Tang Wei Fu Wei Zhou Zhitao Fu Dong Fan
Forest canopy fuel moisture content (FMC) is a critical factor in assessing the vulnerability of a specific area to forest fires. The conventional FMC estimation method, which relies on look-up tables and loss functions, cannot to elucidate the relationship between FMC and simulated data from look-up tables. This study proposes a novel approach for estimating FMC by combining enhanced vegetation index (EVI) and normalized difference moisture index (NDMI). The method employs the PROSAIL + PROGeoSAIL two-layer coupled radiation transfer model to simulate the vegetation index, the water index, and the FMC value, targeting the prevalent double-layer structure in the study area’s vegetation distribution. Additionally, a look-up table is constructed through numerical analysis to investigate the relationships among vegetation indices, water indices, and FMC. The results reveal that the polynomial equations incorporating vegetation and water indices as independent variables exhibit a strong correlation with FMC. Utilizing the EVI–NDMI joint FMC estimation method enables the direct estimation of FMC. The collected samples from Dali were compared with the estimated values, revealing that the proposed method exhibits superior accuracy (R2 = 0.79) in comparison with conventional FMC estimation methods. In addition, we applied this method to estimate the FMC in the Chongqing region one week before the 2022 forest fire event, revealing a significant decreasing trend in regional FMC leading up to the fire outbreak, highlighting its effectiveness in facilitating pre-disaster warnings.
]]>Forests doi: 10.3390/f15040613
Authors: Kateryna Davydenko Natalia Łukaszewska-Skrzypniak Katarzyna Sadowska Justyna Anna Nowakowska Kristina Raitelaitytė Svetlana Markovskaja Daiva Burokienė Olena Shcherbak Jorge Martín-García Julio Javier Diez Casero Tom Hsiang Tomasz Oszako
Pine pitch canker, caused by the ascomycete Fusarium circinatum, poses a substantial threat to pine trees and Douglas firs (Pseudotsuga menziesii), and has been identified as a pervasive issue in forests and nurseries worldwide, particularly in regions where susceptible conifers are cultivated. Given its prevalence in the Iberian Peninsula, assessments of the susceptibility of diverse European provenances of Scots pine (Pinus sylvestris)—specifically those from Poland, Lithuania, and Ukraine—have been conducted. Preliminary evaluations of Polish provenances have raised concerns about the potential threat to Scots pine stands in Poland posed by pitch canker. Under controlled conditions, we examined the impact of F. circinatum inoculation on the survival of seeds and seedlings from ten provenances of Scots pine. In response, the initial assessment of F. circinatum pathogenicity was undertaken in a controlled greenhouse environment. This evaluation uncovered a heightened susceptibility of pine seedlings to pitch canker among the tested provenances. Notably, one Lithuanian provenance demonstrated superior resistance to pitch canker, while two Polish provenances exhibited a higher prevalence of symptomless seedlings. These findings underscore the need for further exploration and identification of resilient individuals within these provenances, offering valuable insights for developing strategies to mitigate the impact of pitch canker on Scots pine in Europe.
]]>Forests doi: 10.3390/f15040611
Authors: Jakub Tomes Peter Fleischer Martin Kubov Peter Fleischer
In recent decades, large-scale forest disturbances such as windthrow and bark beetle infestations have significantly impacted Earth’s carbon balance and forest ecosystems. This impact alters soil respiration (SR), along with decreased gross primary productivity. To investigate the impact of bark beetle (Ips typographus L.) infestations in mountain spruce forests on SR, we measured SR at sites infested by bark beetles and adjacent undisturbed stands in the Tatra National Park (Slovakia) during the vegetation period (May–September) in 2016–2017 five to six years after the initial bark beetle attack. The measurements were taken along an altitudinal gradient (1100–1400 m a.s.l.). The highest rates of SR were observed during the summer months in both years (from June to August). However, yearly SR from May to September at infested sites showed significantly higher rates than uninfested ones in both years. SR showed a decreasing pattern with elevation gain in 2016 at infested sites, but this pattern was not observed in 2017. This study provides important insights into the impact of bark beetle infestations on SR and emphasizes the need for further research on the long-term effects of forest disturbances on carbon cycling. It also underscores the importance of determining the effect of different components of SR on the changed environment due to bark beetle attacks on mountain spruce forests.
]]>Forests doi: 10.3390/f15040612
Authors: Cam Nhung Pham Roman Gorbunov Vladimir Lapchenko Tatiana Gorbunova Vladimir Tabunshchik
In this study, we analyzed the content of chemical elements in rainwater and investigated the influence of forest cover on the composition of precipitation. The results obtained showed that the concentration of some elements in the rainwater collected under the forest canopy was higher than that in the open area. As part of the work, we calculated the enrichment factor and examined the sources of chemical elements in rainwater. We found that all macro-elements had increased values of the enrichment factors compared to the supporting elements of the Earth’s crust. Ca had the highest value. The values of the remaining elements (Sr, Pb, Mn, Cr, Ba, V, Fe) indicated their lithogenic and anthropogenic origins. We noted that the enrichment factor under the forest canopy was significantly lower than in the open area, indicating the dilution of these elements during water passage through the canopy. Elements such as Zn, Co, Cu, and Ni also had high enrichment factors, which indicate their anthropogenic origin. In the open area, most elements had an inverse relationship with pH, except for the alkali metals Na, Mg, and Ca, which had a positive relationship with the pH value. The concentration of K was not dependent on pH. In rainwater that had passed through the forest canopy, the concentrations of Na, Mg, and Ca were also not dependent on pH, while the concentration of K had an inverse relationship with pH. As the concentration of heavy metals in rainwater increases, the role of Na, Mg, and Ca in the process of water neutralization decreases.
]]>Forests doi: 10.3390/f15040610
Authors: Wanyi Zhu Zhenke Zhang Shouming Feng Hang Ren
The Mara River basin (MRB) has a world-famous ecosystem, but the vegetation has been damaged due to economic development in recent years, and there is little known about the area that will experience severe vegetation damage in the future. Based on the vegetation vulnerability system, principal component analysis, and three Shared Socio-Economic Pathways (SSP1-2.6, SSP2-4.5, SSP5-8.5), vegetation vulnerability was calculated for the base period (2010–2019), near future period (2020–2059) and distinct future period (2060–2099) in the MRB. The spatial cluster of vegetation vulnerability was revealed by spatial correlation analysis, and the transition of vegetation vulnerability of different periods was analyzed by stochastic matrix. The results showed that for all periods, the vulnerability showed a high–high cluster in the east, and a low–low cluster midstream and downstream. From the stochastic matrix, the area of high vulnerability increased the least under the SSP1-2.6, while it increased the most under the SSP5-8.5. The vegetation vulnerability upstream increased the most from the base period to the near future period and distinct future period in the MRB. By comparing the vegetation vulnerability under different scenarios and pointing out the areas with the highest vulnerability increase, this study can better provide comprehensive decision-making for vegetation protection in the MRB.
]]>Forests doi: 10.3390/f15040609
Authors: Yueyinglun Cao Yang Zhan Jiale Liu Tianyu Tang Juan Li Rui Zhao Qixiang Zhang Shuai Hu Wenhan Cao Yanli Gao
The deciduous tree hickory (Carya cathayensis) holds economic significance in China due to its high oil content, particularly in unsaturated fatty acids. Oil bodies are crucial for storing triacylglycerol (TAG), with caleosin serving as a predominant oil body protein that aids in oil body formation and stability maintenance. Our study utilized bioinformatics techniques to identify caleosin genes within Carya cathayensis, Carya illinoinensis, and Juglans regia. Three caleosin genes were discovered in the genomes of Carya cathayensis, Carya illi-noinensis, and Juglans regia. These genes encode hydrophilic proteins. Additionally, all caleosin proteins feature a single Ca2+-binding EF-hand, a conserved “proline knot” motif, and a C-terminal hydrophilic region with four potential phosphorylation sites. The caleosin proteins in Carya cathayensis consist of α-helix, β-corner, extended chain, and random curl structures. Cis-acting elements related to stress response and hormone signaling were identified in Carya cathayensis, Carya illinoinensis, and Juglans regia, with distinct cis-acting elements implicated in seed-specific regulation in Carya cathayensis. Additionally, subcellular localization analysis confirmed that CcaCLO1 and CcaCLO2 were localized within oil bodies. Transcriptome analysis and quantitative real-time polymerase chain reaction (qRT-PCR) data demonstrated a significant up-regulation of CcaCLO1 expression during the developmental stages of the Carya cathayensis embryo. Furthermore, qPCR findings indicated that caleosins from Carya cathayensis were responsive to salt stress, with a significant up-regulation of CcaCLO1 following exposure to salt stress treatment. Consequently, caleosin genes in Carya cathayensis, Carya illinoinensis, and Juglans regia share similar physicochemical characteristics and conserved motifs. Specifically, CcaCLO1 in Carya cathayensis primarily responds to embryo development and salt stress. These findings offer foundational insights for future investigations into the regulatory mechanisms of oil accumulation and response to salt stress in hickory.
]]>Forests doi: 10.3390/f15040608
Authors: Zhenyu Zhang Jeremy Cenci Jiazhen Zhang
The development of China’s high-density urbanisation process has made people aware of the widespread injustice in urban green space (UGS) as a means to improving residents’ well-being. The Chinese National Forest City (NFCC) policy is one of China’s construction models that aims to develop urban greening and reduce the inequality of residents’ well-being. This study used a combination of qualitative research and index quantification to explore the relationship between the spatial distribution of NFCCs and the factors affecting inequality in green space allocation and their impacts. The results of the study show that changes in indicators in NFCC policy reflect the national government’s decision-making orientation towards achieving environmental equity, and that the main factors affecting the unequal spatial distribution of NFCCs are highly correlated with inequality in UGS resources. This study analysed the NFCC policy from a new perspective and provides useful information for the development of national forest policy in order to ensure sufficient green space in China and the elimination of environmental inequity.
]]>Forests doi: 10.3390/f15040607
Authors: Alamgir Khan Xu-Dong Liu Muhammad Waseem Shi-Hua Qi Shantwana Ghimire Md. Mahadi Hasan Xiang-Wen Fang
Quantifying the dryland patterns of plant carbon (C), nitrogen (N), and phosphorus (P) concentrations and their stoichiometric values along environmental gradients is crucial for understanding ecological strategies. To understand the plant adaptive strategies and ecosystem nutrient concentrations across three desert ecosystems (e.g., desert, steppe desert, and temperate desert), we compiled a dataset consisting of 1295 plant species across three desert ecosystems. We assessed the element concentrations and ratios across plant growth forms, plant organs, and soils and further analysed the leaf vs. root N, P, and N:P scaling relationships. We found that the leaf N, P, and C concentrations were significantly different only from those of certain other growth forms and in certain desert ecosystems, challenging the generality of such differences. In leaves, the C concentrations were always greater than the N and P concentrations and were greater than those in soils depending on the soil chemistry and plant physiology. Thus, the element concentrations and ratios were greater in the organs than in the soils. The values in the leaf versus the root N, P, and N:P scaling relationships differed across the three desert ecosystems; for example, αN (1.16) was greater in the desert, αP (1.10) was greater in the temperate desert ecosystem, and αN:P (2.11) was greater in the desert ecosystem. The mean annual precipitation (MAP) and mean annual temperature (MAT) did not have significant effects on the leaf elemental concentrations or ratios across the desert ecosystems. This study advances our understanding of plant growth forms and organs, which support resource-related adaptive strategies that maintain the stability of desert ecosystems via divergent element concentrations and environmental conditions.
]]>Forests doi: 10.3390/f15040606
Authors: Zhichao Cheng Song Wu Hong Pan Xinming Lu Yongzhi Liu Libin Yang
Forest fires are among the most influential drivers of changes in forest soil bacterial diversity. Nevertheless, little is known regarding the effects of forest fires on maintaining the complex interactions that preserve forest ecosystem stability. Therefore, this study characterized alterations in soil bacterial community composition and diversity within taiga forests subjected to varying disturbance intensities. Particularly, this study examined the bacterial community within a Larix gmelinii fire-burnt site in Daxinganling, analyzing the changes in bacterial community structure and function across light, moderate, and heavy fire-burnt sites, as well as a control sample site, utilizing Illumina MiSeq technology. Through an assessment of bacterial community diversity and soil physicochemical properties (moisture content (MC), pH, microbial biomass carbon (MBC), organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), available phosphorus (AP), and available potassium (AP)), we explored the influence of the soil microenvironment on the soil bacterial community structure at the burnt site under different disturbance intensities. Our findings demonstrated that (1) there was no significant change in the Chao index of soil bacteria in the burnt site under different disturbance intensities, whereas the Shannon index decreased significantly (p < 0.05) and the Simpson index increased significantly (p < 0.05) in the burnt site under light and moderate disturbance. (2) The relative abundance of dominant phyla, such as Proteobacteria, Proteobacteria, and Actinobacteriota, did not change significantly in the fire-burnt site under different disturbance intensities, whereas rare species, such as Acidipila, Occallatibacter, and Acidibacter, experienced a significant increase in relative abundance at the genus level. (3) The results of principal coordinates analysis (PCoA) and canonical correlation analysis (CCA) revealed significant differences in the Beta diversity of soil bacteria in the fire-burnt site under varying interference intensities. The Beta diversity of soil bacteria exhibited significant differences (p = 0.001), with MC, pH, TN, AN, and AK identified as significant influencing factors. (4) FAPROTAX functional prediction analyses were conducted to assess the changes in soil bacteria involved in Cellulolysis, Chemoheterotrophy, and Aerobic_Chemoheterotrophy in the fire-burnt site, with the relative abundance of bacteria involved in Chemoheterotrophy being significantly increased (p < 0.05) under different disturbance intensities. Collectively, our findings demonstrated that different disturbance intensities caused by fires significantly affected the Alpha diversity, Beta diversity, and functional abundance of soil bacterial communities in taiga forests, with MC, pH, TN, AN, and AK being identified as key influencing factors. Additionally, the presence of numerous rare species suggests their role as pioneer communities in the succession of soil bacterial communities.
]]>Forests doi: 10.3390/f15040604
Authors: Linfeng Yang Haiyang Quan Jiajun Ji Haizhe Zhang Fengwen Sun
The artificial plywood industry in our country relies heavily on industrial flour as a filler for adhesives. Using abundant corn cob powder as the main raw material, corn cob powder was modified by impregnation with a sodium-based bentonite/bayberry tannin and used as filler for urea–formaldehyde resin (UF) adhesive, with NH4Cl as the curing agent and poplar veneer as the raw material to prepare plywood. The results showed that the modified corn cob powder with a particle size of 250 mesh was uniformly dispersed in the UF adhesive. When used as a filler, the modified corn cob powder effectively prevented the premature curing of the UF adhesive and significantly reduced its viscosity. Compared with flour filler, the bonding strength of the prepared plywood increased by 12.1%–19.6% while the formaldehyde emission decreased by 12.7%–27.8%. The cold pressing performance of the plywoods prepared with modified corn cob flour was comparable to the performance of plywood produced with industrial flour.
]]>Forests doi: 10.3390/f15040605
Authors: Sammar Abbas Ruotong Jing Manzar Abbas Zijian Hu Rabia Kalsoom Syed Sarfaraz Hussain Liang Du Jinxing Lin Xi Zhang
The WRKY family of transcription factors (TFs) is one of the most diverse families in plants, playing crucial roles in various plant growth and stress response processes. Asian white birch (Betula platyphylla) is a globally distributed tree species that holds ecological, medical, and economic significance. However, the regulatory mechanisms of WRKY TFs in birch remain poorly understood. Herein, we cloned and characterized the BpWRKY49 gene from birch. Through bioinformatics analyses, we revealed the potential involvement of BpWRKY49 in both biotic and abiotic stress responses. In addition, BpWRKY49 was found to be localized in the nucleus and exhibited transcriptional activity in yeast. Transactivation assays further confirmed that BpWRKY49 exhibited transcriptional activity at its C-terminal end. Notably, our binding specificity assays demonstrated the specific interaction of BpWRKY49 with the W-box cis element in vitro. Furthermore, tissue-specific expression analysis demonstrated that BpWRKY49 exhibited the highest expression level in the roots. Real-time quantitative PCR (RT-qPCR) analysis of birch plants subjected to salt and drought treatments revealed that BpWRKY49 displayed significant 30-fold and 10-fold upregulations under salt and drought stress conditions, respectively. DAP-seq analysis of BpWRKY49 identified a total of 21,832 peaks, with 3477 occurring in the promoter region of genes. Gene ontology (GO) enrichment analysis highlighted prominent terms related to defense against biotic stress, followed by terms associated with abiotic stress and development. Y1H assays of three genes provided evidence for the binding ability of BpWRKY49 to the promoters of BpPUB21, BpBTL15, and BpHIP47 in vitro. Collectively, our findings strongly suggest that BpWRKY49 possesses diverse functions and may activate multiple genes to contribute to various biological processes, including salt stress tolerance, in birch.
]]>Forests doi: 10.3390/f15040603
Authors: Zhiming Tan Ting Liu Chen Ning Xianying Lin Xun Liu Maoping Jiang Shuguang Liu Wende Yan
Camellia oleifera, a key economic forestry species in southern China, struggles with low productivity due to suboptimal planting management. Recently, transforming old or unadopted varieties of C. oleifera plantations has been recognized as a means to enhance economic benefits and production. However, the impact of these transformations on soil properties and fungal communities has received little attention. In this study, we targeted pre-renewal old C. oleifera and post-renewal young C. oleifera, Pinus massoniana, and Cunninghamia lanceolata. Through field sampling and soil physicochemical property analysis, we developed a soil quality evaluation system that effectively analyzes fungal community structures and identifies key arbuscular mycorrhizal fungi (AMF) species for soil health. We found that the soil quality evaluation system for this region comprises pH, TK, AK, NO3−, PO4− BG, ACP, F.simpson, AMF.shannon, and AMF.ace, which collectively indicated significant improvements in soil quality following transformation. Notably, the nutritional characteristics of the dominant fungal communities underwent marked changes, with an increase in pathogenic fungi in young C. oleifera and an expansion of ectomycorrhizal fungi in P. massoniana forests. The AMF communities in all four types of forest exhibited aggregation, and Scutellospora and Diversispora emerged as key species in the AMF community of C. oleifera. Additionally, Mortierella and Trichoderma were found to enhance plant resistance to pathogenic fungi. This study demonstrates that forestland transformation positively impacts soil quality and fungal community structure in C. oleifera, which provides valuable insights for future soil management in the region, both in terms of soil quality evaluation and fungal conservation.
]]>Forests doi: 10.3390/f15040602
Authors: Sihyun Kim Jisoo Kim
Korean wooden architectural heritage buildings are often damaged by termites, and climate change is expected to exacerbate the problem. To prevent termite damage, it is necessary to identify the habitat range and activity period of termites. In this study, we comprehensively analyzed the ecological characteristics of Reticulitermes speratus, the dominant termite species in South Korea, past termite damage records of wooden architectural heritage buildings, and climate data (2000–2019). We determined that termite infestations could potentially occur in 98.5% of the total studied area, except for a few mountainous regions in South Korea. In addition, termites were active for an average of 209 days per year. The habitat range of termites appears to be gradually expanding, possibly as a result of a combination of anthropogenic interventions, rising temperatures caused by climate change, and the ecological characteristics of termites. In the future, it is imperative to implement enhanced preventive and active termite control measures to preserve the original wooden architectural heritage buildings of South Korea.
