Forests doi: 10.3390/f15030554
Authors: Nathan Kasanda Mukendi Héritier Khoji Muteya Dieu-donné N’tambwe Nghonda Fabio Berti Yannick Useni Sikuzani Laurent Ngoy Ndjibu Jean-Paul Katond Mbay Jules Nkulu Mwine 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 Jiuxiu 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.
]]>Forests doi: 10.3390/f15030515
Authors: Wenxue Sun Qianqian Li Bin Qiao Kaitao Jia Chunying Li Chunjian Zhao
Plant–soil feedback (PSF) was initially developed in the field of agricultural practices. In recent years, PSF has been extended to various ecosystems. Root exudates, essential for the exchange of materials, energy, and information at the plant–soil interface, significantly influence PSF. However, how PSF is driven by root secretions and the role of these secretions in different PSF pathways still needs to be further explored, particularly in forest ecosystems. Soil nutrients, microbial communities, and nematodes are important research topics in the process of PSF driven by root exudates. Investigating these aspects driven by root exudates provides valuable insights into the complex interactions both above ground and below the surface. This research can offer theoretical support and guidance for building stable, healthy, and sustainable forest ecosystems in the future.
]]>Forests doi: 10.3390/f15030514
Authors: Wenbo Wang Yuanyuan Yang Jinge Li Pengtu Bu Aijun Lu Hao Wang Wenxing He Ramon Santos Bermudez Jian Feng
Fertilization is an important measure to quickly supplement the soil nutrients required for plantation productivity. However, the response patterns of the microbial community and functional taxa in Larix plantation root, rhizosphere, and bulk soil to short-term and consecutive fertilization have rarely been reported. In this study, we assessed Larix root, rhizosphere, and bulk soil microbial community on days 0, 5, 15, and 30 after the first inorganic fertilization and after three consecutive years of fertilization. The bacterial 16S and fungal ITS high-throughput sequencing technology were used to monitor changes in microbial community composition and potential functional groups, as well as changes in soil nutrient content and enzyme activity to evaluate the status of plantation soil productivity. Consecutive fertilization treatment significantly increased the available nitrogen, phosphorus, and potassium (NPK) content and soil enzyme activity. The nonmetric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM) results showed that there were significant differences in microbial community composition in root samples, rhizosphere soil, and bulk soil samples. The dominant microbial taxa were different between root and soil microbial community composition. Consecutive fertilization treatment had little effect on endophytic microbial community but significantly increased the abundance of Gaiellales in rhizosphere soil and Mortierella in bulk soil. The redundancy analysis (RDA) and co-occurrence network analyses showed that Gaiellales and Mortierellales had significant positive correlations with soil nutrient content and enzyme activity. The fungal functional group compositions were significantly affected by consecutive fertilization treatment and the proportions of ectomycorrhizal and saprotroph significantly decreased, but the proportion of endophyte significantly increased in bulk soil samples. Our results suggested that consecutive fertilization may promote soil nutrient availability by increasing the abundance of Gaiellales and Mortierella. Consecutive fertilization maintained the balance of the soil microbiota under Larix plantation and had a positive effect on promoting soil nutrient availability. This study provided a theoretical basis for consecutive fertilization to promote soil nutrient availability through specific microbial groups.
]]>Forests doi: 10.3390/f15030513
Authors: Emmanuel Chukwudi Ekeoma Mark Sterling Nicole Metje John Spink Niall Farrelly Owen Fenton
Forest preservation and management are paramount for sustainable mitigation of climate change, timber production, and the economy. However, the potential of trees and forests to provide these benefits to the ecosystem is hampered by natural phenomena such as windthrow and anthropogenic activities. The aim of the current research was to undertake a critical thematic review (from 1983 to 2023) informed by a bibliometric analysis of existing literature on tree stability. The results revealed an increase in tree stability research between 2019 and 2022, with the USA, France, and Italy leading in research output, while Scotland and England notably demonstrated high research influence despite fewer publications. A keyword analysis showed that tree stability can be divided into four themes: tree species, architecture, anchorage, and environmental factors. Prominent studies on tree stability have focused on root anchorage. However, more recently, there has been a growing emphasis on urban forestry and disease-induced tree damage, underscoring a shift towards climate change and diversity research. It was concluded that considerable knowledge gaps still exist; that greater geographic diversification of research is needed and should include tropical and sub-tropical regions; that research relating to a wider range of soil types (and textures) should be conducted; and that a greater emphasis on large-scale physical modelling is required. Data and knowledge produced from these areas will improve our collective understanding of tree stability and therefore help decision makers and practitioners manage forestry resources in a more sustainable way into the future.
]]>Forests doi: 10.3390/f15030512
Authors: Yanchun Jing Yongyu Ren Shuwen Zhang Xiangyang Kang
Leaves are crucial photosynthetic plant organs. The development of poplar leaves has spatio-temporal specificity and it is of great significance to study the single-cell transcription atlas of leaves to reveal the temporal regulation of gene expression in different cell types. Here, single-cell RNA sequencing was performed on 17,768 tender leaf and 5846 functional leaf cells of Poplar 84K to construct a transcriptome atlas and developmental trajectory. The results showed that there were five and six cell types in tender and functional leaves, respectively. According to a pseudo-time trajectory analysis and the clustering of expressed genes into different cell types, the development of tender and functional leaves was divided into two temporal stages. Tender leaf epidermal cells developed earliest and were enriched with genes related to cell division and growth, indicating that tender leaves were in the stage of cell expansion and functional differentiation. Functional leaf palisade mesophyll cells were enriched with genes related to photosynthesis and carbon metabolism and cell types performing different functions tended to mature, indicating that functional leaves were in the stage of leaf development and the initial formation of photosynthesis. Our in-depth analysis of the transcriptional regulation at the single-cell level during leaf development provides an important basis for studying the mechanisms involved in cell differentiation and leaf development in poplar as well as other plants.
]]>Forests doi: 10.3390/f15030511
Authors: Valentyna Meshkova Oleksandr Borysenko Tetiana Kucheryavenko Natalia Vysotska Yuriy Skrylnyk Kateryna Davydenko Jaroslav Holusa
The Emerald ash borer (EAB), Agrilus planipennis Fairmaire, 1888 (Coleoptera: Buprestidae), an invasive phloem-boring beetle, was first detected in the Luhansk Region of Ukraine in 2019. Subsequently, it rapidly expanded its presence to encompass a significant portion of the Kharkiv region and the parks of Kyiv. Previous research has established that the climatic conditions in Luhansk and its neighboring regions are conducive to the EAB, and the absence of a host plant (Fraxinus sp.) does not act as a deterrent to the pest’s expansion in Ukraine. Recognizing the urgency of identifying infested trees, our current research aimed to identify the most attractive EAB forest subcompartments based on forest site conditions and stand structure. Utilizing the MaxEnt model, we achieved an average performance in predicting the potential distribution of the EAB (AUC = 0.842). The six most impactful variables, contributing to 88.2% of the model, include “age of trees, years”, “area of forest subcompartment, ha”, “mean height of trees, m”, “proportion of Fraxinus excelsior in the stand composition, %”, “hygrotope index (humidity level), point”, and “number of neighboring-non-forest subcompartments”. Most likely, EAB occurrence is expected in the driest forest site conditions; the well-lit and warmed-up parts of stands, in particular; small subcompartments surrounded by non-forest landscapes; and forest shelter belts near roads and fields. However, the data obtained can be considered preliminary. To enhance the accuracy of our forecasting, it may be imperative to consider data on road localization, along which the pest can spread passively, as well as dominant wind speed.
]]>Forests doi: 10.3390/f15030510
Authors: Tancredo Souza Mário Dobner Diego Silva Batista Damiana Justino Araujo Gislaine dos Santos Nascimento Lucas Jónatan Rodrigues da Silva
Different site quality levels in Araucaria angustifolia (Bert.) O. Kuntze plantations may influence the soil organisms and the interaction between litter and soil chemical properties by providing habitats and nutrients in different pathways. Our aim here was to understand the effect of site quality level in the interaction among litter, soil–solid phase, and organism assemblage on A. angustifolia, Campo Belo de Sul, Santa Catarina, Southern Brazil. In the low site quality, the litter deposition, litter K content, litter Ca content, soil organic matter, soil P content, soil K content, and soil exchangeable Ca reduced by 50.50, 49.54, 11.89, 20.51, 11.74, 61.18, and 35.18%, respectively, when compared to the high site quality. Nonmetric multidimensional scaling (NMDS) grouped the influence of site quality degree into three groups, considering the dissimilarities among soil organisms. The ordination of the soil organisms, richness, and Shannon’s diversity in each studied site quality degree had a stress value of 0.08. The structural equation models showed that the loss of site quality had a negative relationship with soil organism assemblage and soil and litter compartments. Our study highlights the fact that a fertile soil, a soil enriched in organisms, and enough litter support the forest productivity.
]]>Forests doi: 10.3390/f15030509
Authors: Atmawi Darwis Byantara Darsan Purusatama Apri Heri Iswanto Nam-Hun Kim Rudi Hartono Arida Susilowati
This study investigated the qualitative anatomical characteristics and fiber quality of tapped Styrax sumatrana wood to facilitate its further utilization. The transverse surface of the tapped S. sumatrana was light or greyish brown in the sapwood and reddish brown in the heartwood. The resin canals of the tapped wood were formed along the growth rings at the boundaries between the heartwood and sapwood. Furthermore, microscopic analyses revealed an irregular outline and rounded epithelial cells at the edges of the intercellular traumatic canal (TC). Approximately 8–16 epithelial cells surrounded the resin canals. The fibers in the tapped S. sumatrana were generally thin-walled, whereas those near the TC were thick-walled. Moreover, S. sumatrana were diffuse-porous and exhibited intermediately distinct or indistinct growth ring boundaries. The vessels were mainly radial multiples and clusters of 3–5. In addition, they showed a diagonal-to-radial pattern arrangement and a few tangential bands. Deposits were observed in some vessels in the tapped part but were absent in the untapped part. The fiber length of the tapped S. sumatrana wood was classified as moderate to extensive and categorized as second-grade pulp quality. Finally, the cell walls were classified as thin to moderate.
]]>Forests doi: 10.3390/f15030508
Authors: Peipei Guo Yuebo Su Xu Sun Chengtang Liu Bowen Cui Xiangyu Xu Zhiyun Ouyang Xiaoke Wang
Ground-level ozone (O3) pollution has been a severe environmental and health problem for decades. The importance of biogenic volatile organic compounds (BVOCs) in the formation of tropospheric photochemistry O3 has been highlighted, especially in areas of rapid urbanization. We conducted simultaneous measurements of trace gases, including NO, NOX, O3, and BVOCs (i.e., isoprene and α-pinene), in the urban and rural forest areas of Beijing to determine the relationships between them. The results highlight the differences between the urban and rural forest areas of Beijing in terms of ambient air concentrations of BVOCs and O3, and the interrelationships between BVOCs, NOX, and ozone were quantified. Moreover, the isoprene concentration was found to be higher in the atmosphere of the urban site than of the rural site, which had higher α-pinene concentrations and higher O3 concentrations. The NOX concentration was higher at the urban site than at the rural site, and there was a significant exponential relationship between NOX and O3 at the urban site, indicating that the impact of NOx on O3 at the urban site was greater than that at the rural site. The O3 concentration increased with rising isoprene and α-pinene in both sites. In the case of substantially increased BVOC concentrations, declining NOX concentrations strongly promote the formation of O3. Consideration should be given to planting tree species with low-BVOC emissions, as they are crucial for mitigating O3 pollution in urban areas. Additionally, the relationships between BVOCs, NOX, and O3 should be considered in policymaking related to O3 control.
