Forests

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5 pages, 662 KiB

Open AccessEditorial

Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems

by Yanjiang Cai and Scott X Chang

Forests 2020, 11(3), 297; https://doi.org/10.3390/f11030297 - 7 Mar 2020

Cited by 19 | Viewed by 3245

Abstract

Forests cover around 30% of the global land area and forest ecosystems can store over 70% of total soil organic carbon (SOC) of all terrestrial ecosystems, but SOC stocks and greenhouse gas (GHG) emissions may be affected by both natural and anthropogenic disturbances. [...] Read more.

Forests cover around 30% of the global land area and forest ecosystems can store over 70% of total soil organic carbon (SOC) of all terrestrial ecosystems, but SOC stocks and greenhouse gas (GHG) emissions may be affected by both natural and anthropogenic disturbances. Even though the changes in forest soil C pool can have a significant effect on climate change, there are some contradictory results regarding the role of forest disturbance on SOC sequestration, GHG emissions, and the mitigation of global changes. Therefore, there is a need to better understand the impact of different disturbance regimes on forest soil C storage and GHG emissions. A Special Issue was therefore organized for discussing the responses of soil C storage and GHG emissions to various types of disturbances in forest ecosystems and a total of 15 studies were accepted for this special issue to assess these responses. This Special Issue includes the effects of storms and beetle outbreaks, Karstification, rock desertification, warming, nitrogen addition, land-use change, field tillage, and biochar application on soil C dynamics and/or GHG emissions. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

Research

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13 pages, 8060 KiB

Open AccessArticle

CO₂ Transfer Characteristics of Calcareous Humid Subtropical Forest Soils and Associated Contributions to Carbon Source and Sink in Guilin, Southwest China

by Fen Huang, Jianhua Cao, Tongbin Zhu, Mingzhu Fan and Mengmeng Ren

Forests 2020, 11(2), 219; https://doi.org/10.3390/f11020219 - 14 Feb 2020

Cited by 6 | Viewed by 2442

Abstract

In karst landscapes, soil CO₂ is a key factor in weathering processes and carbon cycling, where its distribution and migration characteristics directly affect fluxes in carbon source–sink dynamics. We measured the CO₂ emission and dissolution rates of carbonate tablets in calcareous [...] Read more.

In karst landscapes, soil CO₂ is a key factor in weathering processes and carbon cycling, where its distribution and migration characteristics directly affect fluxes in carbon source–sink dynamics. We measured the CO₂ emission and dissolution rates of carbonate tablets in calcareous soil developed from limestone and red soil developed from clastic rock, in karst and non-karst subtropical forests, in Guilin, southwest China between 2015 and 2018, to analyze their CO₂ transfer characteristics and source–sink effects. The results showed similar average soil respiration rates between calcareous soil and red soil, with an average CO₂ emission flux of 1305 and 1167 t C km⁻² a⁻¹, respectively. Carbonate tablet dissolution rates were bidirectional with increasing depth and were greater in red soil than calcareous soil, averaging 13.88 ± 5.42 and 7.20 ± 2.11 mg cm⁻² a⁻¹, respectively. CO₂ concentration was bidirectional with increasing soil depth, reaching a maximum at the base of the soil–atmosphere interface (50–60 cm), and the bidirectional gradient was more distinctive in red soil. Change in the carbon isotope value of soil CO₂ was also bidirectional in calcareous soils, for which the overall average was 0.87‰ heavier in calcareous than red soil. The carbon sink in calcareous soil in karst regions was estimated to be 11.97 times that of red soil in non-karst regions, whereas its role as a carbon source is just 1.12 times that of red soil, thus indicating the key role of karst soil in the reduction of atmospheric CO₂. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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15 pages, 12640 KiB

Open AccessArticle

The Influence of Land Use Patterns on Soil Bacterial Community Structure in the Karst Graben Basin of Yunnan Province, China

by Jiangmei Qiu, Jianhua Cao, Gaoyong Lan, Yueming Liang, Hua Wang and Qiang Li

Forests 2020, 11(1), 51; https://doi.org/10.3390/f11010051 - 31 Dec 2019

Cited by 24 | Viewed by 3189

Abstract

Land use patterns can change the structure of soil bacterial communities. However, there are few studies on the effects of land use patterns coupled with soil depth on soil bacterial communities in the karst graben basin of Yunnan province, China. Consequently, to reveal [...] Read more.

