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Gundale MJ, Axelsson EP, Buness V, Callebaut T, DeLuca TH, Hupperts SF, Ibáñez TS, Metcalfe DB, Nilsson MC, Peichl M, Spitzer CM, Stangl ZR, Strengbom J, Sundqvist MK, Wardle DA, Lindahl BD. The biological controls of soil carbon accumulation following wildfire and harvest in boreal forests: A review. GLOBAL CHANGE BIOLOGY 2024; 30:e17276. [PMID: 38683126 DOI: 10.1111/gcb.17276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 03/29/2024] [Accepted: 03/30/2024] [Indexed: 05/01/2024]
Abstract
Boreal forests are frequently subjected to disturbances, including wildfire and clear-cutting. While these disturbances can cause soil carbon (C) losses, the long-term accumulation dynamics of soil C stocks during subsequent stand development is controlled by biological processes related to the balance of net primary production (NPP) and outputs via heterotrophic respiration and leaching, many of which remain poorly understood. We review the biological processes suggested to influence soil C accumulation in boreal forests. Our review indicates that median C accumulation rates following wildfire and clear-cutting are similar (0.15 and 0.20 Mg ha-1 year-1, respectively), however, variation between studies is extremely high. Further, while many individual studies show linear increases in soil C stocks through time after disturbance, there are indications that C stock recovery is fastest early to mid-succession (e.g. 15-80 years) and then slows as forests mature (e.g. >100 years). We indicate that the rapid build-up of soil C in younger stands appears not only driven by higher plant production, but also by a high rate of mycorrhizal hyphal production, and mycorrhizal suppression of saprotrophs. As stands mature, the balance between reductions in plant and mycorrhizal production, increasing plant litter recalcitrance, and ectomycorrhizal decomposers and saprotrophs have been highlighted as key controls on soil C accumulation rates. While some of these controls appear well understood (e.g. temporal patterns in NPP, changes in aboveground litter quality), many others remain research frontiers. Notably, very little data exists describing and comparing successional patterns of root production, mycorrhizal functional traits, mycorrhizal-saprotroph interactions, or C outputs via heterotrophic respiration and dissolved organic C following different disturbances. We argue that these less frequently described controls require attention, as they will be key not only for understanding ecosystem C balances, but also for representing these dynamics more accurately in soil organic C and Earth system models.
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Affiliation(s)
- Michael J Gundale
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - E Petter Axelsson
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Vincent Buness
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Timon Callebaut
- Department of Environmental Science and Ecology, Umeå University, Umeå, Sweden
| | - Thomas H DeLuca
- College of Forestry, Oregon State University, Corvallis, Oregon, USA
| | - Stefan F Hupperts
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Theresa S Ibáñez
- Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Daniel B Metcalfe
- Department of Environmental Science and Ecology, Umeå University, Umeå, Sweden
| | - Marie-Charlotte Nilsson
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Matthias Peichl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Clydecia M Spitzer
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Zsofia R Stangl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Joachim Strengbom
- Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Maja K Sundqvist
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - David A Wardle
- Department of Environmental Science and Ecology, Umeå University, Umeå, Sweden
| | - Björn D Lindahl
- Department of Soil Science, Swedish University of Agricultural Sciences, Uppsala, Sweden
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2
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Kong L, Song J, Ru J, Feng J, Hou J, Wang X, Zhang Q, Wang H, Yue X, Zhou Z, Sun D, Zhang J, Li H, Fan Y, Wan S. Nitrogen addition does not alter symmetric responses of soil respiration to changing precipitation in a semi-arid grassland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171170. [PMID: 38402979 DOI: 10.1016/j.scitotenv.2024.171170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 02/09/2024] [Accepted: 02/20/2024] [Indexed: 02/27/2024]
Abstract