]]>Forests doi: 10.3390/f15040601
Authors: Chao Han Qiunuan Xu Hong Chen Huiwu Peng Fangyuan Yu
Approximately 12% of China’s papermaking raw materials are derived from wood, while the majority are sourced from branches. Styrax tonkinensis is a more desirable species for pulpwood in subtropical ultra-short rotations, whose branches are prone to breakage. Lignin has a significant impact on wood quality and pulping yield, and the growth process influences lignin biosynthesis. To explore the lignin biosynthesis pathway in S. tonkinensis, we determined the lignin content in the current-year and biennial branches on 20 July, 20 September, and 20 October and analyzed the transcriptome sequencing results. It was concluded that the lignin content showed an increasing trend in the current-year branches (182.26, 206.17, and 213.47 mg/g, respectively), while that in the biennial branches showed a decrease in the samples taken in October, without significant difference (221.77, 264.43, and 261.83 mg/g, respectively). The transcriptome sequencing results showed that 91,513 unigenes were spliced with a total length of 92,961,618 bp. KEGG pathway analysis indicated that the upregulated DEGs were mainly enriched in the phenylpropanoid biosynthesis pathway. Our study suggested that CCoAOMT, COMT, peroxidase, and F5H may serve as key enzymes regulating lignin synthesis in branches of S. tonkinensis, thereby influencing the lignin content.
]]>Forests doi: 10.3390/f15040600
Authors: Attila Borovics Éva Király Péter Kottek
As forest-based climate change mitigation has become a crucial element of international climate policy it is of increasing importance to understand the processes leading to the carbon offsetting capacity of the sector. In our study, we assessed the climate benefits of contrasting forest management strategies: decreasing harvest and enlarging the forest carbon stock, or increasing harvest to increase carbon uptake, wood product carbon pools, and substitution effects. We developed the Forest Industry Carbon Model (FICM) which is a new carbon accounting tool covering forest biomass, dead organic matter, soil, and harvested wood product pools, as well as avoided emissions through product and energy substitution. We modeled the carbon balance of the Hungarian forest industry under three different scenarios. In the business as usual (BAU) scenario, we assumed no changes in the current harvest and afforestation levels. In the extensification scenario, we assumed that the harvest and afforestation levels drop to half, while in the intensification scenario, we assumed an increase in afforestation, improved industrial wood assortments, and a gradual increase in logging, reaching the highest level as per sustainability criteria by 2050. Our results show that the intensification scenario is characterized by the largest net removals and the maximized product and energy substitution effects. By 2050, the net forest industry carbon balance reaches −8447 kt CO2 eq under the BAU scenario, while −7011 kt CO2 eq is reached under the extensification scenario and −22,135 kt CO2 eq is reached under the intensification scenario. Although substitution effects are not accounted for under the land-based (LULUCF) sector in the greenhouse gas inventory, the emission reductions in the industry and energy sectors have beneficial effects on the national carbon balance. Modeling results show that the 2030 LULUCF greenhouse gas removal target set by EU legislation for Hungary is reached under the intensification scenario. To achieve this outcome, widespread innovation is needed in the wood sector. The modeling results show that nonutilization of forests can only be a very short-term solution; however, its favorable effects will be reversed by 2050 resulting in additional emissions compared to the BAU scenario.
]]>Forests doi: 10.3390/f15040599
Authors: Longpei Cen Xudong Peng Quanhou Dai
The world’s natural wetlands, which have important ecological functions, are being lost at an alarming rate. The erosion and deposition of soil on wetlands is a major cause of wetland conversion to agriculture. An urgent problem to be solved is how to slow down the erosion and deposition of wetlands resulting from land use. Land use patterns affect soil properties, thereby affecting soil aggregate stability and erodibility. Evaluating the effects of land use patterns on soil aggregate stability and erodibility in small watersheds of wetland ecosystems of karst plateau is of great importance. Thus, we compared the soil properties, aggregate stability indicators and soil erodibility of shrubland, grassland, artificial forest land and sloping farmland for evaluating the impact of various land use patterns on soil aggregate stability and erodibility in typical karst plateau wetland ecosystems. Our results showed that the mass fraction of soil aggregates > 0.25 mm was the main component in the four land uses, with greater variation in aggregates > 5 mm; overall, MWD, GMD and WSA0.25 were higher in grassland and shrubland than in sloping farmland and artificial forest land, while K values, PAD and SCAI showed the opposite trend. Correlation analysis showed that effective soil nutrients had a positive effect on soil aggregate stability. In conclusion, the stability of soil aggregates and resistance to soil erosion were strongest under the influence of shrubland. Our study showed that shrubland can better improve soil aggregate stability and erosion resistance, which may provide a guide for protecting and restoring karst plateau wetland ecosystems.
]]>Forests doi: 10.3390/f15040598
Authors: Alexander Kuprin Nicolaj Shevchenko Vladislava Baklanova
Based on our own field data and using modeling of modern potential ranges (in the MaxEnt program), an assessment of the spatial distribution of the rare representative of the longhorn beetle family, Callipogon (Eoxenus) relictus Semenov 1899, was conducted in northeast Asia (220 geographic locations). The generated maps of the potential range of C. relictus demonstrate a high likelihood of the species’ presence in the upland areas of southern far east Russia, the provinces of northeastern China, and the Korean Peninsula. Field data also indicate the extensive association of the species with undisturbed broadleaf and coniferous–broadleaf forests in northeast Asia. Maps of the potential distribution of C. relictus in northeast Asia have been compiled based on four climate change scenarios from the present time to 2070. Under all of the climate scenarios used, it is shown that suitable habitats for the species will persist in certain areas of Primorsky Krai, as well as neighboring provinces of the People’s Republic of China and a small enclave on the Korean Peninsula in Gangwon-do province. Significant reduction in suitable conditions for the rare longhorn beetle will occur in the rest of its distribution range.
]]>Forests doi: 10.3390/f15040597
Authors: Suyeon Won Youngkeun Song
The reference forest serves as a model for forest ecosystem restoration and can be employed to assess the vegetation of the Restored Forest, thereby confirming the success of restoration. When evaluating restoration, employing multireference forests is advantageous for discerning gradual changes in Restored Forests. However, in previous studies, their utilization has been limited to comparisons with individual ecosystems. Therefore, this study investigates the status of Restored Forests in previously damaged areas and their resemblance to reference forests across four forest types, namely Climax Forest (CF), Secondary Forest (SF), Restored Forest (RF), and Planted Forest (PF). Reference forests, serving as model targets for restoration, include CF and SF, while RF and PF represent the restoration forests. Six target sites within two temperate deciduous forests (Quercus acutissima and Quercus variabilis) were selected, and a comparative analysis of species diversity, dominance, and evenness was conducted. This study revealed that the dominant species in the top canopy of restoration forests mirrored those in reference forests, with Q. variabilis and Q. acutissima being prevalent. A similarity index of over 60% and a high correlation of 0.987 were observed in the top canopy layer between the reference and restored ecosystems (CF-RF/SF-PF). These findings enhance our understanding of the current status of Restored Forests and advocate for the utilization of multiple reference forests for successful restoration efforts.
]]>Forests doi: 10.3390/f15040596
Authors: Jinjia Kuang Linfeng Yu Quan Zhou Dewei Wu Lili Ren Youqing Luo
Pine wilt disease (PWD) is known for its high lethality and rapid transmission, earning it the name “cancer of the pine tree”. The prompt removal of infested pine trees is an effective measure for preventing and controlling pine wilt disease. Accurate and efficient monitoring technologies are crucial for the scientific prevention and control of this plant disease. Currently, numerous remote sensing monitoring studies have been conducted on pine wilt disease. However, there is limited research on the temporal identification of PWD-infested forest stands over large areas. To build classification models, this study utilized three machine learning algorithms: artificial neural network (ANN), random forest (RF), and support vector machine (SVM). We aimed to investigate the effectiveness of single-temporal and multi-temporal Landsat and Sentinel-2 satellite images PWD-infested forest stands detection. The results indicated that, at a spatial resolution of 30 m, Landsat-9 and Sentinel-2 remote sensing images effectively identified PWD-infested forest stands, with classification accuracies of 77.87% and 78.91%, respectively. Higher spatial resolutions in Sentinel-2 remote sensing images were associated with improved identification capabilities. Furthermore, multi-temporal Landsat satellite data (with a classification accuracy of 85.95%) significantly enhanced the performance of the monitoring model compared to single-temporal Landsat satellite data (with a classification accuracy of 77.87%). The RGI difference was found to be the optimal vegetation index. In conclusion, by combining multi-temporal and single-time-phase Landsat remote sensing data, a monitoring model for PWD-infested forest stands was constructed. It achieved a classification accuracy of 88.26%. In this study, a higher accuracy in identifying pine wilt disease and a lower economic cost were achieved by Landsat and Sentinel images, offering valuable insights for the management of pine wilt disease.
]]>Forests doi: 10.3390/f15040595
Authors: Stanisław Łyszczarz Jarosław Lasota Ewa Błońska
Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants that can pose a risk to people living near contaminated soils. The role of forest ecosystems around urban agglomerations as a draw to urban dwellers has been highlighted by the COVID-19 pandemic. The pandemic led us to focus this study on the soils beneath forested areas around urban agglomerations, with the aim of assessing the sources and ecological risk of PAHs in the soils. For the study, a 150 km transect was delineated by six sampling sites, located in urban and commercial forests, which were characterised by the same species composition. Samples were taken from the 0–10 cm depth horizon, after removal of the organic layer. The content of 16 PAHs was determined, from which the potential source of contamination, the toxic equivalent quotient (TEQ), the potential ecological risk quotient (RQ) and the incremental lifetime cancer risk quotient (ILCR) were calculated. The mean sums of the PAHs ranged from 12.41 to 52.76 μg·kg−1. Our analysis indicated that the share of pollutants in the soils had resulted from industrial combustion, biomass and coal combustion, and traffic. The RQ of the PAHs in the soils of the Upper Silesian Industrial Region, or within its impact range, were found to be low to moderate. High ILCR ratios for children (1.9 × 10−4) and adults (8.38 × 10−5) were recorded in soils related to a refinery. Our findings confirm that forests around urban areas are vulnerable to pollution. People living in cities should consider spending their leisure time in forest areas at a distance from their homes. Systematic and continuous monitoring of PAHs is necessary to ensure that human safety is guaranteed.
]]>Forests doi: 10.3390/f15040594
Authors: Lei Zu Guanghui Zhou Fayu Long Lipeng Zang Danmei Chen Guangqi Zhang Mingzhen Sui Yuejun He Qingfu Liu
The mechanisms underpinning the soil microbial community assembly are important, particularly in the fragile karst forest ecosystem. Despite such significance, relevant topics remain limited. We investigated a typical karst area, the Maolan National Nature Reserve in China. For this purpose, 30 forest dynamics plots were established on three restoration gradients in degraded karst forests, namely shrub, pioneer tree, and climax communities. Using vegetation surveys, we explored the diversity patterns, driving factors, and community assembly of the soil microbial communities during the restoration of degraded karst forest ecosystems. In addition, the soil physicochemical properties and macrogenomic sequencing data were examined. One-way analysis of variance and principal coordinates analysis showed no significant changes in soil microbial α-diversity during restoration, and the opposite pattern was observed for β-diversity. Variation partitioning analysis revealed that the combined effect of both soil microbial β-diversity and soil was significant (28% and 32% for bacteria and fungi, respectively). Pearson correlation analyses showed that plant species diversity and soil multifunctionality correlated significantly with soil microbial β-diversity. In contrast, the direct effect of plants was smaller (2% and 3% for bacteria and fungi, respectively). According to the dispersal–niche continuum index, stochastic processes were responsible for the assembly of the bacterial and fungal soil microbial communities. During restoration, the dominant influence of stochastic effects on the assembly of bacterial communities intensified. In contrast, the reverse tendency was observed in soil fungi. The investigation of the diversity pattern of soil microbial communities and their assembly can provide theoretical references for the restoration of degraded ecosystems.
]]>Forests doi: 10.3390/f15040593
Authors: Adam Bogacz Dorota Kasowska Paweł Telega Agnieszka Dradrach
Fly ashes produced in huge amounts during coal combustion requires proper management. The purpose of this study was to determine the impact of fly ash from burning hard coal used in large doses (250, 500, 1000 and 2000 t ha−1) on soil properties and vegetation of fresh mixed coniferous forest within 43 years from the ash application. The experiment was established in the Podzols in the forest habitat of Czułów, Katowice Forest district, Upper Silesia, Poland. Eight tree species were planted in ridges created by ploughing: Pinus sylvestris, P. nigra, Larix decidua, Betula pendula, Quercus robur, Q., Acer pseudoplatanus and Fagus sylvatica. The changes in soil morphology caused significant transformations in the physical and chemical properties of the soil such as soil texture, pH, macronutrients (P, K and Mg) content and C:N ratio. Increasing of ash doses changed the granulometric composition of the soil levels from loamy sand (250 t/ha−1) to silt loam (2000 t ha−1). Initially, the acidic Podzols were alkalized under the influence of the fly ash and then acidified, possibly due to the impact of accumulated litter layers, and the reaction of organic soil horizons changed from strongly acidic (250–1000 t ha−1) to alkalis (2000 t/ha−1). The macronutrients content increased in proportion to the fly ash dose, but the subsequent acidification resulted in a gradual decrease in the macronutrients share in the soil layers. The value of the C:N ratio grew after the ash application and then it gradually reduced, even by half. The transformations of soil horizons’ properties also increased the capacity of the soil sorption complex (CEC). All these processes led to a change in the trophic status of the habitat expressed by the soil habitat index (SIG) and the initial coniferous forest site can be classified as a mixed forest habitat even with the lowest ash dose used. The composition of plant communities developed forty years after the ash application was similar at the lower ash doses and the most frequent and abundant tree species were L. decidua, P. nigra and P. silvestris. B. pendula was previously co-dominant, but it was eliminated from the tree stands during the experiment. Planted trees characteristic of late stages of succession, such as Q. robur, Q. rubra, F. sylvatica and A. pseudoplatanus either did not survive or remained in very low quantities. The herb and moss layers developed in the process of spontaneous colonization, and together with the trees led to phytostabilisation of the bare substrates. After acidification of the topsoil horizons, the herb layers consisted mostly of coniferous, mixed, and deciduous forest species, and the most frequent or abundant were Lysimachia europea and Pteridium aquilinum. The moss layers were represented by coniferous forest flora. At the ash dose of 2000 t ha−1, Tilia cordata settled in one of the seral stages of spontaneous succession and this species dominated in the community and formed a dense tree stand. After the soil acidification, a shift from calcicole to calcifuge plant strategy took place among species of the herbaceous layer. The transformations of plant communities’ composition occurred in relation to changes in the soil properties.
]]>Forests doi: 10.3390/f15040592
Authors: David Březina Jakub Michal Petra Hlaváčková
Central European countries are strategic wood exporters in the European and international wood trade. In the context of wood exporters, Czechia, Germany, Poland, Slovenia, and Austria are the important countries providing the development and stability of the forestry and wood sector. The share of these countries’ exports in total EU exports represents more than 52% of the volume of wood exported over 5 years. After the Netherlands, the five mentioned countries recorded the highest increase in roundwood production of all EU and EFTA countries in the years 2000–2022 (from 46% (AT)–126% (CZ)), and the European average is 26%. The last decade has been characterised by a significant destabilisation of the Central European timber market as a result of natural disturbances linked to climate change, which also threatens the long-term competitiveness and preservation of this sector in the economic systems of national economies. The article provides an analytical insight into the historical development of natural calamities and their macroeconomic consequences in Central European countries. The data forecast an unfavourable development of the timber market in Europe caused by the ongoing calamity situation, the pricing policy of the timber trade, the oversaturation of the market with lower-quality calamity timber, insufficient processing capacities for primary processing of wood and its use in secondary processing, and, last but not least, the limited stock of timber in the coming years in selected Central European countries (due to an extreme increase in harvesting plans within the last 5 years, with consequences that will be felt in the coming decade). For the continued economic function of forests and the availability of wood supply for future generations, the current evolution of calamities in forest ecosystems is critical, and long-term strategic measures based on empirical data are necessary. The information presented in this paper can serve as a tool for the objectification of strategic decisions in the development of forestry policies in selected countries.
]]>Forests doi: 10.3390/f15040591
Authors: Xianze Yao Haifeng Lin Di Bai Hongping Zhou
Tea cultivation holds significant economic value, yet the leaves of tea plants are frequently susceptible to various pest and disease infestations. Consequently, there is a critical need for research focused on precisely and efficiently detecting these threats to tea crops. The investigation of a model capable of effectively identifying pests and diseases in tea plants is often hindered by challenges, such as limited datasets of pest and disease samples and the small size of detection targets. To address these issues, this study has chosen TLB, a common pest and disease in tea plants, as the primary research subject. The approach involves the application of transfer learning in conjunction with data augmentation as a fundamental methodology. This technique entails transferring knowledge acquired from a comprehensive source data domain to the model, aiming to mitigate the constraints of limited sample sizes. Additionally, to tackle the challenge of detecting small targets, this study incorporates the decoupling detection head TSCODE and integrates the Triplet Attention mechanism into the E-ELAN structure within the backbone to enhance the model’s focus on the TLB’s small targets and optimize detection accuracy. Furthermore, the model’s loss function is optimized based on the Wasserstein distance measure to mitigate issues related to sensitivity in localizing small targets. Experimental results demonstrate that, in comparison to the conventional YOLOv7 tiny model, the proposed model exhibits superior performance on the TLB small sample dataset, with precision increasing by 6.5% to 92.2%, recall by 4.5% to 86.6%, and average precision by 5.8% to 91.5%. This research offers an effective solution for identifying tea pests and diseases, presenting a novel approach to developing a model for detecting such threats in tea cultivation.
]]>Forests doi: 10.3390/f15040590
Authors: Yuhao Sheng Qingzhan Zhao Xuewen Wang Yihao Liu Xiaojun Yin
The traditional measurement method (e.g., field survey) of tree diameter circumference often has high labor costs and is time-consuming. Mobile laser scanning (MLS) is a powerful tool for measuring forest diameter at breast height (DBH). However, the accuracy of point cloud registration seriously affects the results of DBH measurements. To address this issue, this paper proposes a new method for extracting tree DBH parameters; it achieves the purpose of efficient and accurate extraction of tree DBH by point cloud filtering, single-tree instance segmentation, and least squares circle fitting. Firstly, the point cloud data of the plantation forest samples were obtained by a self-constructed unmanned vehicle-mounted mobile laser scanning system, and the ground point cloud was removed using cloth simulation filtering (CSF). Secondly, fast Euclidean clustering (FEC) was employed to segment the single-tree instances, and the point cloud slices at breast height were extracted based on the point sets of single-tree instances, which were then fitted in two dimensions using the horizontally projected point cloud slices. Finally, a circle fitting algorithm based on intensity weighted least squares (IWLS) was proposed to solve the optimal circle model based on 2D point cloud slices, to minimize the impact of misaligned point clouds on DBH measures. The results showed that the mean absolute error (MAE) of the IWLS method was 2.41 cm, the root mean square error (RMSE) was 2.81 cm, and the relative accuracy was 89.77%. Compared with the random sample consensus (RANSAC) algorithm and ordinary least squares (OLS), the MAE was reduced by 36.45% and 9.14%, the RMSE was reduced by 40.90% and 12.26%, and the relative accuracy was improved by 8.99% and 1.63%, respectively. The R2 value of the fitted curve of the IWLS method was the closest to 1, with the highest goodness of fit and a significant linear correlation with the true value. The proposed intensity weighted least squares circle-fitting DBH extraction method can effectively improve the DBH extraction accuracy of mobile laser scanning point cloud data and reduce the influence of poorly aligned point clouds on DBH fitting.
