Research

14 pages, 4281 KiB

Open AccessArticle

Effects of Stand Types on Ectomycorrhizal Fungal Community Composition and Structure of Pinus massoniana in Subtropical Mountain Forest Ecosystems

by Dandan Jiang, Ming Xu, Yunli Yang and Jian Zhang

Forests 2024, 15(2), 258; https://doi.org/10.3390/f15020258 - 29 Jan 2024

Viewed by 733

Abstract

Tree species composition in forest ecosystems is an important biological factor affecting the diversity of ectomycorrhizal fungi (EMF). However, little is known about the composition and diversity of EMF communities associated with Pinus massoniana in different P. massoniana association habitats (MpAHs) in subtropical [...] Read more.

Tree species composition in forest ecosystems is an important biological factor affecting the diversity of ectomycorrhizal fungi (EMF). However, little is known about the composition and diversity of EMF communities associated with Pinus massoniana in different P. massoniana association habitats (MpAHs) in subtropical mountains. This study investigated the EMF community characteristics of P. massoniana in different MpAHs using plant community surveys, soil property analyses, and mycorrhizal identification. A total of 56 operational taxonomic units (OTUs), belonging to 20 families and 22 genera, were identified. OTU richness of Basidiomycota (58.93%) was higher than that of Ascomycota (41.07%). Unclassified Helotiales, Russula, Lactarius, and Tomentella were the dominant groups. Different stand types significantly altered the EMF communities of P. massoniana (p < 0.05, for Shannon index) and the associations of P. massoniana + Populus adenopoda (Mp_Pa) had the highest diversity of EMF, while P. massoniana + Cunninghamia lanceolata (Mp_Cl) had the lowest diversity. The number of specific OTUs was higher than shared OTUs. Similarity index and principal coordinate analysis indicated that the EMF communities of P. massoniana varied significantly in different MpAHs (R² = 0.21, p = 0.001). The linear regression model showed that the EMF diversity of P. massoniana was positively related to tree species diversity, indicating that the EMF diversity of P. massoniana is influenced by tree species diversity. The findings provide a reasonable reference for tree species configuration in the process of mixed transformation or near-natural management of plantations. Full article

(This article belongs to the Special Issue Influence of Environmental Changes on Forest Soil Quality and Health)

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14 pages, 2755 KiB

Open AccessArticle

Diurnal, Seasonal, and Vertical Changes in Photosynthetic Rates in Cinamomum camphora Forests in Subtropical China

by Zhiqiang Li, Qinxiang Wu, Yuanying Peng, Junjie Lei, Shuguang Liu, Can Mao, Xin Liu, Jun Wang, Wende Yan and Xiaoyong Chen

Forests 2024, 15(1), 183; https://doi.org/10.3390/f15010183 - 17 Jan 2024

Viewed by 761

Abstract

The increase in the global atmospheric CO₂ concentration is expected to increase the productivity of forests, but the dynamic processes of such increased productivity in the forest canopy remain unclear. In this study, diurnal and seasonal variations and vertical changes in photosynthetic [...] Read more.

The increase in the global atmospheric CO₂ concentration is expected to increase the productivity of forests, but the dynamic processes of such increased productivity in the forest canopy remain unclear. In this study, diurnal and seasonal variations and vertical changes in photosynthetic rates were investigated in Camphor tree (Cinnamomum camphora) forests in subtropical China. The effect of photosynthetically active radiation (PAR) and CO₂ concentrations on photosynthetic rates were also examined in the studied forests. Results showed the diurnal patterns of photosynthesis exhibited two peaks on sunny days, but only one peak on cloudy days. The daily average photosynthetic rate on cloudy days was approximately 74% of that on sunny days. The photosynthetic rate decreased along the vertical forest canopy profile. If the photosynthetic rate in the upper canopy layer was 100%, the corresponding rates were 83% and 25% in the middle and lower canopy layers, respectively. The rates of dark respiration derived from the PAR response curve were 1.73, 1.25, and 1.0 µmol m⁻² s⁻¹ for the upper, middle, and lower canopy layers, respectively. The apparent quantum yield of photosynthesis was 0.0183, 0.0186, and 0.0327 µmol CO₂ µmol⁻¹ PAR for the upper, middle, and lower canopy, respectively. The initial slope of the photosynthetic response curve to CO₂ was highest in the upper canopy and lowest in the lower canopy. The seasonal variation in photosynthetic rates exhibited a two-peaked pattern at all canopy positions, with the two peaks occurring in June and September. The stand biomass and biomass carbon storage were 144.7 t ha⁻¹ and 71.6 t C ha⁻¹ in the examined forests, respectively. The study provides a scientific reference for future research on accessing carbon sequestration and designing forest management practices, specifically in regulating canopy structure in subtropical regions. Full article