Land use patterns can change the structure of soil bacterial communities. However, there are few studies on the effects of land use patterns coupled with soil depth on soil bacterial communities in the karst graben basin of Yunnan province, China. Consequently, to reveal the structure of the soil bacterial community at different soil depths across land use changes in the graben basins of the Yunnan plateau, the relationship between soil bacterial communities and soil physicochemical properties was investigated for a given area containing woodland, shrubland, and grassland in Yunnan province by using next-generation sequencing technologies coupled with soil physicochemical analysis. Our results indicated that the total phosphorus (TP), available potassium (AK), exchangeable magnesium (E-Mg), and electrical conductivity (EC) in the grassland were significantly higher than those in the woodland and shrubland, yet the total nitrogen (TN) and soil organic carbon (SOC) in the woodland were higher than those in the shrubland and grassland. Proteobacteria, Verrucomicrobia, and Acidobacteria were the dominant bacteria, and their relative abundances were different in the three land use types. SOC, TN, and AK were the most important factors affecting soil bacterial communities. Land use exerts strong effects on the soil bacterial community structure in the soil’s surface layer, and the effects of land use attenuation decrease with soil depth. The nutrient content of the soil surface layer was higher than that of the deep layer, which was more suitable for the survival and reproduction of bacteria in the surface layer. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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10 pages, 1598 KiB

Open AccessArticle

Effects of Plum Plantation Ages on Soil Organic Carbon Mineralization in the Karst Rocky Desertification Ecosystem of Southwest China

by Hui Yang, Biqin Mo, Mengxia Zhou, Tongbin Zhu and Jianhua Cao

Forests 2019, 10(12), 1107; https://doi.org/10.3390/f10121107 - 4 Dec 2019

Cited by 11 | Viewed by 2549

Abstract

Soil organic carbon (SOC) mineralization is closely related to carbon source or sink of terrestrial ecosystem. Understanding SOC mineralization under plum plantation is essential for improving our understanding of SOC responses to land-use change in karst rocky desertification ecosystem. In this study, 2-year, [...] Read more.

Soil organic carbon (SOC) mineralization is closely related to carbon source or sink of terrestrial ecosystem. Understanding SOC mineralization under plum plantation is essential for improving our understanding of SOC responses to land-use change in karst rocky desertification ecosystem. In this study, 2-year, 5-year, and 20-year plum plantations and adjacent abandoned land dominated by herbs were sampled, and a 90-day incubation experiment was conducted to investigate the effect of plum plantations with different ages on SOC mineralization in subtropical China. Results showed that: (1) Plum plantation significantly decreased SOC content compared with abandoned land, but there was no significant difference in SOC content among plum plantations with different ages. Oppositely, the accumulative SOC mineralization (C_t) and potential SOC mineralization (C₀) showed different responses to plum plantation ages. (2) The dynamics of the SOC mineralization were a good fit to a first-order kinetic model. Both C₀ and C_t in calcareous soil of this study was several- to 10-folds lower than other soils in non-karst regions, indicating that SOC in karst regions has higher stability. (3) Correlation analysis revealed that both C_t and C₀ was significantly correlated with soil calcium (Ca), suggesting an important role of Ca in SOC mineralization in karst rocky desertification areas. In conclusion, a Ca-rich geological background controls SOC mineralization in karst rocky desertification areas. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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11 pages, 1989 KiB

Open AccessArticle

Biochar Is Comparable to Dicyandiamide in the Mitigation of Nitrous Oxide Emissions from Camellia oleifera Abel. Fields

by Bangliang Deng, Haifu Fang, Ningfei Jiang, Weixun Feng, Laicong Luo, Jiawei Wang, Hua Wang, Dongnan Hu, Xiaomin Guo and Ling Zhang

Forests 2019, 10(12), 1076; https://doi.org/10.3390/f10121076 - 27 Nov 2019

Cited by 23 | Viewed by 2755

Abstract

Research Highlights: Intensive nitrogen (N) application for agricultural purposes has substantially increased soil nitrous oxide (N₂O) emissions. Agricultural soil has great potential in the reduction of N₂O emissions, and applications of biochar and nitrification inhibitors may be useful [...] Read more.