]]>Forests doi: 10.3390/f15040589
Authors: He Huang Zhu Li Yuan Li Jiali Jiang Ruiqing Gao
The tensile mechanical behavior of water-saturated earlywood (EW) and latewood (LW) within the same growth ring of Masson pine (Pinus massoniana) was investigated in the hydrothermal environment and discussed with respect to the density and microfibril angle (MFA) of the wood specimens. The tensile modulus, tensile strength, and strain at failure of EW and LW in the longitudinal (L) and tangential (T) directions were determined at different temperature levels ranging from 30 °C to 80 °C. Major differences in the tensile mechanical properties were found between EW and LW in the L and T directions. Compared to LW, EW showed a smaller density and a larger MFA, resulting in a lower tensile modulus, lower tensile strength, and higher strain at failure. Compared to the L specimens, the T specimens showed lower tensile modulus, lower tensile strength, and higher strain at failure. As the hygrothermal temperature increased, the MFAs, tensile modulus, and tensile strength of EW and LW specimens decreased, except for the MFAs of LW, while the strain at failure of the specimens showed the opposite trend. Variations in the tensile mechanical behavior between EW and LW were mainly influenced by the density and MFA of the specimens, and are closely associated with the hydrothermal softening properties of wood. These findings contribute to a further understanding of the structural–mechanical relationships of Masson pine wood at the cell wall level, and provide a scientific basis for the better utilization of plantation softwood in the hydrothermal environment.
]]>Forests doi: 10.3390/f15040588
Authors: Delia S. Donici Diana E. Dumitras
Considered among the fastest-growing industries in the world, tourism brings immense benefits but also creates certain challenges. Conservation of natural resources is a stringent necessity, without which the extraordinary ecosystems’ attributes that create the premises for nature-based tourism would reduce, alter, and subsequently disappear. The aim of the present review is twofold: gaining a general understanding of what nature-based tourism is and providing a systematic literature review of articles on nature-based tourism in European national and natural parks, with emphasis on their applicability. The articles included in the present review were selected based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The review accounts for research conducted between 2000 and 2021 and is divided into two sections: articles aimed at understanding tourists’ behaviour and articles that are focused on other stakeholders or have the local communities in the foreground. While many studies are aimed at understanding tourists’ behaviour as a means of improving parks’ management, participatory strategies including local communities are often indicated as beneficial. The results of this paper can facilitate future research in the field and provide valuable knowledge to policymakers and any interested parties.
]]>Forests doi: 10.3390/f15040587
Authors: Zhiwei Liu Lingli Yi Xiaohang Zhou Yong Xiong Jinhui Liu Haiyan Qiu Weiqiu Liu
The study of functional traits and their relationship to trade-offs has provided valuable insights into how plants adapt to environmental changes. Nonetheless, further research is necessary to fully comprehend the subtropical montane trade-off patterns in moss functional traits and the impact of environmental gradients on the correlation of these traits. To address this gap, we conducted a study of 11 moss species (7 families, 9 genera) in 54 patches from two subtropical mountain ranges, examining 40 functional traits related to photosynthesis, nutrients, water retention, and architecture. Through principal component analysis (PCA) and bi-variate correlation analysis, our findings reveal a strong correlation between light capture and nutrient assimilation strategies, as evidenced by the coordination between the traits of light capture and nutrient per area along a main principal component. Interestingly, we observed a trend towards smaller leaves and leaf cells in species with higher capacity for photosynthesis and metabolism, consistent with global trait spectra in vascular plants. However, we found that the trade-off between light capture and nutrient assimilation strategies was independent of water-holding capacity at shoot levels. Instead, we found that water-holding capacity was closely associated with nutrient utilization, energy metabolism, chlorophyll synthesis, and the primary process of photosynthesis. Our results highlight the multiple dimensions of functional traits in subtropical montane mosses and demonstrate that variation in these traits is driven by water availability, slope, and canopy density. Overall, our study provides valuable insights into the co-variation of moss traits and how environmental changes may impact mosses and ecosystem function.
]]>Forests doi: 10.3390/f15040586
Authors: Wenyu Wang Peiqin Peng Jiangnan Li Xionghui Liao Wei Zhang Kelin Wang Jie Zhao
Soil microorganisms are vital components of the karst terrestrial ecosystem. However, their responses to the vegetation succession on karst mountain peaks remain unclear as to whether soil microbial diversity and community compositions change with vegetation succession. We investigated the diversity and community compositions of soil bacteria and fungi and associated environmental factors along a vegetation succession from moss crusts (MC) to moss crusts with sparse grasses (MCG) to sparse grasses (G) on karst mountain peaks. The results indicated that soil organic carbon and total nitrogen generally increased, and soil pH changed in the range of 8.19–8.44 and slightly declined with vegetation succession. Overall, there was an increase in microbial biomass along the vegetation succession, with the dominant phyla of bacteria, including Proteobacteria, Acidobacteria, Actinobacteria, Choroflexi, Gemmatiomnadates, Bacteroidetes, and Planctomycetes, and the dominated phyla of fungi, including Basidiomycota and Ascomycota. Notably, both the bacterial and fungal community compositions were different among the three successional stages. Spearman’s correction analysis showed that soil organic carbon and total nitrogen had stronger and more significant influences on the soil microbial community compositions compared to soil water content, pH, and C:N ratio. Overall, our results provide evidence for the changes and influencing factors of the microbial community with the succession vegetation on karst mountain peaks.
]]>Forests doi: 10.3390/f15040585
Authors: Zhonglin Pang Yang Zhang Shaojie Han Enheng Wang Xiangwei Chen
Roots anchor plants firmly to the soil, enabling them to effectively resist soil erosion and shear failure. Vegetation restoration has been acknowledged as one of the most useful measures for controlling soil loss; however, which root system characteristics were most beneficial for plant anchoring in the soil remains unclear. In the black soil region of northeastern China, which frequently experiences serious soil erosion, pullout tests were carried out on six species of soil and water conservation woody plants with different growth habits (deciduous shrubs, deciduous trees and evergreen trees), and the root geometry and topology of each species were determined. The results showed that the maximum uprooting force and activation displacement (the displacement at the maximum peak in the relationship curve between pulling force and displacement) of shrubs were significantly greater than those of trees, while deciduous trees were significantly greater than evergreen trees. Therefore, the ability of the whole root system to anchor the soil was the largest for shrubs, followed by deciduous trees, and the smallest for evergreen trees. The uprooting force and activation displacement were mainly affected by the root topological index, total root length and the number of inclined roots. The total root length had the greatest influence on the maximum uprooting force, and the root topology had the greatest influence on the activation displacement, both of which can be used as important predictors of plant root anchorage strength. In addition, the plants with the R-type root structure may have a greater ability to anchor the soi, and can be prioritized for vegetation restoration with black soils. These findings provide references and implications for identifying the effective plant strategies for eroded soil restoration in the black soil region of northeastern China and other areas with similar soil types and bioclimates.
]]>Forests doi: 10.3390/f15040584
Authors: Hajir Al-musawi Christian Huber Bernhard Ungerer Matthias Jakob Maximilian Pramreiter Peter Halbauer Johannes Painer Thomas Krenke Ulrich Müller
The plastic deformation of wood perpendicular to the grain is gaining increasing importance due to advancements in forming technologies and the densification of wood. This study investigates how two hardwood species, i.e., beech (Fagus sylvatica) and birch (Betula pendula), respond to compression in the radial direction and examines the structural changes they undergo during both elastic and plastic deformation. Stress–strain curves at different moisture contents (dry to wet) and temperature conditions (20 to 140 °C) were recorded. In-situ observations at high moisture content and temperatures by means of different microscopic techniques are practically unfeasible. Therefore, the specimens were analysed ex-situ microscopically after the test. In addition to the compression of transversely oriented fibres and vessels, special attention was paid to the deformation behaviour of the wood rays. The results suggest that the wood ray cells carry a relatively higher proportion of the load in the radial loading direction than the surrounding vessels and fibres. This observation is supported by the higher percentage of deformed vessels, seen in the microscopy, in areas where the rays developed kinks, usually in the early wood of beech and anywhere in the cross-section of birch. The weaving of rays around big vessels introduced shear strains under compressive stresses at the kinked rays’ area. Thus, shear deformation is more evident in early wood than in late wood regions of wood. However, when the wood was tested at elevated moistures and temperatures, the material demonstrated a ductile response, namely the absence of localised shear deformations. Notably, wet beech and birch specimens heated to 100 °C and above exhibited pronounced thickness recovery and there was slightly irreversible buckling of rays and vessel deformations. Therefore, under such conditions, wood behaves like a “sponge” and is expected to be successfully processed without introducing clear damage to the material. This characteristic holds promise for replication in the development of bio-based energy-absorbing materials.
]]>Forests doi: 10.3390/f15040583
Authors: Fei Xuan Xuebiao Pan Mei Qin Rui Cao Hongye Shen Yurui Jiang Jianfeng Hou Zhihui Wang Zhuang Wang Qiqian Wu Wanqin Yang
Knowledge regarding the response of soil invertebrate communities to typhoon disturbance is limited, although it is known that soil invertebrates are sensitive to forest disturbances and that tropical cyclones (typhoons/hurricanes) are the most destructive natural disasters affecting the structure and function of forest ecosystems. To fill this knowledge gap, soil invertebrates in both litter and topsoil layers were investigated in four representative subtropical coastal forests of eastern China one week before the first typhoon (Hinnamnor) (T1), one day after the first typhoon (Hinnamnor) (T2), one day after the second typhoon (Muifa) (T3), and one week after the second typhoon (Muifa) (T4) in September 2022. Typhoon disturbances decreased the density and taxa abundance of soil invertebrate communities in litter layer, but the first typhoon disturbance increased these values in the topsoil layer. One week after the second typhoon disturbance, soil invertebrate communities in the litter layer showed a gradual recovery trend. Meanwhile, the soil invertebrate communities in the litter layer were more sensitive to typhoon disturbances than those in the topsoil layer. Furthermore, the responses of the soil invertebrate communities to the typhoon disturbances varied greatly with the forest types. The invertebrate densities in the litter layer decreased by 62.1%, 63.53%, 47.01%, and 46.92% in Chinese fir, second broad-leaved, mixed, and bamboo forests, respectively. Particularly, these two non-catastrophic typhoons significantly altered the functional group composition of detrital food webs in the short term, and the proportion of phytophages in detrital food webs in the litter layer increased after the typhoon disturbances. In conclusion, the effects of typhoon disturbances on soil invertebrate communities vary greatly with forest type and soil layer, and soil invertebrate communities can gradually recover after typhoon disturbances. The legacy effects of typhoon disturbances on the functional group composition of detrital food webs may influence carbon and nutrient cycling in forest ecosystems.
]]>Forests doi: 10.3390/f15040582
Authors: Daniel Koynov Petar Antov Miglena Valyova Viktor Savov Iliyan Dochev Seng Hua Lee
The aim of this research work was to investigate the feasibility of upcycling poplar (Populus spp.) peeler cores as a by-product from the production of plywood in manufacturing lightweight hybrid poplar and beech plywood panels, containing different ratios (60%, 80%, and 100%) of peeler core sections in the core layer. This corresponds to effective percentages of panel surface glued with peeler core slides of 80%, 64%, and 48%, respectively. The physical properties (density, water absorption, and thickness swelling) and mechanical properties (bending strength (MOR) and modulus of elasticity (MOE)) of the laboratory-fabricated hybrid panels were determined in accordance with the applicable European standards (EN 310, EN 317, and EN 323). The highest MOE and MOR values of 3575 N·mm−2 and 28.1 N·mm−2, respectively, were obtained for the hybrid poplar plywood panels with a thickness of 20 mm and 100% peeler core sections. The use of beech veneer in the face layers did not lead to a significant increase in the mechanical properties. In this case, the MOE and MOR values of the hybrid plywood panels with a thickness of 20 mm and 80% peeler core sections were 5954 N·mm−2 and 35.2 N·mm−2, respectively.
]]>Forests doi: 10.3390/f15040581
Authors: Zhiliang Ma Wenjuan Xu Yamei Chen Mei Liu Jiahao Wen
Although soil enzyme activity can act as an effective indicator of soil nutrient status, there is some uncertainty about its accuracy within soil depth across different land uses. To assess the effects of different land uses on the interactions between soil enzyme activity and nutrient status within different soil horizons, in this study we examined soil total carbon (C), nitrogen (N), and phosphorus (P) concentrations, pH, and the activities of five hydrolytic (i.e., amylase, invertase, cellulase, acid phosphatase, and urease) and three oxidative enzymes (i.e., catalase, dehydrogenase, and phenol oxidase) involved in C, N, and P acquisition and evaluated their interactions within the topsoil (0–10 cm), subsoil (10–20 cm), and deeper soil layer (20–30 cm) under various land uses (i.e., rice field, cultivated land, bamboo plantation, forest land, and barren land). We found that the levels of hydrolytic enzyme activities and nutrient concentrations were higher in the topsoil than the deeper layer. The hydrolytic enzyme activities were positive correlated with soil C, N, and P concentrations, while the activities of oxidative enzymes showed strong associations with soil pH. Furthermore, the results of fuzzy comprehensive evaluation models suggest that the overall enzyme activity can serve as an indicator of soil nutrient status in the topsoil and subsoil, but not in the deeper layer. The depth-specific nature of soil enzyme–nutrient relationships may be attributed to different land-use management practices. Our study highlights the complex interactions between soil nutrients, pH, and enzyme activities within soil profiles, and soil enzyme activity as an indicator of soil nutrient status is depth-dependent across the different land uses. The specific functional groups of enzymes and the gradients of resources and environmental conditions within the soil profile that is partly mediated by land use play crucial roles in shaping these relationships. Our results can also provide some new insights into sustainable soil management practices under the background of intense anthropogenic activities and global change.
]]>Forests doi: 10.3390/f15040580
Authors: Hugo Rocha Scharfenberg Ana Carolina Borella Marfil Anhê Victor Almeida De Araujo Maristela Gava Fernando Júnior Resende Mascarenhas Elen Aparecida Martines Morales André Luis Christoforo Marcos Massao Shimano Juliana Cortez-Barbosa
Bamboo is already a convenient construction resource, as it offers an efficient structural performance. As this plant has native varieties adapted to different climates and soils of Brazil, bamboo silviculture can be intensified to supply the national industry. Three bamboo species from Brazil (Dendrocalamus asper, Bambusa tuldoides, and Phyllostachys aurea) were analyzed for the flexural load capacity applied on the internal and external surfaces. Specimens were prepared without knots and with knots centered at the middle of each sample. In total, 240 samples were tested in terms of static bending and dynamic bending (impact). The results showed a higher flexural elasticity and a higher proportional limit strength of knotted P. aurea. The presence of knots provided higher values of ultimate strength in P. aurea, even reducing the bamboo flexibility. Also, P. aurea exhibited the best characteristic of flexural dynamic energy absorption among the three bamboo species under evaluation.
]]>Forests doi: 10.3390/f15040576
Authors: Yishan Yang Jianmin Tang Xianliang Zhu Lipo Pan Rong Zou Yunsheng Jiang Xiao Wei
Karst tiankengs in China are globally significant locations for studying ecological environments and plant diversity. However, there are few reports on how the unique geographical environment of tiankengs affects plant genetic diversity and genetic structure. This study used Hyper-seq gene sequencing technology to develop large-scale genomic SNPs of Manglietia aromatica, both within and outside the tiankengs. Its aim was to investigate the impact of tiankengs on the genetic diversity and genetic structure of the M. aromatica population. The analysis results indicate that the genetic diversity of the populations within the tiankeng (π = 0.2044) is higher than that of the populations outside of it (π = 0.1671), indicating that the tiankengs have a positive impact on species diversity. The genetic differentiation coefficient (FST) between the populations inside and outside the tiankeng was 0.0534 and the FST values of populations within the tiankeng were 0.077, 0.082, and 0.141, meaning that the genetic variation in the tiankengs is very high. The genetic similarity outside the tiankengs is also very high, indicating that the tiankengs are effectively preserving the genetic diversity of M. aromatica. Furthermore, the gene introgression analysis results gave no proof of gene flow between the three tiankeng populations. This suggests that the tiankengs not only protect species diversity, but also hinder gene flow between populations to some extent. However, this hindrance may gradually subside with the evolution of the tiankengs. The genetic structure analysis revealed that the M. aromatica population in Guangxi, China, can be classified into three subpopulations. The first is the tiankeng subpopulation, including all the populations in tiankengs. The second subpopulation consists of populations surrounding the tiankengs. These two subpopulations are distributed in Leye County in northwestern Guangxi, China, and are very close to each other. The third is the Huanjiang subpopulation, which is located far away from the tiankengs. Considering the direction of gene flow and genetic structure, it is speculated that the populations in the tiankengs evolved from the populations near the pit mouth. This study confirms that the tiankengs are shelters and provide a suitable habitat for the endangered plant M. aromatica, because its genetic diversity is well conserved and the species is well adapted to the habitat within the tiankengs.
]]>Forests doi: 10.3390/f15040579
Authors: Vilius Gendvilas Geoffrey M. Downes Marco Lausberg Jonathan J. Harrington David J. Lee
The IML PD series Resi is a device used to assess the drilling resistance of wood. The IML PD series Resi instrument is being widely adopted for commercial wood quality assessment due to its speed, cost-effectiveness, and precision when combined with web-based trace processing. Collecting Resi data with fixed feed speed and RPM settings is challenging due to inherent basic density variations within and between tree species. Altering these settings affects the drilling resistance amplitude of the Resi data, impacting basic density predictions. This study introduces the concept of chip thickness to combine feed speed and RPM into a single parameter to minimise the effects of different sampling conditions on the basic density predictions. Regression models, with chip thickness as the regressor variable, account for 97% to 99% of variance in mean Resi outerwood amplitude across six species. The demonstrated adaptability of chip thickness for adjusting feed speed and RPM settings, along with species-specific functions correlating it with Resi amplitude, holds promise for standardizing amplitude values across diverse feed speeds and RPM settings. Optimal sampling conditions needed to predict basic density lie within the 30%–40% amplitude range. To drill a ~30 cm diameter tree, the recommended fastest settings were 200 cm/min and 3500 RPM for Southern Pine (Pinus elliottii var. elliottii (Engelm) × Pinus caribaea var. hondurensis (Sénéclauze)) and Radiata Pine (Pinus radiata (D. Don.)), 200 cm/min and 2500 RPM for Hoop Pine (Araucaria cunninghamii (Mudie)), 50 cm/min and 5000 RPM for Spotted Gum (Corymbia citriodora subsp. variegata (F. Muell.)), 200 cm/min and 4500 RPM for White Cypress (Callitris glaucophylla (Thompson & Johnson)), and 150 cm/min and 3500 RPM for Shining Gum (Eucalyptus nitens (H. Deane & Maiden) Maiden) based on the billets sampled.