(This article belongs to the Special Issue Influence of Environmental Changes on Forest Soil Quality and Health)

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14 pages, 2032 KiB

Open AccessArticle

The Effects of Shading on the Photosynthetic Performance of Endangered Plant Horsfieldia hainanensis Seedlings

by Renjie Wang, Jinman Ma, Ronglin Huang, Yong Wang, Yi Jiang, Yaming Ling, Jisheng Yang, Huizi Liang, Xiongsheng Liu and Nanyan Liao

Forests 2024, 15(1), 3; https://doi.org/10.3390/f15010003 - 19 Dec 2023

Viewed by 693

Abstract

Shading is one of the management practices for preventing the damage or injury of plant seedlings during extreme weather and climate events, such as very high temperatures and heat stress. In this study, we investigated the effects of different shading conditions on the [...] Read more.

Shading is one of the management practices for preventing the damage or injury of plant seedlings during extreme weather and climate events, such as very high temperatures and heat stress. In this study, we investigated the effects of different shading conditions on the photosynthetic characteristics of the endangered plant Horsfieldia hainanensis in Guangxi, China. The H. hainanensis seedlings in this study underwent five shading treatments, including 20% (L1), 40% (L2), 60% (L3), 80% (L4), and 100% (control) of full sunlight. The net growth of their diameter and height, and photosynthetic gas exchange parameters including their photosynthesis rate (Pn), transpiration rate (Tr), intercellular CO₂ concentration (Ci), and water use efficiency (WUE) were measured for the examined seedlings. The OJIP curve and 820 nm light absorption curve, and the osmotic substances and products of membrane lipid peroxidation were employed to assess photosynthetic capacity, identify the factors constraining photosynthetic carbon assimilation, and investigate the mechanisms influencing photosystem II (PSII) and photosystem I (PSI) in the seedlings under shade stress. The results showed that the seedlings in the L2 treatments had the highest net growth and Pn, the best photosynthetic performance, and the best coordination between PSII and PSI. The net photosynthesis (Pn) levels exhibited a declining trend in the following order: L2 > L3 > L4 > L1. In the L1 treatment, non-stomatal factors emerged as the primary determinant affecting the Pn of the seedlings. The performance index (potential) of PSII, representing the conservation of absorbed photon energy to intersystem electron acceptor reduction (PI_ABS and ΔI/I₀) of the seedlings, decreased in the order of L2 > L3 > L4 > L1. The photosystem performance and the coordination between PSII and PSI (Φ_(PSI/PSII)) of the seedlings decreased in the order of L2 > L1 > L3 > L4. Under the low and moderate shading stresses (L1–L3), more serious damages occurred in PSII than in PSI, including on the donor side of PSII and in the electron transfer from Q_B to the acceptor side of PSI. In contrast, more considerable injury occurred in PSI than in PSII under the stress of the heavy shading treatment (L4). Considering the alterations in their leaf osmotic regulatory substances and membrane lipid peroxidation products, our findings indicate that the L2 treatment was the most conducive to the growth of the H. hainanensis seedlings. In contrast, the L1 treatment subjected H. hainanensis seedlings to the most significant stress, resulting in substantial damage to their growth and photosynthetic mechanisms. Our research provides a scientific insight into and a practical guide for the selection of an appropriate light intensity for the conservation and cultivation of endangered plant species, such as H. hainanensis. Full article

(This article belongs to the Special Issue Influence of Environmental Changes on Forest Soil Quality and Health)

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18 pages, 3073 KiB

Open AccessArticle

Impact of Three Chainsaw Lubricants on Forest Soil Bacterial Community, Soil Respiration and Seedling Growth

by Ikhyun Kim, Keumchul Shin, Jeongjae Kim, Eugene Ha and Byoungkoo Choi

Forests 2023, 14(12), 2287; https://doi.org/10.3390/f14122287 - 22 Nov 2023

Cited by 1 | Viewed by 668

Abstract

Lubricants are applied onto chainsaw blades to achieve their optimum cutting performance; however, during logging or timber operations, lubricants may penetrate the forest soil. The persistent organic pollutants in lubricants may cause environmental damage, and different types of lubricants vary in terms of [...] Read more.