Research Highlights: Intensive nitrogen (N) application for agricultural purposes has substantially increased soil nitrous oxide (N₂O) emissions. Agricultural soil has great potential in the reduction of N₂O emissions, and applications of biochar and nitrification inhibitors may be useful for mitigating agricultural soil N₂O emissions. Background and Objectives: Camellia oleifera Abel. is an important woody oil plant in China. However, intensive N input in C. oleifera silviculture has increased the risk of soil N₂O emissions. As an important greenhouse gas, N₂O is characterized by a global warming potential at a 100-year scale that is 265 times that of carbon dioxide. Thus, mitigation of soil N₂O emissions, especially fertilized soils, will be crucial for reducing climate change. Materials and Methods: Here, we conducted an in situ study over 12 months to examine the effects of C. oleifera fruit shell-derived biochar and dicyandiamide (DCD) on soil N₂O emissions from a C. oleifera field with intensive N application. Results: A three-fold increase of cumulative soil N₂O emissions was observed following N application. Cumulative N₂O emissions from the field with N fertilization were reduced by 36% and 44% with biochar and DCD, respectively. While N₂O emissions were slightly deceased by biochar, the decrease was comparable to that by DCD. Conclusions: Results indicated that biochar may mitigate soil N₂O emissions substantially and similarly to DCD under specific conditions. This result should be examined by prolonged and multi-site studies before it can be generalized to broader scales. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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19 pages, 4450 KiB

Open AccessArticle

Effects of Long-Term Successive Rotations, Clear-Cutting and Stand Age of Prince Rupprecht’s larch (Larix principis-rupprechtii Mayr) on Soil Quality

by Kuangji Zhao, Timothy J. Fahey, Dong Liang, Zhongkui Jia and Lvyi Ma

Forests 2019, 10(10), 932; https://doi.org/10.3390/f10100932 - 22 Oct 2019

Cited by 8 | Viewed by 3106

Abstract

A decline in soil quality is a major factor contributing to the degradation of forest ecological function. Vegetation plays a vital role in maintaining soil quality; however, the influence of plantation length on soil quality remains unclear. In this study, we collected soil [...] Read more.

A decline in soil quality is a major factor contributing to the degradation of forest ecological function. Vegetation plays a vital role in maintaining soil quality; however, the influence of plantation length on soil quality remains unclear. In this study, we collected soil samples in Northern China using a space-for-time substitution method. Soil were collected from control grassland; a clear-cutting site; 16-year-old (young, first, and second generation), 28-year-old (immature, first, and second generation), and 44-year-old (mature, first generation) Larix principis-rupprechtii Mayr stands in May, July, and September 2016. We measured soil physical and chemical properties, microbial communities, and enzymatic activities. We selected soil bulk density, non-capillary porosity, volume humidity, soil organic carbon and activity of polyphenol oxidase to calculate a soil quality index (SQI) for each site. Our data indicated that clear-cutting greatly decreased soil quality of Larix principis-rupprechtii forests but returning the harvesting residues to the forest floor could reduce the negative impact of clear-cutting on soil quality. The soil quality improved significantly by prolonging the cultivation cycle and it took about 39 years for the first-generation forest to restore soil quality to the level of the control plot. Our study confirms that SQI provides a comprehensive measurement of soil quality with the identification of a minimum data set. Comparing SQI with other soil quality indicators would help us to optimize the method for assessing soil quality. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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16 pages, 2367 KiB

Open AccessArticle

Differential Responses and Controls of Soil CO₂ and N₂O Fluxes to Experimental Warming and Nitrogen Fertilization in a Subalpine Coniferous Spruce (Picea asperata Mast.) Plantation Forest

by Dandan Li, Qing Liu, Huajun Yin, Yiqi Luo and Dafeng Hui

Forests 2019, 10(9), 808; https://doi.org/10.3390/f10090808 - 17 Sep 2019

Cited by 13 | Viewed by 4465

Abstract

Emissions of greenhouse gases (GHG) such as CO₂ and N₂O from soils are affected by many factors such as climate change, soil carbon content, and soil nutrient conditions. However, the response patterns and controls of soil CO₂ and N [...] Read more.

