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Qi X, Treydte K, Saurer M, Fang K, An W, Lehmann M, Liu K, Wu Z, He HS, Du H, Li MH. Contrasting water-use strategies to climate warming in white birch and larch in a boreal permafrost region. TREE PHYSIOLOGY 2024; 44:tpae053. [PMID: 38769900 DOI: 10.1093/treephys/tpae053] [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: 12/19/2023] [Revised: 05/11/2024] [Accepted: 05/18/2024] [Indexed: 05/22/2024]
Abstract
The effects of rising atmospheric CO2 concentrations (Ca) with climate warming on intrinsic water-use efficiency and radial growth in boreal forests are still poorly understood. We measured tree-ring cellulose δ13C, δ18O, and tree-ring width in Larix dahurica (larch) and Betula platyphylla (white birch), and analyzed their relationships with climate variables in a boreal permafrost region of northeast China over past 68 years covering a pre-warming period (1951-1984; base period) and a warm period (1985-2018; warm period). We found that white birch but not larch significantly increased their radial growth over the warm period. The increased intrinsic water-use efficiency in both species was mainly driven by elevated Ca but not climate warming. White birch but not larch showed significantly positive correlations between tree-ring δ13C, δ18O and summer maximum temperature as well as vapor pressure deficit in the warm period, suggesting a strong stomatal response in the broad-leaved birch to temperature changes. The climate warming-induced radial growth enhancement in white birch is primarily associated with a conservative water-use strategy. In contrast, larch exhibits a profligate water-use strategy. It implies an advantage for white birch over larch in the warming permafrost regions.
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Affiliation(s)
- Xi Qi
- Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Renmin Street, Nanguan District, Changchun 130024, China
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf CH-8903, Switzerland
| | - Kerstin Treydte
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf CH-8903, Switzerland
| | - Matthias Saurer
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf CH-8903, Switzerland
| | - Keyan Fang
- Key Laboratory of Humid Subtropical Eco-Geographical Process, Ministry of Education, College of Geographical Sciences, Fujian Normal University, Shangsan Road, Cangshan District, Fuzhou 350007, China
| | - Wenling An
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf CH-8903, Switzerland
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beitucheng West Road, Chaoyang District, Beijing 100029, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
| | - Marco Lehmann
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf CH-8903, Switzerland
| | - Kunyuan Liu
- Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Renmin Street, Nanguan District, Changchun 130024, China
| | - Zhengfang Wu
- Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Renmin Street, Nanguan District, Changchun 130024, China
| | - Hong S He
- School of Natural Resources, University of Missouri, 230 Jesse Hall, Columbia, MO 65211, USA
| | - Haibo Du
- Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Renmin Street, Nanguan District, Changchun 130024, China
- Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Renmin Street, Nanguan District, Changchun 130024, China
| | - Mai-He Li
- Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Renmin Street, Nanguan District, Changchun 130024, China
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, Birmensdorf CH-8903, Switzerland
- School of Life Sciences, Hebei University, Wusi East Road, Lianchi District, Baoding 071000, China
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Gessler A, Zweifel R. Beyond source and sink control - toward an integrated approach to understand the carbon balance in plants. THE NEW PHYTOLOGIST 2024; 242:858-869. [PMID: 38375596 DOI: 10.1111/nph.19611] [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: 10/10/2023] [Accepted: 02/03/2024] [Indexed: 02/21/2024]
Abstract
A conceptual understanding on how the vegetation's carbon (C) balance is determined by source activity and sink demand is important to predict its C uptake and sequestration potential now and in the future. We have gathered trajectories of photosynthesis and growth as a function of environmental conditions described in the literature and compared them with current concepts of source and sink control. There is no clear evidence for pure source or sink control of the C balance, which contradicts recent hypotheses. Using model scenarios, we show how legacy effects via structural and functional traits and antecedent environmental conditions can alter the plant's carbon balance. We, thus, combined the concept of short-term source-sink coordination with long-term environmentally driven legacy effects that dynamically acclimate structural and functional traits over time. These acclimated traits feedback on the sensitivity of source and sink activity and thus change the plant physiological responses to environmental conditions. We postulate a whole plant C-coordination system that is primarily driven by stomatal optimization of growth to avoid a C source-sink mismatch. Therefore, we anticipate that C sequestration of forest ecosystems under future climate conditions will largely follow optimality principles that balance water and carbon resources to maximize growth in the long term.
