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Ferdous J, Islam M, Rahman M. The role of tree size, wood anatomical and leaf stomatal traits in shaping tree hydraulic efficiency and safety in a South Asian tropical moist forest. Glob Ecol Conserv 2023. [DOI: 10.1016/j.gecco.2023.e02453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023] Open
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Zhang Y, Qin Q, Zhu Q, Sun X, Bai Y, Liu Y. Stable isotopes in tree rings record physiological trends in Larix gmelinii after fires. TREE PHYSIOLOGY 2023:tpad033. [PMID: 36928744 DOI: 10.1093/treephys/tpad033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Fire is an important regulator of ecosystem dynamics in boreal forests, and especially has a complicated association with growth and physiological processes of fire-tolerant tree species. Stable isotope ratios in tree rings are used extensively in eco-physiological studies for evaluating the impact of past environmental (e.g., drought, air pollution) factors on tree growth and physiological processes. Yet, such studies based on carbon (δ13C) and oxygen (δ18O) isotope ratios in tree rings are rarely conducted on fire effect, especially not well explored for fire-tolerant trees. In this study, we investigated variations in basal area increment and isotopes of Larix gmelinii (Rupr.) Rupr. before and after three moderate fires (different fire years) at three sites across the Great Xing'an Mountains, Northeastern China. We found that the radial growth of L. gmelinii trees has significantly declined after the fires across study sites. Following the fires, a simultaneous increase in δ13C and δ18O has strengthened the link between the two isotopes. Further, fires have significantly enhanced the 13C-derived intrinsic water-use efficiency (iWUE) and largely altered the relationships between δ13C, δ18O, iWUE and climate (temperature and precipitation). A dual-isotope conceptual model revealed that an initial co-increase in δ13C and δ18O in the fire year can be mainly attributed to a reduction in stomatal conductance with a constant photosynthetic rate. However, this physiological response would shift to different patterns over post-fire time between sites, which might be partly related to spring temperature. This study is beneficial to better understand, in a physiological perspective, how fire-tolerant tree species adapt to a fire-prone environment. We also remind that the limitation of model assumptions and constraints may challenge model applicability and further inferred physiological response.
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Affiliation(s)
- Yujian Zhang
- School of Ecology and Nature Conservation, Beijing Forestry University, 100083, Beijing, China
| | - Qianqian Qin
- School of Ecology and Nature Conservation, Beijing Forestry University, 100083, Beijing, China
| | - Qiang Zhu
- School of Ecology and Nature Conservation, Beijing Forestry University, 100083, Beijing, China
| | - Xingyue Sun
- School of Ecology and Nature Conservation, Beijing Forestry University, 100083, Beijing, China
| | - Yansong Bai
- School of Ecology and Nature Conservation, Beijing Forestry University, 100083, Beijing, China
| | - Yanhong Liu
- Beijing Key Laboratory of Forest Resources and Ecosystem Process, Beijing Forestry University, 100083, Beijing, China
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Lobo AKM, Catarino ICA, Silva EA, Centeno DC, Domingues DS. Physiological and Molecular Responses of Woody Plants Exposed to Future Atmospheric CO2 Levels under Abiotic Stresses. PLANTS 2022; 11:plants11141880. [PMID: 35890514 PMCID: PMC9322912 DOI: 10.3390/plants11141880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 11/16/2022]
Abstract
Climate change is mainly driven by the accumulation of carbon dioxide (CO2) in the atmosphere in the last century. Plant growth is constantly challenged by environmental fluctuations including heat waves, severe drought and salinity, along with ozone accumulation in the atmosphere. Food security is at risk in an increasing world population, and it is necessary to face the current and the expected effects of global warming. The effects of the predicted environment scenario of elevated CO2 concentration (e[CO2]) and more severe abiotic stresses have been scarcely investigated in woody plants, and an integrated view involving physiological, biochemical and molecular data is missing. This review highlights the effects of elevated CO2 in the metabolism of woody plants and the main findings of its interaction with abiotic stresses, including a molecular point of view, aiming to improve the understanding of how woody plants will face the predicted environmental conditions. Overall, e[CO2] stimulates photosynthesis and growth and attenuates mild to moderate abiotic stress in woody plants if root growth and nutrients are not limited. Moreover, e[CO2] does not induce acclimation in most tree species. Some high-throughput analyses involving omics techniques were conducted to better understand how these processes are regulated. Finally, knowledge gaps in the understanding of how the predicted climate condition will affect woody plant metabolism were identified, with the aim of improving the growth and production of this plant species.