Emissions of greenhouse gases (GHG) such as CO₂ and N₂O from soils are affected by many factors such as climate change, soil carbon content, and soil nutrient conditions. However, the response patterns and controls of soil CO₂ and N₂O fluxes to global warming and nitrogen (N) fertilization are still not clear in subalpine forests. To address this issue, we conducted an eight-year field experiment with warming and N fertilization treatments in a subalpine coniferous spruce (Picea asperata Mast.) plantation forest in China. Soil CO₂ and N₂O fluxes were measured using a static chamber method, and soils were sampled to analyze soil carbon and N contents, soil microbial substrate utilization (MSU) patterns, and microbial functional diversity. Results showed that the mean annual CO₂ and N₂O fluxes were 36.04 ± 3.77 mg C m⁻² h⁻¹ and 0.51 ± 0.11 µg N m⁻² h⁻¹, respectively. Soil CO₂ flux was only affected by warming while soil N₂O flux was significantly enhanced by N fertilization and its interaction with warming. Warming enhanced dissolve organic carbon (DOC) and MSU, reduced soil organic carbon (SOC) and microbial biomass carbon (MBC), and constrained the microbial metabolic activity and microbial functional diversity, resulting in a decrease in soil CO₂ emission. The analysis of structural equation model indicated that MSU had dominant direct negative effect on soil CO₂ flux but had direct positive effect on soil N₂O flux. DOC and MBC had indirect positive effects on soil CO₂ flux while soil NH₄⁺-N had direct negative effect on soil CO₂ and N₂O fluxes. This study revealed different response patterns and controlling factors of soil CO₂ and N₂O fluxes in the subalpine plantation forest, and highlighted the importance of soil microbial contributions to GHG fluxes under climate warming and N deposition. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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13 pages, 2563 KiB

Open AccessArticle

The Characteristics of Soil C, N, and P Stoichiometric Ratios as Affected by Geological Background in a Karst Graben Area, Southwest China

by Hui Yang, Peng Zhang, Tongbin Zhu, Qiang Li and Jianhua Cao

Forests 2019, 10(7), 601; https://doi.org/10.3390/f10070601 - 19 Jul 2019

Cited by 30 | Viewed by 10669

Abstract

Understanding ecological stoichiometric characteristics of soil nutrient elements is crucial to guide ecological restoration and agricultural cultivation in karst rocky desertification region, but the information about the effect of the geological background on ecological stoichiometric ratios remains unknown. Soils from different landforms, including [...] Read more.

Understanding ecological stoichiometric characteristics of soil nutrient elements is crucial to guide ecological restoration and agricultural cultivation in karst rocky desertification region, but the information about the effect of the geological background on ecological stoichiometric ratios remains unknown. Soils from different landforms, including a basin, slope, and plateau, were sampled to investigate the spatial variance of the ecological stoichiometric characteristics of soil carbon (C), nitrogen (N), and phosphorus (P) under different rocky desertification grades (LRD: light rocky desertification; MRD: moderate rocky desertification; and SRD: severe rocky desertification) in a karst graben basin of Southwest China. Soil C:N ratio was not significantly influenced by rocky desertification grade, which was at a relatively stable level in the same landform, but soil C:P and N:P ratios increased with increasing rocky desertification grade. This change was consistent with increased soil organic carbon (SOC) and total nitrogen (TN) concentrations in the same geomorphic location along with the intensification of rocky desertification, but soil P concentration remained at a relatively stable level, indicating that P may be the limiting macronutrient for plant growth during vegetation restoration in a karst graben area. The soil C:N ratio of slope land was larger than that of the basin and plateau, while the soil C:P ratio and N:P ratio of the slope and plateau were significantly larger than that of the basin. The correlations between pH and C, N, and P stoichiometry decreased significantly when Ca was used as a control variable. In sharp contrast, the correlations between Ca and C, N, and P stoichiometry were highly significant no matter whether pH was used as a control variable, suggesting the important role of Ca in soil C, N, and P stoichiometry in karst graben basins. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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14 pages, 1408 KiB

Open AccessArticle

Effect of Woodchips Biochar on Sensitivity to Temperature of Soil Greenhouse Gases Emissions

by Irene Criscuoli, Maurizio Ventura, Andrea Sperotto, Pietro Panzacchi and Giustino Tonon

Forests 2019, 10(7), 594; https://doi.org/10.3390/f10070594 - 17 Jul 2019

Cited by 7 | Viewed by 4096

Abstract

Research Highlights: Biochar is the carbonaceous product of pyrolysis or the gasification of biomass that is used as soil amendment to improve soil fertility and increase soil carbon stock. Biochar has been shown to increase, decrease, or have no effect on the emissions [...] Read more.