Concurrent changing precipitation regimes and atmospheric nitrogen (N) deposition can have profound influences on soil carbon (C) cycling. However, how N enrichment regulates the responses of soil C fluxes to increasing variability of precipitation remains elusive. As part of a field precipitation gradient experiment with nine levels of precipitation amounts (-60 %, -45 %, -30 %, -15 %, ambient precipitation, +15 %, +30 %, +45 %, and +60 %) and two levels of N addition (0 and 10 g N m-2 yr-1) in a semi-arid temperate steppe on the Mongolian Plateau, this work was conducted to investigate the responses of soil respiration to decreased and increased precipitation (DP and IP), N addition, and their possible interactions. Averaged over the three years from 2019 to 2021, DP suppressed soil respiration by 16.1 %, whereas IP stimulated it by 27.4 %. Nitrogen addition decreased soil respiration by 7.1 % primarily via reducing microbial biomass C. Soil respiration showed symmetric responses to DP and IP within all the four precipitation variabilities (i.e., 15 %, 30 %, 45 %, and 60 %) under ambient N. Nevertheless, N addition did not alter the symmetric responses of soil respiration to changing precipitation due to the comparable sensitivities of microbial biomass and root growth to DP and IP under the N addition treatment. These findings indicate that intensified precipitation variability does not change but N addition could alleviate soil C releases. The unchanged symmetric responses of soil respiration to precipitation variability under N addition imply that N deposition may not change the response pattern of soil C releases to predicted increases in precipitation variability in grasslands, facilitating the robust projections of ecosystem C cycling under future global change scenarios.
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Affiliation(s)
- Lingjie Kong
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
| | - Jian Song
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
| | - Jingyi Ru
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
| | - Jiayin Feng
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
| | - Jiawei Hou
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
| | - Xueke Wang
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
| | - Qingshan Zhang
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
| | - Haidao Wang
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
| | - Xiaojing Yue
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
| | - Zhenxing Zhou
- International Joint Research Laboratory for Global Change Ecology, School of Life Sciences, Henan University, Kaifeng, Henan 475004, China
| | - Dasheng Sun
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
| | - Jiajia Zhang
- International Joint Research Laboratory for Global Change Ecology, School of Life Sciences, Henan University, Kaifeng, Henan 475004, China
| | - Heng Li
- International Joint Research Laboratory for Global Change Ecology, School of Life Sciences, Henan University, Kaifeng, Henan 475004, China
| | - Yongge Fan
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China
| | - Shiqiang Wan
- School of Life Sciences, Institute of Life Science and Green Development, Hebei University, Baoding, Hebei 071002, China.
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3
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Houle D, Moore JD, Renaudin M. Eastern Canadian boreal forest soil and foliar chemistry show evidence of resilience to long-term nitrogen addition. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e2958. [PMID: 38425036 DOI: 10.1002/eap.2958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/23/2023] [Accepted: 01/10/2024] [Indexed: 03/02/2024]
Abstract
The boreal forest is one of the world's largest terrestrial biome and plays crucial roles in global biogeochemical cycles, such as carbon (C) sequestration in vegetation and soil. However, the impacts of decades of N deposition on N-limited ecosystems, like the eastern Canadian boreal forest, remain unclear. For 13 years, N deposition was simulated by periodically adding ammonium nitrate on soils of two boreal coniferous forests (i.e., balsam fir and black spruce) of eastern Canada, at low (LN) and high (HN) rates, corresponding to 3 and 10 times the ambient N deposition, respectively. We show that more than a decade of N addition had no strong effects on mineral soil C, N, P, and cation concentrations and on foliar total Ca, K, Mg, and Mn concentrations. In organic soil, C stock was not affected by N addition while N stock increased, and exchangeable Ca2+ and Mg2+ decreased at the balsam fir site under HN treatment. At both sites, LN treatment had nearly no impact on foliage and soil chemistry but foliar N and N:P significantly increased under HN treatment, potentially leading to foliar nutrient imbalance. Overall, our work indicates that, in the eastern Canadian boreal forest, soil and foliar nutrient concentrations and stocks are resilient to increasing N deposition potentially because, in the context of N limitation, extra N would be rapidly immobilized by soil micro-organisms and vegetation. These findings could improve modeling future boreal forest soil C stocks and biomass growth and could help in planning forest management strategies in eastern Canada.