]]>Forests doi: 10.3390/f15030507
Authors: Carlos Augusto Zangrando Toneli Fernando Paiva Scardua Rosana de Carvalho Cristo Martins Eraldo Aparecido Trondoli Matricardi Andressa Ribeiro Antonio Carlos Ferraz Filho
Adaptations to climate change rely on understanding the dynamics of plant biomass stocks on the planet. The high levels of deforestation in Cerrado have transformed this biome into the second-largest Brazilian source of carbon emissions. The objective of this study was to develop a method to accurately estimate aboveground and total biomass values among shrublands, savannas, and forests located in the Cerrado biome using an allometric equation adjusted from canopy height obtained through optical and laser sensors. The results show similarity between the estimates employed by our method and the data found in the literature review for different phytophysiognomies in the Cerrado biome. Shrubland formations showed higher biomass estimation uncertainties due to the discontinuity of isolated trees and the lower canopy height when compared to more clustered tree canopies in savannas and taller canopies in forests. Aboveground biomass estimates are related to expansion factors, and specific maps were developed for each compartment by root, litter, and necromass. The sum of these compartments is presented in the aboveground and below forest biomass map. This study presents, for the first time, the mapping of total biomass in 10 m pixels of all regions of the Cerrado biome.
]]>Forests doi: 10.3390/f15030506
Authors: Jiawei Liu Boxiang Yang Mingshi Li Da Xu
Forest and its dynamics are of great significance for accurately estimating regional carbon sequestration, emissions and carbon sink capacity. In this work, an efficient framework that integrates remote sensing, deep learning and statistical modeling was proposed to extract forest change information and then derive forest carbon storage dynamics during the period 2017 to 2020 in Jiangning District, Nanjing, Eastern China. Firstly, the panchromatic band and multi-spectral bands of GF-1 images were fused by using four different methods; Secondly, an improved Mask-RCNN integrated with Swin Transformer was devised to extract forest distribution information in 2020. Finally, by using the substitution strategy of space for time in the 2017 Forest Management and Planning Inventory (FMPI) data, local carbon density allometric growth equations were fitted by coniferous forest and broad-leaved forest types and compared, and the optimal fitting was accordingly determined, followed by the measurements of forest-change-induced carbon storage dynamics. The results indicated that the improved Mask-RCNN synergizing with the Swin Transformer gained an overall accuracy of 93.9% when mapping the local forest types. The carbon storage of forest standing woods was calculated at 1,449,400 tons in 2020, increased by 14.59% relative to that of 2017. This analysis provides a technical reference for monitoring forest change and lays a data foundation for local agencies to formulate forest management policies in the process of achieving dual-carbon goals.
]]>Forests doi: 10.3390/f15030505
Authors: Yuanmei Zhang Yan Lu Guili Sun Li Li Zhihao Zhang Xiaoguo Zhou
The Tarim Basin is located in an arid inland area; the ecological environment is fragile, and it is extremely sensitive to climate change. For the purpose of studying dynamic changes in the vegetation response of vegetation in the Tarim Basin to extreme climate, this study used the Vegetation Ecological Quality Index (EQI) as a vegetation indicator and calculated 12 extreme climate indices using Rclimdex. Pearson correlation analysis was used to explore the relationship between EQI values and various extreme climate indices at both inter-annual and intra-annual scales. Additionally, geographic detector analysis was employed to examine the single and interactive effects of extreme climate on the EQI for different vegetation types. The following was found: (1) During 2000–2022, the EQI showed an upward trend in the Tarim Basin, and the increase in agricultural vegetation was the fastest. (2) Since 2000, the extreme warm temperature indices have risen, whereas the extreme cold temperature indices have declined. The warming rate of nighttime temperatures exceeds that of daytime, and the extreme precipitation rises intensively. Simultaneously, continuous dry days have also increased. (3) On an inter-annual scale, the EQI is primarily negatively correlated with the most extreme warm temperature indices, while it is positively correlated with extreme cold temperatures and extreme precipitation indices. On an intra-annual scale, there is an obvious regional concentration in the correlation between the EQI and extreme climate indices. The diurnal temperature range (DTR) and cold daytimes (TX10P) have inhibitory and promoting effects on areas with high and low EQI, respectively. The extremum indices, temperature warm indices, and precipitation intensity indices have a promoting effect on areas with a high EQI and an inhibiting effect on areas with a low EQI. The interaction between extreme climate indices has a greater impact on the EQI than the effect of a single extreme climate index, especially with a significant impact on forests and shrubs. This study provides a reference for the early warning of meteorological disasters, ecosystem protection, and sustainable management in the Tarim Basin.
]]>Forests doi: 10.3390/f15030504
Authors: Yiqing Qi Ziqiang Zhang Yue Sun Liming Shen Jianlin Han
Wood staining is a crucial technique for enhancing the decorative effect of wood. Different mordants and mordant processes can influence the staining effect of wood. In this study, three types of mordants and mordant methods were selected to improve the color difference and colorfastness to the washing of poplar veneer, using green peanut pigment as the dye. An orthogonal test was conducted to investigate the effects of mordant temperature, mordant time, and mordant concentration on color difference and colorfastness to washing. Range and variance analysis were employed to determine these properties’ main factors. A fuzzy comprehensive evaluation method was used to evaluate and optimize the color difference value and colorfastness of washing. The results revealed that all three factors had significant impacts on both color difference and colorfastness to washing during the process of mordant staining. The optimal process conditions (temperature, concentration, time) for achieving desirable staining effects on poplar veneer were determined as 50 °C, 0.8%, and 2 h, respectively. Furthermore, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses demonstrated that the dye formed complexes with poplar wood, enabling it to adhere to wood grain apertures and tube walls effectively. Mordant treatment increased the crystallinity of stained wood significantly while improving its overall staining performance considerably. This study provides substantial data support for future optimization processes involving natural pigment coal staining in wood.
]]>Forests doi: 10.3390/f15030503
Authors: Hyeon Kwon Ahn Huicheul Jung Chul-Hee Lim
The frequency of forest fires worldwide has increased recently due to climate change, leading to severe and widespread damage. In this study, we investigate potential changes in the fire susceptibility of areas in South Korea arising from climate change. We constructed a dataset of large-scale forest fires from the past decade and employed it in machine learning models that integrate climatic, socioeconomic, and environmental variables to assess the risk of forest fires. According to the results of these models, the eastern region is identified as highly vulnerable to forest fires during the baseline period, while the western region is classified as relatively safe. However, in the future, certain areas along the western coast are predicted to become more susceptible to forest fires. Consequently, as climate change continues, the risk of domestic forest fires is expected to increase, leading to the need for proactive prevention measures and careful management. This study contributes to the understanding of forest fire occurrences under diverse climate scenarios.
]]>Forests doi: 10.3390/f15030502
Authors: Yunting Huang Kangning Xiong Jie Xiao
The ongoing degradation of fragile ecosystems increasingly diminishes the availability of natural resources. Consequently, the conservation and utilization of ecosystem assets have emerged as a focal point of global research. This study focuses on integrating agroforestry ecosystem assets (AEA) with their capacity to provide ecosystem services, aiming to explore their interconnections and enhance their optimization. We employed a comprehensive literature review method, utilizing the Scopus database to select, analyze, and include 61 pertinent studies on AEA globally. The systematic literature review results show the following: (1) The overall number of published papers is showing an upward trend, indicating that research in this field is gradually expanding. The geographical focus of the literature is primarily in Europe and Asia, with academic institutions being the main contributors to this research. (2) Landmark research findings are mainly concentrated in the areas of identification, quantitative assessment, and decision management. Among these, quantitative assessment is the main focus, while the research on identification, decision management, and influencing factors is relatively limited and explores the relevant key scientific questions. (3) The above information highlights the key areas for improvement in the karst desertification control agroforestry ecosystem, focusing on two aspects: fragile habitats and human–land relationships. Furthermore, this review furnishes essential recommendations for agroforestry practitioners and policymakers across various regions, emphasizing the critical need to thoroughly evaluate and leverage the connections between the quantity and quality of ecosystem assets. Such an approach is pivotal for facilitating the strategic restructuring and optimization of agroforestry ecosystems. This, in turn, aims to elevate the sustainability of AEA utilization and enhance their ability to provide ecosystem services (ES).
]]>Forests doi: 10.3390/f15030501
Authors: Jing Liu Xiaoying Li Tao Xu Yilun Han Jingtao Li Yang Shen Kui Chen
The frequency of forest fires has increased dramatically due to climate change. The occurrence of forest fires affects the carbon and nitrogen cycles and react to climate change to form a positive feedback mechanism. These effects further impact the distribution of microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) and the soil microbial community structure. In addition, permafrost degradation can significantly affect the microorganisms in the soil. Based on these findings, this review examines the effects of fire intensity and post-fire recovery time on permafrost, the soil microbial community, MBC, MBN, and their interrelationships. This review demonstrated that (1) fires alter the condition of surface vegetation, reduce the organic layer thickness, redistribute snow, accelerate permafrost degradation, and even lead to permanent changes, where the restoration of the pre-fire state would require several decades or even centuries; (2) soil microbial community structure, soil MBC, and MBN negatively correlate with fire intensity, and the effects become more pronounced with increasing fire intensity; and (3) the structural diversity and stability of the soil microbial community were improved with time, and the amount of MBC and MBN increases as the years after a fire go by; it would still take more than ten years to recover to the pre-fire level. However, the relationship between permafrost degradation and soil microbes after forest fires is still unclear due to a lack of quantitative research on the mechanisms underlying the changes in soil microorganisms resulting from fire-induced permafrost degradation. Therefore, expanding quantitative studies and analyses of the mechanisms of interactions between forest fires, permafrost, and soil microorganisms can provide a scientific basis for understanding ecosystem carbon pools and dual-carbon targets in Arctic–boreal permafrost regions.
]]>Forests doi: 10.3390/f15030500
Authors: Malluri Goñas Nilton B. Rojas-Briceño Darwin Gómez Fernández Daniel Iliquín Trigoso Nilton Atalaya Marin Verónica Cajas Bravo Jorge R. Díaz-Valderrama Jorge L. Maicelo-Quintana Manuel Oliva-Cruz
Currently, the economic profitability of cocoa is being affected by the increasing incidence of pests, low selling prices, high production costs, and the presence of cadmium in cocoa farms, posing a potential risk of crop abandonment. Therefore, the objective of the present research was to evaluate the economic profitability of carbon sequestration of fine-aroma cacao agroforestry systems in Amazonas, Peru, using the economic indicators of NPV, EIRR, and the benefit–cost ratio. For this purpose, 53 small cocoa producers of the APROCAM cooperative were involved, from which data were obtained on the general characteristics of the production system, production and maintenance costs, indirect costs, and administrative costs; in addition, the costs of implementation and maintenance of an environmental services project were calculated to finally make a cash flow projected over 5 years. As part of the results, the economic analysis was carried out on 104.25 hectares of cocoa belonging to the total number of farmers evaluated, who reported an average yield of 957.32 kg of dry cocoa per he. In addition, it was found that the production cost is PEN 3.91/kg of dry cocoa, and the average selling price is PEN 7.38/kg of dry cocoa. After the economic analysis, it was found that the implementation of an environmental services project is profitable (NPV = PEN 1,454,547.8; EIRR = 44% and B/C = 1.86). These results open up an opportunity for cocoa farmers to diversify and increase their income by contributing to climate change mitigation.