Lubricants are applied onto chainsaw blades to achieve their optimum cutting performance; however, during logging or timber operations, lubricants may penetrate the forest soil. The persistent organic pollutants in lubricants may cause environmental damage, and different types of lubricants vary in terms of their environmental impact. Hence, selecting appropriate lubricants for timber operations is important for sustainable forest management. In this study, the effects of three lubricant types—biodegradable oil (bio-oil), petroleum-based bar-and-chain oil (mineral oil), and petroleum-based recycled oil (recycled oil)—on soil health were evaluated. The study was conducted in a controlled nursery setting, simulating post-logging reforestation. Sixteen types of polycyclic aromatic hydrocarbons and the total petroleum hydrocarbon concentrations in the soil samples were analyzed. Bio-oil facilitated faster recovery from soil contamination, whereas mineral oil exhibited slow and incomplete recovery. Recycled lubricants appear to be more environmentally sustainable options, indicating lower long-term soil contamination risks than petroleum-based lubricants. From a productivity perspective, the lubricant that supported the growth of seedlings was bio-oil. The findings of our study contribute to responsible lubricant selection for enhancing the overall health and sustainability of forest ecosystems. Full article

(This article belongs to the Special Issue Influence of Environmental Changes on Forest Soil Quality and Health)

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19 pages, 12729 KiB

Open AccessArticle

Spatial and Temporal Variations of Carbon Dioxide Fluxes in Urban Ecosystems of Changsha, China

by Zijun Deng, Xin Liu, Haoran Zu, Junyi Luo, Ying Chen, Meiling Yi, Xiao Wang, Xiaocui Liang, Xiang Zhang and Wende Yan

Forests 2023, 14(11), 2201; https://doi.org/10.3390/f14112201 - 06 Nov 2023

Viewed by 1007

Abstract

Understanding the spatial and temporal variations of urban carbon dioxide fluxes (

F_{C O_{2}}

) and their influencing factors is crucial for solving urban climate problems and promoting the development of low-carbon cities. In this study, the carbon dioxide flux ( [...] Read more.

Understanding the spatial and temporal variations of urban carbon dioxide fluxes (

F_{C O_{2}}

) and their influencing factors is crucial for solving urban climate problems and promoting the development of low-carbon cities. In this study, the carbon dioxide flux (

F_{C O_{2}}

) in Changsha City, China, was analyzed using the eddy covariance technique and flux footprint model. The results showed that the extent of the flux footprint within the observation site was mostly limited to 500 m. Diurnal variation of

F_{C O_{2}}

showed a regular pattern influenced by plant photosynthesis and traffic flow. Meanwhile, photosynthesis was directly regulated by photosynthetically active radiation and indirectly regulated by air temperature and water vapor pressure differences. The average value of

F_{C O_{2}}

was lower during the daytime than at night, indicating the high vegetation cover (43.5%) in the study area. In addition, there were spatial characteristics of

F_{C O_{2}}

in each wind direction due to different surface land use in the study area. Notably, a decreasing trend in carbon dioxide content was observed after the area covered by vegetation was 1.8 times the area of buildings and major roads combined. These findings guide climate management, urban planning, and sustainable development toward a low-carbon society. Full article

(This article belongs to the Special Issue Influence of Environmental Changes on Forest Soil Quality and Health)

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12 pages, 6689 KiB

Open AccessArticle

Intelligent Analysis Strategy for the Key Factor of Soil Nitrogen and Phosphorus Loss via Runoff under Simulated Karst Conditions

by Yuqi Zhang, Rongchang Zeng, Tianyang Li, Lan Song and Binghui He

Forests 2023, 14(10), 2109; https://doi.org/10.3390/f14102109 - 21 Oct 2023

Viewed by 808

Abstract

Given the complex influence of various factors on soil nitrogen (N) and phosphorus (P) loss through runoff in a karst environment, analyzing the importance of different factors to determine the most efficient method for soil nutrient conservation remains a key challenge. Herein, we [...] Read more.

Given the complex influence of various factors on soil nitrogen (N) and phosphorus (P) loss through runoff in a karst environment, analyzing the importance of different factors to determine the most efficient method for soil nutrient conservation remains a key challenge. Herein, we proposed a novel intelligent analysis strategy based on the Random Forest (RF) regression algorithm to identify the main features and discover the fundamental mechanisms among them under a rock-exposed karst slope with synchronous existence of surface runoff and subsurface leakage. Typically, the results indicated that the rock–soil angle (β) was the main factor influencing soil N and P loss, which was further confirmed based on the RF regression-multifactor analysis. The proposed strategy was used to characterize the relationships of inflow rate, soil bed–ground angle, and rock–soil angle with soil N and P concentrations in soil surface runoff, subsurface runoff, and fissure runoff to study the potential application of soil N and P loss under karst conditions. Our results provide a new approach and promising potential for soil nutrient conservation and related soil and plant research. Full article

(This article belongs to the Special Issue Influence of Environmental Changes on Forest Soil Quality and Health)

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20 pages, 10272 KiB

Open AccessArticle

Impacts of Climate Warming and Humidification on Vegetation Activity over the Tibetan Plateau

by Zhe He, Ting Zhou, Jiaqi Chen, Yajing Fu, Yuanying Peng, Li Zhang, Tongyu Yao, Taimoor Hassan Farooq, Xiaohong Wu, Wende Yan and Jun Wang

Forests 2023, 14(10), 2055; https://doi.org/10.3390/f14102055 - 14 Oct 2023

Cited by 1 | Viewed by 1133

Abstract

Vegetation is the most vulnerable component of terrestrial ecosystems to climate change. In recent decades, there has been a significant warming and humidification trend in the Tibetan Plateau. It is crucial to study and analyze the impact of these changes on the ecosystem [...] Read more.