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Affiliation(s)
- Arthur Gessler
- Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
- Institute of Terrestrial Ecosystems, ETH Zurich, 8092, Zurich, Switzerland
| | - Roman Zweifel
- Swiss Federal Research Institute WSL, 8903, Birmensdorf, Switzerland
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Pernicová N, Urban O, Čáslavský J, Kolář T, Rybníček M, Sochová I, Peñuelas J, Bošeľa M, Trnka M. Impacts of elevated CO 2 levels and temperature on photosynthesis and stomatal closure along an altitudinal gradient are counteracted by the rising atmospheric vapor pressure deficit. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 921:171173. [PMID: 38401718 DOI: 10.1016/j.scitotenv.2024.171173] [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: 12/04/2023] [Revised: 02/09/2024] [Accepted: 02/20/2024] [Indexed: 02/26/2024]
Abstract
The efficiency of water use in plants, a critical ecophysiological parameter closely related to water and carbon cycles, is essential for understanding the interactions between plants and their environment. This study investigates the effects of ongoing climate change and increasing atmospheric CO2 concentration on intrinsic (stomata-based; iWUE) and evaporative (transpiration-based; eWUE) water use efficiency in oak trees along a naturally small altitudinal gradient (130-630 m a.s.l.) of Vihorlat Mountains (eastern Slovakia, Central Europe). To assess changes in iWUE and eWUE values over the past 60 years (1961-2020), stable carbon isotope ratios in latewood cellulose (δ13Ccell) of annually resolved tree rings were analyzed. Such an approach was sensitive enough to distinguish tree responses to growth environments at different altitudes. Our findings revealed a rising trend in iWUE, particularly in oak trees at low and middle altitudes. However, this increase was negligible at high altitudes. Warmer and drier conditions at lower altitudes likely led to significant stomatal closure and enhanced efficiency in photosynthetic CO2 uptake due to rising CO2 concentration. Conversely, the increasing intracellular-to-ambient CO2 ratio (Ci/Ca) at higher altitudes indicated lower efficiency in photosynthetic CO2 uptake. In contrast to iWUE, eWUE showed no increasing trends over the last 60 years. This suggests that the positive impacts of elevated CO2 concentrations and temperature on photosynthesis and stomatal closure are counteracted by the rising atmospheric vapor pressure deficit (VPD). These differences underscore the importance of the correct interpretation of stomata-based and transpiration-based WUEs and highlight the necessity of atmospheric VPD correction when applying tree-ring δ13C-derived WUE at ecosystem and global levels.
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Affiliation(s)
- Natálie Pernicová
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; Mendel University in Brno, Department of Agrosystems and Bioclimatology, Faculty of AgriSciences, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Otmar Urban
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic.
| | - Josef Čáslavský
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic
| | - Tomáš Kolář
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; Mendel University in Brno, Department of Wood Science and Technology, Faculty of Forestry and Wood Technology, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Michal Rybníček
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; Mendel University in Brno, Department of Wood Science and Technology, Faculty of Forestry and Wood Technology, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Irena Sochová
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; Mendel University in Brno, Department of Wood Science and Technology, Faculty of Forestry and Wood Technology, Zemědělská 1, CZ-613 00 Brno, Czech Republic
| | - Josep Peñuelas
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra 08193, Catalonia, Spain; CREAF, Cerdanyola del Vallès 08193, Catalonia, Spain
| | - Michal Bošeľa
- Faculty of Forestry, Technical University in Zvolen, T. G. Masaryka 24, SK-960 01 Zvolen, Slovakia
| | - Miroslav Trnka
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, CZ-603 00 Brno, Czech Republic; Mendel University in Brno, Department of Agrosystems and Bioclimatology, Faculty of AgriSciences, Zemědělská 1, CZ-613 00 Brno, Czech Republic
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Fajardo A, Gazol A, Meynard PM, Mayr C, Martínez Pastur GJ, Peri PL, Camarero JJ. Climate change-related growth improvements in a wide niche-breadth tree species across contrasting environments. ANNALS OF BOTANY 2023; 131:941-951. [PMID: 36996263 PMCID: PMC10332394 DOI: 10.1093/aob/mcad053] [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: 01/24/2023] [Accepted: 03/29/2023] [Indexed: 06/19/2023]
Abstract
BACKGROUND AND AIMS The vulnerability and responsiveness of forests to drought are immensely variable across biomes. Intraspecific tree responses to drought in species with wide niche breadths that grow across contrasting climatically environments might provide key information regarding forest resistance and changes in species distribution under climate change. Using a species with an exceptionally wide niche breath, we tested the hypothesis that tree populations thriving in dry environments are more resistant to drought than those growing in moist locations. METHODS We determined temporal trends in tree radial growth of 12 tree populations of Nothofagus antarctica (Nothofagaceae) located across a sharp precipitation gradient (annual precipitation of 500-2000 mm) in Chile and Argentina. Using dendrochronological methods, we fitted generalized additive mixed-effect models to predict the annual basal area increment as a function of year and dryness (De Martonne aridity index). We also measured carbon and oxygen isotope signals (and estimated intrinsic water-use efficiency) to provide potential physiological causes for tree growth responses to drought. KEY RESULTS We found unexpected improvements in growth during 1980-1998 in moist sites, while growth responses in dry sites were mixed. All populations, independent of site moisture, showed an increase in their intrinsic water-use efficiency in recent decades, a tendency that seemed to be explained by an increase in the photosynthetic rate instead of drought-induced stomatal closure, given that δ18O did not change with time. CONCLUSIONS The absence of drought-induced negative effects on tree growth in a tree species with a wide niche breadth is promising because it might relate to the causal mechanisms tree species possess to face ongoing drought events. We suggest that the drought resistance of N. antarctica might be attributable to its low stature and relatively low growth rate.