Research Highlights: Biochar is the carbonaceous product of pyrolysis or the gasification of biomass that is used as soil amendment to improve soil fertility and increase soil carbon stock. Biochar has been shown to increase, decrease, or have no effect on the emissions of greenhouse gases (GHG) from soil, depending on the specific soil and biochar characteristics. However, the temperature sensitivity of these gas emissions in biochar-amended soils is still poorly investigated. Background and Objectives: A pot experiment was set up to investigate the impact of woodchips biochar on the temperature sensitivity of the main GHG (CO₂, CH₄, and N₂O) emissions from soil. Materials and Methods: Nine pots (14 L volume) were filled with soil mixed with biochar at two application rates (0.021 kg of biochar/kg of soil and 0.042 kg of biochar/kg of soil) or with soil alone as the control (three pots per treatment). Pots were incubated in a growth chamber and the emissions of CO₂, CH₄, and N₂O were monitored for two weeks with a cavity ring-down gas analyzer connected to three closed dynamic chambers. The temperature in the chamber increased from 10 °C to 30 °C during the first week and decreased back to 10 °C during the second week, with a daily change of 5 °C. Soil water content was kept at 20% (w/w). Results: Biochar application did not significantly affect the temperature sensitivity of CO₂ and N₂O emissions. However, the sensitivity of CH₄ uptake from soil significantly decreased by the application of biochar, reducing the CH₄ soil consumption compared to the un-amended soil, especially at high soil temperatures. Basal CO₂ respiration at 10 °C was significantly higher in the highest biochar application rate compared to the control soil. Conclusions: These results confirmed that the magnitude and direction of the influence of biochar on temperature sensitivity of GHG emissions depend on the specific GHG considered. The biochar tested in this study did not affect soil N₂O emission and only marginally affected CO₂ emission in a wide range of soil temperatures. However, it showed a negative impact on soil CH₄ uptake, particularly at a high temperature, having important implications in a future warmer climate scenario and at higher application rates. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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16 pages, 2658 KiB

Open AccessArticle

Conversion of Natural Evergreen Broadleaved Forests Decreases Soil Organic Carbon but Increases the Relative Contribution of Microbial Residue in Subtropical China

by Liuming Yang, Silu Chen, Yan Li, Quancheng Wang, Xiaojian Zhong, Zhijie Yang, Chengfang Lin and Yusheng Yang

Forests 2019, 10(6), 468; https://doi.org/10.3390/f10060468 - 29 May 2019

Cited by 13 | Viewed by 3694

Abstract

It has been recognized that land use change affects soil organic carbon (SOC) dynamics and the associated microbial turnover. However, the contribution of microbial residue to SOC storage remains largely unknown in land use change processes. To this end, we adopted a “space [...] Read more.

It has been recognized that land use change affects soil organic carbon (SOC) dynamics and the associated microbial turnover. However, the contribution of microbial residue to SOC storage remains largely unknown in land use change processes. To this end, we adopted a “space for time” approach to examine the dynamics of SOC and amino sugars, which was a biomarker of microbial residue C, in different natural forest conversions. Three typical converted forests were selected: an assisted natural regeneration (ANR) and two coniferous plantations of Cunninghamia lanceolata (Lamb.) Hook (Chinese fir) and Pinus massoniana Lamb. (pine) each. All of these were developed at the same time after the harvest of an old natural forest and they were used to evaluate the effects of forest conversions with contrasting anthropogenic disturbance on SOC and microbial residue C, along with the natural forest. Natural forest conversion led to an approximately 42% decrease in SOC for ANR with low anthropogenic disturbance, 60% for the Chinese fir plantation, and 64% for the pine plantation. In contrast, the natural forest conversion led to a 32% decrease in the total amino sugars (TAS) for ANR, 43% for the Chinese fir plantation, and 54% for the pine plantation at a soil depth of 0–10 cm. The ratios of TAS to SOC were significantly increased following natural forest conversion, with the highest ratio being observed in the Chinese fir plantation, whereas the ratios of glucosamine to muramic acid (GluN/MurA) were significantly decreased in the two plantations, but not in ANR. The contents of SOC, individual amino sugar, or TAS, and GluN/MurA ratios were consistently higher at a soil depth of 0–10 cm than at 10–20 cm for all of the experimental forests. Redundancy analysis showed that microbial residue C was significantly correlated with SOC, and both were positively correlated with fine root biomass, annual litterfall, and soil available phosphorus. Taken together, our findings demonstrated that microbial residue C accumulation varied with SOC and litter input, and played a more important role in SOC storage following forest conversion to plantations with higher anthropogenic disturbance. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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16 pages, 3780 KiB