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Affiliation(s)
- Daniel Houle
- Science and Technology Branch, Environment and Climate Change Canada, Montréal, Québec, Canada
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, Québec, Canada
| | - Jean-David Moore
- Direction de la recherche forestière, Ministère des Ressources naturelles et des Forêts, Québec City, Québec, Canada
| | - Marie Renaudin
- Science and Technology Branch, Environment and Climate Change Canada, Montréal, Québec, Canada
- Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, Québec, Canada
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4
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Forsmark B, Bizjak T, Nordin A, Rosenstock NP, Wallander H, Gundale MJ. Shifts in microbial community composition and metabolism correspond with rapid soil carbon accumulation in response to 20 years of simulated nitrogen deposition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 918:170741. [PMID: 38325494 DOI: 10.1016/j.scitotenv.2024.170741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/21/2023] [Accepted: 02/04/2024] [Indexed: 02/09/2024]
Abstract
Anthropogenic nitrogen (N) deposition and fertilization in boreal forests frequently reduces decomposition and soil respiration and enhances C storage in the topsoil. This enhancement of the C sink can be as strong as the aboveground biomass response to N additions and has implications for the global C cycle, but the mechanisms remain elusive. We hypothesized that this effect would be associated with a shift in the microbial community and its activity, and particularly by fungal taxa reported to be capable of lignin degradation and organic N acquisition. We sampled the organic layer below the intact litter of a Norway spruce (Picea abies (L.) Karst) forest in northern Sweden after 20 years of annual N additions at low (12.5 kg N ha-1 yr-1) and high (50 kg N ha-1 yr-1) rates. We measured microbial biomass using phospholipid fatty-acid analysis (PLFA) and ergosterol measurements and used ITS metagenomics to profile the fungal community of soil and fine-roots. We probed the metabolic activity of the soil community by measuring the activity of extracellular enzymes and evaluated its relationships with the most N responsive soil fungal species. Nitrogen addition decreased the abundance of fungal PLFA markers and changed the fungal community in humus and fine-roots. Specifically, the humus community changed in part due to a shift from Oidiodendron pilicola, Cenococcum geophilum, and Cortinarius caperatus to Tylospora fibrillosa and Russula griseascens. These microbial community changes were associated with decreased activity of Mn-peroxidase and peptidase, and an increase in the activity of C acquiring enzymes. Our results show that the rapid accumulation of C in the humus layer frequently observed in areas with high N deposition is consistent with a shift in microbial metabolism, where decomposition associated with organic N acquisition is downregulated when inorganic N forms are readily available.
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Affiliation(s)
- Benjamin Forsmark
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden.