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Affiliation(s)
- Alex Fajardo
- Instituto de Investigación Interdisciplinaria (I), Vicerrectoría Académica, Universidad de Talca, Campus Lircay, Talca 3460000, Chile
| | - Antonio Gazol
- Instituto Pirenaico de Ecología (IPE-CSIC), Avda. Montañana 1005, E-50192 Zaragoza, Spain
| | - Paulo Moreno Meynard
- Centro de Investigación en Ecosistemas de la Patagonia (CIEP), Camino Baguales s/n, Coyhaique 5951601, Chile
| | - Christoph Mayr
- Institut für Geographie, Friedrich-Alexander-Universität, Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Guillermo J Martínez Pastur
- Centro Austral de Investigaciones Científicas (CADIC), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Houssay 200 (9410) Ushuaia, Tierra del Fuego, Argentina
| | - Pablo L Peri
- Instituto Nacional de Tecnología Agropecuaria (INTA)-CONICET, cc332 (9400) Río Gallegos, Santa Cruz, Argentina
| | - J Julio Camarero
- Instituto Pirenaico de Ecología (IPE-CSIC), Avda. Montañana 1005, E-50192 Zaragoza, Spain
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Duque-Marín E, Rojas-Palma A, Carrasco-Benavides M. A soil water indicator for a dynamic model of crop and soil water interaction. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2023; 20:13881-13899. [PMID: 37679115 DOI: 10.3934/mbe.2023618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
Water scarcity is a critical issue in agriculture, and the development of reliable methods for determining soil water content is crucial for effective water management. This study proposes a novel, theoretical, non-physiological indicator of soil water content obtained by applying the next-generation matrix method, which reflects the water-soil-crop dynamics and identifies the minimum viable value of soil water content for crop growth. The development of this indicator is based on a two-dimensional, nonlinear dynamic that considers two different irrigation scenarios: the first scenario involves constant irrigation, and the second scenario irrigates in regular periods by assuming each irrigation as an impulse in the system. The analysis considers the study of the local stability of the system by incorporating parameters involved in the water-soil-crop dynamics. We established a criterion for identifying the minimum viable value of soil water content for crop growth over time. Finally, the model was calibrated and validated using data from an independent field study on apple orchards and a tomato crop obtained from a previous field study. Our results suggest the advantages of using this theoretical approach in modeling the plants' conditions under water scarcity as the first step before an empirical model. The proposed indicator has some limitations, suggesting the need for future studies that consider other factors that affect soil water content.
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Affiliation(s)
- Edwin Duque-Marín
- Doctorado en Modelamiento Matemático Aplicado, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca 3460000, Chile
| | - Alejandro Rojas-Palma
- Doctorado en Modelamiento Matemático Aplicado, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca 3460000, Chile
- Departamento de Matemática, Física y Estadística, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca 3460000, Chile
| | - Marcos Carrasco-Benavides
- Doctorado en Modelamiento Matemático Aplicado, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca 3460000, Chile
- Departamento de Ciencias Agrarias, Facultad de Ciencias Agrarias y Forestales, Universidad Católica del Maule, Curicó 3340000, Chile
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Hong Y, Liu X, Camarero JJ, Xu G, Zhang L, Zeng X, Aritsara ANA, Zhang Y, Wang W, Xing X, Lu Q. The effects of intrinsic water-use efficiency and climate on wood anatomy. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2023:10.1007/s00484-023-02475-7. [PMID: 37072578 DOI: 10.1007/s00484-023-02475-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
Climate warming may induce growth decline in warm-temperate areas subjected to seasonal soil moisture deficit, whereas increasing atmospheric CO2 concentration (Ca) is expected to enhance tree growth. An accurate understanding of tree growth and physiological processes responding to climate warming and increasing Ca is critical. Here, we analyzed tree-ring stable carbon isotope and wood anatomical traits of Pinus tabuliformis from Qinling Mountains in China to understand how lumen diameter (LD) determining potential hydraulic conductivity and cell-wall thickness (CWT) determining carbon storage responded to climate and Ca. The effects of climate and Ca on intrinsic water-use efficiency (iWUE) were isolated, and iWUE values due to only-climate (iWUEClim) and only-CO2 effects (iWUECO2) were obtained. During a low-iWUE period, the influences of climate on earlywood (EW) LD and latewood (LW) CWT prevailed. During a high-iWUE period, CO2 fertilization promoted cell enlargement and carbon storage but this was counteracted by a negative influence of climate warming. The limiting direct effects of iWUEClim and indirect effects of climate on EW LD were greater than on LW CWT. P. tabuliformis in temperate forests will face a decline of growth and carbon fixation, but will produce embolism-resistant tracheids with narrow lumen responding to future hotter droughts.