Open AccessArticle

Nitrogen Addition Affects Soil Respiration Primarily through Changes in Microbial Community Structure and Biomass in a Subtropical Natural Forest

by Jiacong Zhou, Xiaofei Liu, Jinsheng Xie, Maokui Lyu, Yong Zheng, Zhangtian You, Yuexin Fan, Chengfang Lin, Guangshui Chen, Yuehmin Chen and Yusheng Yang

Forests 2019, 10(5), 435; https://doi.org/10.3390/f10050435 - 20 May 2019

Cited by 18 | Viewed by 4169

Abstract

Forest soil respiration plays an important role in global carbon (C) cycling. Owing to the high degree of C and nitrogen (N) cycle coupling, N deposition rates may greatly influence forest soil respiration, and possibly even global C cycling. Soil microbes play a [...] Read more.

Forest soil respiration plays an important role in global carbon (C) cycling. Owing to the high degree of C and nitrogen (N) cycle coupling, N deposition rates may greatly influence forest soil respiration, and possibly even global C cycling. Soil microbes play a crucial role in regulating the biosphere–atmosphere C exchange; however, how microbes respond to N addition remains uncertain. To better understand this process, the experiment was performed in the Castanopsis kawakamii Hayata Nature Reserve, in the subtropical zone of China. Treatments involved applying different levels of N (0, 40, and 80 kg ha⁻² year⁻¹) over a three-year period (January 2013–December 2015) to explore how soil physicochemical properties, respiration rate, phospholipid fatty acid (PLFA) concentration, and solid state ¹³C nuclear magnetic resonance responded to various N addition rate. Results showed that high levels of N addition significantly decreased soil respiration; however, low levels of N addition significantly increased soil respiration. High levels of N reduced soil pH and enhanced P and C co-limitation of microorganisms, leading to significant reductions in total PLFA and changes in the structure of microbial communities. Significant linear relationships were observed between annual cumulative respiration and the concentration of microbial biomass (total PLFA, gram-positive bacteria (G⁺), gram-negative bacteria (G⁻), total bacteria, and fungi) and the microbial community structure (G⁺: G⁻ ratio). Taken together, increasing N deposition changed microbial community structure and suppressed microbial biomass, ultimately leading to recalcitrant C accumulation and soil C emissions decrease in subtropical forest. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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14 pages, 2376 KiB

Open AccessArticle

Evaluation of Forest Conversion Effects on Soil Erosion, Soil Organic Carbon and Total Nitrogen Based on ¹³⁷Cs Tracer Technique

by Xi Zhu, Jie Lin, Qiao Dai, Yanying Xu and Haidong Li

Forests 2019, 10(5), 433; https://doi.org/10.3390/f10050433 - 20 May 2019

Cited by 11 | Viewed by 3613

Abstract

Soil erosion can affect the horizontal and the vertical distribution of soil carbon at the landscape scale. The ¹³⁷Cs tracer technique can overcome the shortcomings of traditional erosion research and has proven to be the best method to study soil erosion. To [...] Read more.

Soil erosion can affect the horizontal and the vertical distribution of soil carbon at the landscape scale. The ¹³⁷Cs tracer technique can overcome the shortcomings of traditional erosion research and has proven to be the best method to study soil erosion. To understand the responses of soil organic carbon and nitrogen to soil erosion and forest conversion in the development of slope economic forests in rocky mountain areas, three representative types of economic forests that were all formed after clear-cutting and afforestation on the basis of CBF (coniferous and broad-leaved mixed forests) were selected: CF (chestnut forests) with small human disturbance intensity, AF (apple forests), and HF (hawthorn forests) with high interference intensity. The results showed that all land use types have significantly eroded since 1950; the average annual loss of soil was 0.79 mm in the CBF, 2.31 mm in the AF, 1.84 mm in the HF, and 0.87 mm in the CF. The results indicated aggravation of soil erosion after the transformation of the CBF into an economic forest. The economic forest management reduced the average carbon storage and accelerated nutrient loss. The better vegetation coverage and litter coverage of CF made them stand out among the three economic forest varieties. Therefore, when developing economic forests, we should select species that can produce litter to ensure as much soil conservation as possible to reduce the risk of soil erosion. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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16 pages, 2313 KiB

Open AccessArticle

Response of Soil Surface Respiration to Storm and Ips typographus (L.) Disturbance in Boreal Norway Spruce Stands

by Maiju Kosunen, Päivi Lyytikäinen-Saarenmaa, Paavo Ojanen, Minna Blomqvist and Mike Starr

Forests 2019, 10(4), 307; https://doi.org/10.3390/f10040307 - 3 Apr 2019

Cited by 10 | Viewed by 3278

Abstract

Disturbances such as storm events and bark beetle outbreaks can have a major influence on forest soil carbon (C) cycling. Both autotrophic and heterotrophic soil respiration may be affected by the increase in tree mortality. We studied the effect of a storm in [...] Read more.