| | - Tinkara Bizjak
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Annika Nordin
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Nicholas P Rosenstock
- Center for Environmental and Climate Research, Lund University, SE-223 62 Lund, Sweden
| | - Håkan Wallander
- Department of Microbial Ecology, Lund University, SE-223 62 Lund, Sweden
| | - Michael J Gundale
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
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5
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Xiao S, Wang C, Yu K, Liu G, Wu S, Wang J, Niu S, Zou J, Liu S. Enhanced CO 2 uptake is marginally offset by altered fluxes of non-CO 2 greenhouse gases in global forests and grasslands under N deposition. GLOBAL CHANGE BIOLOGY 2023; 29:5829-5849. [PMID: 37485988 DOI: 10.1111/gcb.16869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 06/01/2023] [Indexed: 07/25/2023]
Abstract
Despite the increasing impact of atmospheric nitrogen (N) deposition on terrestrial greenhouse gas (GHG) budget, through driving both the net atmospheric CO2 exchange and the emission or uptake of non-CO2 GHGs (CH4 and N2 O), few studies have assessed the climatic impact of forests and grasslands under N deposition globally based on different bottom-up approaches. Here, we quantify the effects of N deposition on biomass C increment, soil organic C (SOC), CH4 and N2 O fluxes and, ultimately, the net ecosystem GHG balance of forests and grasslands using a global comprehensive dataset. We showed that N addition significantly increased plant C uptake (net primary production) in forests and grasslands, to a larger extent for the aboveground C (aboveground net primary production), whereas it only caused a small or insignificant enhancement of SOC pool in both upland systems. Nitrogen addition had no significant effect on soil heterotrophic respiration (RH ) in both forests and grasslands, while a significant N-induced increase in soil CO2 fluxes (RS , soil respiration) was observed in grasslands. Nitrogen addition significantly stimulated soil N2 O fluxes in forests (76%), to a larger extent in grasslands (87%), but showed a consistent trend to decrease soil uptake of CH4 , suggesting a declined sink capacity of forests and grasslands for atmospheric CH4 under N enrichment. Overall, the net GHG balance estimated by the net ecosystem production-based method (forest, 1.28 Pg CO2 -eq year-1 vs. grassland, 0.58 Pg CO2 -eq year-1 ) was greater than those estimated using the SOC-based method (forest, 0.32 Pg CO2 -eq year-1 vs. grassland, 0.18 Pg CO2 -eq year-1 ) caused by N addition. Our findings revealed that the enhanced soil C sequestration by N addition in global forests and grasslands could be only marginally offset (1.5%-4.8%) by the combined effects of its stimulation of N2 O emissions together with the reduced soil uptake of CH4 .
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Affiliation(s)
- Shuqi Xiao
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, Nanjing, China
| | - Chao Wang
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, Nanjing, China
| | - Kai Yu
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, Nanjing, China
| | - Genyuan Liu
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, Nanjing, China
| | - Shuang Wu
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, Nanjing, China
- Key Laboratory of Low-carbon and Green Agriculture in Southeastern China, Ministry of Agriculture and Rural Affairs, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Jinyang Wang
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, Nanjing, China
- Key Laboratory of Low-carbon and Green Agriculture in Southeastern China, Ministry of Agriculture and Rural Affairs, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Shuli Niu
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Jianwen Zou
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, Nanjing, China
- Key Laboratory of Low-carbon and Green Agriculture in Southeastern China, Ministry of Agriculture and Rural Affairs, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China
| | - Shuwei Liu
- Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation, Nanjing, China
- Key Laboratory of Low-carbon and Green Agriculture in Southeastern China, Ministry of Agriculture and Rural Affairs, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
- Jiangsu Key Lab and Engineering Center for Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China
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6
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Marshall JD, Tarvainen L, Zhao P, Lim H, Wallin G, Näsholm T, Lundmark T, Linder S, Peichl M. Components explain, but do eddy fluxes constrain? Carbon budget of a nitrogen-fertilized boreal Scots pine forest. THE NEW PHYTOLOGIST 2023; 239:2166-2179. [PMID: 37148187 DOI: 10.1111/nph.18939] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 03/22/2023] [Indexed: 05/08/2023]
Abstract
Nitrogen (N) fertilization increases biomass and soil organic carbon (SOC) accumulation in boreal pine forests, but the underlying mechanisms remain uncertain. At two Scots pine sites, one undergoing annual N fertilization and the other a reference, we sought to explain these responses. We measured component fluxes, including biomass production, SOC accumulation, and respiration, and summed them into carbon budgets. We compared the resulting summations to ecosystem fluxes measured by eddy covariance. N fertilization increased most component fluxes (P < 0.05), especially SOC accumulation (20×). Only fine-root, mycorrhiza, and exudate production decreased, by 237 (SD = 28) g C m-2 yr-1 . Stemwood production increases were ascribed to this partitioning shift, gross primary production (GPP), and carbon-use efficiency, in that order. The methods agreed in their estimates of GPP in both stands (P > 0.05), but the components detected an increase in net ecosystem production (NEP) (190 (54) g C m-2 yr-1 ; P < 0.01) that eddy covariance did not (19 (62) g C m-2 yr-1 ; ns). The pairing of plots, the simplicity of the sites, and the strength of response provide a compelling description of N effects on the C budget. However, the disagreement between methods calls for further paired tests of N fertilization effects in simple forest ecosystems.