]]>Forests doi: 10.3390/f15030499
Authors: Nikos Nanos Eduardo Garcia-del-Rey Luis Gil
Optimal seed-tree selection during natural regeneration of shade-intolerant species requires ensuring an ample and uniform seed supply from residual trees with the smallest possible seed-tree density. Here, we propose a novel approach for seed-tree selection using the genetic algorithm. Data are derived from a 3-hectare even-aged stand of Pinus canariensis C.Sm. ex DC, comprising 364 mature trees and 103 seed-traps. Seeds were collected in 2007 and 2008. After constructing a seed-dispersal model for each seed-crop year, we employ the multi-objective non-dominated sorting genetic algorithm to identify the smallest seed-tree set that maximizes post-treatment seed supply and its spatial homogeneity. Optimal solutions range from a maximum of 68.4% to a minimum of 38.1% reduction in stand density, resulting in a 59.5% to 28% reduction in post-felling seed supply. The coefficient of variation of among-site seed-flux varies from 28% to 59.5%. Proposing a treatment involving the removal of 240 trees (65.9% stand-density reduction) and leaving 40 seed-trees per hectare, our findings provide insights into balancing the conflicting objectives of sufficient post-treatment seed supply at a minimum seed-tree density. This approach marks a departure from traditional practices, as the decision about which trees to cut is historically left to the discretion of field managers.
]]>Forests doi: 10.3390/f15030498
Authors: Hui Shi Han Luo Yawei Wei Won-Sop Shin
Previous studies have reported that exposure to forest landscapes has many benefits on human physiological and psychological health, as well as effectiveness in reducing stress and improving mood depending on different types of landscape. This study examined the effects of different types of forest landscapes for indirect visual experiences on the physical and mental health of college students (N = 33). Three types of landscape images were selected, in which forest landscapes included vegetated landscapes and water features, and as a control, we set up images of urban landscapes without natural elements. Physiological and psychological assessment was performed before the experiment for each student, followed by each student being exposed consecutively to nine landscape images for 3 min (each type) and assessed after each exposure. The results showed that both forest landscapes decreased stress (p < 0.05 for all) and improved mood and self-esteem (p < 0.01 for all). In contrast, water landscapes showed a slightly higher impact on physical and mental health than vegetated landscapes, but there was no significant difference. Conversely, only for self-esteem, the response after viewing vegetated landscapes (VL, SD = 29.06 ± 3.38) was better than after water views (WL, SD = 28.21 ± 2.48). Despite significant differences between the two types of forest landscapes not being found in our findings, the benefits of forest landscapes were observed through understanding the health-promoting capacities of different forest landscapes.
]]>Forests doi: 10.3390/f15030497
Authors: Dan Qiao Zhao Zhang Hongxun Li
This paper presents an in-depth analysis of the impact of forest carbon sink trading in China, examining its effects from 2018 to 2030 under various carbon pricing scenarios. Using the Global Timber Market Model (GFPM) along with the IPCC Carbon Sink Model, we simulate the potential shifts in China’s forest resources and the global timber market. The study finds that forest carbon trading markedly boosts China’s forest stock and carbon sequestration, aligning with its dual carbon objectives. China’s implementation of forest carbon trading is likely to result in a degree of carbon leakage on a global scale. During the forecast period, our study reveals that the carbon leakage rates under three different forest carbon trading price scenarios, which at estimated at 81.5% (USD 9.8/ton), 64.0% (USD 25/ton), and 57.8% (USD 54/ton), respectively. Notably, the leakage rate diminishes as the forest carbon sink price increases. Furthermore, analysis also suggests that regional variations in the average carbon sequestration capacity of forests, alongside the structure of China’s timber imports, emerge as significant factors influencing the extent of carbon leakage.
]]>Forests doi: 10.3390/f15030496
Authors: Ziliang Zhao Chunling Tao Xu Liu Xuekun Cheng Chi Zhou Siyao Huang Menghan Shou Qihan Zhang Banghui Huang Chong Li Guoqing Tu Yufeng Zhou
As a crucial forest resource in southern China and a significant economic forest species for forestry production, moso bamboo has a notable influence on carbon stocks across the entire bamboo forest ecosystem. Studying the impact of different management measures on carbon stocks in moso bamboo forests and soil carbon stocks can assist bamboo forest operators in incorporating the carbon sequestration capacity of bamboo into forest production and management decisions, which can contribute to achieving carbon sequestration, emission reduction, and sustainable development in the decision-making processes of forest production and management. In this study, we utilized a randomized block design to investigate the changes in moso bamboo forests’ carbon stocks and soil carbon stocks under different management measures across three intensities: high-intensity intensive management (HT), moderate-intensity intensive management (MT), and regular management (CK). Additionally, we employed meta-analysis methods to enhance the accuracy of our conclusions. The experimental results showed that MT increased the carbon storage in moso bamboo forests by 19.86%, which was significantly different from CK (p < 0.05), while there was no significant difference between the HT group and the MT and CK groups. For soil carbon stocks, in the 10–30 m and 0–50 m soil layers, HT decreased soil carbon storage by 29.89% and 22.38%, while MT increased soil carbon storage by 64.15% and 31.02%, respectively. Both HT and MT were significantly different from CK (p < 0.05). However, for the soil layers of 0–10 m and 30–50 m, there was no significant difference between the treatments within the experimental group. The results of the meta-analysis indicate that, compared to traditional regular management, intensive management, especially high-intensity intensive management, can significantly increase the carbon storage in bamboo forests (p < 0.05). However, it will significantly reduce soil carbon storage (p < 0.05). Moreover, a significant difference in soil carbon storage is observed only within the 0–20 cm soil layer group. Therefore, from the perspective of the long-term ecological benefits of bamboo forest management, the selection of management measures should prioritize reasonable and moderate-intensity intensive management. Additionally, adopting appropriate and moderate-intensity fertilization, ploughing, and other management methods is recommended to enhance the productivity of moso bamboo forests while concurrently protecting the natural environment and improving the carbon sequestration capacity of moso bamboo forests.
]]>Forests doi: 10.3390/f15030495
Authors: Jiahao Zhao Xiaodan Sun Dong Wang Meiquan Wang Junjie Li Jun Wang Qingwei Guan
Fine roots play an essential role in biogeochemical cycling in forest ecosystems; however, little is known about the response of fine root morphology and chemistry in different root orders to forest management activities such as forest thinning. We investigated the fine root morphological and chemical traits in different root orders of Pinus massoniana under different thinning intensities, namely no thinning, low-intensity thinning (LIT), middle-intensity thinning (MIT), and high-intensity thinning (HIT) (0%, 25%, 45%, and 65% of individual trees eliminated, respectively). We found that forest thinning increased the root diameter (RD) of absorptive roots and decreased that of transport roots, while the trend for the specific root length (SRL) was the opposite. LIT and MIT could increase specific surface area (SSA), especially the SSA of absorptive roots in the MIT treatment. The root tissue density (RTD) of all root sequences in the LIT treatment decreased but increased in the HIT treatment. For the fine root chemical traits, thinning increased the root carbon concentration (RCC) of absorptive roots. The root nitrogen concentration (RNC) and root phosphorus concentration (RPC) of first- to fourth-order roots increased in the LIT and MIT treatments after thinning. Meanwhile, thinning increased root lignin, cellulose, and non-structural carbohydrate (NSC) concentrations. Soil temperature, nitrate, and microbial biomass carbon were factors affecting variations in fine root morphology and chemistry. Forest thinning was likely to shift the absorptive roots’ foraging strategy into a resource-conserving one. Thinning increased fine root chemical traits in most root orders. These findings contributed to our ability to predict how belowground ecological processes are mediated by fine roots under forest management activities.
]]>Forests doi: 10.3390/f15030494
Authors: Evrim A. Şahan Nesibe Köse H. Tuncay Güner Dario Martin-Benito Guillermo Gea-Izquierdo María Conde David Almagro Irem Sena Kızılaslan Ünal Akkemik H. Nüzhet Dalfes
Recent climate and societal changes have increased wildfire activity and prolonged the fire season in many regions of the world. The precision of fire seasonality analysis from tree-ring records can be improved by complementing the subjectively determined intra-ring position of fire scars with more precise studies of wood formation. With this aim, we monitored the wood formation dynamics of Pinus nigra J.F. Arnold (black pine) trees along a climatic gradient in western Anatolia to better understand the wood formation for the interpretation of fire seasonality. Wood microcores were collected from April to November 2021 from trees at four sites across (from north; the Black Sea climate in Bolu to the south; and the Mediterranean climate in Isparta) the areas where previous fire history reconstructions were conducted. These previous studies showed that most fires occurred during the latewood formation period. We found that matured latewood tracheids were observed between September (August) and November, thus suggesting that these fires occurred during late summer and fall. Our results show the importance of temperature and water availability for the timing of earlywood and latewood formations. These findings can be used to better inform planning activities for fire management and as a proxy to reconstruct past fire seasonality.
]]>Forests doi: 10.3390/f15030493
Authors: Wenxiu Zhang Li Rong Kangning Xiong Zhenzhen Zhang Huanhuan Chang
Karst nature reserve (NR) ecosystems are vulnerable, and the development of regulatory and cultural services industries is still in its infancy. Realization of ecological product value (EPV) is a crucial way to promote the integration of eco-protection and industrial development in nature reserves (NRs). This study calculates EPV using a modified equivalent factor, analyzes the spatial pattern of EPV using the fishnet tool in Arc GIS, and constructs a model for realizing EPV. Finally, the driving factors for the formation of eco-industry are identified using the grey correlation analysis (GCA) method. The results show that (1) the regulatory service products in karst NRs play a decisive role in EPV, and forest ecosystems have significant EPV potential; (2) high-value grids are concentrated in the core and buffer zones of karst NRs and the spatial distribution of EPV in the experimental zone is highly heterogeneous, with high and low-value grids in mixed distribution; (3) the realization model of EPV in karst NRs follows the logic of “preservation, transformation, and appreciation”; (4) human resources (0.813), ecology (0.798), industry (0.693), policy (0.783), the market (0.778), and economy (0.715) are essential drivers for the formation of eco-industry in karst NRs. Overall, karst NRs can promote the realization of EPV through planning and regulation of land use, based on the interaction between internal and external factors, to promote the coordinated development of eco-industry in karst NRs. This study provides a reference for the scientific management of eco-resources and the sustainable development of eco-industry in karst NRs.
]]>Forests doi: 10.3390/f15030492
Authors: Yali Song Jinmei Xing Chun Hu Chenggong Song Qian Wang Shaojun Wang
Atmospheric nitrogen (N) deposition has rapidly increased due to anthropogenic activities, which can exert a crucial effect on biochemical cycling process such as litter decomposition in the subtropical forests. However, the is still uncertainty about the knowledge of N deposition in regulating nutrient release from the leaf and twig litter. For this study, a 2 yr litterbag decomposition experiment was conducted under three levels of N addition treatments in a subtropical evergreen broad-leaved forest, in southwest China. This study aimed to identify the effects of low (LN: 10 g·N·m−2·y−1), medium (MN: 20 g·N·m−2·y−1), and high N addition (HN: 25 g·N·m−2·y−1) on litter decomposition and nutrient release from leaves and twigs. We observed that there was significantly lower litter decomposition (8.13%–13.86%) and nutrient release (7.24%–36.08%) in the HN treatment compared to the LN treatment. The decay of mass, lignin, and cellulose and the nutrient release were faster in leaf litter than in twig litter after N addition (p < 0.05). The ratios of C/phosphorus (P), C/N, and N/P were also significantly greater in twig litter than in leaf litter. Furthermore, the N addition treatments resulted in higher contents of the mass, lignin, and cellulgapose remaining in leaf and twig litter compared to the control (CK). The amount of C, N, and P remaining in leaf (51.4%–59.1%) and twig (44.1%–64.8%) debris was significantly higher in the N treatment compared to CK treatment (p < 0.05). In addition, the litter C/N and C/P were smaller and the litter N/P was larger for each N treatment compared to CK (p < 0.05). The results suggest that N inputs restrain lignin and cellulose degradation and C and N release, and increase the N/P ratio that limits P release in litter. These effects vary with the level of N treatments.