]]>Forests doi: 10.3390/f15040578
Authors: Zhineng Wei Lin Liu Yidan Lei Sisi Xie Jiangming Ma Yibo Tan Nianwu Tang Zhangqi Yang Chenbing Ai
Lactarius hatsudake is a common ectomycorrhizal edible mushroom in Pinus massoniana forests, and has important ecological and potential economic values. However, there are only a few reports on the establishment of Pinus massoniana–Lactarius hatsudake symbiosis. Here, we isolated a new strain of L. Lactarius hatsudake (GX01) from a local masson pine forest and established its ectomycorrhizal symbiosis with the P. massoniana. Potato dextrose agar (PDA) medium was optimal for the growth of L. hatsudake GX01. The saffron-to-brown ectomycorrhiza formed by L. hatsudake GX01 are usually bifurcated or coralloid shape, with a rod and a smooth surface, without emanating hyphae. The characteristic mantle and Hartig net structures of ectomycorrhizae were confirmed by microscope and scanning electron microscope (SEM). L. hatsudake GX01 can significantly promote the formation and development of lateral roots of P. massoniana seedlings during the early interaction. This study thus lays the foundation for subsequent study of the symbiotic molecular mechanism and application of P. massoniana–L. hatsudake symbiosis.
]]>Forests doi: 10.3390/f15040577
Authors: Min-Ja Shin Jaeuk U. Kim Jin-Hee You Won-Sop Shin
The purpose of this study was to examine the effects of exercise intensity and the duration of an exercise-based forest therapy program on physiological changes in older adults. The forest therapy program consisted of 20 sessions over 10 weeks. Forty-one older adults aged 65 years and older were divided into no treatment (daily activity group) and experimental (forest therapy) groups. The experimental group was further divided into the medium-intensity forest exercise group and the high-intensity forest exercise group to analyze physiological changes according to exercise intensity and duration. The physiological changes were analyzed by collecting saliva and measuring changes in the levels of immunoglobulin A and dehydroepiandrosterone, a hormone used to predict aging. Changes within the daily activity group and the forest therapy group after their respective exercises were analyzed using paired t-tests. Saliva testing was performed before and in weeks 5 and 10 of the program and analyzed using a repeated measures analysis of variance to assess the effects of the forest therapy on the medium-intensity forest exercise group and the high-intensity forest exercise group based on the duration of exercise. As a result of the study, a significant increase in immunoglobulin A was observed in the medium-intensity forest exercise group. The daily activity group and the high-intensity forest exercise group showed an increase, but there was very little change and no significance. Changes in dehydroepiandrosterone decreased in the daily activity group and significantly increased in the moderate-intensity forest exercise group at 5 and 10 weeks, showing that regular moderate-intensity forest exercise has an effect on dehydroepiandrosterone. The high-intensity forest exercise group improved over time, but no significant level of change was observed. This study shows that forest exercise has a beneficial effect on immunoglobulin A and dehydroepiandrosterone levels in older adults.
]]>Forests doi: 10.3390/f15040575
Authors: Jinming Yang Wenwen Yuan Huicui Lu Yuehan Liu Yongkang Wang Letong Sun Shimei Li Haifang Li
Precise individual tree or sample-based inventories derived from 3D point cloud data of mobile laser scanning can improve our comprehensive understanding of the structure, function, resilience, biodiversity, and ecosystem services of urban forests. This study assessed the performance of a handheld laser scanning system (HLS) for the extraction of tree position, diameter at breast height (DBH), and tree height (H) in an urban area. A total of 2083 trees of 13 species from 34 plots were analyzed. The results showed that the registration of tree positions using ground control points (GCPs) demonstrated high accuracy, with errors consistently below 0.4 m, except for a few instances. The extraction accuracy of DBH for all trees and individual species remained consistently high, with a total root mean square error (RMSE) of 2.06 cm (6.89%) and a bias of 0.62 cm (2.07%). Notably, broad-leaved trees outperformed coniferous trees, with RMSE and bias values of 1.86 cm (6%) and 0.76 cm (2.46%), respectively, compared to 2.54 cm (9.46%) and 0.23 cm (0.84%), respectively. The accuracy of H extraction varied significantly among different species, with R2 values ranging from 0.65 to 0.92. Generally, both DBH and H were underestimated compared to ground measurements. Linear mixed-effects models (LMEs) were applied to evaluate factors affecting the performance of HLS with the plot as a random factor. LME analysis revealed that plant type and terrain significantly influenced the accuracy of DBH and H derived from HLS data, while other fixed factors such as plot area, tree density, and trajectory length showed no significance. With a large sample size, we concluded that the HLS demonstrated sufficient accuracy in extracting individual tree parameters in urban forests.
]]>Forests doi: 10.3390/f15040574
Authors: Jinghang Zhou Jingjun Yang Jie Qin Jinhua Li Xiu Liu Penglian Wei
Mangrove plant seedling cultivation is crucial for the protection, management, and restoration of the mangrove ecosystem. In this study, we focused on Kandelia obovata Sheue & al., a typical mangrove, and evaluated nursery cultivation with different combinations of three salinity levels (S1: 0 ppt, S2: 10 ppt, and S3: 20 ppt), three genealogies (EZD, JX, and YZ), and five growth media (M1: 100% loess, M2: 100% sandy, M3: 50% loess + 50% sandy, M4: 40% loess + 40% sandy + 20% peat, and M5: 40% loess + 40% sandy + 20% coir), by measuring the growth parameters such as mortality rate, seedling height, seedling diameter, and biomass partition. These growth indexes were significantly affected by salinity and medium, and genealogies also had significant effects on mortality rate and biomass accumulation. S2 or S3 both had lower mortality and higher growth indexes than S1. M1 was the medium that increased seedling height, diameter, and biomass the most and had the lowest death rate. EZD and JX were also at higher levels than YZ in these indicators, but the difference between them was not obvious. S3, M1, and EZD consistently performed well in fuzzy evaluation and quality assessment (Dickson quality index: 1.179, 1.478, and 1.089, respectively). Furthermore, combinations involving these treatments also produced highly favorable results. This indicates that the quality of seedlings produced under these conditions was high. These results furnish both a theoretical and practical foundation for advancing nursery cultivation techniques and germplasm breeding of K. obovata in mangroves.
]]>Forests doi: 10.3390/f15030573
Authors: Mikołaj Jalinik Tomasz Pawłowicz Piotr Borowik Tomasz Oszako
The paper looks at the potential benefits of mushrooms in terms of health, recreation, and tourism. Mycotourism is an innovative, specialised tourism product that has been successfully introduced in some regions of the world, helping to combat seasonality and promote economic development in rural areas. The aim of the study was to analyse the development of mycotourism in Poland in comparison with other countries. As a method, a questionnaire on the cultural significance of mushrooms was developed and disseminated via social media. It was found that there are strong mycophilic tendencies in Poland, leading to a strong interest in mushrooms, both in terms of cultural and culinary traditions. They are also a factor that attracts tourists to the forest areas. In contrast, the UK and Germany are more mycophobic, resulting in a lower interest in mushrooms, limited culinary use, and a lower awareness of their role in the ecosystem and their potential health benefits. The low average score for knowledge of mushrooms in countries such as the UK indicates a need for increased mycological education that can contribute to a better understanding of the conservation of these important components of the forest floor. The high proportion of people who see mushroom picking in Poland as a form of recreation emphasises its role as an important cultural and potential nature tourism asset. In Poland, where long traditions are associated with mushrooms and mushroom picking, they have a strong influence on the choice of mycological tourism, especially in regions with a rich tradition of mushroom picking. The high percentage of mushrooms used for culinary purposes, especially in Poland, emphasises their value and influences the health component of the diet, which is rich in proteins, vitamins, and minerals. Research has shown that mushroom consumption and its effects on health are perceived positively. This is evidenced by higher ratings in Poland than in the UK and Germany, indicating a general awareness of the health benefits of mushrooms, even though their use in medicine remains limited. The low level of awareness of the role of mushrooms and their potential health benefits suggests that educational and promotional activities should be increased to sensitise the public to mushrooms.
]]>Forests doi: 10.3390/f15030572
Authors: Natsumi Yasuki Wakana Saso Hiroshi Koizumi Yasuo Iimura Toshiyuki Ohtsuka Shinpei Yoshitake
Changes in soil nutrient dynamics after biochar application may affect indirect carbon sequestration through changes in plant productivity in forest ecosystems. In the present study, we examined the effects of woody biochar application on soil nitrogen (N) cycling over 8 months in a warm-temperate deciduous broad-leaved forest. Mineral soil samples were collected from the plots treated with different biochar applications (0, 5, and 10 Mg ha−1), and the soil inorganic N concentration was measured. Net mineralization and nitrification rates were determined in each plot using the resin–core method. Soil temperature and water content did not change significantly, but the pH increased significantly following biochar application. Soil inorganic N concentrations (NH4+ and NO3−) and net N transformation rates (mineralization and nitrification rates) were significantly reduced. Microbial biomass and the nitrification ratio (the ratio of nitrification rate to mineralization rate) were unchanged, indicating that the decrease in soil inorganic N concentration was due to the reduced mineralization rate. Adsorption of substrates (from organic matter) by the applied biochar is the most likely reason for the reduction in the N mineralization rate. The results indicate that biochar application does not necessarily stimulate N transformation, which will affect indirect carbon sequestration.
]]>Forests doi: 10.3390/f15030571
Authors: Changkun Ma Wanyu Yang Beibei Zhou Quanjiu Wang Mingan Shao
Large-scale vegetation restoration campaigns have been implemented on the Chinese Loess Plateau, which have resulted in higher soil moisture deficits in this region. This, in turn, has hampered the healthy growth of planted trees, leading to a decline and, in severe cases, mortality of trees. Therefore, the rational regulation and utilization of rainwater, the primary water source in this region, may alleviate drought stress, ensuring the sustainability of the ecosystem. In this study, we investigated the impact of in situ rainwater collection and infiltration systems (IRCISs) on soil water, fine-root distribution, xylem vascular, and hydraulic conductivity characteristics in declining Robinia pseudoacacia forests. The results demonstrated that the application of an IRCIS can effectively increase plant available moisture content (0–5.0 m) of declining Robinia pseudoacacia forests. In particular, IRCIS treatment significantly increased xylem conduit diameter and plant hydraulic conductivity while substantially reducing the percentage loss of hydraulic conductivity in both roots and branches. Furthermore, IRCIS treatment significantly reduced the root biomass and distribution depth of Robinia pseudoacacia during both wet and dry years. This implies that IRCISs are beneficial for plant growth and survival. The findings of this study are significant for devising strategic methodologies for the planning and management of rainwater resources.
]]>Forests doi: 10.3390/f15030570
Authors: Zhili Chen Qinqin Liu Mingshi Li Da Xu
Urban park green spaces (PGSs) are crucial social public resources that provide various ecological services and enhance human health and well-being. However, with the acceleration of urbanization, the accessibility and equity of urban PGS resources are increasingly threatened. This study aims to propose an integrated framework that considers accessibility and equity simultaneously to optimize the planning and layout of urban PGS within the high-speed ring road of Hefei City. This study first used an improved two-step floating catchment area (2SFCA) method to quantify the level of accessibility of urban PGS within the ring road. Then, with the use of Lorenz curves, Gini coefficients, and bivariate correlation coefficients, the equity characteristics of these PGSs were quantified and evaluated, followed by an analysis of their relationships to the accessibility levels. Based on this comprehensive evaluation, the particle swarm optimization (PSO) algorithm was employed to the areas with low accessibility and equity levels to propose targeted PGS optimization strategies. The results showed that the accessibility of PGS was unevenly distributed, exhibiting a clear spatial difference of “east–west clustering”. The number of subdistricts with good (52.24–94.78) and best (94.79–283.58) accessibility was four, which was less than one-tenth of the total number of subdistricts in the study area. At the subdistrict level, the Gini coefficients for the accessible area of all types of PGSs were substantially higher than the international warning line of 0.4, indicating a substantial inequity in the population’s access to PGS. The implemented PSO algorithm resulted in eight new parks being planned at the specific optimized locations. Based on the actual land use status of the selected sites, recommendations are provided for the planning and layout of PGS. This proposed framework offers valuable data and theoretical insights for urban public green space planning and design in similar regions.
]]>Forests doi: 10.3390/f15030569
Authors: Xiaofei Yan Wen Zhou Yiguan Zhang Chong Zuo Qiang Cheng
Near-surface soil hydraulic properties (SHPs) are fundamental for describing and predicting water and energy exchange processes, particularly at the soil–atmosphere interface, and regulating evapotranspiration, infiltration, and runoff in different ecosystems. In this study, a new method was proposed to estimate near-surface SHPs by combining sensor-based soil infiltrability measurements with inverse modeling using HYDRUS-2D. The infiltration rate (IR) was estimated by combining the linear source inflow method with image processing, and Ks was estimated from the near-surface steady-state IR (NSIRM). The SWRC parameters described by the van Genuchten model were estimated using the inverse modeling method of HYDRUS-2D for the fitting of sensor-measured infiltration data. Subsequently, the parameters of the van Genuchten model, including α, n, and l, were inversely estimated. Three undisturbed soils, including two stand humus samples from cork oak (Quercus suber L.) and oleander (Pinus tabuliformis L.) stands and one sandy loam from a farmland, were sampled near the soil surface to validate the proposed method. The estimated Ks was evaluated by the constant head method (CHM). The estimated parameters of the SWRC were validated by those determined through the simultaneous measurement of the soil moisture content and water potential using sensor techniques. The results showed that the Ks estimated from the NSIRM for each soil sample were 23.40 ± 1.21, 23.86 ± 1.83, and 22.99 ± 2.26 mm h−1, respectively. In comparison, the Ks determined by the CHM were 24.41 ± 1.53, 24.26 ± 0.37, and 23.81 ± 0.10 mm/h, respectively. The relative errors of the proposed method were 4.14%, 1.64%, and 3.42%, respectively. For the SWRC estimation, the normalized root mean square errors (NRMSEs) between the measurements and the estimates for each soil sample were 0.1724, 0.1454, and 0.0606, respectively. Based on this, the AWC was obtained, and Ku was deduced from the estimated Ks and SWRC parameters for each soil sample. In general, the proposed method successfully estimates near-surface SHPs, simplifies the measurement device, and provides a new perspective for the in situ determination of near-surface SHPs under field conditions in the near future.
]]>Forests doi: 10.3390/f15030568
Authors: Yujing Yang Wei Xia Yixuan Fan Yujie Chong Jiatai Xiong Wenjing Yu
Determining which species to utilize for the artificial restoration of subtropical secondary forests has become a focal point in forestry and ecology. To compare the effects of the subtropical secondary forest artificial restoration model on soil microbial nutrient acquisition and limitation, we examined secondary forests (CKs), evergreen coniferous forests (GCPs), evergreen coniferous mixed broad-leaved forests (GCBMs), evergreen mixed broad-leaved forests (GBMs), and natural deciduous broad-leaved mixed forests (DBMs) as research subjects. Among them, GCPs, GCBMs, and GBMs were dominated by the species of the early, middle, and climax stages of subtropical forest succession, respectively. The activities and stoichiometry of β-1,4-glucosidase (BG), β-1,4-N-acetylglucosaminidase (NAG), leucine aminopeptidase (LAP), and acid phosphatase (ACP) in the topsoil were analyzed. The results showed that the forest type significantly affects the activities of BG and LAP rather than NAG or ACP. The BG activity in DBMs was the lowest, while the LAP activity in CKs was significantly higher than that in plantations. Furthermore, the nutrient limitation of microbes was quantitatively analyzed by using the vector analysis of enzyme stoichiometry. The soil microbes in the study area were co-limited by C and P, and the nutrient limitation was in the order of C > P > N. Among the forests, the enzyme stoichiometric ratios in GCPs and DBMs were closest to 1:1:1. From CKs to GBMs, the microbial C limitation was increased, while the P limitation was decreased. The C limitation in DBMs was slightly lower than that in CKs. Overall, the P limitation in evergreen plantations was less than that in CKs. The soil bulk density, C/P, and N/P significantly influenced enzyme activities and stoichiometry. These results suggest that the artificial restoration of subtropical forests using evergreen species alleviated P limitation, while using deciduous broad-leaved species offered potential for alleviating microbial C limitation. Compared with evergreen broad-leaved species, employing pioneer and mid-successional or deciduous broad-leaved species can better achieve balanced microbial nutrient requirements.
]]>Forests doi: 10.3390/f15030567
Authors: Reeta Stöd Juhani Marttila Laura Tomppo Antti Haapala Erkki Verkasalo
The static bending properties of Scots pine (Pinus sylvestris L.) clear wood were studied using a material collected from commercial thinning forests in eastern Finland. In Myrtillus type, the modulus of elasticity and bending strength of the first thinning wood were 7.8 GPa and 66.0 MPa, respectively, whereas for more mature wood from the second thinnings, the modulus of elasticity and bending strength were 10.0 GPa and 80.3 MPa. The results were compared with final fellings, which resulted in the modulus of elasticity of 10.1 GPa and bending strength of 81.8 MPa. The bending properties of the first thinning material were low, and thus they did not indicate any potential for applications requiring high strength or stiffness and material homogeneity. On the contrary, the properties of Scots pine wood from the second commercial thinnings may be comparable with or sometimes even better than those of the final-felling wood. The results can be utilised in wood marketing, procurement, sorting, allocation to different industries and end-uses, as well as in wood processing, product sales, and branding.
]]>Forests doi: 10.3390/f15030566
Authors: Eunjin Kim Suyeon Yang Byeong Bae Jeon Eugene Song Hwayong Lee
Plant resources are used as raw materials in various industries related to humans, such as edible, medicinal, taste, and flavor industries, depending on processes such as drying, processing, and collection period. In this study, we investigated the terpene compound composition and antioxidant activity of essential oils extracted from the needles of Pinus densiflora, Pinus koraiensis, Abies holophylla, and Juniperus chinensis collected in the harvest period (February, April, July, and October) planted on the campus of Chungbuk National University. The essential oil was separated by hydrodistillation. According to the analysis results of gas chromatography–mass spectrometry, the terpene compounds changed depending on the season and tree species. The proportions of monoterpene and sesquiterpene classes in the needles of P. densiflora, P. koraiensis, A. holophylla, and J. chinensis changed depending on the harvest period. The antioxidant activity by DPPH and ABTS assays varied depending on the species and seasons, and needles harvested from P. koraiensis showed the highest activity in all harvest periods. High antioxidant activity has been confirmed even at low concentrations in pine trees, so it is expected to play a role as a natural antioxidant. Additionally, since the composition of terpene compounds varies depending on the harvesting time and species, it is expected to have various uses in the pharmaceutical, cosmetics, and food industries.
]]>Forests doi: 10.3390/f15030565
Authors: Rui Zhang Xueping Bai Xun Tian Zhenju Chen Haiyue Zhang Haiting Liu
Against the background of global warming, trees in high-latitude and high-altitude areas are more sensitive to rapid warming. Revealing the response patterns of trees at different altitudes to rapid warming in typical alpine mountain environments can help to predict the future distribution of forests in the region and the associated changes in the timberline. This study used tree-ring width data (band sampling) from Dahurian larch (Larix gmelinii Rupr.) along an altitudinal gradient (970–1409 m) on Oakley Mountain to establish 10 chronologies and to analyze the growth–climate response of larch to warming and altitudinal changes along a gradient. The results showed that before rapid warming, larch growth was strongly influenced mainly by precipitation in July–August, while after warming, the growth was controlled mainly by precipitation (snowfall) in winter (October–April) and showed a significant positive correlation with the SPEI in winter and a negative correlation with temperature in February–April (early spring). This indicates that the rapid warming event led to a drastic change in the water heat balance during the pre-growth period of the trees in the study area, which shifted the tree growth from being restricted by drought in the growing season before warming to being restricted by winter drought (i.e., the lagged effect of snowfall in the pre-growing season) after warming and that the trees at low altitudes suffered from more severe winter drought. In the future, as the global climate warms further, the growth of mountain larch at low altitudes (below 1200 m) will continue to decrease, and the coupling of winter snowfall and seasonal (February–April) warming will increase the upper altitude limit at which winter drought occurs for larch in the study area; additionally, larch at higher altitudes will be able to cope with this ecological process better.