Vegetation is the most vulnerable component of terrestrial ecosystems to climate change. In recent decades, there has been a significant warming and humidification trend in the Tibetan Plateau. It is crucial to study and analyze the impact of these changes on the ecosystem and their future trends for protecting the Tibetan Plateau’s ecosystem. This study collected and analyzed climate (temperature, precipitation) data and vegetation index data (the normalized difference vegetation index (NDVI) and the leaf area index (LAI)), as well as data from significance tests combined with Mann–Kendall tests and Sen’s slope estimation. The effects of temperature and precipitation factors on vegetation indices were revealed, leading to a multiple regression model predicting NDVI and LAI value changes under climate change from 2021 to 2100. The results indicate a general increase in temperature and precipitation levels across the Tibetan Plateau between 2000 and 2020. The climate experienced a clear pattern of warming and moist conditions, with the southeast region experiencing warmer and wetter conditions, and the northwest region experiencing drier and colder conditions. The trends of the LAI and NDVI values of the Tibetan Plateau indicated a general increase, with a gradual decline from the southeast to the northwest. Precipitation and temperature were differentially correlated with the NDVI and LAI values across various regions of the plateau. Between 2021 and 2100, the Tibetan Plateau is expected to experience year-on-year increases in both precipitation and temperature levels. However, the increase in precipitation was found to be less significant than that of the climate and, comparatively, smoother. There is a certain correlation between the NDVI and LAI values, and the changes in temperature and precipitation. The variations of both are more influenced by temperature than precipitation, with an overall increasing trend observed over the years, which is also quite evident. This study could serve as a scientific foundation and a point of reference for monitoring vegetation changes over a long period of time on the plateau, as well as for the planning and execution of ecological development in the Tibetan Plateau. Full article

(This article belongs to the Special Issue Influence of Environmental Changes on Forest Soil Quality and Health)

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16 pages, 2902 KiB

Open AccessArticle

Assessment of Soil Quality in the Transformation from Pure Chinese Fir Plantation to Mixed Broad-Leaved and Cunninghamia lanceolata Plantation in Subtropical China

by Xiaoyu Cao, Zelian Zhang, Wende Yan, Yongjun Mo, Shuping Wu, Menglei Wang and Yuanying Peng

Forests 2023, 14(9), 1867; https://doi.org/10.3390/f14091867 - 13 Sep 2023

Viewed by 835

Abstract

To assess the alterations in soil properties resulting from the interplanting of broad-leaved tree species within coniferous forests, we conducted an investigation into soil quality in a mixed Chinese fir and broad-leaved forest, as well as in a Chinese fir pure forest (used [...] Read more.

To assess the alterations in soil properties resulting from the interplanting of broad-leaved tree species within coniferous forests, we conducted an investigation into soil quality in a mixed Chinese fir and broad-leaved forest, as well as in a Chinese fir pure forest (used as a control) in subtropical China. A total of 15 soil physicochemical properties were assessed across three soil depths—0–15 cm, 15–30 cm, and 30–45 cm—for the two forest types in the experimental study. Principal component analysis in conjunction with the Norm value was employed to create a minimal data set (MDS) for assessing six indicators, including bulk density (BD), total nitrogen (TN), total phosphate (TP), available potassium (AK), soil pH, and catalase (CAT). The soil quality index (SQI) was calculated for both forest types. The results demonstrated that following the interplanting of broad-leaved tree species in the Chinese fir forest, all soil physicochemical indicators were significantly improved compared to the control, and significant differences were also observed in the 0–15 cm and 15–30 cm soil layers (p < 0.05). The overall average of the SQI of the mixed forest (0.8523, 0.6636) was significantly higher than that of the control (0.4477, 0.3823) (p < 0.05) in the 0–15 cm and 15–30 cm soil layers, respectively. However, there was no significant difference in the SQI in the 30–45 cm soil layer (p > 0.05) between the two forest types. The results indicated that the SQI based on the minimal dataset (MDS) can reflect the SQI of the total dataset (TDS) when assessing soil quality in forests. Our research provides valuable scientific insights into soil science and an understanding of the relationships between soil properties, forest structure, and species composition in sustainable forest management. Full article

(This article belongs to the Special Issue Influence of Environmental Changes on Forest Soil Quality and Health)

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