]]>Forests doi: 10.3390/f15030491
Authors: Huayong Zhang Pengfei Sun Hengchao Zou Xiande Ji Zhongyu Wang Zhao Liu
Climate change has had an almost irreversible impact on the distribution patterns of tree species on the Tibetan Plateau, driving some vulnerable species to the brink of extinction. Therefore, it is important to assess the vulnerability of tree species in climate-sensitive areas under the following three IPCC-CMIP6 scenarios: SSP126, SSP370, and SSP585. The MaxEnt model was used to predict adaptive distribution for one endangered (Acer wardii W. W. Smith (A. wardii)) and six vulnerable maple plants on the Tibetan Plateau under current and future conditions. We then evaluated their vulnerability using the landscape fragmentation index. Our results showed that the current adaptive areas of vulnerable maple species were mainly distributed in the southeast of the Tibetan Plateau. The dominant factors affecting adaptive areas were temperature annual range (BIO7) for Acer sikkimense Miq. and Acer sterculiaceum Wall.; annual precipitation (BIO12) for Acer cappadocicum Gled.; precipitation of driest month (BIO14) for Acer pectinatum Wall. ex G. Nicholson, Acer taronense Hand.-Mazz., and A. wardii; and subsoil clay fraction (S_CLAY) for Acer campbellii Hook.f. & Thoms. ex Hiern (A. campbellii) Under the three future scenarios, the adaptive areas of maple on the Tibetan Plateau area shifted to the northwest, and habitat suitability increased in the northwestern part of the adaptive areas. In the SSP370 scenario, all seven species showed an increase in adaptive areas, while certain species decreased in some periods under the SSP126 and SSP585 scenarios. The status of the endangered maple species is likely to be even more fragile under the three future scenarios. A. wardii and A. campbellii are more vulnerable and may face extinction, requiring immediate attention and protection. In contrast, the vulnerability of the remaining five species decreased. In conclusion, this study provides recommendations for conserving vulnerable maple species on the Tibetan Plateau. Our data support understanding the distributional changes and vulnerability assessment of these tree species.
]]>Forests doi: 10.3390/f15030490
Authors: Xiang-Rong Zheng Mao-Jiao Zhang Feng-Mao Chen
Cyclocarya paliurus, native to China, is a medicinal and edible plant with important health benefits. Anthracnose is an emerging disease in southern China that causes severe economic losses and poses a great threat to the C. paliurus tea industry. However, to date, the species diversity of pathogens causing C. paliurus anthracnose has remained limited. From 2018 to 2022, a total of 331 Colletotrichum isolates were recovered from symptomatic leaves in eight major C. paliurus planting provinces of southern China. Phylogenetic analyses based on nine loci (ITS, GAPDH, ACT, CHS-1, TUB, CAL, HIS3, GS and ApMat) coupled with phenotypic characteristics revealed that 43 representative isolates belonged to seven known Colletotrichum species, including C. brevisporum, C. fructicola, C. gloeosporioides sensu stricto, C. godetiae, C. nymphaeae, C. plurivorum and C. sojae. Pathogenicity tests demonstrated that all species described above were pathogenic to wounding detached leaves of C. paliurus, with C. fructicola being the most aggressive species. However, C. brevisporum, C. plurivorum and C. sojae were not pathogenic to the intact plant of C. paliurus. These findings reveal the remarkable species diversity involved in C. paliurus anthracnose and will facilitate further studies on implementing effective control of C. paliurus anthracnose in China.
]]>Forests doi: 10.3390/f15030489
Authors: Zhuangyue Lu Qibo Wang Zhenxin Yang Lin Chen Nianhui Cai Yulan Xu
Plant height plays a crucial role in both the structure and quality of plants. Pinus yunnanensis is a distinctive species of the forest found in Southwest China, where the height of the plants significantly influences both yield performance and plant architecture. Although the phenotypes of P. yunnanensis seedlings with different plant heights were quite different at their seedling stage, the molecular mechanisms controlling the seedling differentiation remain poorly understood. This study is aimed to investigate the underlying mechanisms of P. yunnanensis seedling differentiation using phenotypic, transcriptomic, and endogenous phytohormone analyses. The P. yunnanensis seedlings were categorized into three grades, i.e., Grades A, B, and C, by mean ± 1/2 standard deviation method (H ± 1/2σ), and the seedling height and ground diameter were measured. We conducted the measurements of endogenous hormone levels in the young shoot apexes of seedlings at different grades during the fast-growth period (March). The DEGs were identified through transcriptome sequencing and analyzed by qRT-PCR validation. Significant differences were observed in the content and ratio of endogenous phytohormones among various grades of P. yunnanensis seedlings (p < 0.05). The ABA content in Grade A was prominently more than that in Grades B and C, and the order of the content of auxins was Grade B > C > A. Furthermore, when compared to Grade A, the ratios of auxins/CTKs, auxins/ABA, CTKs/ABA, and (auxins + CTKs)/ABA exhibited significant increases in Grades B and C. Moreover, GO functional annotation analysis indicated the more pronounced enrichment of DEGs in molecular functions. KEGG metabolic pathway analysis revealed notable differences in enrichment pathways between the pairwise comparisons. The “plant hormone signal transduction” pathway exhibited enrichment in the two groups, followed by “plant–pathogen interaction” pathway in the organism system that was enriched in the three groups. In addition, the results for endogenous phytohormone metabolism pathways indicate a significant up-regulation in the expression of AUX1, while AHP and PP2C exhibited significant down-regulation. To sum up, we aimed at investigating the underlying mechanisms of P. yunnanensis seedling differentiation using phenotypic, transcriptomic, and endogenous phytohormone analyses. The results suggested that individual phytohormones have a limited capacity to regulate gene expression, and seedling differentiation results from the combined regulation of multiple hormones. In addition, several candidate genes associated with phytohormone biosynthesis and signal transduction pathways were identified, including AUX1, GH3, AHP, B-ARR, PP2C, etc., which provided candidate genes for the following hormone-related gene overexpression and knockout experiments. These findings provide insights into the molecular genetic control of seedling height growth of P. yunnanensis.
]]>Forests doi: 10.3390/f15030488
Authors: Xin Wang Rumeng Ye Bai-Lian Li Kai Tian
Microplastics enter forest ecosystems in a variety of ways, including through atmospheric deposition, anthropogenic waste, and leaching. There is growing evidence of the ecotoxicity of microplastics to soil decomposers. Soil animals and microorganisms are the main decomposers of plant litter, and their interactions play important roles in determining the terrestrial biochemical cycle. However, how emerging microplastics in forests affect the influence of soil animals on the fungal community in decomposed litter is still unclear. Here, by constructing a rigorous mesocosm experiment, we investigated soil enzyme activities and the variation in fungal community characteristics in the leaf litter of a deciduous tree, Lindera glauca, which was decomposed by contrasting decomposer structures (with or without soil animals) under different contamination conditions (with or without microplastic contamination), aiming to determine the impacts of these factors on litter decomposition. We found that soil animals can significantly depress the litter decomposition rate by reducing fungal diversity and largely changing the community structure in the litter. However, these critical changes caused by soil animals were inhibited in the mesocosms contaminated with high-density polyethylene microplastics (HDPE−MPs), during which soil animal activities were significantly reduced. These findings represent a step forward in illustrating the potential effect of emerging contamination stress on forest litter decomposition and biogeochemical cycles under global environmental change.
]]>Forests doi: 10.3390/f15030487
Authors: Zhen Wang Liangxin Fan Jingxuan Su Zhijun Wang
The ecological water transfer project (EWTP) plays a pivotal role in reinstating the flow of dried-up rivers in arid regions, promoting river connectivity and vegetation resurgence. An essential facet in ensuring the efficacious execution of the EWTP lies in determining the optimal duration of irrigation to facilitate vegetation recovery. Nevertheless, comprehensive reports concerning the EWTP process in arid river ecosystems are scarce. Here, we leverage remote sensing imagery to assess changes in surface water and vegetation dynamics before and after the implementation of the EWTP in a dried-up river. The results show that before the EWTP (1987–2016), riparian vegetation’s mean normalized difference vegetation index (NDVI) decreased from 0.181 to 0.066. After EWTP (2017–2022), the river’s flow was restored for a distance of 347 km. This restoration resulted in the formation of 81.47 km2 of intermittent water bodies along the river. The mean NDVI increased from 0.065 to 0.093. As irrigation duration increased, the NDVI growth rate exhibited an initial rise followed by a subsequent decline, reaching its peak growth rate by irrigating for 18 days per year. The regions showing increased NDVI values exhibited a pronounced spatial correlation with the areas subjected to water transfer. These improvements in NDVI were predominantly concentrated on both sides of the river within a 550 m range. Interestingly, as moves farther away from the river, the growth rate of NDVI exhibited an initial increase followed by a subsequent decline. The pinnacle of NDVI growth rate materialized at a distance of 40–50 m from the river. These findings reveal the response characteristics of desert riparian vegetation to EWTP, providing valuable insights for selecting appropriate water transfer timing in future EWTP.
]]>Forests doi: 10.3390/f15030486
Authors: Chenxiao Kong Jinghua Huang Sheng Du Guoqing Li
China has implemented several ecological projects in the Loess Plateau region to address severe land degradation and soil erosion. Accurately assessing ecological restoration and its driving factors remains challenging. Previous studies in this area concentrated on driving factors have mainly focused on natural factors at the regional or watershed scale, with limited consideration of socioeconomic factors at the county scale. In this study conducted in Huanglong County on the Loess Plateau, the focus was to fill the gaps in previous research and provide insights into the socioeconomic driving forces behind vegetation greening. Remote sensing image data (NDVI) from 1999 to 2019 were used to analyze vegetation greenness dynamics in the region. Five socioeconomic variables were considered, including afforestation intensity, deforestation intensity, agricultural intensity, village intensity, and road intensity layers, to characterize the impact of afforestation, agriculture, and urbanization policies. The RESTREND (residual trends) method was employed to assess the relative importance of climate and human activities on vegetation dynamics. This study found that temperature–NDVI relationships are more suitable for building RESTREND models than precipitation–NDVI relationships. Human activity was the main driver of vegetation dynamics, contributing 62% compared to 38% from climate change. Agricultural practices and afforestation were found to have a positive impact on ecological restoration, while deforestation and urbanization had no significant impact. These findings highlight a conceptual framework for understanding the intricate relationship between ecological restoration, climatic factors, and human activity on the Loess Plateau. This study suggests that significant progress has been made in ecological restoration through human efforts in combating land degradation. However, it emphasizes the need to strengthen natural conservation efforts and gradually transition toward restoration processes driven by natural forces for sustainable socioeconomic development. The methodology used in this study can be applied to explore the driving forces of ecological restoration in other regions facing human-driven land degradation.
]]>Forests doi: 10.3390/f15030485
Authors: Monika Aniszewska Arkadiusz Gendek Barbora Tamelová Jan Malaťák Jan Velebil Jozef Krilek Iveta Čabalová Ireneusz Mikłaszewicz Witold Zychowicz Michał Drożdżek Andrzej Mazurek
The objective of the present work was to determine the physico-mechanical and energy properties of pine (Pinus sylvestris) and beech (Fagus sylvatica) wood from railroad ties. The ties were divided into internal and external parts as well as into parts impregnated and unimpregnated with creosote oil. The effects of creosote impregnation on wood hardness, compressive strength parallel to the grain, static bending strength, and calorific value were studied. The obtained results show that the parameters of the analyzed samples meet the standard requirements (EN 338) for construction wood (compressive and bending strength class: C50—pine; D70—beech). Depending on the particular property being studied, both pine and beech samples belong to the highest or one of the highest wood quality classes. Creosote oil considerably increased wood density (by 9% for beech and 19% for pine) but did not affect its hardness. Creosote impregnation significantly improved the compressive strength parallel to the grain of both wood species (beech: σc=51.99 MPa (IN); σc=57.78 MPa (OUT); pine: σc=36.56 MPa (IN); σc=42.45 MPa (OUT)); in the case of static bending strength, its value was increased for beech wood (σg=106.13 MPa (IN); σg=113.18 MPa (OUT)) and reduced for pine wood (σg=66.34 MPa (IN); σg=82.62 MPa (OUT)). The oil contained in wood from ties significantly elevated its calorific value (by 25% for beech and 10% for pine). Unfortunately, the presence of creosote oil currently prevents wood from railroad ties from being reused as the oil is deemed hazardous and carcinogenic. However, if it were possible to isolate the unimpregnated parts of railroad ties, they could be reapplied for construction or other uses.