]]>Forests doi: 10.3390/f15030564
Authors: Xin Zhao Ke Zhang Rong Zhao
In the policy arena of the rapid development of China’s digital village, understanding how internet use enhances the happiness of forest farmers’ families holds theoretical and practical significance for promoting the protection of the ecological environment and the sustainable development of forests. This study utilizes survey data from 2023 on forest farmers in ecologically fragile ethnic areas in China. Based on sustainability, a five-dimensional evaluation index system for the happiness of forest farmers’ families has been constructed. First, the CRITIC-TOPSIS model is employed to calculate the happiness scores of forest farming households. Subsequently, the Tobit model and the mediation effect model are applied to examine and analyze the influencing factors and mechanisms of internet usage on the happiness of forest farmers’ families. The study finds that, first, an increase of one unit in terms of internet use is associated with a 0.031-unit increase in the happiness of forest farmers’ families, and that education, social perception, and policy perception all have a positive effect on the happiness of forest farmers’ families. Second, the mechanism of action suggests that internet use significantly increases forest farmers’ families’ happiness through subjective class identity. Third, further heterogeneity analyses revealed that internet use contributed to the happiness of forest farmers’ families in the male group, the low human capital group, and the group with an ecological forest ranger in the family. Therefore, it is necessary to strengthen the construction of digital rural infrastructure and develop new models such as digital forestry; cultivate and introduce specialized digital talents in rural areas and enhance the digital literacy of forestry farmers; and assist forestry farmers in establishing class identity concepts and social values conducive to the sustainable development of forests and implement ecological values in production practices, thereby improving the happiness of forest farmers’ families.
]]>Forests doi: 10.3390/f15030563
Authors: Jibin Ning Hui Liu Wennan Yu Jifeng Deng Long Sun Guang Yang Mingyu Wang Hongzhou Yu
With the development of computer technology, forest fire spread simulation using computers has gradually developed. According to the existing research on forest fire spread, the models established in various countries have typical regional characteristics. A fire spread model established in a specific region is only suitable for the local area, and there is still a great deal of uncertainty as to whether or not the established model is suitable for fire spread simulation for the same fuel in other regions. Although many fire spread models have been established, the fuel characteristics applicable to each model, such as the fuel loading, fuel moisture content, combustibility, etc., are not similar. It is necessary to evaluate the applicability of different fuel characteristics to different fire spread models. We combined ground investigation, historical data collection, model improvements, and statistical analysis to establish a multi-model forest fire spread simulation method (FIRER) that shows the burning time, perimeter, burning area, overlap area, and spread rate of fire sites. This method is a large-scale, high-resolution fire growth model based on fire spread in eight directions on a regular 30 m grid. This method could use any one of four different physical models (McArthur, Rothermel, FBP, and Wang Zhengfei (China)) for fire behavior. This method has an option to represent fire breaks from roads, rivers, and fire suppression. We can evaluate which model is more suitable in a specific area. This method was tested on a single historical lightning fire in the Daxing’an Mountains. Different scenarios were tested and compared: using each of the four fire behavior models, with fire breaks on or off, and with a single or suspected double fire ignition location of the historical fire. The results show that the Rothermel model is the best model in the simulation of the Hanma lightning fire; the overlap area is 5694.4 hm2. Meanwhile, the real fire area in FIRER is 5800.9 hm2; both the Kappa and Sørensen values exceed 0.8, providing high accuracy in fire spread simulations. FIRER performs well in the automatic identification of fire break zones and multiple ignited points. Compared with FARSITE, FIRER performs well in predicting accuracy. Compared with BehavePlus, FIRER also has advantages in simulating large-scale fire spread. However, the complex data preparation stage of FIRER means that FIRER still has great room for improvement. This research provides a practical basis for the comparison of the practicability and applicability of various fire spread models and provides more effective practical tools and a scientific basis for decision-making and the management of fighting forest fires.
]]>Forests doi: 10.3390/f15030562
Authors: Kinga Drzewiecka Monika Gąsecka Zuzanna Magdziak Michał Rybak Sylwia Budzyńska Paweł Rutkowski Przemysław Niedzielski Mirosław Mleczek
The aim of this study was to determine the tolerance to metals (Zn, Cu) and drought of male and female Salix × fragilis L. under isolated and combined treatments, and to assess the metal uptake and profiling of metabolic plant responses. The 14-day experiment was performed in a hydroponic system, and metals were applied at 1.5 mM in a Knop’s solution. Drought simulation was achieved by adding sorbitol at a moderate level (200 mM). Isolated Zn treatment enhanced plant growth, more pronouncedly in females. Equimolar Cu treatment caused diverse reactions, and females exhibited significantly higher tolerance. Male specimens were less tolerant to isolated drought and to combined drought and metal presence. The highest contents of Cu and Zn were found in roots, compared to the aboveground tissues (wooden rods and leaves), of both female and male metal-treated plants. Simultaneously applied drought limited Zn accumulation in roots and elevated its translocation to leaves while increasing Cu accumulation, predominantly in females showing higher tolerance. Both isolated and combined drought and metals reduced leaf water content, caused the allocation of mineral nutrients (Ca, Mg, K, and Na), and affected metabolism in a stressor-specific and sex-dependent manner. For males, Cu accumulation in the leaves was significantly correlated with the majority of metabolites, while for both sexes, kaempferol and salicylic acid were strongly correlated, indicating their role in tolerance against the metal. The obtained results are an excellent starting point for the practical use of male and female Salix × fragilis L. in areas heavily polluted with Cu or Zn and exposed to drought, for the purpose of their recultivation.
]]>Forests doi: 10.3390/f15030561
Authors: Zhen Wu Keyi Xu Yan Li Xinyang Zhao Yanping Qian
Urban street greening, a key component of urban green spaces, significantly impacts residents’ physical and mental well-being, contributing substantially to the overall quality and welfare of urban environments. This paper presents a novel framework that integrates street greenery with accessibility, enabling a detailed evaluation of the daily street-level greenery visible to residents. This pioneering approach introduces a new measurement methodology to quantify the quality of urban street greening, providing robust empirical evidence to support its enhancement. This study delves into Nanjing’s five districts, employing advanced image semantic segmentation based on machine learning techniques to segment and extract green vegetation from Baidu Street View (BSV) images. Leveraging spatial syntax, it analyzes street network data sourced from OpenStreetMap (OSM) to quantify the accessibility values of individual streets. Subsequent overlay analyses uncover areas characterized by high accessibility but inadequate street greening, underscoring the pressing need for street greening enhancements in highly accessible zones, thereby providing valuable decision-making support for urban planners. Key findings revealed that (1) the green view index (GVI) of sampled points within the study area ranged from 15.79% to 38.17%, with notably better street greening conditions observed in the Xuanwu District; (2) the Yuhua District exhibited comparatively lower pedestrian and commuting accessibility than the Xuanwu District; and (3) approximately 139.62 km of roads in the study area demonstrated good accessibility but lacked sufficient greenery visibility, necessitating immediate improvements in their green landscapes. This research utilizes the potential of novel data and methodologies, along with their practical applications in planning and design practices. Notably, this study integrates street greenery visibility with accessibility to explore, from a human-centered perspective, the tangible benefits of green landscapes. These insights highlight the opportunity for local governments to advance urban planning and design by implementing more human-centered green space policies, ultimately promoting societal equity.
]]>Forests doi: 10.3390/f15030560
Authors: Bianca Ambrose-Oji Maddy Pearson Emma Cross Jackie Shallcross Sarah Polschneider Robert Hattersley Olivia FitzGerald
Forest restoration and tree-planting projects initiated as a response to climate change and biodiversity loss are increasingly important around the globe. Small-scale and community-based tree nurseries have been promoted as a potential route to meeting some local or regional supply-side bottlenecks. A study in the UK used a mixed methods approach to assess the potential contribution of community tree nurseries (CTNs) to tree material supply. Semi-structured interviews (SSIs) were undertaken with 16 CTNs across the UK to generate a sector-wide characterisation of CTNs. A UK-wide online survey assessed the total number of CTNs, production methods and volumes, biosecurity practices and benefits of community involvement. Another 13 CTNs receiving support to establish and extend their operations took part in SSIs assessing their development. The results indicate that there are four broad types of CTN (Organisation- and project-based, Community-based, Enterprise and Network CTNs). A significant number of CTNs in Britain are new and establishing. The sustainability of CTNs relies in large part on grant support rather than income from tree sales. Production is almost exclusively native broadleaves and local provenances. There are policy implications concerning: i. the suitability of species being produced to future climatic and market conditions and ii. the tension around financial viability, grant dependence and CTN sustainability for those CTNs focused on social and environmental benefits rather than income generation. Identifying gaps in the provision of trees by commercial nurseries, e.g., uncommon or recalcitrant species, could be a feasible financial strategy. It is likely that financial support and skills development are likely to be required as social innovation in the community-supported tree nursery sector establishes and develops. Judging the success and impact of some types of CTNs in terms of production and finance measures may be unfair, as other social and environmental benefits may be as important and valuable. It is clear that more evaluative research is needed to quantify and better understand these kinds of outcomes and the added value they accrue.
]]>Forests doi: 10.3390/f15030559
Authors: Fayu Long Guanghui Zhou Lei Zu Lipeng Zang Danmei Chen Guangqi Zhang Mingzhen Sui Yuejun He Qingfu Liu
The biodiversity–ecosystem function (BEF) relationship is the basis for studying the restoration of degraded ecosystems, and the simultaneous assessment of multi-trophic-level biodiversity and ecosystem multifunctionality relationship is more conducive to unravelling the restoration mechanism of degraded ecosystems, especially for degraded forest ecosystems with harsh habitats and infertile soils such as karst. In this study, we evaluated the biodiversity and soil multifunctionality (SMF) of degraded karst forests (scrub, SB; secondary growth forests, SG; old-growth forests, OG) in the Maolan National Nature Reserve, China, using 30 sample plots. Biodiversity and soil multifunctionality (SMF) at three trophic levels (plant–soil fauna–soil microorganisms), were assessed through vegetation surveys and soil sampling. One-way ANOVA showed that SMF increased with natural restoration, but multi-trophic level biodiversity showed different trends. Pearson’s correlation analysis showed a positive correlation between plant species diversity and SMF (p < 0.001), whereas soil fauna and soil microorganisms were negatively correlated with SMF. Structural equation modeling revealed a cascading effect of the multi-trophic level on the stimulation of the SMF during restoration. Only soil microorganisms exhibited a direct driving effect on SMF (p < 0.001), whereas plants indirectly influenced soil microorganisms through soil fauna, which subsequently affected the SMF. Although we observed the negative effects of increased plant diversity on soil fauna and soil microbial diversity in terms of quantitative relationships, the increase in soil fauna species and the evenness of soil microbial function still contributed to SMF restoration. This study revealed the cascading effects of multi-trophic diversity in promoting SMF restoration and emphasized that soil microbes are key to unraveling restoration mechanisms and processes, whereas soil fauna is an important intermediate link.
]]>Forests doi: 10.3390/f15030558
Authors: Yanyan Gao Haitao Shi Yangen Chen Sha Huang Enhui Wang Zelong Ni Yufeng Zhou Yongjun Shi
Forest management, especially understory vegetation conversion, significantly affects soil greenhouse gas (GHG) emissions and soil C and N pools. However, it remains unclear what effect renovating understory vegetation has on GHG emissions and soil C and N pools in plantations. This study investigates the impact of renovating understory vegetation on these factors in Chinese hickory (Carya cathayensis Sarg) plantation forests. Different understory renovation modes were used in a 12-month field experiment: a safflower camellia (SC) (Camellia chekiangoleosa Hu) planting density of 600 plants ha−1 and wild rape (WR) (Brassica napus L.) strip sowing (UM1); SC 600 plants ha−1 and WR scatter sowing (UM2); SC 1200 plants ha−1 and WR strip sowing (UM3); SC 1200 plants ha−1 and WR scatter sowing (UM4); and removal of the understory vegetation layer (CK). The results showed that understory vegetation modification significantly increased soil CO2 and emission fluxes and decreased soil CH4 uptake fluxes (p < 0.01). The understory vegetation transformation significantly improved soil labile carbon and labile nitrogen pools (p < 0.01). This study proposes that understory vegetation conversion can bolster soil carbon sinks, preserve soil fertility, and advance sustainable development of Chinese hickory plantation forests.
]]>Forests doi: 10.3390/f15030557
Authors: Thony Huera-Lucero Antonio Lopez-Piñeiro Bolier Torres Carlos Bravo-Medina
Currently, there are several studies related to climate change, carbon sequestration, and floristic composition in different scenarios and land uses. In this context, the objective of this research is: (a) to characterize biodiversity based on ecological indicators and diversity indices and (b) to evaluate carbon sequestration in different components of chakra-type agroforestry systems and secondary tropical humid forests of the Ecuadorian Amazon. For this, temporary sampling plots of 1600 m2 are established on the properties to be investigated. The study found that the structural characteristics and floristic composition vary according to the forest arrangement and the management system. Secondary forests are the most diverse, according to the Shannon (3.49), Simpson (0.96), and Margaleft (9.34) diversity indices, in addition to having the largest carbon stores with 233 (Mg C ha−1), followed by agroforestry systems in association with timber trees (TAFS) and fruit trees (FAFS) with 97.8 and 95.1 (Mg C ha−1) respectively, and cocoa monoculture (CMC) with 90.4 (Mg C ha−1). These results demonstrate the importance of conserving the remnants of tropical forests that still remain, due to the diversity of species, ecosystem services, and the total carbon they contain, as well as the agroforestry systems (AFS), systems analogous to forests, which are gradually becoming important management systems, especially if they are associated with potential species to sequester carbon, such as those documented in this and several other studies that seek solutions to global climate change.
]]>Forests doi: 10.3390/f15030556
Authors: Xi Pan Zhiming Yu Zhong Yang
The swift and non-destructive classification of wood species holds crucial significance for the utilization and trade of wood resources. Portable near-infrared (NIR) spectrometers have the potential for rapid and non-destructive wood species identification, and while several studies have explored related methodologies, further research on their practical application is needed. To address this research gap, this study proposes a multi-scale convolutional neural network (CNN) combined with a portable NIR spectrometer (wavelengths range: 908 to 1676 nm) for wood species identification. To enhance the capability of directly extracting robust features from NIR spectral data collected by a portable spectrometer, the Gramian angular field (GAF) method is introduced to transform 1-dimensional (1D) NIR spectral data into 2-dimensional (2D) data matrices. Furthermore, a multi-scale CNN model is utilized for direct feature extraction. The representation by 2D matrices, instead of 1D NIR spectral data, aligns with 2D convolutional operations and enables a more robust extraction of discriminative features. In the experimental phase, eight wood species were identified using the proposed method, alongside commonly used multivariate data analysis and machine learning (ML) methods. The StratifiedGroupKFold dataset partitioning approach and five-fold cross-validation were used. Additionally, nine spectral preprocessing methods were compared, and principal component analysis (PCA) was used for feature extraction in the ML method. Evaluation metrics, such as accuracy, precision, and recall, were adopted to assess the performance of the methods. The proposed multi-scale CNN model, in combination with 2D GAF matrices of the 1D spectral data, yielded the most accurate results with a mean accuracy of 97.34% in the five-fold validation. These findings present a new approach for the construction of a rapid, non-destructive, and automatic wood species identification method using a portable NIR spectrometer.
]]>Forests doi: 10.3390/f15030555
Authors: Bo Yang Weishuai Ta Wen Dong Danping Ma Jihan Duan Huajun Lin Dubin Dong Jian Chen Songwei Zeng Yan Shi Jianyun Pan Yuan Ren
The growing awareness of the health advantages offered by forests has underscored the significance of forest exposure as an upstream preventive measure against disease. While numerous studies have confirmed the physical and mental health benefits associated with forests, there is still a lack of quantitative understanding regarding the relationship between forest exposure and physiological health benefits (PHB). Particularly, there is insufficient knowledge about the threshold effects derived from short-term forest exposure. In this study, we propose a PHB threshold model for assessing forest exposure that introduces the concepts of efficiency threshold and benefits threshold. A pilot study was conducted in three typical natural forest sites to validate the proposed model. Electroencephalogram (EEG) was continuously measured as the physiological indicator, while meteorological, environmental, and demographic factors were simultaneously collected. The results show that: (1) the proposed PHB threshold model is applicable in a natural forest environment; (2) despite the longer time required to reach the PHB thresholds, forest exposure yielded more significant and prolonged health benefits compared to urban green spaces; (3) meteorological factors, such as temperature and relative humidity, play a crucial role in impacting the PHB threshold model; and (4) exposure to forests is better for deep thinking and relaxation than urban green spaces. These findings emphasize the potential of forests to offer a respite from the stresses of modern life and promote holistic well-being.
]]>Forests doi: 10.3390/f15030554
Authors: Nathan Mukendi Héritier Muteya Dieu-donné Nghonda Fabio Berti Yannick Useni Sikuzani Laurent Ndjibu Jean-Paul Mbay Jules Fyama Philippe Lebailly Jan Bogaert
Although charcoal production is a source of income, it is often associated with deforestation due to the felling of trees in rural areas. In this study, we quantified the yield of carbonization in the rural area of Lubumbashi, Democratic Republic of the Congo (DR Congo), and identified its determinants. By analyzing 20 kilns of professional producers in different villages, we found that these charcoal producers build large kilns, which contained an average of 46.9 ± 21.5 m3 of wood from 19 species of Miombo woodland trees, with a predominance of Julbernardia paniculata (Benth.) Troupin, alongside Brachystegia microphylla Harms and B. spiciformis Benth. The average carbonization yield was 10.2%, varying from village to village due to parameters such as kiln size, quantity of wood used, kiln coverage time, wind exposure, substrate type, and tree species. It was noted that the moisture content and dimensions of the wood did not significantly correlate with the quantity of charcoal harvested per kiln. Yield improvement should, therefore, take these parameters into account to enable charcoal producers to increase their income while adopting sustainable production practices.
]]>Forests doi: 10.3390/f15030553
Authors: Kai Yan Xingjian Zhang Rui Peng Si Gao Jinxiu Liu
Monitoring vegetation dynamics (VD) is crucial for environmental protection, climate change research, and understanding carbon and water cycles. Remote sensing is an effective method for large-scale and long-term VD monitoring, but it faces challenges due to changing data uncertainties caused by various factors, including observational conditions. Previous studies have demonstrated the significance of implementing proper quality control (QC) of remote sensing data for accurate vegetation monitoring. However, the impact of different QC methods on VD results (magnitude and trend) has not been thoroughly studied. The fraction of absorbed photosynthetically active radiation (FPAR) characterizes the energy absorption capacity of the vegetation canopy and is widely used in VD monitoring. In this study, we investigated the effect of QC methods on vegetation monitoring using a 20-year MODIS FPAR time series. The results showed several important findings. Firstly, we observed that the Mixed-QC (no QC on the algorithm path) generally produced a lower average FPAR during the growing season compared to Main-QC (only using the main algorithm). Additionally, the Mixed-QC FPAR showed a very consistent interannual trend with the Main-QC FPAR over the period 2002–2021 (p < 0.05). Finally, we found that using only the main algorithm for QC generally reduced the trend magnitude (p < 0.1), particularly in forests. These results reveal differences in FPAR values between the two QC methods. However, the interannual FPAR trends demonstrate greater consistency. In conclusion, this study offers a case study on evaluating the influence of different QC methods on VD monitoring. It suggests that while different QC methods may result in different magnitudes of vegetation dynamics, their impact on the time series trends is limited.