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Affiliation(s)
- John D Marshall
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Umeå, SE-901 83, Sweden
- Leibniz-Zentrum für Agrarlandschaftsforschung, Isotopen-Biogeochemie and Gasflüsse, Müncheberg, 15374, Germany
| | - Lasse Tarvainen
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Umeå, SE-901 83, Sweden
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, SE-405 30, Sweden
| | - Peng Zhao
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Umeå, SE-901 83, Sweden
| | - Hyungwoo Lim
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Umeå, SE-901 83, Sweden
- Institute of Ecology and Earth Sciences, University of Tartu, Juhan Liivi 2, Tartu, 50409, Estonia
| | - Göran Wallin
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, SE-405 30, Sweden
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, South Parks Road, Oxford, OX1 3QY, UK
| | - Torgny Näsholm
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Umeå, SE-901 83, Sweden
| | - Tomas Lundmark
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Umeå, SE-901 83, Sweden
| | - Sune Linder
- Southern Swedish Forest Research Centre, SLU, PO Box 190, Lomma, SE-234 22, Sweden
| | - Matthias Peichl
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Umeå, SE-901 83, Sweden
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7
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Bizjak T, Sellstedt A, Gratz R, Nordin A. Presence and activity of nitrogen-fixing bacteria in Scots pine needles in a boreal forest: a nitrogen-addition experiment. TREE PHYSIOLOGY 2023; 43:1354-1364. [PMID: 37073466 PMCID: PMC10423461 DOI: 10.1093/treephys/tpad048] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/11/2023] [Indexed: 05/03/2023]
Abstract
Endophytic nitrogen-fixing bacteria have been detected and isolated from the needles of conifer trees growing in North American boreal forests. Because boreal forests are nutrient-limited, these bacteria could provide an important source of nitrogen for tree species. This study aimed to determine their presence and activity in a Scandinavian boreal forest, using immunodetection of nitrogenase enzyme subunits and acetylene-reduction assays of native Scots pine (Pinus sylvestris L.) needles. The presence and rate of nitrogen fixation by endophytic bacteria were compared between control plots and fertilized plots in a nitrogen-addition experiment. In contrast to the expectation that nitrogen-fixation rates would decline in fertilized plots, as seen, for instance, with nitrogen-fixing bacteria associated with bryophytes, there was no difference in the presence or activity of nitrogen-fixing bacteria between the two treatments. The extrapolated calculated rate of nitrogen fixation relevant for the forest stand was 20 g N ha-1 year-1, which is rather low compared with Scots pine annual nitrogen use but could be important for the nitrogen-poor forest in the long term. In addition, of 13 colonies of potential nitrogen-fixing bacteria isolated from the needles on nitrogen-free media, 10 showed in vitro nitrogen fixation. In summary, 16S rRNA sequencing identified the species as belonging to the genera Bacillus, Variovorax, Novosphingobium, Sphingomonas, Microbacterium and Priestia, which was confirmed by Illumina whole-genome sequencing. Our results confirm the presence of endophytic nitrogen-fixing bacteria in Scots pine needles and suggest that they could be important for the long-term nitrogen budget of the Scandinavian boreal forest.