]]>Forests doi: 10.3390/f15030484
Authors: Jinfeng Rao Xunzhi Ouyang Ping Pan Cheng Huang Jianfeng Li Qinglong Ye
It is highly valuable to analyze and assess the landscape ecological risk of nature reserves to prevent and resolve ecological risks, as well as to effectively protect and maintain the sustainable development of nature reserves. Taking the forest landscape of the Lushan National Nature Reserve as its study object, this study performed grid processing for the nature reserve and classified forest landscape types using the Forest Resource Inventory Database in 2019. A landscape ecological index model was constructed to evaluate the ecological risk. Global and local Moran index values were used to reveal the autocorrelations for ecological risk. The geodetector method was used to comprehensively analyze the effects of natural and human factors on ecological risk. The results showed that, in general, the ecological risk level of the nature reserve was relatively low, as the proportion of the lowest-, lower-, and medium-risk areas to the total forestry land area accounted for 91.03%. The ecological risk ranking of each functional zone, from high to low, was in the order of the experimental zone, the buffer zone, and the core zone. The ecological risk levels of different forest landscape types were closely related to their area, spatial distribution, and succession stage, as well as human factors, such as the proximity to roads and settlements, etc. The forest landscape with the highest ecological risk was the Cunninghamia lanceolata (Lamb.) Hook. forest, and the forest landscape with the lowest ecological risk was other forestry land. Ecological risk had a positive spatial correlation and tended to be aggregated in space, demonstrating coupling with the proximity to roads and settlements. The ecological risk was affected by both human and natural factors, among which human factors played a dominant role. The proximity to roads and settlements, the relative humidity, and the temperature were the main driving factors. The interaction of pairwise factors had a stronger influence than that of single factors. Therefore, controlling the intensity of human activities and enhancing the coordination between humans and nature are beneficial for alleviating the ecological risks in the forest landscapes of nature reserves.
]]>Forests doi: 10.3390/f15030483
Authors: Dengwei Xu Jie Chen Qi Wu Zheng Wang
To solve the problems of low recognition accuracy and large amounts of computation required in forest fire detection algorithms, this paper, aiming to make improvements in these two aspects, proposes a G-YOLOv5n-CB forest fire detection algorithm based on the YOLOv5 algorithm and develops a set of real-time fire monitoring systems applicable to campus forest land with the aid of deep learning technology. The system employs an unmanned vehicle to navigate automatically and collect image information through a camera and deploys its algorithm on the unmanned vehicle’s Jetson Nano hardware platform. The results demonstrate that the proposed YOLOv5n-CB algorithm increased the mAP value index by 1.4% compared with the original algorithm on the self-made forest fire dataset. The improved G-YOLOv5n-CB model was deployed on the Jetson Nano platform for testing, and its detection speed reached 15 FPS. It can accurately detect and display real-time forest fires on campus and has, thus, a high application value.
]]>Forests doi: 10.3390/f15030482
Authors: Nova D. Doyog Chinsu Lin
Provision of multi-temporal wall-to-wall canopy height information is one of the initiatives to combat deforestation and is necessary in strategizing forest conversion and reforestation initiatives. This study generated wall-to-wall canopy height information of the subtropical forest of Lishan, Taiwan, using discrete data provided by spaceborne LiDARs, wall-to-wall passive and active remote sensing imageries, topographic data, and machine learning (ML) regression models such as gradient boosting (GB), k-nearest neighbor (k-NN), and random forest (RF). ICESat-2- and GEDI-based canopy height data were used as training data, and medium-resolution passive satellite image (Sentinel-2) data, active remote sensing data such as synthetic aperture radar (SAR), and topographic data were used as regressors. The ALS-based canopy height was used to validate the models’ performance using root mean square error (RMSE) and percentage RMSE (PRMSE) as validation criteria. Notably, GB displayed the highest accuracy among the regression models, followed by k-NN and then RF. Using the GEDI-based canopy height as training data, the GB model can achieve optimum accuracy with an RMSE/PRMSE of 8.00 m/31.59%, k-NN can achieve an RMSE/PRMSE of as low as 8.05 m/31.78%, and RF can achieve optimum RMSE/PRMSE of 8.16 m/32.24%. If using ICESat-2 data, GB can have an optimum RMSE/PRMSE of 13.89 m/54.86%; k-NN can have an optimum RMSE/PRMSE of 14.32 m/56.56%, while RF can achieve an RMSE/PRMSE of 14.72 m/58.14%. Additionally, integrating Sentinel-1 with Sentinel-2 data improves the accuracy of canopy height modeling. Finally, the study underlined the crucial relevance of correct canopy height estimation for sustainable forest management, as well as the potential ramifications of poor-quality projections on a variety of biological and environmental factors.
]]>Forests doi: 10.3390/f15030481
Authors: Dangjun Wang Fang Yuan Wuyang Xie Juan Zuo Huakun Zhou
Leaf litter quality has been acknowledged as a crucial determinant affecting litter decomposition on broad spatial scales. However, the extent of the contribution of soil fauna to litter decomposability remains largely uncertain. Nor are the effects of leaf size and defensive traits on soil fauna regulating litter decomposability clear when compared to economics traits. Here, we performed a meta-analysis of 81 published articles on litterbag experiments to quantitatively evaluate the response ratio of soil fauna to litter decomposition at the global level. Our results revealed that soil fauna significantly affected litter mass loss across diverse climates, ecosystems, soil types, litter species, and decomposition stages. We observed significantly positive correlations between the response ratio of soil fauna and leaf length, width, and area, whereas the concentrations of cellulose, hemicellulose, total phenols, and condensed tannins were negatively correlated. Regarding economic traits, the response ratio of soil fauna showed no relationship with carbon and nitrogen concentrations but exhibited positive associations with phosphorus concentration and specific leaf area. The mean annual temperature and precipitation, and their interactions were identified as significant moderators of the effects of soil fauna on litter decomposition. We evidenced that the contribution of soil fauna to litter decomposability is expected to be crucial under climate change, and that trait trade-off strategies should be considered in modulating litter decomposition by soil fauna.
]]>Forests doi: 10.3390/f15030480
Authors: Guangping Qie Jianneng Ye Guangxing Wang Minzi Wang
Accurately mapping urban above-ground vegetation carbon density presents challenges due to fragmented landscapes, mixed pixels, and shadows induced by buildings and mountains. To address these issues, a novel methodological framework is introduced, utilizing a linear spectral unmixing analysis (LSUA) for shadow removal and vegetation information extraction from mixed pixels. Parametric and nonparametric models, incorporating LSUA-derived vegetation fraction, are compared, including linear stepwise regression, logistic model-based stepwise regression, k-Nearest Neighbors, Decision Trees, and Random Forests. Applied in Shenzhen, China, the framework integrates Landsat 8, Pleiades 1A & 1B, DEM, and field measurements. Among the key findings, the shadow removal algorithm is effective in mountainous areas, while LSUA-enhanced models improve urban vegetation carbon density mapping, albeit with marginal gains. Integrating kNN and RF with LSUA reduces errors, and Decision Trees, especially when integrated with LSUA, outperform other models. This study underscores the potential of the proposed framework, particularly the integration of Decision Trees with LSUA, for advancing the accuracy of urban vegetation carbon density mapping.
]]>Forests doi: 10.3390/f15030479
Authors: Ziwei Yang Yin An Qian Ye Nannan Zhang Xin Liu Fayin He Yue Zeng Ming Tang Zhengting Yang Kun Li
Soil salinity affects approximately 20% of the world’s arable land, presenting a significant challenge for studying the mechanisms by which plants adapt to saline environments. Cyclocarya paliurus, an invaluable research model due to its ecological and medicinal significance, is primarily concentrated in central and southern China. Nevertheless, Cyclocarya paliurus faces challenges from environmental factors such as soil salinization, which adversely impacts its growth, subsequently affecting the yield and quality of its bioactive compounds. The NAC gene family, a critical group of plant-specific transcription factors, plays pivotal roles in responding to abiotic stresses. However, there has not yet been any studies on NAC genes under salt stress in Cyclocarya paliurus. In this study, we identified 132 NAC genes within the Cyclocarya paliurus genome. Our analysis of the conserved structures and gene organization revealed a high degree of conservation in the proteins of the CpNAC gene family. Cis-element analysis unveiled the participation of these genes in a variety of biological processes, including light responses, phytohormone responses, cell cycle responses, and abiotic stress responses. Under salt stress conditions, the expression of 35 CpNAC genes changed significantly, indicating a response to salt treatment. Furthermore, we provided additional evidence for the identification of the NAC gene family and revealed their potential positive regulatory role in signal transduction by conducting a transcriptional activation activity analysis of CpNAC132(D) and CpNAC040, which are homologous to Arabidopsis thaliana NAC062/91 and NAC103, respectively. This research not only advances our comprehension of the salt stress adaptation in Cyclocarya paliurus but also provides robust support for future investigations into plant responses to environmental stress and the cultivation of salt-tolerant crops.
]]>Forests doi: 10.3390/f15030478
Authors: Sijie Niu Ge Han Xinran Chen Jiale Liu Chuangui Wang
As the most promising biomass material, bamboo has been widely used, but at the same time, it is subject to many problems, such as processing residues and the failure of high-value utilization of residues. In this paper, bamboo powder and polybutylene succinate (PBS) were used as the main raw materials, and by changing the ratio of bamboo powder to PBS and adding polypropylene (PP) or polyethylene (PE) in combination with PBS, the effects of the ratio, as well as the effects of the use of PP and PE, on the physical–mechanical, thermal, and degradation properties of bamboo–plastic composites were investigated, and the microscopic changes of the materials were studied by chemical component analysis. The optimal formulation of bamboo powder/PBS composite material has been identified through experimentation, yielding a flexural strength of 24.87 MPa and a compressive strength of 29.74 MPa. This material can be used for outdoor furniture, wall panels, flooring, road barriers, and other applications, providing a new environmentally friendly approach to the consumption of residual bamboo materials.
]]>Forests doi: 10.3390/f15030477
Authors: Ju-Yeong Youn Sang-wook Kim
This study aimed to identify changes in visitor behavior and visitor interest in healing forests before and after the COVID-19 pandemic. The study used text mining analysis techniques to identify changes in visitation behavior over time, divided into three periods, as follows: pre-COVID-19 (1 January to 31 December 2019), during the COVID-19 pandemic (1 November 2020 to 31 October 2022), and post-COVID-19 (1 November 2022 to 31 October 2023). After the COVID-19 outbreak, healing forest use behavior did not revert to pre-COVID-19 patterns. Moreover, the keywords “tourism” and “hiking” stood out as the main drivers of this change in behavior. Therefore, the Korea Forest Service and related authorities must examine the scalability of the functions, services, and programs of healing forests from a general healing space to a space for leisure and tourism. These findings will contribute to the development of future marketing strategies and programs for healing forests.