Disturbances such as storm events and bark beetle outbreaks can have a major influence on forest soil carbon (C) cycling. Both autotrophic and heterotrophic soil respiration may be affected by the increase in tree mortality. We studied the effect of a storm in 2010 followed by an outbreak of the European spruce bark beetle (Ips typographus L.) on the soil surface respiration (respiration by soil and ground vegetation) at two Norway spruce (Picea abies L.) dominated sites in southeastern Finland. Soil surface respiration, soil temperature, and soil moisture were measured in three types of plots—living trees (undisturbed), storm-felled trees, and standing dead trees killed by I. typographus—during the summer–autumn period for three years (2015–2017). Measurements at storm-felled tree plots were separated into dead tree detritus-covered (under storm-felled trees) and open-vegetated (on open areas) microsites. The soil surface total respiration for 2017 was separated into its autotrophic and heterotrophic components using trenching. The soil surface total respiration rates at the disturbed plots were 64%–82% of those at the living tree plots at one site and were due to a decrease in autotrophic respiration, but there was no clear difference in soil surface total respiration between the plots at the other site, due to shifts in either autotrophic or heterotrophic respiration. The soil surface respiration rates were related to plot basal area (living and all trees), as well as to soil temperature and soil moisture. As storm and bark beetle disturbances are predicted to become more common in the future, their effects on forest ecosystem C cycling and CO₂ fluxes will therefore become increasingly important. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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11 pages, 1699 KiB

Open AccessArticle

Forest Soil Profile Inversion and Mixing Change the Vertical Stratification of Soil CO₂ Concentration without Altering Soil Surface CO₂ Flux

by Xiaoling Wang, Shenglei Fu, Jianxiong Li, Xiaoming Zou, Weixin Zhang, Hanping Xia, Yongbiao Lin, Qian Tian and Lixia Zhou

Forests 2019, 10(2), 192; https://doi.org/10.3390/f10020192 - 21 Feb 2019

Cited by 12 | Viewed by 3837

Abstract

In order to gain more detailed knowledge of the CO₂ concentration gradient in forest soil profiles and to better understand the factors that control CO₂ concentration along forest soil profiles, we examined the soil surface CO₂ flux, soil properties and [...] Read more.

In order to gain more detailed knowledge of the CO₂ concentration gradient in forest soil profiles and to better understand the factors that control CO₂ concentration along forest soil profiles, we examined the soil surface CO₂ flux, soil properties and soil profile CO₂ concentration in upright (CK), inverted and mixed soil columns with a depth of 60 cm in two subtropical forests in China from May 2008 to December 2009. The results showed that: (1) The SOC (soil organic carbon), TN (total N) and microbial biomass were higher in the deeper layers in the inverted soil column, which was consistent with an increase in CO₂ concentration in the deeper soil layer. Furthermore, the biogeochemical properties were homogenous among soil layers in the mixed soil column. (2) CO₂ concentration in the soil profile increased with depth in CK while soil column inversion significantly intensified this vertical stratification as the most active layer (surface soil) was now at the bottom. The stratification of CO₂ concentration along the soil profile in the mixed soil column was similar to that in CK but it was not intensified after soil was mixed. (3) The soil surface CO₂ flux did not significantly change after the soil column was inverted. The surface CO₂ flux rate of the mixed soil column was higher compared to that of the inverted soil column but was not significantly different from CK. Our results indicated that the profile soil CO₂ production was jointly controlled by soil properties related to CO₂ production (e.g., SOC content and soil microbial biomass) and those related to gas diffusion (e.g., soil bulk density and gas molecular weight), but the soil surface CO₂ flux was mainly determined by soil surface temperature and may be affected by the intensity of soil disturbance. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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13 pages, 2988 KiB

Open AccessArticle

Methane Emission from Mangrove Wetland Soils Is Marginal but Can Be Stimulated Significantly by Anthropogenic Activities

by Xiawan Zheng, Jiemin Guo, Weimin Song, Jianxiang Feng and Guanghui Lin

Forests 2018, 9(12), 738; https://doi.org/10.3390/f9120738 - 27 Nov 2018

Cited by 36 | Viewed by 5350

Abstract

Mangrove wetland soils have been considered as important sources for atmospheric CH₄, but the magnitude of CH₄ efflux in mangrove wetlands and its relative contribution to climate warming compared to CO₂ efflux remains controversial. In this study, we measured [...] Read more.