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Affiliation(s)
- Yixue Hong
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, 710119, China
- State Key Laboratory of Biocontrol, School of Ecology, Shenzhen Campus of Sun Yat-Sen University, Shenzhen, 518107, China
| | - Xiaohong Liu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, 710119, China.
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
| | - J Julio Camarero
- Instituto Pirenaico de Ecología (IPE-CSIC), Zaragoza, 50092, Spain
| | - Guobao Xu
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Lingnan Zhang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, 710119, China
| | - Xiaomin Zeng
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, 710119, China
| | - Amy Ny Aina Aritsara
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning, 530004, China
| | - Yu Zhang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, 710119, China
| | - Wenzhi Wang
- The Key Laboratory of Mountain Environment Evolution and Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, 610041, China
| | - Xiaoyu Xing
- Qinling National Botanical Garden, Xi'an, 710061, China
| | - Qiangqiang Lu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, 710119, China
- Xi'an Botanical Garden of Shaanxi Province (Institute of Botany of Shaanxi Province), Xi'an, 710061, China
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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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Urrutia-Jalabert R, Barichivich J, Szejner P, Rozas V, Lara A. Ecophysiological responses of Nothofagus obliqua forests to recent climate drying across the Mediterranean-Temperate biome transition in south-central Chile. JOURNAL OF GEOPHYSICAL RESEARCH. BIOGEOSCIENCES 2022; 128:2022jg007293. [PMID: 37484604 PMCID: PMC7614787 DOI: 10.1029/2022jg007293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 03/02/2023] [Indexed: 07/25/2023]
Abstract
The forests of south-central Chile are facing a drying climate and a megadrought that started in 2010. This study addressed the physiological responses of five Nothofagus obliqua stands across the Mediterranean-Temperate gradient (35.9 ° -40.3° S) using carbon isotope discrimination (Δ13 C) and intrinsic water use efficiency (iWUE) in tree rings during 1967-2017. Moreover, δ18O was evaluated in the northernmost site to better understand the effects of the megadrought in this drier location. These forests have become more efficient in their use of water. However, trees from the densest stand are discriminating more against 13C, probably due to reduced photosynthetic rates associated with increasing competition. The strongest associations between climate and Δ13C were found in the northernmost stand, suggesting that warmer and drier conditions could have reduced 13C discrimination. Tree growth in this site has not decreased, and δ18O was negatively related to annual rainfall. However, a shift in this relationship was found since 2007, when both precipitation and δ18O decreased, while correlations between δ18O and growth increased. This implies that tree growth and δ18O are coupled in recent years, but precipitation is not the cause, suggesting that trees probably changed their water source to deeper and more depleted pools. Our research demonstrates that forests are not reducing their growth in central Chile, mainly due to a shift towards the use of deeper water sources. Despite a common climate trend across the gradient, there is a non-uniform response of N. obliqua forests to climate drying, being their response site specific. Keywords: Tree rings, stable isotopes, tree physiology, climate gradient, megadrought, climate change.