]]>Forests doi: 10.3390/f15030476
Authors: Jing Ma Taotao Wang Hongyong Wang Jie Yang Tingting Xie Zhengzhong Zhang Cai He Lishan Shan
The variation and correlation among desert plant traits are helpful to understanding the adaptation strategies of plants to the environment and the mechanism of community assembly. However, the diversity and covariation among fine root traits of desert plants and their phylogenetic relationships remain unclear. Principal component analysis, Pearson’s correlations, phylogenetic independent comparison, mixed linear model, and variance decomposition were used to investigate the variation and correlation among 10 fine root traits of 25 common desert plants in arid areas. The results are as follows: (1) We found that all fine root traits varied more among interspecific variation, with the coefficient of variation ranging from 21.83% to 105.79%. Most traits were predominantly shaped by interspecific variation, whereas root phosphorus content (RPC) and intraspecific variation in root carbon/nitrogen ratio (RCN) were more important. (2) Root traits were correlated with four axes of variation. Root nitrogen content (RNC) correlated positively with root diameter (AD) and tissue density (RTD) but negatively with specific root length (SRL), which was inconsistent with the inference of the root economics spectrum (RES). (3) Covariance and trade-off strategies of fine root traits in different life forms of plants were different. Herb RNC was negatively correlated with SRL and positively correlated with AD, while this relationship did not exist in shrubs. Moreover, shrub AD was negatively correlated with RTD, but herbs showed no significant correlation. (4) Influenced by phylogenetic factors, fine root traits exhibited a covariant or trade-off pattern. Taken together, fine root traits were predominantly shaped by interspecific variation, but intraspecific variation also played a significant role. Concurrently, distinct patterns in fine root covariation and trade-off strategies among different life forms of plants were also observed. Future studies should explore the variation and correlation among traits at different scales within and between species from the perspective of life form.
]]>Forests doi: 10.3390/f15030475
Authors: Yongxi Zou Ke Shi Shuai Liao Zhoubing Xiang Jifan Luo Xinge Nan Hai Yan Zhiyi Bao Wenbin Nie Renwu Wu
Since the mid-17th century, Western plant collectors have explored Asia, particularly China, to collect native species for economic and botanical development. Ernest Henry Wilson (1876–1930) stands among the foremost figures in this pursuit. He conducted five plant collections in China between 1899 and 1918, gaining recognition for numerous valuable ornamental species. However, precise details such as the total number of specimens, a comprehensive species list, and the collection locations remained elusive, hindering a thorough assessment of his scientific contributions. To address this gap, we compiled data from various online databases and relevant publications, constructing a comprehensive dataset encompassing species names, collection dates, locations, and additional pertinent information. Employing Python, we organized and translated the species names and locations, facilitating analysis of families, genera, species, and the completeness and preferences of his collection. The conclusions drawn from the available data include 19,218 specimens, with 11,884 collection numbers, belonging to 200 families, 1046 genera, and 3794 species (including 342 infraspecific taxa). Wilson exhibited a preference for woody and flowering plants, resulting in a collection completeness of 25%. His collection spanned seven provinces, 28 prefecture-level cities, and 38 county-level areas, underscoring his significant contributions to the global dissemination of Chinese plant knowledge. This study conducts a comprehensive analysis of the plant specimens collected by Wilson in China, investigating their taxonomy, distribution, and historical context and evaluating Wilson’s contribution to plant dissemination. The findings serve as a valuable reference for subsequent biodiversity research endeavors.
]]>Forests doi: 10.3390/f15030474
Authors: Ben Yang Ling Wu Meiling Liu Xiangnan Liu Yuxin Zhao Tingwei Zhang
Accurate classification of forest tree species holds great significance in the context of forest biodiversity assessment and the management of forest resources. In this study, we utilized Sentinel-2 time series data with high temporal and spatial resolution for tree species classification. To address potential classification errors stemming from spectral differences due to tree age variations, we implemented the Continuous Change Detection and Classification (CCDC) algorithm to estimate tree ages, which were integrated as additional features into our classification models. Four different combinations of classification features were created for both the random forest (RF) algorithm and extreme gradient boosting (XGB) algorithm: spectral band (Spec), spectral band combined with tree age feature (SpecAge), spectral band combined with spectral index (SpecVI), and spectral band combined with spectral index and tree age feature (SpecVIAge). The results demonstrated that the XGB-based models outperformed the RF-based ones, with the SpecVIAge model achieving the highest accuracy at 78.8%. The incorporation of tree age as a classification feature led to an improvement in accuracy by 2% to 3%. The improvement effect on classification accuracy varies across tree species, due to the varying uniformity of tree age among different tree species. These results also showed it is feasible to accurately map regional tree species based on a time-series multi-feature tree species classification model which takes into account tree age.
]]>Forests doi: 10.3390/f15030473
Authors: Yan Zhang Zhanhui Jia Guoming Wang Mengxin Hou Min Zhai Longjiao Hu Jiping Xuan Zhenghai Mo
Response regulator (RR) is the core component of cytokinin (CK) signaling, and it regulates the expression of numerous downstream CK-responsive genes. However, the knowledge regarding the pecan RR (CiRR) gene family is still limited. In this study, we first monitored trans-zeatin riboside (tZR) content in the graft union 0, 7, 14, and 32 days after grafting and then conducted genome-wide analysis and expression profiling of the CiRR gene family using an available genome sequence and RNA-seq dataset, aiming to better understand the roles of CK during pecan grafting. The dynamic contents of tZR showed an increased trend during the specific period for both the scion and rootstock. There were 20 CiRRs in the pecan genome, including 12 type A CiRRs, 5 type B members, and 3 type C genes. All members contained a receiver domain and type B CiRRs possessed an additional Myb-like DNA-binding domain. Promoter analysis showed that the CiRR gene family contained cis-elements associated with growth and development, hormones, and stress. A total of 10 genes, including CiRR18/9/4a/14a/12c/5/12b/14b/2b/2a, were abundantly expressed in the samples of different tissues, drought stress, and kernel development. There were 12 genes (CiRR5/18/4a/12b/2b/12c/14b/2a/14a/4b/9/11a) showing active expressions during grafting, and weighted gene co-expression network analysis (WGCNA) grouped them into six modules. Among them, CiRR14a and CiRR12b were the hub genes for the turquoise and brown modules, respectively. Functional annotation indicated that the turquoise module was associated with gene transcription and translation, while the brown module was related to cell proliferation. Our results suggest that the CiRR gene family central to CK signaling is probably involved in callus formation during pecan grafting.
]]>Forests doi: 10.3390/f15030472
Authors: Yoon-Young Choi Inhyung Cho Hae-ryoung Chun Sujin Park Eun-Yi Cho Sunghyun Park Sung-il Cho
Forest therapy is associated with several health advantages, such as stress reduction and improved psychological health. Mindfulness, an important component of forest therapy, is also associated with improved health outcomes. However, few studies have empirically evaluated mindfulness in forest therapy settings. This study translated the Freiburg Mindfulness Inventory (FMI) in the context of forest therapy into Korean and then validated it. (1) Methods: This study included 352 individuals. Four other psychometric tools were administered to ensure criterion validity. Exploratory and confirmatory factor analyses were implemented to determine the factor structure. Furthermore, item validity was assessed using item response theory. (2) Findings: A two-factor structure of the FMI, comprising acceptance and presence, was the most suitable. However, excluding item 13 enhanced the model fit (χ2 [df] = 169.9 [64], comparative fit index = 0.93, Tucker-Lewis index = 0.92, root mean square error of approximation = 0.069). The FMI had satisfactory psychometric properties. (3) Conclusion: The FMI was translated into Korean and validated, serving as a valuable instrument for assessing mindfulness in the context of forest therapy. We identified that item 13 should be excluded. Our results demonstrate the potential effects of mindfulness on mental health in forest therapy.
]]>Forests doi: 10.3390/f15030471
Authors: Qingyan He Qianhua Yang Shouzheng Jiang Cun Zhan
The Loess Plateau (LP) is a typical climate-sensitive and ecologically delicate area in China. Clarifying the vegetation–climate interaction in the LP over 40+ years, particularly pre- and post-Grain to Green Program (GTGP) implementation, is crucial for addressing potential climate threats and achieving regional ecological sustainability. Utilizing the kernel Normalized Difference Vegetation Index (kNDVI) and key climatic variables (precipitation (PRE), air temperature (TEM), and solar radiation (SR)) between 1982 and 2022, we performed an extensive examination of vegetation patterns and their reaction to changes in climate using various statistical methods. Our findings highlight a considerable and widespread greening on the LP from 1982 to 2022, evidenced by a kNDVI slope of 0.0020 yr−1 (p < 0.001) and a 90.9% significantly increased greened area. The GTGP expedited this greening process, with the kNDVI slope increasing from 0.0009 yr−1 to 0.0036 yr−1 and the significantly greened area expanding from 39.1% to 84.0%. Over the past 40 years, the LP experienced significant warming (p < 0.001), slight humidification, and a marginal decrease in SR. Post-GTGP implementation, the warming rate decelerated, while PRE and SR growth rates slightly accelerated. Since the hurst index exceeded 0.5, most of the vegetated area of the LP is expected to be greening, warming, and humidification in the future. In the long term, 75% of the LP vegetated area significantly benefited from the increase in PRE, especially in relatively dry environments. In the LP, 61% of vegetated areas showed a positive correlation between kNDVI and TEM, while 4.9% exhibited a significant negative correlation, mainly in arid zones. SR promoted vegetation growth in 23% of the vegetated area, mostly in the eastern LP. The GTGP enhanced the sensitivity of vegetation to PRE, increasing the area corresponding to a significant positive correlation from 15.3% to 59.9%. Overall, PRE has emerged as the dominant climate driver for the vegetation dynamics of the LP, followed by TEM and SR. These insights contribute to a comprehensive understanding of the climate-impact-related vegetation response mechanisms, providing guidance for efforts toward regional sustainable ecological development amid the changing climate.
]]>Forests doi: 10.3390/f15030470
Authors: Francis K. Dwomoh Roger F. Auch
Variability in the effects of disturbances and extreme climate events can lead to changes in tree cover over time, including partial or complete loss, with diverse ecological consequences. It is therefore critical to identify in space and time the change processes that lead to tree cover change. Studies of change are often hampered by the lack of data capable of consistently detecting different types of change. Using the Landsat satellite record to create a long time-series of land cover and land cover change, the U.S. Geological Survey Land Change Monitoring Assessment and Projection (LCMAP) project has made an annual time series of land cover across the conterminous United States for the period 1985 to 2018. Multiple LCMAP products analyzed together with map validation reference plots provide a robust basis for understanding tree cover change. In LCMAP (Collection 1.2), annual change detection is based on harmonic model breaks calculated at each Landsat pixel from the Continuous Change Detection and Classification (CCDC) algorithm. The results showed that the majority of CCDC harmonic model breaks (signifying change) indicated partial tree cover loss (associated with management practices such as tree cover thinning) as compared to complete tree cover loss (associated with practices like clearcut harvest or fire disturbance). Substantially fewer occurrences of complete tree cover loss were associated with change in land cover state. The area of annual tree cover change increased after the late 1990s and stayed high for the rest of the study period. The reference data showed that tree harvest dominated across the conterminous United States. The majority of tree cover change occurred in evergreen forests. Large estimates of disturbance-related tree cover change indicated that tree cover loss may have previously been underreported due to omission of partial tree cover loss in prior studies. This has considerable implications for forest carbon accounting along with tracking ecosystem goods and services.