Mangrove wetland soils have been considered as important sources for atmospheric CH₄, but the magnitude of CH₄ efflux in mangrove wetlands and its relative contribution to climate warming compared to CO₂ efflux remains controversial. In this study, we measured both CH₄ and CO₂ effluxes from mangrove soils during low or no tide periods at three tidal zones of two mangrove ecosystems in Southeastern China and collected CH₄ efflux data from literature for 24 sites of mangrove wetlands worldwide. The CH₄ efflux was highly variable among our field sites due to the heterogeneity of mangrove soil environments. On average, undisturbed mangrove sites have very low CH₄ efflux rates (ranging from 0.65 to 14.18 μmol m⁻² h⁻¹; median 2.57 μmol m⁻² h⁻¹), often less than 10% of the global warming potentials (GWP) caused by the soil CO₂ efflux from the same sites (ranging from 0.94 to 9.50 mmol m⁻² h⁻¹; median 3.67 mmol m⁻² h⁻¹), even after considering that CH₄ has 28 times more GWP over CO₂. Plant species, study site, tidal position, sampling time, and soil characteristics all had no significant effect on mangrove soil CH₄ efflux. Combining our field measurement results and literature data, we demonstrated that the CH₄ efflux from undisturbed mangrove soils was marginal in comparison with the CO₂ efflux in most cases, but nutrient inputs from anthropogenic activities including nutrient run-off and aquaculture activities significantly increased CH₄ efflux from mangrove soils. Therefore, CH₄ efflux from mangrove wetlands is strongly influenced by anthropogenic activities, and future inventories of CH₄ efflux from mangrove wetlands on a regional or global scale should consider this phenomenon. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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12 pages, 1970 KiB

Open AccessArticle

Estimation of Forest Carbon Stocks for National Greenhouse Gas Inventory Reporting in South Korea

by Sun Jeoung Lee, Jong Su Yim, Yeong Mo Son, Yowhan Son and Raehyun Kim

Forests 2018, 9(10), 625; https://doi.org/10.3390/f9100625 - 10 Oct 2018

Cited by 25 | Viewed by 4683

Abstract

The development of country-specific emission factors in relation to the Agriculture, Forestry, and Other Land Use (AFOLU) sector has the potential to improve national greenhouse gas inventory systems. Forests are carbon sinks in the AFOLU that can play an important role in mitigating [...] Read more.

The development of country-specific emission factors in relation to the Agriculture, Forestry, and Other Land Use (AFOLU) sector has the potential to improve national greenhouse gas inventory systems. Forests are carbon sinks in the AFOLU that can play an important role in mitigating global climate change. According to the United Nations Framework Convention on Climate Change (UNFCCC), signatory countries must report forest carbon stocks, and the changes within them, using emission factors from the Intergovernmental Panel on Climate Change (IPCC) or from country-specific values. This study was conducted to estimate forests carbon stocks and to complement and improve the accuracy of national greenhouse gas inventory reporting in South Korea. We developed country-specific emissions factors and estimated carbon stocks and their changes using the different approaches and methods described by the IPCC (IPCC_EF: IPCC default emission factors, CS_FT: country-specific emission factors by forest type, and CS_SP: country-specific emission factors by species). CS_FT returned a result for carbon stocks that was 1.2 times higher than the value using IPCC_EF. Using CS_SP, CO₂ removal was estimated to be 60,648 Gg CO₂ per year with an uncertainty of 22%. Despite a reduction in total forest area, forests continued to store carbon and absorb CO₂, owing to differences in the carbon storage capacities of different forest types and tree species. The results of this study will aid estimations of carbon stock changes and CO₂ removal by forest type or species, and help to improve the completeness and accuracy of the national greenhouse gas inventory. Furthermore, our results provide important information for developing countries implementing Tier 2, the level national greenhouse gas inventory systems recommended by the IPCC. Full article

(This article belongs to the Special Issue Disturbance Effects on Soil Carbon and Greenhouse Gas Emissions in Forest Ecosystems)

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