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Affiliation(s)
- Ana Karla M. Lobo
- Department of Biodiversity, Institute of Biosciences, São Paulo State University, UNESP, Rio Claro 13506-900, Brazil;
- Correspondence: (A.K.M.L.); (D.S.D.)
| | - Ingrid C. A. Catarino
- Department of Biodiversity, Institute of Biosciences, São Paulo State University, UNESP, Rio Claro 13506-900, Brazil;
| | - Emerson A. Silva
- Institute of Environmental Research, São Paulo 04301-002, Brazil;
| | - Danilo C. Centeno
- Centre for Natural and Human Sciences, Federal University of ABC, São Bernardo do Campo 09606-045, Brazil;
| | - Douglas S. Domingues
- Department of Biodiversity, Institute of Biosciences, São Paulo State University, UNESP, Rio Claro 13506-900, Brazil;
- Correspondence: (A.K.M.L.); (D.S.D.)
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Rahman M, Islam M, Masood M, Gebrekirstos A, Bräuning A. Flood signals in tree-ring δ 18O and wood anatomical parameters of Lagerstroemia speciosa: Implications for developing flood management strategies in Bangladesh. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 809:151125. [PMID: 34688736 DOI: 10.1016/j.scitotenv.2021.151125] [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: 05/04/2021] [Revised: 10/16/2021] [Accepted: 10/17/2021] [Indexed: 06/13/2023]
Abstract
Bangladesh consists of 80% of the flood plain of the Ganges-Brahmaputra-Meghna river system (GBM), making the country one of the highest flood prone countries of the world. Due to the high rate of discharge of the GBM caused by the summer monsoon and the snowmelt of the Eastern Himalaya and Southern Tibetan Plateau due to climate change, Bangladesh witnessed 16 flood events over 1954-2017. We performed a multiproxy tree-ring analysis to investigate the impact of extreme flood events on tree growth, xylem anatomical parameters and oxygen isotope composition of tree-ring cellulose (δ18Otr) in a Bangladeshi moist tropical forest and to establish relationships between water level of the regional rivers and tree-ring parameters. By using pointer year analysis and comparing the pointer years with historical flood records (a cut-off threshold of the country's flooded land area of 33.3%), we identified the three extreme flood events (hereafter called flood years) 1974, 1988, and 1998 in Bangladesh. Superposed epoch analysis revealed significant changes in Tree-ring width (TRW), total vessel area (TVA), vessel density (VD), and δ18Otr during flood years. Flood associated hypoxic soil conditions reduced TRW up to 53% and TVA up to 28%, varying with flood events. In contrast, VD increased by 23% as a safety mechanism against flood induced hydraulic failure. Tree-ring δ18O significantly decreased during the flood years due to the amount effect in regional precipitation. Bootstrapped Pearson correlation analysis showed that wood anatomical variables encoded stronger river level signals than TRW and δ18Otr. Among the wood anatomical parameters, VD showed a strong relationship (r = -0.58, p < 0.01) with the water level of the Manu River, a regional river of the north-eastern part of Bangladesh, indicating that VD can be used as a reliable proxy for river level reconstruction. Our analyses suggest that multiproxy tree-ring analysis is a potential tool to study tropical moist forest responses to extreme flood events and to identify suitable proxies for reconstructing hydrological characteristics of South Asian rivers.
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Affiliation(s)
- Mizanur Rahman
- Department of Forestry and Environmental Science, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh; Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Wetterkreuz 15, 91058 Erlangen, Germany.
| | - Mahmuda Islam
- Department of Forestry and Environmental Science, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh; Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Wetterkreuz 15, 91058 Erlangen, Germany
| | - Muhammad Masood
- Design Circle-9, Bangladesh Water Development Board (BWDB), Pani Bhaban, 72, Green Road, Dhaka 1215, Bangladesh
| | - Aster Gebrekirstos
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Wetterkreuz 15, 91058 Erlangen, Germany; World Agroforestry Centre (ICRAF), United Nations Avenue, P.O. Box 30677-00100, Nairobi, Kenya
| | - Achim Bräuning
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Wetterkreuz 15, 91058 Erlangen, Germany
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Cintra BBL, Gloor M, Boom A, Schöngart J, Baker JCA, Cruz FW, Clerici S, Brienen RJW. Tree-ring oxygen isotopes record a decrease in Amazon dry season rainfall over the past 40 years. CLIMATE DYNAMICS 2021; 59:1401-1414. [PMID: 35971539 PMCID: PMC9372001 DOI: 10.1007/s00382-021-06046-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 11/07/2021] [Indexed: 06/01/2023]
Abstract
UNLABELLED Extant climate observations suggest the dry season over large parts of the Amazon Basin has become longer and drier over recent decades. However, such possible intensification of the Amazon dry season and its underlying causes are still a matter of debate. Here we used oxygen isotope ratios in tree rings (δ18OTR) from six floodplain trees from the western Amazon to assess changes in past climate. Our analysis shows that δ18OTR of these trees is negatively related to inter-annual variability of precipitation during the dry season over large parts of the Amazon Basin, consistent with a Rayleigh rainout model. Furthermore δ18OTR increases by approximately 2‰ over the last four decades (~ 1970-2014) providing evidence of an Amazon drying trend independent from satellite and in situ rainfall observations. Using a Rayleigh rainout framework, we estimate basin-wide dry season rainfall to have decreased by up to 30%. The δ18OTR record further suggests such drying trend may not be unprecedented over the past 80 years. Analysis of δ18OTR with sea surface temperatures indicates a strong role of a warming Tropical North Atlantic Ocean in driving this long-term increase in δ18OTR and decrease in dry season rainfall. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s00382-021-06046-7.