]]>Forests doi: 10.3390/f15030469
Authors: Václav Zumr Oto Nakládal Jiří Remeš
The saproxylic beetles (deadwood-dependent) belong to frequently studied groups of forest insects. Eucnemidae is a rare and poorly studied saproxylic family with a hidden life strictly related to deadwood. We studied the family Eucnemidae in a beech reserve, using 59 window traps placed on standing deadwood (snags) and lying logs. A total of 348 specimens in eight species were recorded in two seasons. The identified species included one critically endangered species (CR): Hylis cariniceps; five endangered species (EN): H. olexai, H. foveicollis, Isorhipis melasoides, Eucnemis capucina, and Microrhagus lepidus; one new species found in Bohemia (a region of the Czech Republic): Clypeorhagus clypeatus; and one common species: Melasis buprestoides. Most species preferred lying logs, but E. capucina and M. buprestoides preferred snags. Species richness (q = 0) was higher on lying logs than on snags, and similarly, Shannon diversity (q = 1) was significantly higher on lying logs compared to snags. The species C. clypeorghagus, H. foveicollis, H. cariniceps, and M. lepides preferred moist lying logs, while M. buprestoides and E. capucina preferred drier snags with cavities. The results suggest that in beech forests, lying logs serve as a fundamental habitat for the existence of Eucnemids. This could be due to the more stable microclimatic conditions inside the lying deadwood. From this perspective, our study may help better understand the biology of hidden and understudied rare saproxylic Eucnemids.
]]>Forests doi: 10.3390/f15030468
Authors: Mihnea Ioan Cezar Ciocîrlan Elena Ciocîrlan Dănuț Chira Gheorghe Raul Radu Victor Dan Păcurar Emanuel Beșliu Ourania Grigoriadou Zormpa Oliver Gailing Alexandru Lucian Curtu
Phenology is considered an indicator of environmental changes, with direct implications in the length of the growing season; therefore, it offers essential information for a better understanding of the tree–environment relationships that could lead to the right decisions for forests’ sustainable use and conservation. A better understanding of how European beech (Fagus sylvatica) phenology responds to predicted climate change effects is important for forest management. This study aimed to assess bud burst and senescence among and within beech populations located along a steep elevational gradient. Phenological observations were carried out on 150 beech individuals along an altitudinal transect in the south-eastern Carpathian Mountains, from 550 to 1450 m, in five study sites in two consecutive years. The start of the bud burst, of senescence, and the duration of the growing season varied inversely proportionally to the elevational gradient in both monitored years. Individuals located at the highest altitude need 28 more days to start the growing season than those at the lowest altitude. There is an average difference of 14 days at the start of the growing season in the same beech populations between the two consecutive years. The first stage of senescence (yellowing of leaves) lasted longer in 2021 (21–32 days) than in 2022 (18–25 days), with a difference of 16%–28%, proportional to the increase in altitude. The association of field phenological data with meteorological data indicates that the start of the growing season occurs when the thermal threshold of 10 °C is exceeded, with an accumulation of a least 60 GDD (growing degree days) with a threshold of 0 °C in the last 7 days as a complementary condition. The appearance of the first stage of senescence, the yellowing of the leaves, was also influenced by the temperature and the accumulation of at least 72 SDD (senescence degree days) with a threshold of 0 °C in the last 7 days. Our results confirm that the temperature is the triggering meteorological factor for the onset of bud burst and leaf senescence in European beech.
]]>Forests doi: 10.3390/f15030467
Authors: Sivuyisiwe Situngu Nigel P. Barker
Mite communities inhabiting plants are known to be affected by several environmental factors, including temperature and humidity. This pilot study aimed to assess seasonal variation in mite abundance and species richness in three Southern African woody species: Gardenia thunbergia, Rothmannia globosa (both Rubiaceae), and Tecomaria capensis (Bignoniaceae). Furthermore, we investigated the influence of rainfall, maximum and minimum temperature, and relative humidity on mite abundance and species richness. The study was conducted in 2014–2015 in Makhanda, formerly known as Grahamstown, in the Eastern Cape, South Africa. Twenty mature leaves were collected from all aspects of the plant fortnightly over 34 weeks. Following sampling, the leaves were viewed under a dissecting microscope, and mites were collected from inside the domatia and surrounding leaf surface area. Species diversity and abundance were calculated for each season and compared. A multiple linear regression analysis was performed in R Studio to test relationships between species richness and abundance, minimum and maximum daily temperatures, relative humidity, rainfall the day before, and accumulative rainfall over the preceding two-week period. We found that mites were present in the leaves of the sampled plants across all seasons, but that mite abundance and species richness changed with each season. None of the environmental variables were correlated with mite abundance, and only relative humidity influenced species richness. These results were not consistent across the three plant species studied, and we point to weaknesses in our sampling approach for the observed results. This pilot study, one of the first from southern Africa, provides a window into the complex interactions between plants and mites. We advocate for more studies on mite seasonality to better understand if it is specific to a region, vegetation type, or host species.
]]>Forests doi: 10.3390/f15030466
Authors: Trisna Priadi Muhammad Hilmy Badruzzaman Nurul Sofiaturizkiyah Andi Hermawan Jamaludin Malik Rudi Hartono
Boron preservatives have insecticidal and fungicidal effects. The leaching problem of boron preservative-treated wood can be overcome using oil treatment. This study evaluated the resistance in a biodeterioration field test and the mechanical properties of manii wood (Maesopsis eminii Engl.) treated with boric acid and plant oils. Manii wood samples were impregnated in two stages with boric acid and vegetable oils (neem, tamanu, and candlenut oils). The impregnation process was performed in a chamber at a pressure of 7 kg cm−2 for approximately 4 h. Next, the sample was heated at temperatures of 60 °C, 120 °C, and 180 °C. The biodeterioration field test was conducted in ground contact for 100 days. In addition, mechanical tests in terms of modulus of elasticity (MOE), modulus of rupture (MOR), and hardness were conducted using an Instron universal testing machine. The test results prove that the combination of boric acid preservation with neem, tamanu, or candlenut oil treatment increases the resistance of manii wood to subterranean termites, especially when the treatment is accompanied by heating at 120 °C. The combination treatment of boric acid and plant oils also increases the MOE, MOR, and hardness values of manii wood.
]]>Forests doi: 10.3390/f15030465
Authors: Xiaochen Du Yilei Zheng Hailin Feng
Stress wave tomography technology uses instruments to collect stress wave velocity data via sensors, visualizes those velocity data, and reconstructs an image of internal defects using estimated velocity distribution. This technology can be used to detect the size, position, and shape of internal defects in hardwood, and it has increasingly attracted the attention of researchers. In order to obtain enough stress wave signals, 12 sensors are usually equidistantly positioned around the cross-section of trunks like a clock. Although this strategy is reasonable and convenient, it is obviously not the optimal signal acquisition strategy for all defects. In this paper, a novel sensor position’s optimization method for high-quality stress wave tomography is proposed. The relationship between the shape of defects and the planar distribution of sensors is established by taking the ray penetration ratio and degree of equidistant distribution of sensors as indicators. Through the construction of the fitness function and optimization conditions, the optimal strategy for the planar distribution of sensors was determined using the Genetic Algorithm. Seven samples containing simulated defects and real tree trunks were used to test the proposed algorithm, and the comparison results show that the image of internal defects in hardwood can be reconstructed with high accuracy after optimizing the sensor positions.
]]>Forests doi: 10.3390/f15030464
Authors: Xueli Zhang Yimin Fu Qinghao Pei Jinjun Guo Shengqi Jian
The Loess Plateau region of China suffers from severe soil erosion, and the selection of effective slope-protection vegetation is essential to prevent soil and water loss. This study focused on individual plants of common species in the Loess Plateau, such as Caragana korshinski Kom., Hippophae rhamnoides Linn., Pinus tabuliformis Carr., Robinia Pseudoacacia Linn., Populus tomentosa Carr., Prunus armeniaca Lam. The root spatial distribution, geometric morphology, and fractal characteristics of these plants were measured using the whole-root-excavation method, and the vertical pull-out force of their root systems was quantified using the in situ whole-plant root-pulling method. The results showed that H. rhamnoides dominates in the vertical spatial distribution of its root system through a larger number of inclined roots. C. korshinskii, P. tomentosa, R. pseudoacacia, and P. armeniaca dominate in the horizontal spatial distribution of their root systems through a greater number of horizontal roots. P. tabuliformis, on the other hand, achieves a relatively balanced distribution in both horizontal and vertical spaces through its well-developed taproot and numerous lateral roots. In terms of the geometric morphology and fractal characteristics of their root systems, H. rhamnoides and C. korshinskii exhibit a larger number of fine roots and complex branching, resulting in a higher total-root length, total-root surface area, and root fractal dimension. The soil-stabilizing ability of H. rhamnoides, C. korshinskii, and R. pseudoacacia was stronger, mainly influenced by their total-root length, total-root surface area, and inclined root quantity, and these species can be prioritized as typical vegetation for soil and water conservation in the construction of Loess Plateau vegetation. From the perspective of slope stabilization and soil conservation alone, we strongly recommend planting shrub vegetation in the Chinese Loess Plateau.
]]>Forests doi: 10.3390/f15030462
Authors: Claudia Pisuttu
Environmental pollution, unintended harm to beneficial organisms, and the development of herbicide resistance among weeds are the main consequences of the massive and consistent use of chemical herbicides in recent decades. The growing need for alternative solutions has been reinforced by restrictive policies, leading to a search for natural herbicidal candidates. Mycoherbicides, formulations containing plant pathogenic fungi, are viewed as promising substitutes for chemical herbicides. In the case of Ailanthus altissima (Mill.) Swingle, one of the worst invasive alien tree species in the world, Verticillium-based mycoherbicides offer a viable method for control, inducing a lethal wilt disease and leading plants to death within a few years. The demonstrated significant effectiveness enables addressing challenges posed by other—conventional—approaches. The current analysis matches key internal (strengths and weaknesses) and external factors (opportunities and threats) of Verticillium Nees isolates as environmentally-friendly control agents against the invasive A. altissima, by listing each singularly and then crossing them among the categories, drawing from the collaborative efforts of American, Austrian, and Italian research teams.
]]>Forests doi: 10.3390/f15030463
Authors: Manuel José Delgado-Capel Paloma Egea-Cariñanos Paloma Cariñanos
In the context of escalating global temperatures and intensified heat waves, the Mediterranean region emerges as a noteworthy hotspot, experiencing a surge in the frequency and intensity of these extreme heat events. Nature-based solutions, particularly management of urban green infrastructure (UGI) areas, have shown promising outcomes in adapting urban areas to the challenges posed by heat waves. The objective of the current study is twofold: firstly, to identify the compositional patterns of strategically distributed small public green spaces, demonstrating their enhanced capacity to mitigate the impact of heat waves in the Mediterranean region; secondly, to assess the association, direction, and explanatory strength of the relationship between the composition elements of the UGI areas and area typology, specifically focusing on the variation in land surface temperature (LST) values during heat wave episodes spanning from 2017 to 2023. The methodology involved obtaining land surface temperature (LST) values from satellite images and classifying green areas based on composition, orientation, and typology. Ordinal multiple regressions were conducted to analyze the relationship between the considered variables and LST ranges during heat wave episodes that occurred from 2017 to 2023. The findings indicate an increase in LST ranges across many areas, emphasizing heightened thermal stress in a Mediterranean medium-sized compact city, Granada (in the southeast of the Iberian Peninsula). Traditional squares, pocket parks and gardens, and pedestrian areas with trees and impervious surfaces performed better in reducing the probability of exceeding LST values above 41 °C compared to other vegetated patches mainly occupied by herbaceous vegetation and grass. The study concludes by advocating for the strategic incorporation of vegetation, especially trees, along with traditional squares featuring semipermeable pavement with trees and shrubbery, as a potential effective strategy for enhancing resilience against extreme heat events. Overall, this research enhances our understanding of LST dynamics during heat waves and offers guidance for bolstering the resilience of urban green spaces in the Mediterranean region.