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Affiliation(s)
- Tinkara Bizjak
- Umeå Plant Science Centre (UPSC), Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden
| | - Anita Sellstedt
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, 901 87 Umeå, Sweden
| | - Regina Gratz
- Umeå Plant Science Centre (UPSC), Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden
| | - Annika Nordin
- Umeå Plant Science Centre (UPSC), Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden
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Baek G, Lim H, Noh NJ, Kim C. No impact of nitrogen fertilization on carbon sequestration in a temperate Pinus densiflora forest. Sci Rep 2023; 13:1743. [PMID: 36878968 PMCID: PMC9988963 DOI: 10.1038/s41598-023-27989-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 01/11/2023] [Indexed: 03/08/2023] Open
Abstract
Carbon (C) sequestration capacity in forest ecosystems is generally constrained by soil nitrogen (N) availability. Consequently, N fertilization is seen as a promising tool for enhancing ecosystem-level C sequestration in N-limited forests. We examined the responses of ecosystem C (vegetation and soil) and soil N dynamics to 3 years of annual nitrogen-phosphorus-potassium (N3P4K1 = 11.3 g N, 15.0 g P, 3.7 g K m-2 year-1) or PK fertilization (P4K1), observed over 4 years in a 40-year-old Pinus densiflora forest with poor N nutrition in South Korea. PK fertilization without N was performed to test for PK limitation other than N. Neither tree growth nor soil C fluxes responded to annual NPK or PK fertilization despite an increase in soil mineral N fluxes following NPK fertilization. NPK fertilization increased the rate of N immobilization and 80% of the added N was recovered from mineral soil in the 0-5 cm layer, suggesting that relatively little of the added N was available to trees. These results indicate that N fertilization does not always enhance C sequestration even in forests with poor N nutrition and should therefore be applied with caution.
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Affiliation(s)
- Gyeongwon Baek
- Division of Environmental and Forest Science, Gyeongsang National University, Jinju, 52725, South Korea
| | - Hyungwoo Lim
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden.,Institute of Ecology and Earth Sciences, University of Tartu, 50409, Tartu, Estonia
| | - Nam Jin Noh
- Department of Forest Resources, Kangwon National University, Chuncheon, 24341, South Korea
| | - Choonsig Kim
- Division of Environmental and Forest Science, Gyeongsang National University, Jinju, 52725, South Korea.
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Blaško R, Forsmark B, Gundale MJ, Lim H, Lundmark T, Nordin A. The carbon sequestration response of aboveground biomass and soils to nutrient enrichment in boreal forests depends on baseline site productivity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156327. [PMID: 35640755 DOI: 10.1016/j.scitotenv.2022.156327] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/23/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Nutrient enrichment can alleviate productivity limitations and thus substantially increase carbon (C) uptake in northern coniferous forests. Yet, factors controlling stand-to-stand variation of forest ecosystem responses to nutrient enrichment remain unclear. We used five long-term (13 years) nutrient-enrichment experiments across Sweden, where nitrogen (N), phosphorus, and potassium were applied annually to young Norway spruce forests that varied in their baseline ecosystem properties. We measured tree biomass and soil C and N stocks, litterfall C inputs, soil CO2 efflux, and shifts in composition and biomass of soil microbial communities to understand the links between above and belowground responses to nutrient enrichment. We found that the strongest responses in tree biomass occurred when baseline site productivity was lowest. High increases in tree biomass C stocks were generally balanced by weaker responses in organic soil C stocks. The average ecosystem C-N response rate was 35 kg C kg-1 N added, with a nearly five-fold greater response rate in tree biomass than in soil. The positive nutrient enrichment effects on ecosystem C sinks were driven by a 95% increase in tree biomass C stocks, 150% increase in litter production, 67% increase in organic layer C stocks, and a 46% reduction in soil CO2 efflux accompanied by compositional changes in soil microbial communities. Our results show that ecosystem C uptake in spruce forests in northern Europe can be substantially enhanced by nutrient enrichment; however, the strength of the responses and whether the enhancement occurs mainly in tree biomass or soils are dependent on baseline forest productivity.