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Affiliation(s)
- Bruno B. L. Cintra
- School of Geography, University of Leeds, Garstang North Building, Leeds, LS2 9JT UK
- Institute of Biosciences, University of São Paulo, Rua do Matão 14, São Paulo, 05508-090 Brazil
| | - Manuel Gloor
- School of Geography, University of Leeds, Garstang North Building, Leeds, LS2 9JT UK
| | - Arnoud Boom
- School of Geography, Geology and the Environment, University of Leicester, Bennet Building, University Road, Leicester, LE1 7RH UK
| | - Jochen Schöngart
- Coordination of Environmental Dynamics, National Institute for Amazon Research, Av. André Araújo 2936, Petrópolis, Manaus, 69067-375 Brazil
| | | | - Francisco W. Cruz
- Institute of Geosciences, University of São Paulo, Rua do Lago 562, São Paulo, 05508-080 Brazil
| | - Santiago Clerici
- School of Geography, University of Leeds, Garstang North Building, Leeds, LS2 9JT UK
| | - Roel J. W. Brienen
- School of Geography, University of Leeds, Garstang North Building, Leeds, LS2 9JT UK
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Islam M, Rahman M, Gebrekirstos A, Bräuning A. Tree-ring δ 18O climate signals vary among tree functional types in South Asian tropical moist forests. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 756:143939. [PMID: 33310218 DOI: 10.1016/j.scitotenv.2020.143939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 11/13/2020] [Accepted: 11/13/2020] [Indexed: 06/12/2023]
Abstract
We present the first annually resolved and statistically reliable tree-ring δ18O (δ18OT) chronologies for the three South Asian tropical moist forest tree species (Chukrasia tabularis A. Juss., Toona ciliata M. Roem., and Lagerstroemia speciosa Roxb.) which differ in their shade tolerance and resistance to water stress. We found significantly higher mean δ18OT values in light-demanding T. ciliata than in intermediate shade tolerant C. tabularis and shade tolerant L. speciosa (p < 0.001). δ18OT in C. tabularis was mainly influenced by pre-monsoon vapor pressure deficit (VPD; r = -0.54, p < 0.01) and post monsoon maximum temperature (Tmax) (r = 0.52, p < 0.01). δ18OT in T. ciliata was strongly negatively correlated with a dry season drought index PDSI (r = -0.65, p < 0.001) and VPD (r = -0.58, p < 0.001). Pre-monsoon Tmax was strongly positively linked with δ18OT in L. speciosa (r = 0.65, p < 0.001), indicating that climatic influences on δ18OT are species-specific and vary among tree functional types. Although there was a week correlation between local precipitation and δ18OT in our studied species, we found a strong correlation between δ18OT and precipitation at a larger spatial scale. Linear mixed effect models revealed that multiple factors improved model performance only in C. tabularis, yielding the best model, which combined VPD and Tmax. The top models in T. ciliata and L. speciosa included only the single factors PDSI and Tmax, highlighting that the way C. tabularis interacts with climate is more complex when compared with other two species. Our analyses suggest that stable oxygen isotope composition in tree rings of South Asian tropical moist forest trees are a suitable proxy of local and regional climate variability and are an important tool for understanding the physiological mechanisms associated with the global hydrological cycle.
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Affiliation(s)
- Mahmuda Islam
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Wetterkreuz 15, 91058 Erlangen, Germany; Department of Forestry and Environmental Science, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh.
| | - Mizanur Rahman
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Wetterkreuz 15, 91058 Erlangen, Germany; Department of Forestry and Environmental Science, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
| | - Aster Gebrekirstos
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Wetterkreuz 15, 91058 Erlangen, Germany; World Agroforestry Centre (ICRAF), United Nations Avenue, P.O. Box 30677-00100, Nairobi, Kenya
| | - Achim Bräuning
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Wetterkreuz 15, 91058 Erlangen, Germany
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