]]>Forests doi: 10.3390/f15030552
Authors: Jiaqian Sun Fangjie Mao Huaqiang Du Xuejian Li Cenheng Xu Zhaodong Zheng Xianfeng Teng Fengfeng Ye Ningxin Yang Zihao Huang
Subtropical forests have strong carbon sequestration potential; however, the spatiotemporal patterns of their carbon sink are unclear. The BIOME-BGC model is a powerful tool for forest carbon sink estimation while the numerous parameters, as well as the localization, limit their application. This study takes three typical subtropical forests (evergreen broadleaf forest, EBF; evergreen needleleaf forest, ENF; and bamboo forest, BF) in China as examples, assesses the sensitivity of 43 ecophysiological parameters in the BIOME-BGC model both by the Morris method and the extended Fourier amplitude sensitivity test (EFAST), and then evaluates the net ecosystem productivity (NEP) estimation accuracy based on the dataset of the fiveFi long-term carbon flux sites of those three typical forests from 2000 to 2015. The results showed that (1) both sensitivity analysis methods can effectively screen out important parameters affecting NEP simulation while the Morris method is more computationally efficient and the EFAST is better in the quantitative evaluation of sensitivity. (2) The highly sensitive parameters obtained using the two methods are basically the same; however, their importance varies across sites and vegetation types, e.g., the most sensitive parameters are k for the EBF and ENF and Ract25 for the BF, respectively. (3) The optimized parameters successfully improved the NEP simulation accuracy in subtropical forests, with average correlation coefficients increased by 25.19% and normalized root mean square error reduced by 21.74% compared with those simulated by original parameters. This study provides a theoretical basis for the optimization of process model parameters and important technical support for accurate NEP simulations of subtropical forest ecosystems.
]]>Forests doi: 10.3390/f15030551
Authors: Young-Gyun Son Yohan Lee Jang-Hwan Jo
South Korea is one of the countries with a significant proportion of its national territory covered by forests. However, it remains unclear what management strategies for providing forest ecosystem services are preferred by the residents. This study explores South Korean residents’ preferences for managing local forest ecosystem services, with a focus on how these preferences vary by forest ownership. Using the choice experiment method, this research identified residents’ willingness to pay for seven key local forest ecosystem services, along with a tax measure. The findings indicate a strong preference for biodiversity as the primary ecosystem service in both national/public and private forests, with residents willing to pay an average of KRW 28,370 (USD 21.80) per household per year and KRW 31,670 (USD 24.34) per household per year, respectively, for its enhancement. Preferences varied depending on forest ownership, with noticeable differences in perceptions of services like water supply, non-timber forest product supply, carbon storage, and recreation. Based on forest ownership, these variations in perceptions highlight the importance of managing ecosystem services in line with national/public forests and private forests, which significantly influences residents’ preferences. The study emphasizes the necessity of formulating ecosystem service management policies that account for the region’s unique natural resource characteristics, aiming to maximize ecological benefits for the local population.
]]>Forests doi: 10.3390/f15030549
Authors: Jing Kang Miao Yu Ye Xia Shanlei Sun Botao Zhou
Climate extremes, such as heatwaves and droughts, significantly impact terrestrial ecosystems. This study investigates the influence of compound hot–dry (CHD) events on vegetation productivity in northern East Asia. Four of the most widespread CHD events occurring during the summer from 2003 to 2019 were selected as the focus of this research. We first verified the performance of the Community Land Model version 5 (CLM5) in the region and then conducted factor-controlled experiments using CLM5 to assess the effects of different climate factors on gross primary productivity (GPP) changes during CHD events. Our results show that vegetation productivity exhibits greater sensitivity to CHD events within the transitional climatic zone (TCZ) than in other affected areas. In grassland areas within the TCZ, precipitation deficit is the primary factor leading to the decrease in GPP (explaining 56%–90% of GPP anomalies), while high temperatures serve as a secondary detrimental factor (explaining 13%–32% of GPP anomalies). In high-latitude forests outside the TCZ, high temperature has a more significant impact on suppressing GPP, while the decrease in soil moisture has a synchronously negligible impact on GPP. There are differences in the effects of high solar radiation on grasslands and woodlands during CHD events. It was observed that high radiation benefits trees by increasing the maximum carboxylation rate (Vcmax) and maximum electron transport rate (Jmax), as well as enhancing photosynthesis, but has a negligible impact on grasses. Furthermore, this study highlights the potential for compound events to impact vegetation productivity more than expected from individual events due to confounding nonlinear effects between meteorological factors. More than 10% of the negative anomalies in GPP during two CHD events in 2017 and 2010 were attributed to these nonlinear effects. These research findings are significant for understanding ecosystem responses to climate extremes and their influence on carbon cycling in terrestrial ecosystems. They can also contribute to more precisely evaluating and predicting carbon dynamics in these regions.
]]>Forests doi: 10.3390/f15030550
Authors: Carlos Diniz Mathew Smidt John Sessions
Dynamic prices and markets create value for contractors who can readily evaluate the gross and net income differences for alternative merchandizing systems. The majority of the southern U.S.A. relies on tree-length merchandizing, with occasional identification and merchandizing of logs for a specific market or specific tree dimensions or qualities. Cut-to-length (CTL) merchandizing has generated more value when compared to tree-length (TL) marketing, but these comparisons have been limited to specific stands and markets (specifications and prices). The study objective was to demonstrate a process for evaluating cut-to-length and tree-length merchandizing systems in their production of gross value by applying a dynamic programming stem-level optimum bucking approach that maximizes the stem value given specific market conditions. TL merchandizing resulted in a better volume recovery for both regions, but the value recovery was better for CTL merchandizing. Observing the value recovery by diameter class, DSH classes of up to 100 mm had a similar value in both merchandizing systems, but CTL merchandizing yielded a greater or similar value per cubic meter across the range for larger tree sizes. Access to tree data and merchandizing tools needs to be addressed so wood suppliers and landowners may benefit from stem optimization and sensor technology being embedded into modern harvesters and processors.
]]>Forests doi: 10.3390/f15030548
Authors: Jiaqi Cheng Xuexia Zhang Jianjun Zhang Yanni Zhang Yawei Hu Jiongchang Zhao Yang Li
Robinia pseudoacacia is widely planted in the Loess Plateau as a major soil and water conservation tree species because of its dense canopy, complex structure, and strong soil and water conservation ability. The precise measurement of small-scale locust forest biomass is crucial to monitoring and evaluating the carbon sequestration functions of soil and water conservation vegetation. This study focuses on an artificial locust forest planted in the early 1990s in Caijiachuan Basin, Jixian County, Shanxi Province. A drone equipped with LiDAR was used to obtain point cloud data and generate a canopy height model. A watershed segmentation algorithm was used to identify tree vertices and extract individual trees. A relationship model between tree height, diameter at breast height, and biomass, combined with sample survey data, was established to explore the spatial distribution of biomass in the artificial locust forest at the level of the entire basin. The results show the following: (1) the structural parameters of locust extracted using UAV point cloud data have a good degree of fit and accuracy, and the recall rate is 72.7%; (2) the average error rate of the extracted maximum tree height value of locust is 7%, that of the minimum tree height value is 14%, and that of the average tree height value is 18%; (3) the average error rate of the extracted maximum diameter at breast height of locust is 15%, that of the minimum diameter at breast height is 37%, and that of the average diameter at breast height is 36%; and (4) the average error rate of the biomass estimation of locust calculated using point cloud data is 16.0%.
]]>Forests doi: 10.3390/f15030547
Authors: Mengmeng Zhang Yiteng Liu Zhuo Chen Zhaokun Zhi Aning Wang Huafeng Yue Fangdong Li Shulin Zhang Gaopu Zhu
Fruit cracking or splitting is a severe physiological disease that significantly affects appearance and quality, compromising the commodity value of fruit and causing substantial economic losses to the producers of several fleshy fruit crops. The growth-promoting plant hormone gibberellins (GAs) and growth-inhibiting abscisic acid (ABA) antagonistically regulate numerous processes throughout the plant life cycle. The homeostasis of GA and ABA plays a significant role in the normal growth and development of fruits, and the imbalance of them may lead to the occurrence of cracking or splitting during the process of fruit growth, development, ripening and postharvest storage. The pathways of GA and ABA metabolism and signaling have been studied widely, and the major components are well characterized, including the genes encoding major biosynthesis and catabolism enzymes and the key signaling components. Nevertheless, our knowledge of the mechanisms of GA and ABA governing fruit cracking is not comprehensive enough. In this review, we summarize the advances in understanding the effects of endogenous GAs and ABA contents in fruits and exogenous GAs and ABA treatments on fruit cracking, and we endeavor to provide some genetic cues on the function of GAs and ABA responsible for fruit cracking modulation. The progress in understanding the molecular bases underlying the actions of GAs and ABA in fruit cracking coordination control will facilitate breeding strategies of cracking-resistant ideotypes of fruits, and also carry great theoretical significance in guiding the establishment of integrated prevention and control measures in fruit cracking.
]]>Forests doi: 10.3390/f15030546
Authors: Xing Jin Shu Lin Jing Zhu Fanglin Tan Huiguang Zhang Qichao Chen Yu Hong Jinfu Liu Daowei Xu Zhongsheng He
Evaluating the carbon storage of forests and identifying the factors that influence it are essential in working towards the “dual carbon” goal. This assessment will facilitate research on carbon neutrality and promote regional ecological protection and development. This study utilized the “One Map” data of forest resources (2020) and the first year (2017) of the establishment of the national park in Wuyi Mountain National Park (WMNP). The continuous biomass expansion factor method, in conjunction with the vegetation carbon content coefficient, was employed to estimate the forest carbon storage within the park’s forested areas. Subsequently, the distribution of forest carbon storage was analyzed using remote sensing estimation methods, and a comparison was made between the forest carbon storage of these two years. Finally, correlation analysis and path analysis were conducted to identify the primary factors influencing forest carbon storage. The study findings reveal that in 2020, the total carbon storage in forests reached 4.851 × 106 t C, with an average carbon density of 49.55 t C·hm−2. Furthermore, the study identified positive correlations between dominant tree species, age groups, and elevation with carbon storage, whereas slope length and aspect were found to have negative correlations. Dominant tree species were observed to have the greatest impact on forest carbon storage in both 2017 and 2020, followed by age groups. These findings offer valuable scientific insights for the implementation of forest carbon storage pilot projects in WMNP.
]]>Forests doi: 10.3390/f15030545
Authors: Thomas Kronholm Rikard Olsson Mikael Thyrel Carola Häggström
Forestry has many dangers, and much effort has been put into supporting accident prevention by developing legislation and certification systems. In Sweden, forestry contractors have an important role in developing and maintaining a good working environment for the employed forestry workers. The objectives of this study were to describe forestry contractors’ current practices regarding occupational safety and health (OSH) management and identify variations in relation to the contractors’ characteristics and finances, as well as to highlight areas that need improvement. In 2023, data were collected through a survey distributed to 1200 limited liability companies registered to perform logging or silvicultural services, with a response rate of 22%. Multi- and univariate analyses were performed to compare contractor groups, and the results show that larger companies had more well-developed and formalized routines and guidelines for their operations. Geographical differences were also identified; for example, employees in the north were more likely to have access to staff facilities when working in the forest. However, no clear connection between OSH management practices and the contractors’ finances could be demonstrated. The study concludes that there is a need for improvements in OSH work within the industry because many companies do not meet all of the formal requirements that exist today.
]]>Forests doi: 10.3390/f15030544
Authors: Umer Hayat Aqsa Abbas Juan Shi
Infestations of pests are perhaps an anthropogenic catastrophe for trees. Aeolesthes sarta (Sart longhorned beetle—SLB) is one of the most severe pests that cause serious damage to a number of hardwood tree species, i.e., Populus, Salix, Acer, Juglans, and Malus. To investigate people’s attitudes towards pest damage cost and future control extent of SLB, a door-to-door method was adopted to survey two major cities (Quetta—QU and Peshawar—PE) of the northwestern region of Pakistan where this pest has caused severe damage. Respondents were asked about SLB pest knowledge, pest damage costs, preferences for control choices, and program extent. According to respondents, more trees (181 ± 1.20 trees/ha/annum) were damaged in QU compared to PE. Populus spp. was the dominant tree genre that attacked and damaged the most. Around 85% of respondents from both cities stated the pest damage cost was calculated as high for QU (480,840.80 ± 4716.94$/annum) compared to PE. Respondents in both locations strongly supported (more than 82%) biological control of future SLB outbreaks. They all agreed that protecting ecologically vulnerable places and wildlife habitats should be the primary priority in a future SLB outbreak. Respondents from both cities who preferred to protect more land area in future SLB outbreaks were calculated to be high for QU (61%) compared to PE (58%). However, city variations in opinions regarding forest-type priority that should be protected and control options were observed. Socio-demographic characteristics were discovered to impact pest damage cost positively, as well as preferred SLB control extent. The findings of this study can help policymakers and forest managers develop publicly permissible pest control plans and make more accurate predictions about future pest outbreaks.
]]>Forests doi: 10.3390/f15030543
Authors: Alessandro Paletto Sandra Notaro Carlotta Sergiacomi Francesca Di Mascio
In the mid-1980s, forest bathing was established in Japan to improve citizens’ physical and mental health. In the literature, many studies have investigated the role of forest bathing in decreasing people’s stress and anxiety as well as in reducing hypertension and coronary artery disease. Forest bathing is also a practice with important social and economic implications at a local level. This study investigated the economic value of forest bathing in a case study in northern Italy (i.e., the Parco del Respiro, in Trentino-Alto Adige) using the Zonal Travel Cost Method. To achieve this aim, 243 forest bathers in the study area were interviewed in the summer of 2022. The findings highlighted that an actively managed forest with an average–low amount of deadwood and clean open areas is the scenario preferred by participants. In addition, the results of the Zonal Travel Cost Method showed a relevant annual consumer surplus of EUR 8700 for the forest bathing activity in the study area, corresponding to EUR 35.80 per visit per person.
]]>Forests doi: 10.3390/f15030542
Authors: Ivan A. Kerchev Elvina M. Bisirova Nikita A. Smirnov Igor G. Grachev Artem N. Nikiforov Daria A. Kalashnikova
Invasions of dendrophagous insects pose major threats to forest ecosystems and to the timber industry. The alien species bark beetle Polygraphus proximus Blandf. of Far Eastern origin has caused Siberian fir dieback in vast areas within several regions of Russia. Rapid spread of the pest and its outbreaks raise the issue of preserving the most important functions, including carbon sequestration, by the damaged forests. In this study, monitoring of carbon pool dynamics was carried out during 2012–2023 on four sample plots showing various degrees of damage in the southern taiga zone of Western Siberia in the Larinsky Landscape Reserve. Dynamics of the forest stands’ vitality were reflected in a rapid decline of the number of viable trees and an increase in amounts of deadwood, debris, and soil composition, resulting in a transformation of the natural biological carbon cycle in the native dark coniferous ecosystems.
]]>Forests doi: 10.3390/f15030541
Authors: Lei Cui Jiaying Zhang Yiqun Dai Rui Xie Zhongzheng Zhu Mei Sun Xiaoning Zhang Long He Hu Zhang Yadong Dong Kaiguang Zhao
Multi-angular remote sensing observation contains crucial information on forest structure parameters. Here, our goal is to examine the ability of multi-angular indices, which are constructed by the typical-angular reflectances in red and NIR bands from MODIS observations, for the retrieval of forest biomass based on the field-measured above-ground biomass (AGB) data. Specifically, we employed the updated version of the MCD43A1 BRDF parameter product as an input for BRDF models to reconstruct the MODIS typical-angular reflectances. Furthermore, we evaluated the effects of different configurations of BRDF models and solar zenith angles (SZA) on forest AGB estimation using our developed multi-angular indices. The semivariogram analysis strategy combined with Landsat ground-surface reflectance data was employed to determine the MODIS pixel heterogeneity; the survey data from field sites of homogeneous pixels was used in our analysis and validation. The results show that our developed multi-angular indices based on a hot-revised BRDF model, under a SZA of 45°, when combined with forest cover information, can account for up to 72% of the variation forest AGB, with an RMSE = 45 Mg/ha. We also found that different kernels for the BRDF models influenced the weight parameters of the biomass inversion equation but did not significantly affect the estimated AGB. In conclusion, our method can enable the better usage of MODIS multi-angular observations for forest AGB estimation.
]]>Forests doi: 10.3390/f15030540
Authors: Wanling Shen Zhanghua Xu Na Qin Lingyan Chen Yuanyao Yang Huafeng Zhang Xier Yu Anqi He Lei Sun Xia Li
The objective of this study was to deeply understand the adaptation mechanism of the functional traits of Moso bamboo Phyllostachys pubescens syn. edulis (Poales: Poaceae) leaves to the environment under different Pantana phyllostachysae Chao damage levels, analyzing the changes in the relationship between specific leaf area (SLA) and leaf dry matter content (LDMC). We combined different machine learning models (decision tree, RF, XGBoost, and CatBoost regression models), and used different canopy heights and different levels of infestation, to analyze the changes in the relationship between the two under different levels of infestation based on the results of the best estimation model. The results showed the following: (1) The SLA of Ph. pubescens showed a decreasing trend with the increase om insect pest degree, and LDMC showed an inverse trend. (2) The SLA of bamboo leaves was negatively correlated with the LDMC under different insect pest degrees; the correlation of the data under the healthy class was higher than that of other insect pest levels, and at the same time better than that of the full sample, which laterally confirmed the effect of insect pest stress on the functional traits of Ph. pubescens leaves. (3) When modeling under different infestation levels, the CatBoost model was used for heavy damage and the RF model was used for the rest of the cases; the decision tree regression model was used when modeling different canopy heights. The findings contribute certain insights into the nuanced responses and adaptive mechanisms of Ph. pubescens forests to environmental fluctuations. Moreover, these results furnish a robust scientific foundation, essential for ensuring the enduring sustainability of Ph. pubescens forest ecosystems.
]]>Forests doi: 10.3390/f15030539
Authors: Mouna Feki Giovanni Ravazzani Gaetano Pellicone Tommaso Caloiero
The concept of integrated forest management offers a framework for understanding how forest ecosystem services interact with efforts to conserve natural resources. Forests face various disturbances stemming from human activities, management approaches, and shifts in climate patterns. This study aims to explore how forested watersheds respond to diverse silvicultural practices amidst changing climate conditions. The research is centered in the Bonis catchment, situated in the mountainous region of Sila Greca (latitude 39°25′15″ N, longitude 16°12′38″ W) within Southern Italy’s Calabria region. Nearly 93% of the catchment area is cloaked in a forest dominated by approximately 50-year-old Pinus laricio Poiret stands. To model the catchment’s response to various climate and management scenarios, the FEST-FOREST eco-hydrological model, which is distributed and based on physical principles, has been employed. This model accounts for the dynamic interactions between vegetation and the watershed’s hydrological processes. The monitoring of the basin has been ongoing since 1986, with runoff measurements collected at the catchment outlet using dedicated gauging structures. These data have been utilized to calibrate and validate the model, ensuring its accuracy in simulating future scenarios. These simulation results offer stakeholders some qualitative and scientifically based recommendations for the sustainable management of the catchment. In fact, thinning intensity affects hydrological processes, with a 50% stand density reduction identified as a threshold for significant impact on processes like rainfall partitioning and evapotranspiration. Under heavy thinning scenarios, runoff can change by over 60%, and the impact decreases with larger thinning intervals. Furthermore, different climate scenarios influence stem yield levels, with higher production under RCP 4.5 and RCP 8.5 compared to the base climate scenario. In particular, the RCP 8.5 scenario produces the highest yield due to better forest growth under different climate scenarios. This implies the idea that in regions with a Mediterranean climate and coniferous forests, amidst climate change, meticulous forest management involving precisely calibrated thinning schedules and intensities, tailored to unique biotic and abiotic factors, could potentially enhance carbon sequestration while positively influencing runoff rates.