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Affiliation(s)
- Rocío Urrutia-Jalabert
- Departamento de Ciencias Naturales y Tecnología, Universidad de Aysén, Coyhaique, Chile
- Laboratorio de Dendrocronología y Cambio Global, Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Valdivia, Chile
- Centro de Ciencia del Clima y la Resiliencia, CR2, Santiago, Chile
| | - Jonathan Barichivich
- Laboratoire des Sciences du Climat et de l'Environnement, IPSL, CRNS/CEA/UVSQ, France
- Instituto de Geografía, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Paul Szejner
- Departamento de Ciencias Ambientales y del suelo, Instituto de Geología, Universidad Nacional Autónoma de México. Ciudad Universitaria CDMX, México
| | - Vicente Rozas
- iuFOR-EiFAB, Área de Botánica, Campus Duques de Soria, Universidad de Valladolid, 42004 Soria, Spain
| | - Antonio Lara
- Laboratorio de Dendrocronología y Cambio Global, Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Valdivia, Chile
- Centro de Ciencia del Clima y la Resiliencia, CR2, Santiago, Chile
- Fundación Centro de los Bosques Nativos FORECOS, Valdivia, Chile
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Laffitte B, Seyler BC, Wang W, Li P, Du J, Tang Y. Declining tree growth rates despite increasing water-use efficiency under elevated CO 2 reveals a possible global overestimation of CO 2 fertilization effect. Heliyon 2022; 8:e11219. [PMID: 36339991 PMCID: PMC9626951 DOI: 10.1016/j.heliyon.2022.e11219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/27/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022] Open
Abstract
Though rising atmospheric CO2 concentrations (Ca) harm the environment and society, they may also raise photosynthetic rates and enhance intrinsic water-use efficiency (iWUE). Numerous short-term studies have investigated tree growth under elevated CO2 (eCO2) conditions, but no long-duration study has investigated eCO2 impacts on tree growth and iWUE under natural conditions. Utilizing a new dendrochronological experimental design in a heavily-touristed nature preserve in Southwest China (Jiuzhaigou National Nature Reserve), we compared tree growth (e.g., basal area increment) and iWUE in two biophysically and environmentally similar valleys with contrasting anthropogenic activities. Trees in the control valley with ambient CO2 benefited from increasing Ca, possibly due to the CO2 fertilization effect and optimal environmental conditions. However, trees in the treatment valley with intensive tourism experienced comparatively higher localized eCO2 and growth rate declines. While iWUE increased (1959–2017) in the control (25.3%) and treatment sites (47.8%), declining tree growth rates in the treatment site was likely because comparatively extreme CO2 exposure levels encouraged stomatal closures. As the first long-term study investigating eCO2 impacts on tree growth and iWUE under natural conditions, we demonstrate that increased forest iWUE is unlikely to overcome negative drought stress and rising temperature impacts. Thus, forest potential for mitigating eCO2 and global climate change is likely overestimated, particularly under dry temperate conditions.
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Affiliation(s)
- Benjamin Laffitte
- Department of Environment, College of Architecture and Environment, Sichuan University, No. 24, South Section One, First Ring Road, Chengdu, Sichuan 610065, China
| | - Barnabas C. Seyler
- Department of Environment, College of Architecture and Environment, Sichuan University, No. 24, South Section One, First Ring Road, Chengdu, Sichuan 610065, China
| | - Wenzhi Wang
- The Key Laboratory of Mountain Environment Evolution and Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China
| | - Pengbo Li
- Department of Environment, College of Architecture and Environment, Sichuan University, No. 24, South Section One, First Ring Road, Chengdu, Sichuan 610065, China
| | - Jie Du
- Jiuzhaigou Administrative Bureau, Zhangzha, Jiuzhaigou, Sichuan 623402, China
| | - Ya Tang
- Department of Environment, College of Architecture and Environment, Sichuan University, No. 24, South Section One, First Ring Road, Chengdu, Sichuan 610065, China,Corresponding author.
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10
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Treml V, Tumajer J, Jandová K, Oulehle F, Rydval M, Čada V, Treydte K, Mašek J, Vondrovicová L, Lhotáková Z, Svoboda M. Increasing water-use efficiency mediates effects of atmospheric carbon, sulfur, and nitrogen on growth variability of central European conifers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156483. [PMID: 35675888 DOI: 10.1016/j.scitotenv.2022.156483] [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: 03/01/2022] [Revised: 05/31/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Climate controls forest biomass production through direct effects on cambial activity and indirectly through interactions with CO2, air pollution, and nutrient availability. The atmospheric concentration of CO2, sulfur and nitrogen deposition can also exert a significant indirect control on wood formation since these factors influence the stomatal regulation of transpiration and carbon uptake, that is, intrinsic water use efficiency (iWUE). Here we provide 120-year long tree-ring time series of iWUE, stem growth, climatic and combined sulfur and nitrogen (SN) deposition trends for two common tree species, Pinus sylvestris (PISY) and Picea abies (PCAB), at their lower and upper distribution margins in Central Europe. The main goals were to explain iWUE trends using theoretical scenarios including climatic and SN deposition data, and to assess the contribution of climate and iWUE to the observed growth trends. Our results showed that after a notable increase in iWUE between the 1950s and 1980s, this positive trend subsequently slowed down. The substantial rise of iWUE since the 1950s resulted from a combination of an accelerated increase in atmospheric CO2 concentrations (Ca) and a stable level of leaf intercellular CO2 (Ci). The offset of observed iWUE values above the trajectory of a constant Ci/Ca scenario was explained by trends in SN deposition (all sites) together with the variation of drought conditions (low-elevation sites only). Increasing iWUE over the 20th and 21st centuries improved tree growth at low-elevation drought-sensitive sites. In contrast, at high-elevation PCAB sites, growth was mainly stimulated by recent warming. We propose that SN pollution should be considered in order to explain the steep increase in iWUE of conifers in the 20th century throughout Central Europe and other regions with a significant SN deposition history.