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Affiliation(s)
- Róbert Blaško
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden; Slovak Environment Agency, Tajovského 28, 975 90 Banská Bystrica, Slovakia.
| | - Benjamin Forsmark
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden; Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, SE-230 53 Alnarp, Sweden
| | - Michael J Gundale
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Hyungwoo Lim
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden; Institute of Ecology and Earth Sciences, University of Tartu, 50409 Tartu, Estonia
| | - Tomas Lundmark
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Annika Nordin
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Umeå University/Swedish University of Agricultural Sciences, SE-90736/SE-901 83 Umeå, Sweden
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10
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Verma P, Sagar R. Soil respiration response to nitrogen fertilization experiment in tropical grassland. Ecol Res 2022. [DOI: 10.1111/1440-1703.12307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Preeti Verma
- Department of Botany Banaras Hindu University Varanasi India
- Department of Botany Government Degree College Basti India
| | - R. Sagar
- Department of Botany Banaras Hindu University Varanasi India
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11
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Gundale MJ. The impact of anthropogenic nitrogen deposition on global forests: Negative impacts far exceed the carbon benefits. GLOBAL CHANGE BIOLOGY 2022; 28:690-692. [PMID: 34706121 DOI: 10.1111/gcb.15959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Humans have drastically altered the nitrogen (N) cycle during the past century, enriching ecosystems from the tropics to the tundra with unpresented inputs of novel nitrogen. The study by Schulte-Uebbing et al. (2021) quantified the impact of atmospheric N deposition on C uptake by forests globally, and weighed this climate benefit against the global warming impact of N2 O emissions. A major conclusion was that the C benefits of atmospheric deposition in global forests are smaller than previously estimated (only 41 Tg C year-1 ), accounting for only 2% of the net annual forest C uptake.
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Affiliation(s)
- Michael J Gundale
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SLU, Umeå, Sweden
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12
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Schulte‐Uebbing LF, Ros GH, de Vries W. Experimental evidence shows minor contribution of nitrogen deposition to global forest carbon sequestration. GLOBAL CHANGE BIOLOGY 2022; 28:899-917. [PMID: 34699094 PMCID: PMC9299138 DOI: 10.1111/gcb.15960] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/09/2021] [Indexed: 05/12/2023]
Abstract
Human activities have drastically increased nitrogen (N) deposition onto forests globally. This may have alleviated N limitation and thus stimulated productivity and carbon (C) sequestration in aboveground woody biomass (AGWB), a stable C pool with long turnover times. This 'carbon bonus' of human N use partly offsets the climate impact of human-induced N2 O emissions, but its magnitude and spatial variation are uncertain. Here we used a meta-regression approach to identify sources of heterogeneity in tree biomass C-N response (additional C stored per unit of N) based on data from fertilization experiments in global forests. We identified important drivers of spatial variation in forest biomass C-N response related to climate (potential evapotranspiration), soil fertility (N content) and tree characteristics (stand age), and used these relationships to quantify global spatial variation in N-induced forest biomass C sequestration. Results show that N deposition enhances biomass C sequestration in only one-third of global forests, mainly in the boreal region, while N reduces C sequestration in 5% of forests, mainly in the tropics. In the remaining 59% of global forests, N addition has no impact on biomass C sequestration. Average C-N responses were 11 (4-21) kg C per kg N for boreal forests, 4 (0-8) kg C per kg N for temperate forests and 0 (-4 to 5) kg C per kg N for tropical forests. Our global estimate of the N-induced forest biomass C sink of 41 (-53 to 159) Tg C yr-1 is substantially lower than previous estimates, mainly due to the absence of any response in most tropical forests (accounting for 58% of the global forest area). Overall, the N-induced C sink in AGWB only offsets ~5% of the climate impact of N2 O emissions (in terms of 100-year global warming potential), and contributes ~1% to the gross forest C sink.