]]>Forests doi: 10.3390/f15030538
Authors: Xinman Li Min Jiang Yachao Ren Jiushuai Pang Junjie Ren Guifen Li Yangchen Yuan Xueding Xing Miaomiao Zhou Jinmao Wang Minsheng Yang
Mongolian oak (Quercus mongolica) is a common building material and landscaping tree species in northern China, with significant economic and ecological value. Its seedling growth is inhibited by high light intensity, but the mechanism by which light stress affects the growth and development of its seedlings remains unclear. In this study, we investigated the phenotypes, physiological processes, and molecular responses of 3-year-old Mongolian oak seedlings under different light treatments: full light (Sck), light shading (S1; 40% light), moderate shading (S2; 20% light), and severe shading (S3; 3% light). Compared to Sck, the S1 and S2 treatments resulted in higher leaf area, photosynthetic pigment content, photosynthesis rates, soluble sugar contents, and soluble protein contents in Mongolian oak seedlings. The S1 and S2 treatments also promoted seedling height and diameter growth and resulted in lower degrees of membrane lipid peroxidation, cell membrane permeability, and antioxidant enzyme activity. In contrast, severe shading (S3) significantly inhibited seedling height and diameter growth due to the lower net photosynthetic rate, and exhibiting higher degrees of membrane lipid peroxidation and cell membrane permeability. Shading treatments (S1 and S2) alleviated the negative effects of strong light on the growth and development of Mongolian oak seedlings, with the S2 treatment having the greatest effect. However, severe shading (S3) inhibited growth and development. A total of 3726 differentially expressed genes (DEGs) were detected in leaves under different shading treatments in RNA sequencing analysis. Among these, 1691, 3150, and 824 DEGs were detected in the Sck-S1, Sck-S2, and S1-S2 comparison groups, respectively. The different shading treatments determined common expression regulation pathways, including carotenoid biosynthesis, photosynthetic antenna proteins, and mitogen activated protein kinase (MAPK) signal transduction. Shading induced increases in gene expression levels in light harvesting complexes, which are related to changes in gene expression in the photosynthetic system, leading to changes in photosynthetic physiology. The expression levels of genes related to reactive oxygen species signal perception and activation enzymes were upregulated in Sck. Together, these findings revealed the response mechanisms of Mongolian oak seedlings to different shading levels at the physiological and molecular levels, providing a scientific basis and technical support for the cultivation and large-scale production of Mongolian oak seedlings.
]]>Forests doi: 10.3390/f15030536
Authors: Yan Liu Yadong Liu Shuanglei Qi Ziying Fan Yadan Xue Qingxuan Tang Zhengyuan Liu Xiaomin Zheng Chuangye Wu Benye Xi Jie Duan
Water is a vital resource for tree growth, and changes in plantation and canopy structure can affect stand transpiration (Ec), consequently influencing water use efficiency (WUE). Populus tomentosa is a fast-growing and productive timber species in China. In recent years, thinning combined with pruning has become a widely used silvicultural practice for timber management. However, its effect on water utilization has been less well studied. To address this gap, we designed experiments with two thinning intensities and three pruning treatments. Thermal dissipation probes were employed to monitor tree sap flow density (Js), and estimated Ec and canopy conductance (gc). We established a relationship between the canopy transpiration per unit leaf area (EL) and gc and climatic factors. Finally, we compared basal area increment (BAI) and WUE among treatments under different rainfall conditions. The results indicated that: (1) The pattern of transpiration changes was consistent at both the individual tree and stand level. (2) The combined effect of T1 (thinning intensity of 833 trees per hectare) and pruning reduced Ec, decreasing the sensitivity of tree transpiration to the climate, with no discernible impact on EL and gc. Conversely, T2 (thinning intensity of 416 trees per hectare) and pruning increased EL and gc but had no effect on Ec, enhancing the sensitivity of tree transpiration to the climate. The sensitivity of gc to VPD suggested a flexible stomatal regulation of transpiration under different combined thinning and pruning treatments. (3) Under T1, only P2 (4 m pruning from ground) promoted WUE, while pruning effects significantly reduced WUE under T2. Overall, the WUE of T2P0 (thinning intensity of 416 trees per hectare combined with no pruning) was significantly higher than that of the other treatments, and that of T1P0 (thinning intensity of 833 trees per hectare combined with no pruning) was significantly lower than that of the other treatments. Additionally, significant differences in Ec and BAI were observed among treatments under different rainfall conditions, with the promotion effect of Ec on BAI being more pronounced in the dry season.
]]>Forests doi: 10.3390/f15030537
Authors: Yao Li Chao Tan Wenxu Zhang Lu Wang Zhi Yang Yanming Fang Yong Yang Lingfeng Mao
Evergreen sclerophyllous oak forests (ESOFs) in southwestern China are a special vegetation type developed in response to the expansion of arid habitats after the uplift of the Himalayas. Here, we used chloroplast (cp) DNA and nuclear ribosomal (nr) DNA to investigate the fine-scale genetic variation patterns of six sympatric oaks (Quercus, Fagaceae) in the hot-dry valley ESOFs of the Jinsha River, southwestern China. Three cp genomes were assembled for each species. Nine cp genome haplotypes and 16 nrDNA haplotypes were identified based on single-nucleotide variants and indels. Our results demonstrated that discordance existed between the cpDNA and nrDNA phylogenies of the sclerophyllous oaks in section Ilex. The nrDNA phylogeny was consistent with species boundaries, while the cpDNA phylogeny was decoupled from taxonomy. Interspecific sharing of closely related cp genome haplotypes was detected between Quercus cocciferoides and the other two sclerophyllous oaks, Q. longispica and Q. franchetii. Specifically, Q. cocciferoides and Q. longispica sampled in a mixed stand exhibited two haplotypes that differed by a 9 bp indel. The local distribution of the two highly similar haplotypes suggested that they may have arisen from ancient introgression. Given that the two species have diverged for a long time, it is possible that the ancestral cp genome of one species was captured by another species through asymmetric introgression in early times, and an indel event occurred subsequently. Phylogenetic analyses using more previously published cp genome sequences indicated that Q. cocciferoides and Q. franchetii shared multiple cpDNA lineages of Ilex oaks, which may be caused by shared ancestral polymorphism and/or ancient introgression. Our study showed that at least three highly variable regions (ψycf1, ndhF-rpl32, and trnKUUU-rps16 or rpl32-trnLUAG) can distinguish the nine haplotypes identified by whole-cp genome sequences. These markers are useful for the evolutionary studies of the maternal lineages of oaks in hot-dry valley ESOFs.
]]>Forests doi: 10.3390/f15030535
Authors: Zhi Liang Xi Zhou Yinlong Li Min Zhou Xutao Yang Shengnan Zhang Jacob D. Wickham Qing-He Zhang Longwa Zhang
Carya illinoinensis (Wangenh.) K. Koch (Pecan), a deciduous tree native to North America, faces significant challenges from pests. This study investigated the insecticidal efficacy and food safety of using the broad-spectrum insecticide emamectin benzoate via trunk injection for potential pecan pest management. Injections were given at dosages of 0.4, 0.8, 1.6, and 2.4 mL/cm of tree diameter at breast height (DBH), and leaf samples were collected at 10, 30, 60, and 100 days post-injection, while fruit samples were obtained during the swelling, ripening, and harvest stages. We established an analytical method for the determination and quantification of emamectin benzoate content in pecans using ultra-performance liquid chromatography–mass spectrometry (UPLC-MS). Leaf emamectin benzoate content was significantly higher compared to nuts (p ≤ 0.036). The content in leaves following the four dosage treatments decreased over time and at 100 days was 0.1943/0.2799 mg/kg (upper crown/lower crown), 0.1910/0.3957 mg/kg, 0.3663/0.6235 mg/kg, and 1.3988/1.9123 mg/kg, respectively. The pesticide residues of 0.4 mL/cm and 0.8 mL/cm treatment groups in kernels at harvest time were 0.0016 mg/kg and 0.0039 mg/kg, respectively, below the latest European Union Regulation (0.005 mg/kg). All four dosage treatments (0.4, 0.8, 1.6, and 2.4 mL/cm of tree diameter at DBH) in the leaf feeding test caused significant mortalities of the fourth instar Hyphantria cunea (Drury) larvae. The mortality rates at 10 days post-injection were 64.7%, 73.3%, 79.3%, and 84.7%, respectively, while at 60 days post-injection, the rates were 26.0%, 47.3%, 53.7%, and 81.7%, respectively. In summary, this study successfully established a sensitive analytical method for the detection and quantification of trunk-injected emamectin benzoate residues in pecans and demonstrates its safety and effectiveness as a chemical control option against foliar pecan pest insects.
]]>Forests doi: 10.3390/f15030534
Authors: Pingyu Yan Lei Zhang Junfei Hao Guofei Sun Zhenyu Hu Jiaxing Wang Ruiqi Wang Zhixin Li Hanguo Zhang
To improve the ecological and economic benefits of Korean pine (Pinus koraiensis), we analysed and evaluated its germplasm resources. This promotes in-depth research and utilisation of germplasm resources, providing excellent genetic resources for Korean pine breeding. We performed genetic analysis based on morphological and physiological traits and nuclear SSR molecular marker data was performed by collecting 314 clones (5 ramets of each clone) of Korean pine from eight (8) locations within the Korean pine range. The core collection underwent testing and evaluation for representativeness using variable rate (VR), coincidence rate (CR), variance difference percentage (VD), mean difference percentage (MD), Shannon index (I), and other indicators. The results indicated significant differences in morphological and physiological traits among the populations. All traits had a coefficient of variation (CV) greater than 10%, except for the water content of the needles (WC), which had an average CV of 17.636%. The populations showed high overall genetic diversity, with the HL (Helong) population exhibiting the highest genetic diversity, with an Ne (number of effective alleles), I, and He (expected heterozygosity) of 3.171, 1.103, and 0.528, respectively. Genetic variation mainly originated from individuals within populations, while the variation between populations was relatively small, at only 3%. The population did not exhibit any distinct subpopulation structures and was mainly derived from two admixed gene pools. Six core sets were obtained using different sampling strategies, and subset 6 was identified as the core collection, consisting of 114 individuals, representing a selection rate of 36.31%. In conclusion, the most appropriate method for constructing the core collection of Korean pines is the M-strategy (maximizing the number of alleles), based on both phenotypic and molecular data. The resulting core collection effectively represents the genetic diversity of the entire population effectively.
]]>Forests doi: 10.3390/f15030533
Authors: Shangqin Lin Qingqing Wen Dasheng Wu Huajian Huang Xinyu Zheng
The assessment of a forest’s structure is pivotal in guiding effective forest management, conservation efforts, and ensuring sustainable development. However, traditional evaluation methods often focus on isolated forest parameters and incur substantial data acquisition costs. To address these limitations, this study introduces a cost-effective and innovative evaluation model that incorporates remote sensing imagery and machine learning algorithms. This model holistically considers the forest composition, the tree age structure, and spatial configuration. Using a comprehensive approach, the forest structure in Longquan City was evaluated at the stand level and categorized into three distinct categories: good, moderate, and poor. The construction of this evaluation model drew upon multiple data sources, namely Sentinel-2 imagery, digital elevation models (DEMs), and forest resource planning and design survey data. The model employed the Recursive Feature Elimination with Cross-Validation (RFECV) method for feature selection, alongside various machine learning algorithms. The key findings from this research are summarized as follows: The application of the RFECV method proved effective in eliminating irrelevant factors, reducing data dimensionality and, subsequently, enhancing the model’s generalizability; among the tested machine learning algorithms, the CatBoost model emerged as the most accurate and stable across all the datasets; specifically, the CatBoost model achieved an impressive overall accuracy of 88.07%, a kappa coefficient of 0.6833, and a recall rate of 76.86%. These results significantly surpass the classification precision of previous methods. The forest structure assessment of Longquan City revealed notable variations in the forest quality distribution. Notably, forests classified as “good” quality comprised 11.18% of the total, while “medium” quality forests constituted the majority at 76.77%. In contrast, “poor” quality forests accounted for a relatively minor proportion of the total, at 12.05%. The distribution findings provide valuable insights for targeted forest management and conservation strategies.
]]>Forests doi: 10.3390/f15030532
Authors: Robert Tatina Brice B. Hanberry John L. Willis
The southeastern United States was historically characterized by open forests featuring fire-adapted species before land-use change. We compared tree composition and densities of historical tree surveys (1802 to 1841) to contemporary tree surveys, with the application of a similarity metric, in the Coastal Plain ecological province of Mississippi, southeastern USA. We detected the boundary between historical pine and oak-pine open forests and differentiated historical and current forests. In the Coastal Plain, historical open forests converted from fire-tolerant longleaf pine (Pinus palustris) dominance, with pines comprising 88% of all trees, to loblolly (Pinus taeda) and slash (P. elliottii) pines within monocultures (45% of all trees). Wetland and successional tree species increased to 33% of all trees. Contemporary forests have greater tree densities, transitioning from closed woodlands (range of 168 to 268 trees ha−1) to closed forests (336 trees ha−1). In the ecotonal boundary of the northern Coastal Plain between historical pine and pine-oak woodlands, the pine component shifted over space from 88% to 34% of all trees due to a greater oak component. Fire-tolerant shortleaf pine and oak dominance converted to planted loblolly pine (52% of all trees), while successional tree species increased (20% of all trees). Historical tree densities represented woodlands (range of 144 to 204 trees ha−1) but developed into closed forests (400 trees ha−1). Historical Coastal Plain longleaf pine woodlands differed more from historical ecotonal oak-pine woodlands than contemporary forests differed from each other, demonstrating unique historical ecosystems and landscape-scale homogenization of ecosystems through forestation.
]]>Forests doi: 10.3390/f15030531
Authors: Ting Li Jun Hu Li Li Jin Liang Dandan Li Qing Liu
Given the importance of net primary productivity (NPP) as an indicator of ecosystem productivity and its role in the global carbon cycle, understanding the factors that influence its stability can greatly improve our understanding of shrubland ecosystems and their response to global change. Between 2015 and 2022, we visited most of the primary shrubland in China and surveyed 751 shrubland patches. We collected data on community structure (canopy cover), shrub and herb species diversity, and soil physicochemical properties (soil nitrogen content and soil phosphorus content). We also used remote sensing data to obtain NPP from 2001 to 2022. We quantified temporal trends in shrubland stability in China and used structural equation modeling to disentangle the direct and indirect effects of climate, soil, and shrub community structural properties. We found that 85.3% of China’s shrublands remained stable in terms of productivity from 2001 to 2022, 10.6% of the shrublands increased in stability, and 4.1% of the shrublands need to be alerted to a significant decrease in stability. These changes in stability were mainly related to precipitation changes. We found that changes in precipitation directly affected the stability of net productivity and also indirectly through changes in shrub cover and species richness. Some aspects of community structure moderated these effects. We further found that the portion of shrubland with an upward trend in stability did not have a significant correlation between the stability of net primary productivity and community structure and soil N. Instead, soil phosphorus was the largest direct influence.
]]>Forests doi: 10.3390/f15030530
Authors: Gwendolen J. Keller Dustin Bronson Robert A. Slesak Marcella A. Windmuller-Campione
Forested wetlands are common ecosystems within the Great Lakes region (Michigan, Minnesota, and Wisconsin), USA. Projected increases in extreme flooding events and shifting disturbance regimes create challenges for tree regeneration. Forest managers are considering the use of enrichment planting to increase tree species diversity, but limited information is available that quantifies the interactions between the flooding and shade tolerances of candidate tree species. We used a microcosm experiment to manipulate shade and flooding conditions to determine the effects on early survival, growth, and leaf gas exchange of 23 different tree species that vary in shade and flood tolerance. Seedlings were planted in pots and placed in 227 L tanks that were randomly assigned to light reduction (full sun, 40% and 70% reduced sunlight) and flood treatments (water levels of 0, 14, or 27 cm below the soil surface). In general, flooding treatments had a greater influence on seedling growth and leaf gas exchange rates than light reduction treatments. Of the species studied, bald cypress (Taxodium distichum (L.) Rich.) was the most flood-tolerant, but American sycamore (Platanus occidentalis L.) and river birch (Betula nigra L.) were also highly tolerant of flooding conditions throughout the entire growing season. The flood tolerances of the remaining species varied, but none were tolerant of water table depths within 14 cm of the soil surface for the entire growing season. Most species did not respond to the shade treatments in terms of early growth, survival, and leaf gas exchange. When considering species for planting in forested wetlands, matching the flood tolerance of candidate species to local site hydrology is an important step.
]]>Forests doi: 10.3390/f15030529
Authors: Xiaoqing Zhao Linhai Jing Gaoqiang Zhang Zhenzhou Zhu Haodong Liu Siyuan Ren
Accurate classification of forest stand is crucial for protection and management needs. However, forest stand classification remains a great challenge because of the high spectral and textural similarity of different tree species. Although existing studies have used multiple remote sensing data for forest identification, the effects of different spatial resolutions and combining multi-source remote sensing data for automatic complex forest stand identification using deep learning methods still require further exploration. Therefore, this study proposed an object-oriented convolutional neural network (OCNN) classification method, leveraging data from Sentinel-2, RapidEye, and LiDAR to explore classification accuracy of using OCNN to identify complex forest stands. The two red edge bands of Sentinel-2 were fused with RapidEye, and canopy height information provided by LiDAR point cloud was added. The results showed that increasing the red edge bands and canopy height information were effective in improving forest stand classification accuracy, and OCNN performed better in feature extraction than traditional object-oriented classification methods, including SVM, DTC, MLC, and KNN. The evaluation indicators show that ResNet_18 convolutional neural network model in the OCNN performed the best, with a forest stand classification accuracy of up to 85.68%.
]]>Forests doi: 10.3390/f15030528
Authors: Kexin Tang Liang He Jianbin Guo Qunou Jiang Long Wan
In the context of global warming, terrestrial ecosystems have undergone significant variations. China has implemented a variety of ecological engineering methods to enhance carbon stocks. However, understanding the spatial and temporal dynamics of carbon and water in drylands under climate change remains limited. Here, our research elucidates carbon and water dynamics in China’s drylands over the last two decades, with a focus on understanding spatial–temporal changes and the effects of ecological engineering on the carbon–water cycle. Furthermore, this study investigates the relationships among climate change, water use efficiency (WUE), and its components—Gross Primary Productivity (GPP) and Evapotranspiration (ET)—identifying key climatic drivers and assessing possible directions for enhancing WUE under changing climate conditions. Our research indicates that both GPP and ET have significantly increased over the past 20 years, with growth rates of 4.96 gC·m−2·yr−1 and 4.26 mm·yr−1, respectively. Meanwhile, WUE exhibited a slight declining trend, at a rate of −0.004 gC·mmH2O·yr−1. This confirms the positive impact of vegetation restoration efforts. We found that fluctuations in interannual WUE were influenced by human activities and climate change. Precipitation (Prec) was the key climatic factor driving the GPP increase. Both solar radiation (Solra) and Prec were crucial for the interannual variation of WUE. Interestingly, WUE was the main factor affecting GPP development. The decline in WUE in drylands is linked to interannual variability in WUE and increased Vapor Pressure Deficit (VPD) due to warming. Seasonal variations in how WUE responds to climatic factors were also observed. For instance, fall rainfall increased WUE, while spring rainfall decreased it. Fall WUE was highly sensitive to VPD. Spatially, we found higher WUE in China’s eastern and Xinjiang regions and lower in inland areas and the Tibetan Plateau. Geomorphologic factors and soil conditions were the main drivers of this spatial variability in WUE. Temperature (Tem), Solra, VPD, and relative humidity (Relah) also played significant roles. Our results show a generalized inverse persistence in WUE variability. This suggests a potential for increased WUE in the eastern regions and a risk of decreased WUE on the Tibetan Plateau. Addressing the threat of vegetation decline in arid regions, particularly within the Tibetan Plateau, is crucial. It is essential to adapt forestry practices to complement the carbon and water cycles in these landscapes.