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Affiliation(s)
- Václav Treml
- Faculty of Science, Charles University, Prague, Czechia.
| | - Jan Tumajer
- Faculty of Science, Charles University, Prague, Czechia
| | | | | | - Miloš Rydval
- Faculty of Forestry and Wood Science, Czech University of Life Science, Prague, Czechia
| | - Vojtěch Čada
- Faculty of Forestry and Wood Science, Czech University of Life Science, Prague, Czechia
| | - Kerstin Treydte
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Jiří Mašek
- Faculty of Science, Charles University, Prague, Czechia
| | | | | | - Miroslav Svoboda
- Faculty of Forestry and Wood Science, Czech University of Life Science, Prague, Czechia
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11
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Oberleitner F, Hartmann H, Hasibeder R, Huang J, Losso A, Mayr S, Oberhuber W, Wieser G, Bahn M. Amplifying effects of recurrent drought on the dynamics of tree growth and water use in a subalpine forest. PLANT, CELL & ENVIRONMENT 2022; 45:2617-2635. [PMID: 35610775 DOI: 10.1111/pce.14369] [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: 11/07/2021] [Revised: 04/16/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
Despite recent advances in our understanding of drought impacts on tree functioning, we lack knowledge about the dynamic responses of mature trees to recurrent drought stress. At a subalpine forest site, we assessed the effects of three years of recurrent experimental summer drought on tree growth and water relations of Larix decidua Mill. and Picea abies (L. Karst.), two common European conifers representative for contrasting water-use strategies. We combined dendrometer and xylem sap flow measurements with analyses of xylem anatomy and non-structural carbohydrates and their carbon-isotope composition. Recurrent drought increased the effects of soil moisture limitation on growth and xylogenesis, and to a lesser extent on xylem sap flow. P. abies showed stronger growth responses to recurrent drought, reduced starch concentrations in branches and increased water-use efficiency when compared to L. decidua. Despite comparatively larger maximum tree water deficits than in P. abies, xylem formation of L. decidua was less affected by drought, suggesting a stronger capacity of rehydration or lower cambial turgor thresholds for growth. Our study shows that recurrent drought progressively increases impacts on mature trees of both species, which suggests that in a future climate increasing drought frequency could impose strong legacies on carbon and water dynamics of treeline species.
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Affiliation(s)
| | - Henrik Hartmann
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Roland Hasibeder
- Department of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Jianbei Huang
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Adriano Losso
- Department of Botany, University of Innsbruck, Innsbruck, Austria
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia
| | - Stefan Mayr
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Walter Oberhuber
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Gerhard Wieser
- Department of Botany, University of Innsbruck, Innsbruck, Austria
- Department of Alpine Timberline Ecophysiology, Federal Research and Training Centre for Forests, Natural Hazards and Landscape (BFW), Innsbruck, Austria
| | - Michael Bahn
- Department of Ecology, University of Innsbruck, Innsbruck, Austria
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12
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Responses of Tree Growth and Intrinsic Water Use Efficiency to Environmental Factors in Central and Northern China in the Context of Global Warming. FORESTS 2022. [DOI: 10.3390/f13081209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The Loess Plateau is a fragile ecological zone that is sensitive to climate change. The response, adaptation, and feedback of tree growth in forest ecosystems to global warming and CO2 enrichment are urgent scientific issues. Intrinsic water use efficiency (iWUE) is an important indicator for understanding forest ecosystem adaptability to climate change and CO2 enrichment. In this study, tree-ring width, tree-ring stable carbon isotope ratio (δ13C), and iWUE of P. tabulaeformis Carr. were established. Climate response analysis showed that temperature was the main limiting factor affecting radial tree growth and that relative humidity significantly affected the stable carbon isotope fractionation of tree rings. During 1645–2011, the iWUE increased by 27.1%. The responses of iWUE to climate factors and atmospheric CO2 concentrations (Ca) showed that the long-term variation in iWUE was affected by Ca, which could explain 69% of iWUE variation, and temperature was the main factor causing iWUE interannual variation. The ecosystem of P. tabulaeformis showed a positive response to rising Ca, as its carbon sequestration capacity increased. In response to global warming and CO2 enrichment, rising Ca promoted increases in iWUE but ultimately failed to offset the negative impact of warming on tree growth in the study area.