]]>Forests doi: 10.3390/f15030461
Authors: Yi Zhang Junjie Lei Yuanying Peng Xiaoyong Chen Bowen Li Yazhen Chen Yichen Xu Taimoor Hassan Farooq Xiaohong Wu Jun Wang Wende Yan
Soil and water loss represent a significant environmental challenge in purple soil cropland in China. However, the quantity and mechanism of nutrient loss from purple soil remain unclear. To understand water and soil conservation and address nitrogen (N) and phosphorus (P) mitigation in Camellia oleifera forest stands on purple soil slope farmland, this study aimed to explore the resistance control effect of forest stands on N and P loss in such agricultural landscapes. In the study, a runoff plot experiment was conducted in purple soil slope farmland. The experiment included three distinct treatments: intercropping of oil tea (Camellia oleifera) and ryegrass (Lolium perenne L.), Camellia oleifera monoculture, and barren land served as the control treatment (CK). Water samples were collected and analyzed from the soil surface runoff and the middle soil layer at a depth of 20 cm (interflow) in three treatment plots under natural rainfall conditions in 2023. Various nutrient components, including total nitrogen (TN), dissolved nitrogen (DN), nitrate nitrogen (NO3−-N), ammonium nitrogen (NH4+-N), particulate nitrogen (PN), total phosphorus (TP), dissolved phosphorus (DP), phosphate (PO4+-P), and particulate phosphorus (PP), were measured in the water samples. The results indicated that intercropping effectively mitigated the loss of various forms of N and P in both surface runoff and interflow within purple soil slope farmland. Compared to the CK, the ryegrass intercropping reduced TN and TP loss by 29.3%–37.3% and 25.7%–38.9%, respectively. The ryegrass intercropping led to a decrease in the average total loss of TN, DN, NO3—N, and NH4+-N by 63.0, 24.3, 4.5, and 6.8 g/ha, corresponding to reductions of 33.3%, 47.6%, 58.3%, and 49.1%, respectively, compared to the CK. The average total loss of TP, DP, and PP decreased by 4.4, 1.8, and 1.4 g/hm2 in the intercropping, reflecting reductions of 32.3%, 31.3%, and 31.1%, respectively. The most significant proportion was observed in PN and PP within the runoff water solution, accounting for 53.3%–74.8% and 56.9%–61.0% of the TN and TP, respectively. These findings establish a foundation for purple soil and water conservation. The research provides valuable insights for land management and policymakers in developing erosion prevention and control programs for sloping cultivated land with Camellia oleifera forests in purple soils. Additionally, it offers guidance for soil and water conservation and prevention of surface source pollution in purple soil regions.
]]>Forests doi: 10.3390/f15030460
Authors: Man Zhou Qin Zhu He Wang Xiaopeng Wang Yuanyuan Zhan Jinshi Lin Yue Zhang Yanhe Huang Fangshi Jiang
The occurrence and development of Benggang is closely related to the decreased shear strength of collapsing walls. Plant roots can improve the soil shear resistance, and their soil reinforcing effect is restricted by soil moisture content (SMC). However, the effect and mechanism of SMC on the shear properties of rooted soil with different soil properties remain unknown. Therefore, the dominant soil erosion-resistant plant Dicranopteris linearis was selected as the research object, and shear tests were conducted to determine the shear strength response of rooted soil to SMC in the lateritic layer (LL), sandy layer (SL) and detritus layer (DL) with SMCs from 15% to 30%. The results showed that, compared with 15% SMC, the average decrease in shear strength of 30% SMC in the LL, SL and DL rooted soil were 17.37%, 21.96% and 23.36%, respectively. The rooted soil cohesion changed with increasing SMC in a binomial function, and the optimal SMC in the LL was 22.78%, which was higher than that of the SL (19.67%) and DL (18.39%). The cohesion increment of rooted soil weakened with increasing SMC, and the decrease was greatest in the SL. When the SMC increased from 15% to 30%, the internal friction angle of the rooted soil decreased by 34%, 11% and 12% in the LL, SL and DL, respectively. The Wu and Waldron’s model (WWM) correction parameters k′¯ of the LL, SL and DL were 0.59, 0.14 and 0.05, respectively. With the modified WWM, a new prediction model for the shear strength of rooted soil based on SMC was established. In short, a high SMC weakened the mechanical effect of Dicranopteris linearis-rooted soil, especially in the SL and DL of the collapsing wall, and attention should be given to drainage facilities when treating Benggang erosion.
]]>Forests doi: 10.3390/f15030459
Authors: Shaocheng Li Guangzhou Xu Chenkan Jiang Hailong Hu
A new method for the determination of the dynamic modulus of elasticity (Ed) of pine wood, based on the transverse vibration excitation and electromechanical impedance (EMI) response of the lead zirconate titanate (PZT) transducer is proposed. The influence of the length to thickness ratio of the pine specimen on the measurement accuracy was studied through modal simulation analysis. Based on the results of the modal simulation, the size of the pine specimen was optimized, and the scanning frequency range of the EMI response was determined. On this basis, the EMI simulation and test of the pine specimen coupled with a PZT patch were carried out to verify the effectiveness of the novel method. The impedance simulation results of three kinds of pine specimens show that a unique and significant formant appears in the real part of each EMI response curve, and the maximum relative errors of the rectangular PZT patch and circular PZT patch are 1.34% and 1.81%, respectively. The impedance test results of three kinds of pine specimens indicate that the maximum relative errors of the rectangular PZT patch and circular PZT patch are 1.41% and 1.68%, respectively, compared with the corresponding results obtained by the traditional transverse vibration method. Simulation and experimental results verify the validity of the proposed method for the elastic modulus determination of pine wood.
]]>Forests doi: 10.3390/f15030458
Authors: Andrii Bilous Roman Zadorozhniuk Anatolii Makarevych Viktor Svynchuk Andrii Lashko Maksym Bilous Viktor Myroniuk Maksym Matsala
The sustainable management of urban green areas requires clear and efficient protocols for measuring the biometric properties of tree vegetation. Specifically, operational in situ sampling solutions are essential to inventory forked (multi-stemmed) trees. This study aimed to assess the efficiency of two different sampling protocols for mean tree diameter at breast height (DBH) measurement of forked urban trees. The protocols were tested on a dataset of 76 forked trees, each having more than three stems and sampled in urban areas of Kyiv, Ukraine. First, we tested the efficiency of mean tree DBH estimations using measurements of randomly selected one, two, or three stems (random sampling, or RSM). Second, we examined different combinations of the thinnest, thickest, and average stems (identified visually) for each tree to estimate mean tree DBH (targeted sampling, or TSM). The distributions of mean tree DBH and root mean square errors (RMSE) were utilized to compare the utility of the two approaches. The TSM of three stems (the thinnest, thickest, and average) provided the highest accuracy of mean tree DBH estimation (RMSE% = 6.3% of the mean), compared to the RSM (RMSE% = 12.1%). The TSM of the four thickest stems demonstrated the overestimation of mean tree DBH for forked trees with five or more stems. Accurate mean tree DBH estimates can be derived with negligible systematic errors applying the RSM over a large number of measured trees. However, these estimates will not likely match the measurements from previous inventories due to random stem selection. We recommend using the TSM with measuring three specific stems as a balanced solution in terms of estimation accuracy, bias, and time costs.
]]>Forests doi: 10.3390/f15030457
Authors: Ting Gao Changming Chen Zhen Zhu
In recent years, stricter environmental rules have affected the entire bamboo industry in China. The increased costs for managing environmental issues hinder the growth of the bamboo forest harvesting and transportation sector in the upstream part of the industry chain. Analyzing how environmental changes affect the entire bamboo industry can give a deeper understanding of the regional transfer within the bamboo industry in China, and it can give more experience to the bamboo industry in developing countries. This study, based on the Pollution Haven Hypothesis and the theory of externalities, collected panel data from 16 provinces in China from 2000 to 2020 and examined the discrepancies in bamboo industry development and the varying intensities of market-oriented environmental regulation (MER). By constructing a fixed effects model and employing econometric methods, this study analyzed the spatiotemporal impact of MER on the output value of the bamboo harvesting and transportation industry (BHTI) and explored whether MER is a crucial factor causing the transfer of the bamboo industry across regions. The findings indicate that there is a noticeable shift of BHTI from the eastern to the central and western regions. Additionally, there is a substantial adverse effect of MER on the BHTI output value, especially in the eastern region. This confirms the transfer of industries between regions, which is a novel contribution of this article. Based on the findings of this study, some recommendations have been given for the response to the environmental regulation for bamboo industries in the future.
]]>Forests doi: 10.3390/f15030456
Authors: Junxiang Zhang Cui Zhou Gui Zhang Zhigao Yang Ziheng Pang Yongfeng Luo
The estimation of forest above-ground biomass (AGB) can be significantly improved by leveraging remote sensing (RS) and deep learning (DL) techniques. In this process, it is crucial to obtain appropriate RS features and develop a suitable model. However, traditional methods such as random forest (RF) feature selection often fail to adequately consider the complex relationships within high-dimensional RS feature spaces. Moreover, challenges related to parameter selection and overfitting inherent in DL models may compromise the accuracy of AGB estimation. Therefore, this study proposes a novel framework based on freely available Sentinel-1 synthetic aperture radar (SAR) and Sentinel-2 optical data. Firstly, we designed new indices through the formula analogous with vegetation index calculation to integrate multidimensional spectral and structural information. Then, leveraging the simplicity of computational principles, a pigeon-inspired optimization algorithm (PIO) was introduced into a bi-directional long short-term memory neural network (PIO-BiLSTM), which achieved the set objective function through repeated iteration and validation to obtain the optimal model parameters. Finally, to verify the framework’s effect, we conducted experiments in two different tree species and compared another seven classical optimization algorithms and machine learning models. The results indicated that the new indices significantly improved the inversion accuracy of all models in both categories, and the PIO-BiLSTM model achieved the highest accuracy (Category-1: R2 = 0.8055, MAE = 8.8475 Mg·ha−1, RMSE = 12.2876 Mg·ha−1, relative RMSE = 18.1715%; Category-2: R2 = 0.7956, MAE = 1.7103 Mg·ha−1, RMSE = 2.2887 Mg·ha−1, relative RMSE = 9.3000%). Compared with existing methods, the proposed framework greatly reduced the labor costs in parameter selection, and its potential uncertainty also decreased by up to 9.0%. Furthermore, the proposed method has a strong generalization ability and is independent of tree species, indicating its great potential for future forest AGB inversion in wider regions with diverse forest types.
]]>Forests doi: 10.3390/f15030455
Authors: Qiaoling Li Zhiyuan Huang Zheke Zhong Fangyuan Bian Xiaoping Zhang
Bamboo shoot processing wastewater (BBPW) is rich in organic matter and organic acids and can be used as a nutrient source for microbial growth and biofertilization. In this study, Pseudomonas K22-D and Terribacillus goriness CS3 were isolated from bamboo forest soil with plant growth-promoting properties. Biofertilizers were prepared by inoculating bacteria into BBPW, and the effects of their application in a bamboo forest were evaluated. The chemical oxygen demand, TOC, TN, and NH4-N contents decreased after inoculation, indicating that the bacteria were able to degrade macromolecules in BBPW. The BBPW biofertilizer produced by mixed bacteria (CS3 + K22-D) significantly improved the soil organic carbon and mineral-associated organic carbon content and reduced the pH, alkali-hydrolysable nitrogen, available phosphorus, and available potassium content of the soils in the bamboo forest, which might be attributed to the high C:N ratio and microbial synergism in the biofertilizer and the fast growth period of bamboo shoots. Notably, the CS3 biofertilizer significantly increased soil-available phosphorus (90.25%), and the K22-D biofertilizer significantly decreased soil-available phosphorus (70.33%) compared with CK, suggesting that the presence of inorganic phosphorus-solubilizing bacteria can promote soil P. We believe that the return of inoculated bamboo shoot processing wastewater to bamboo plantations can be an eco-friendly, sustainable practice for bamboo forest management.
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