]]>Forests doi: 10.3390/f15030527
Authors: Hang Qiao Caixia Liu Chenghua Deng Qi Sun Shaohong Deng Xun Duan Longsheng Chen Xiangbi Chen Yirong Su Yajun Hu
Soil nutrient transformation and the microbial metabolism are primarily regulated by soil microorganisms, including fungi and bacteria, which exhibit distinct growth patterns, energy substrate utilization, and survival strategies. Despite their significance, our understanding of the key microorganisms governing the soil microbial metabolism and multifunctionality in subtropical woodlands remains limited. To address this knowledge gap, we conducted a large-scale investigation and assessment of the soil microbial metabolic limitation and soil multifunctionality in Camellia oleifera Abel and Pinus massoniana Lamb. woodlands in subtropical China. Our results reveal that the microbial phosphorus limitation was more severe in C. oleifera compared to P. massoniana woodlands. Nonetheless, the pattern of carbon metabolic limitation for microbes and soil multifunctionality was similar in both types of woodland. Specifically, the microbial carbon limitation was positively associated with both bacterial and fungal richness, while the microbial phosphorus limitation was significantly correlated with fungi including the richness and community structure in the P. massoniana woodland. By contrast, we did not observe significant correlations between microbial metabolic limitation indices and microbial parameters in C. oleifera woodlands. Regarding soil multifunctionality, the results reveal a strong positive correlation between the soil multifunctionality and fungal community in both P. massoniana and C. oleifera woodlands. Furthermore, our structural equation modeling revealed that the soil fungal community, rather than the bacterial community, had a significant effect on the microbial metabolic limitation and soil multifunctionality. Overall, our study provides profound insights into the relative importance of bacterial and fungal communities in shaping the soil microbial metabolic limitation and soil multifunctionality in subtropical woodlands. The findings of our study have important implications for the management and conservation of subtropical woodlands.
]]>Forests doi: 10.3390/f15030526
Authors: Adefemi Adebisi Alade Christoph Hoette Holger Militz
Synergizing coating and wood modification is a promising concept to develop wood products that have multi-qualities that include excellent dimensional stability, durability, and weathering resistance. However, the nature of the modified substrate is a critical parameter for coating adhesion. Chemical modification of wood impacts the physicochemical properties of the wood, which could in turn impact the adhesion of coatings. Therefore, this study investigated the adhesion of seven different coatings to Pinus sylvestris L. woods chemically modified through esterification with acetic anhydride (acetylated), etherification with 1.3-dimethylol-4.5-dihydroxyethyleneurea (DMDHEU), and esterification with sorbitol/citric acid formulation (SorCA). The selected coatings include water-based and solvent-based examples with different binder constituents that include acrylate, alkyd, natural oil, and hybrids. Coating adhesion to the modified wood was evaluated in terms of crosscut resistance to detachment, wear-resistant hardness, and pull-off strength. Chemical modifications yielded positive impacts on coating adhesion compared to unmodified wood. Coatings adhered better to acetylated and DMDHEU-modified P. sylvestris wood than on SorCA-modified wood. Solvent-based coatings had higher adhesion strength on the acetylated, DMDHEU-modified, and unmodified woods than water-based coatings. On the other hand, water-based coatings mostly adhered better to SorCA-modified wood compared to solvent-based coating. Overall, the coating of chemically modified P. sylvestris wood is promising for the development of an enhanced wood protection system.
]]>Forests doi: 10.3390/f15030525
Authors: Wenai Liu Lifeng Li Yunhong Xue Qiuxia Liang Yancheng Tao Huiying Wu Weiguo Jiang
Sonneratia apetala Buch., an alien species with strong growth and adaptability, has been introduced and cultivated in Southeastern China. Meanwhile, Derris trifoliata Lour., native to coastal and riparian areas in Guangdong, Guangxi, and Fujian provinces, has experienced a rapid surge in population, impacting the health of mangrove ecosystems. Our research focuses on understanding the interactions between Oriental mangroves and D. trifoliata, particularly their proliferation and long-term symbiotic relationships. We investigated how Oriental mangrove proliferation promotes excessive D. trifoliata growth and explored the underlying mechanisms. In Leizhou Bay, Guangxi, the annual growth rate surged from 12.03% (2005–2015) to 55.36% (2015–2019), indicating a significant acceleration post-2015 and a concerning trend towards overgrowth. D. trifoliata failed to produce seeds on sea rockets or bulrushes, instead yielding 10.5 and 97.43 seeds/m2 on native red mangroves and Oriental mangroves, respectively. Along riverbanks, 68% of Oriental mangroves hosted D. trifoliata, and the suitable regions for these species overlapped significantly. Oriental mangroves reach 15 m tall with 10 × 10 m crown diameters, providing ample vine space, optimal photosynthesis conditions, sturdy support, and convenient dispersal routes. This study offers insights into introduced–native species interactions in mangrove ecosystems, with significance for management and preservation.
]]>Forests doi: 10.3390/f15030524
Authors: Yonglei Shi Zhihui Wang Guojun Zhang Xiaoyan Wei Wentao Ma Haoran Yu
Forests serve as the largest carbon reservoir in terrestrial ecosystems, playing a crucial role in mitigating global warming and achieving the goal of “carbon neutrality”. Forest biomass is intrinsically related to carbon sinks and sources in forest ecosystems, and thus, the accurate monitoring of forest biomass is of great significance in ensuring ecological security and maintaining the global carbon balance. Significantly, remote sensing is not only able to estimate forest biomass at a large spatial scale but does so quickly, accurately, and without loss. Moreover, it can obtain forest biomass in areas inaccessible to human beings, which have become the main data source for forest biomass estimation at present. For this reason, this study analyzes the current research status, research hotspots, and future research trends in the field of remote sensing monitoring of forest biomass based on 1678 forest biomass remote sensing monitoring results from 1985 to 2023 obtained from the Web of Science Core Collection database. The results showed that the following: (1) The number of publications showed an exponential upward trend from 1985 to 2023, with an average annual growth rate of 2.64%. The top ten journals contributed to 53.76% of the total number of publications and 52.89% of the total number of citations in the field. (2) In particular, Remote Sensing of Environment has maintained a leading position in the field for an extended period, boasting the highest impact factor. Additionally, the author Saatchi S. stands out with the highest total number of citations for articles. (3) Keyword clustering analysis revealed that the main research topics in the remote sensing monitoring of forest biomass can be categorized into the following: optical remote sensing, LiDAR remote sensing, SAR remote sensing, and carbon stock. The explosion of keywords in the last six years indicates that an increasing number of researchers are focusing on carbon, airborne LiDAR data, biomass mapping, and constructing optimal biomass models.
]]>Forests doi: 10.3390/f15030523
Authors: Yu Bao Xiao Liu Cong-Hua Feng Meng-Xue Niu Chao Liu Hou-Ling Wang Weilun Yin Xinli Xia
This review synthesizes the current understanding on the dynamic influence of light on the developmental morphology of woody plants. It explores the regulatory effects of photosynthesis and photomorphogenesis in response to varying light conditions including intensity, quality, and photoperiodicity, and their subsequent impact on plant growth and architecture. Additionally, this review elucidates the role of the circadian system in synchronizing internal rhythms with external light cycles, a process mediated by photoreceptors such as PHYTOCHROME A (PHYA) and PHYTOCHROME B (PHYB), which are pivotal for seasonal growth and dormancy in species like poplar. The molecular perspective is provided on the light-regulated transcription of genes, along with their influence on the plant’s growth cycles and seasonal adaptions. Furthermore, the interactive role of plant hormones, including auxin, ethylene, and abscisic acid (ABA), is explored in the context of light signal transduction and its subsequent effect on plant physiology. By providing a comprehensive view of the light-dependent mechanisms that govern woody plant growth, this review contributes to our understanding of plant adaptation strategies and informs approaches to enhance forestry production and biodiversity conservation in the face of climate change.
]]>Forests doi: 10.3390/f15030522
Authors: Jinmei Xing Chun Hu Chenggong Song Keqin Wang Yali Song
Nitrogen (N) deposition influences litter decomposition and its water-holding capacity in forest ecosystems. Water conservation remains a priority, so understanding these interactions is vital for managing forests, especially in the Yunnan Plateau region. This study aimed to investigate the effects of simulated N deposition on litter decomposition and water-holding capacity in the Evergreen broad-leaf and Quercus aquifolioides forest in the central Yunnan Plateau. Indoor flooding experiments were performed alongside varied nitrogen deposition treatments. Litter decomposition rates under these treatments were evaluated using the Olson model. In the decomposition study, the N treatments in the Evergreen broad-leaved forest increased the remaining mass by 4.75%–17.50% and 2.09%–16.36% compared with the control (20.97 ± 0.44% and 42.43 ± 0.47%), while in the Quercus aquifolioides forest, the remaining mass of leaves and twigs decreased by 5.00% and 0.70% in the LN treatment compared with the control (35.47 ± 0.39% and 44.10 ± 1.18%) and the MN and HN treatments increased by 2.55%–8.13% and 5.61%–11.28%, respectively. Effects of increased N deposition on litter decomposition changed from promoting to inhibiting, as low N sped up decomposition but higher levels inhibited it. Additionally, N boosted the water-holding capacity of litter, especially in leaves. The litter from both forests displayed a notable ability to absorb water. Nitrogen deposition modulates litter decomposition and water retention properties. Specifically, high nitrogen deposition increases litter water-holding capacity by inhibiting the rate of litter decomposition, which in turn alters its mass remaining rate, lignin, and cellulose remaining rates. Efficient management of the studied forests leveraging nitrogen deposition can boost their water conservation potential, aiding in atmospheric precipitation absorption and surface runoff regulation.
]]>Forests doi: 10.3390/f15030521
Authors: Yujun Wang Yan Zhang Hongbo Yang Jiamei Niu Xiaodong Chen
Non-grain agricultural land use (NGALU) could be an alternative to payments for ecosystem services (PES) to achieve ecosystem benefits, given their joint contribution to forest transition. Unraveling the correlation between PES and NGALU can enhance cost-effective decisions. While farmland abandonment and non-grain cash crops (NGCCs) plantation are two main manifestations of NGALU, previous studies have primarily assessed the effects of PES on farmland abandonment. Little is known about the effects of PES on NGCC planting. This study evaluated the effects of China’s two nationwide PES programs (i.e., the Grain to Green Program, GTGP, and the Ecological Welfare Forest Program, EWFP) on NGALU in the Black River Basin of Shaanxi province. The study found a wide adoption of NGALU, with 52% of households adopting NGALU. The total area of NGALU is more than half of the afforested area through the GTGP. A quarter of the NGALU area is abandoned farmland, while the remaining NGALU area is planted with NGCCs. The two PES programs did not have effects on NGCC planting, but reduced farmland abandonment. Engagement in labor migration and local non-farm employment increased NGALU, while livestock breeding and farmland area reduced NGALU. Furthermore, the large area and unfavorable geographical conditions of farmland parcels promoted NGALU. These results highlight the important implications of leveraging NGALU to boost ecological gains from conservation investments.
]]>Forests doi: 10.3390/f15030520
Authors: Austin M. Thomas Mark V. Coggeshall Philip A. O’Connor C. Dana Nelson
Climate change poses a significant threat to the resilience and sustainability of forest ecosystems. This study examines the performance of white oak (Quercus alba, L.) across a range of provenances in a common garden planting, focusing on the species’ response to climatic variables and the potential role of assisted migration in forest management. We evaluated the survival and growth rates of white oak provenances originating from various points along a latitudinal gradient over a period of 40 years. These provenances were planted in a common garden situated near the midpoint of this latitudinal gradient, where we also monitored their phenological traits, such as budburst and leaf senescence. The results revealed substantial variation in phenological responses and growth patterns among the provenances, with southern provenances demonstrating faster growth and later senescence relative to local sources, with limited impact on survival. In contrast, the northern provenances demonstrated slower growth, resulting in later-aged competition-induced mortality. The findings highlight the necessity of incorporating genetic diversity into white oak reforestation and conservation strategies, as the local provenance may no longer be the most suitable option for current and future conditions. We advocate for a nuanced approach to forest management that leverages genetic insights to optimize seed source selection for reforestation, fostering resilient forest landscapes in the face of ongoing climate shifts.
]]>Forests doi: 10.3390/f15030519
Authors: Hongling Lin Jieru Xu Kunlin Wu Chenxiao Gong Yuying Jie Bo Yang Jinhui Chen
Bougainvillea, an evergreen climbing shrub of the Nyctaginaceae family, holds significant ornamental, economic, and medicinal value. Bougainvillea glabra ‘New River’ is widely used in landscapes due to its strong adaptability to the environment, abundance of flowers, and frequent flowering. Traditionally, Bougainvillea glabra ‘New River’ cultivation has relied on methods such as cuttings or grafting, with limited research on in vitro tissue culture propagation. This study aimed to optimize the tissue culture system, exploring a combination of plant growth regulators (PGRs) for Bougainvillea regeneration from in vitro stem segments. The Murashige and Skoog (MS) medium supplemented with indole-3-butyric acid (IBA), 6-benzylaminopurine (6-BA), and 1-naphthlcetic acid (NAA) was employed. The optimal sterilization of Bougainvillea stem segments involved a 30 s treatment with 75% alcohol and 10 min with 1% NaClO. The synergistic effect of 0.1 mg·L−1 of NAA and 2.5 mg·L−1 of 6-BA maximized the shoot sprouting frequency, while 2.5 mg·L−1 of 6-BA and 0.1 mg·L−1 of NAA produced the maximum shoots. Furthermore, 1.5 mg·L−1 of IBA and 0.1 mg·L−1 of NAA induced the highest rooting levels. This work demonstrates the successful adaptation of a greenhouse environment to efficiently regenerate plants in vitro from stem segments. This approach allows for the mass production of Bougainvillea glabra ‘New River’.
]]>Forests doi: 10.3390/f15030518
Authors: Jian Zheng Zilong Li Bohong Zheng
Greenery impacts the urban thermal environment, but the benefits of the three-dimensional green volume of space have not been effectively evaluated. In this paper, we analyzed the impact of 3D greenery on urban heat island intensity and thermal comfort in residential areas from the perspective of the green plot ratio (GPR). We selected a typical residential area, set up simulation models, and then analyzed the effect of different GPR values on the outdoor thermal environment using the validated ENVI-MET simulation. The results showed that increasing GPR in residential areas can effectively reduce the intensity of urban heat island and improve thermal comfort. When the GPR reaches 0.5 and 1.5, the thermal comfort level of the building overhead space and the north–south street space decreases from “very strong thermal stress” to “strong thermal stress”. When the GPR reaches 2.5, the outdoor thermal comfort of the east–west street space and courtyard space is reduced to “hot”. When the GPR is higher than 0.5, the urban heat island intensity in the north–south street space decreases by one level, from “very strong” to “strong”. When the GPR reaches 3.5, all four types of spaces have “moderate” urban heat island intensity. Increased GPR exacerbates urban heat island intensity to some extent and worsens outdoor thermal comfort due to the nocturnal insulating effect of plants. Based on the results, the study proposes the bottom-line control of the GPR index from the perspective of urban heat island mitigation and thermal comfort improvement. This paper points out the benefits of GPR in residential areas in improving the human environment, which is of great practical value for developing urban residential environment from “increasing quantity” to “improving quality”.
]]>Forests doi: 10.3390/f15030517
Authors: Zefu Zhang Kangning Xiong Yu Zhang Youze Ning
Karst desertification (KD) is a phenomenon in which the surface of the karst region presents a landscape similar to desertification, which restricts the social development of the karst region. How to develop values based on karst desertification control is the focus of current research, with the continuous promotion of karst desertification control (KDC). Planted forests for KDC are an important part of the value realization of ecological products (EPs) and ecological industry (EI) in karst areas. The statistical analysis of 265 relevant papers in this paper shows the following: (1) the literature focuses on EP and EI research; (2) the overall research shows a year-on-year growth trend. It includes three stages: budding (2001–2006), fluctuating growth (2007–2015) and rapid development (2016–2023), with 6, 58 and 211 articles published in each stage, respectively; (3) China is the country with the largest number of articles published, followed by the United States and then Canada, accounting for 47.74%, 11.93% and 6.17%. This paper summarizes the landmark results and key scientific issues to be solved in the study directions of EP supply capacity, EP value accounting, eco-products value realization (EPVR) and EI, taking into account the above results.
]]>Forests doi: 10.3390/f15030516
Authors: Xiaomei Liao Xuan Fang Xin Gao Songlin Yi Yongdong Zhou
High-intensity microwave (HIMW) treatment is a time-saving and environmentally friendly method widely applied in the wood processing industry. It enhances wood permeability, making it suitable for drying and impregnation modification. This study aimed to investigate the effects of HIMW on macroscopic and microscopic cracks, tracheid cell wall damage, and the chemical structure of Chinese fir [Cunninghamia lanceolata (Lamb.) Hook] wood. Through the use of a camera, optical microscope, scanning electron microscope, transmission electron microscope, Fourier-transform infrared spectroscopy, and X-ray diffraction, the morphology of cracks, cell wall damage, the chemical composition of the cell wall, and the crystalline structure of cellulose treated with HIMW were examined and analyzed. The results revealed that the initial moisture content (MC) and microwave energy density (MWED) significantly influenced the crack characteristics and cell wall structure and slightly influenced the chemical composition and crystalline structure of cellulose of the Chinese fir cell wall. HIMW treatment can produce different characteristics of wood cracks. The size and number of cracks were significantly increased with the increase in MWED, and more cracks were found in low MC. Microcracks caused by HIMW treatment tended to initiate at the ray parenchyma, resulting in the stripping of ray cells along its radial direction. Meanwhile, the cracking of adjacent cell junctions, the rupturing of the pit margo and pit torus, and cell wall parts tearing along the direction of microfibers occurred as a result of the HIMW treatment. The most severe damage to the cell walls occurred at the interface of S1/S2, S1, and ML layers, and the cell walls were torn in the S2 layer. There were no significant changes in the FTIR spectra of the HIMW treatment samples. Hemicellulose degradation occurred first, which increased with the increase in MWED. The recrystallization of cellulose and the lignin content increased because of the change in the aromatic C=O groups. As MWED increased, both the crystallinity index (CI) and cellulose crystal width (D200) of the samples that underwent HIMW treatment increased accordingly, and the number of low-MC samples was greater than that of the high-MC samples. The findings contribute to understanding the crack characteristics and damage mechanism induced by HIMW treatment on wood. This study provides valuable insights into regulating the effects of HIMW treatment and expanding its application in wood processing, such as wood drying and functionalized impregnation, according to the specific end-use requirements.
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