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13
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Juan-Ovejero R, Castro J, Querejeta JI. Low acclimation potential compromises the performance of water-stressed pine saplings under Mediterranean xeric conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 831:154797. [PMID: 35341843 DOI: 10.1016/j.scitotenv.2022.154797] [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: 02/11/2022] [Revised: 03/17/2022] [Accepted: 03/20/2022] [Indexed: 06/14/2023]
Abstract
Predicted hotter and drier climatic conditions in the Mediterranean Basin will probably hamper current afforestations and reforestations by negatively influencing tree performance. Understanding how saplings can adjust their physiology to shortages in water availability is essential to predict early-stage success of forest ecological restoration. Pines are common target species used in afforestations and reforestations; however, the capacity of their saplings for physiological plasticity to promote drought tolerance remains largely unexplored. In this study, we evaluated the demographical and resource-use consequences of short-term irrigation among four pine species (Pinus halepensis, Pinus pinea, Pinus nigra and Pinus sylvestris) growing under water-limiting conditions in a common garden experiment. Summer irrigation increased the survival rate of those pines that were suffering from hydric stress under the xeric conditions of the common garden (i.e. P. pinea, P. nigra and P. sylvestris). Moreover, short-term water supplementation slightly enhanced aboveground biomass production across species. However, leaf isotopic composition and nutrient concentrations did not change after summer irrigation. Independently of water supplementation, P. halepensis was the best adapted species to water scarcity and showed the best physiological and growth performance. By contrast, P. pinea, P. nigra and P. sylvestris saplings exhibited drought-induced reductions in stomatal conductance and low water-use efficiency, nutrient deficiency, and severe N:P and N:K stoichiometric imbalances, leading to impaired growth. We conclude that the lack of physiological plasticity of water-stressed pine saplings to withstand the impacts of climate aridification will likely cause severe impairment of their nutrient status, growth and survival, with dire implications for the successful establishment of Mediterranean afforestation and reforestation programs.
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Affiliation(s)
| | - Jorge Castro
- Departamento de Ecología, Universidad de Granada, 18071 Granada, Spain
| | - José I Querejeta
- Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC), Murcia, Spain
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14
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Jia G, Chen L, Yu X, Liu Z. Soil water stress overrides the benefit of water-use efficiency from rising CO 2 and temperature in a cold semi-arid poplar plantation. PLANT, CELL & ENVIRONMENT 2022; 45:1172-1186. [PMID: 35037279 DOI: 10.1111/pce.14260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 09/15/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
The counteractive effect of atmospheric CO2 (ca ) enrichment and drought stress on tree growth results in great uncertainty in the growth patterns of forest plantations in cold semi-arid regions. We analysed tree ring chronologies and carbon isotopes in Populus simonii plantations in cold semi-arid areas in northern China over the past four decades. We hypothesized that the hydraulic stress from drought would override the stimulating effect of increasing ca and temperature (T) on stem growth (basal area increment [BAI]). We found the stimulating effect of rising ca and T on the growth, indicated by continuous increase of intrinsic water-use efficiency in all stands and a positive correlation between T and BAI. However, these effects failed to alleviate the negative impacts of drought on tree growth. Concurrent acceleration of BAI reversed during the intensive drought episodes. Water stress resulted from inaccessibility of roots to deep soil water rather than from lack of precipitation, suggested by the decoupling of BAI from precipitation and vapour pressure deficit. Local soil water limitation might also cause greater stomatal regulation in declining trees, indicated by lower intercellular CO2 concentration. Thus, site-specific soil moisture conditions growth sensitivity to global warming resulting in site-specific decline episodes in drought-prone areas.