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Affiliation(s)
- Lena F. Schulte‐Uebbing
- Environmental Systems Analysis GroupWageningen University & ResearchWageningenthe Netherlands
| | - Gerard H. Ros
- Environmental Systems Analysis GroupWageningen University & ResearchWageningenthe Netherlands
- Nutrient Management InstituteWageningenthe Netherlands
| | - Wim de Vries
- Environmental Systems Analysis GroupWageningen University & ResearchWageningenthe Netherlands
- Wageningen Environmental ResearchWageningen University & ResearchWageningenthe Netherlands
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13
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Effects of Moderate Nitrate and Low Sulphate Depositions on the Status of Soil Base Cation Pools and Recent Mineral Soil Acidification at Forest Conversion Sites with European Beech (“Green Eyes”) Embedded in Norway Spruce and Scots Pine Stands. FORESTS 2021. [DOI: 10.3390/f12050573] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
High N depositions of past decades brought changes to European forests including impacts on forest soil nutrition status. However, the ecosystem responses to declining atmospheric N inputs or moderate N depositions attracted only less attention so far. Our study investigated macronutrient (N, S, Ca2+, Mg2+, K+) pools and fluxes at forest conversion sites over 80 years old in Central Germany with European beech (so-called “Green Eyes” (GE)). The GE are embedded in large spruce and pine stands (coniferous stands: CS) and all investigated forest stands were exposed to moderate N deposition rates (6.8 ± 0.9 kg ha−1 yr−1) and acidic soil conditions (pHH2O < 4.7). Since the understanding of forest soil chemical and macronutrient status is essential for the evaluation of forest conversion approaches, we linked patterns in water-bound nutrient fluxes (2001–2018) and in predicted macronutrient storage in the herbaceous and tree layer to patterns in litter fall (2016–2017) and in forest floor and mineral soil macronutrient stocks at GE and CS assessed in 2018. Our results exhibited 43% (Nt) and 21% (S) higher annual throughfall fluxes at CS than at GE. Seepage water at 100 cm mineral soil depth (2001–2018) of CS is characterized by up to fivefold higher NO3− (GE: 2 ± 0.7 µmolc L−1; CS: 9 ± 1.4 µmolc L−1) and sevenfold higher SO42− (GE: 492 ± 220 µmolc L−1; CS: 3672 ± 2613 µmolc L−1) concentrations. High base cation (∑ Ca2+, Mg2+, K+) concentrations in CS mineral soil seepage water (100 cm depth: 2224 ± 1297 µmolc L−1) show significant positive correlations with SO42−. Tree uptake of base cations at GE is associated especially with a Ca2+ depletion from deeper mineral soil. Foliar litter fall turns out to be the main pathway for litter base cation return to the topsoil at GE (>59%) and CS (>66%). The litter fall base cation return at GE (59 ± 6 kg ha−1 yr−1) is almost twice as large as the base cation deposition (30 ± 5 kg ha−1 yr−1) via throughfall and stemflow. At CS, base cation inputs to the topsoil via litter fall and depositions are at the same magnitude (24 ± 4 kg ha−1 yr−1). Macronutrient turnover is higher at GE and decomposition processes are hampered at CS maybe through higher N inputs. Due to its little biomass and only small coverage, the herbaceous layer at GE and CS do not exert a strong influence on macronutrient storage. Changes in soil base cation pools are tree species-, depth- and might be time-dependent, with recently growing forest floor stocks. An ongoing mineral soil acidification seems to be related to decreasing mineral soil base cation stocks (through NO3− and especially SO42− leaching as well as through tree uptake).
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14
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Forsmark B, Wallander H, Nordin A, Gundale MJ. Long‐term nitrogen enrichment does not increase microbial phosphorus mobilization in a northern coniferous forest. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13701] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Benjamin Forsmark
- Department of Forest Ecology and Management Swedish University of Agricultural Sciences Umeå Sweden
| | | | - Annika Nordin
- Department of Forest Genetics and Plant Physiology Umeå Plant Science Centre Swedish University of Agricultural Sciences Umeå Sweden
| | - Michael J. Gundale
- Department of Forest Ecology and Management Swedish University of Agricultural Sciences Umeå Sweden
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