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Affiliation(s)
- Guodong Jia
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Lixin Chen
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Xinxiao Yu
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing, China
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
| | - Ziqiang Liu
- School of Forestry, Nanjing Forestry University, Nanjing, China
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15
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A Tree Ring Proxy Evaluation of Declining Causes in Pinus sylvestris L. and Pinus nigra J.F. Arnold in Northeastern Romania. FORESTS 2022. [DOI: 10.3390/f13020336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Drought-induced dieback has been extensively studied in various forests habitats. We used a retrospective tree ring width (TRW), basal area increment (BAI), oxygen isotope ratios in tree ring cellulose (δ18OTR) and carbon isotope ratios in tree ring cellulose (δ13CTR) to assess causes in declining Pinus sylvestris L. and Pinus nigra J.F. Arnold. The climate data analysis indicates a significant increased trend occurred after 1980 in minimum, mean and maximum temperature and a reduced amount of precipitation compared to the 1920–1980-time scale. According to the Palmer Drought Severity Index, we found two extreme drought years (1946 and 2000) and three years with severe drought (1990, 2003 and 2012). One-way ANOVA indicated no significant difference between P. nigra and P sylvestris tree ring width, basal area increment, but a considerable difference between δ13CTR and δ18OTR. Basal area increment evaluated the climate-growth relationship most accurately, comparing to δ18OTR and δ13CTR, which explained the influences of environmental factors in tree rings formation. The δ13CTR was mainly negatively correlated with high temperatures from April-August current growing seasons. The negative correlation between δ13CTR and NDVI indices (June, August) shows a decreased carbon uptake induced by drought from summer to early autumn. The low δ18OTR signal was associated with a complex of factors, including the strong influence of heavy precipitation occurring in the growing season and a weak reaction of declined trees to resources. Species-specific responses to drought in 1990, 2003 and 2012 indicated P. sylvestris as more sensitive to drought whit higher demand for water supply in the optimal compared with P. nigra. Weak and unstable correlations in time with increasing/decreasing values in drought periods were obtained more accurately using δ18OTR compared to δ13CTR. The species-specific resilience response to drought years showed a weak resilience and resistance in P. sylvestris occurred more evident after the 2012 event compared to less sensitive P. nigra trees. Decision-makers can use presented results to reinforce specific management plans capable of protecting and changing local compositions where is the case with species more resistant to drouth.
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16
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Rapid increases in shrubland and forest intrinsic water-use efficiency during an ongoing megadrought. Proc Natl Acad Sci U S A 2021; 118:2118052118. [PMID: 34930849 DOI: 10.1073/pnas.2118052118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2021] [Indexed: 11/18/2022] Open
Abstract
Globally, intrinsic water-use efficiency (iWUE) has risen dramatically over the past century in concert with increases in atmospheric CO2 concentration. This increase could be further accelerated by long-term drought events, such as the ongoing multidecadal "megadrought" in the American Southwest. However, direct measurements of iWUE in this region are rare and largely constrained to trees, which may bias estimates of iWUE trends toward more mesic, high elevation areas and neglect the responses of other key plant functional types such as shrubs that are dominant across much of the region. Here, we found evidence that iWUE is increasing in the Southwest at one of the fastest rates documented due to the recent drying trend. These increases were particularly large across three common shrub species, which had a greater iWUE sensitivity to aridity than Pinus ponderosa, a common tree species in the western United States. The sensitivity of both shrub and tree iWUE to variability in atmospheric aridity exceeded their sensitivity to increasing atmospheric [CO2]. The shift to more water-efficient vegetation would be, all else being equal, a net positive for plant health. However, ongoing trends toward lower plant density, diminished growth, and increasing vegetation mortality across the Southwest indicate that this increase in iWUE is unlikely to offset the negative impacts of aridification.
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17
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Wang W, McDowell NG, Liu X, Xu G, Wu G, Zeng X, Wang G. Contrasting growth responses of Qilian juniper (Sabina przewalskii) and Qinghai spruce (Picea crassifolia) to CO2 fertilization despite common water-use efficiency increases at the northeastern Qinghai-Tibetan plateau. TREE PHYSIOLOGY 2021; 41:992-1003. [PMID: 33367904 DOI: 10.1093/treephys/tpaa169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 12/11/2020] [Indexed: 06/12/2023]
Abstract
Rising atmospheric carbon dioxide (CO2) may enhance tree growth and mitigate drought impacts through CO2 fertilization. However, multiple studies globally have found that rising CO2 has not translated into greater tree growth despite increases in intrinsic water-use efficiency (iWUE). The underlying mechanism discriminating between these two general responses to CO2 fertilization remains unclear. We used two species with contrasting stomatal regulation, the relatively anisohydric Qilian juniper (Sabina przewalskii) and the relatively isohydric Qinghai spruce (Picea crassifolia), to investigate the long-term tree growth and iWUE responses to climate change and elevated CO2 using tree ring widths and the associated cellulose stable carbon isotope ratios (δ13C). We observed a contrasting growth trend of juniper and spruce with juniper growth increasing while the spruce growth declined. The iWUE of both species increased significantly and with similar amplitude throughout the trees' lifespan, though the relatively anisohydric juniper had higher iWUE than the relatively isohydric spruce throughout the period. Additionally, with rising CO2, the anisohydric juniper became less sensitive to drought, while the relatively isohydric spruce became more sensitive to drought. We hypothesized that rising CO2 benefits relatively anisohydric species more than relatively isohydric species due to greater opportunity to acquire carbon through photosynthesis despite warming and droughts. Our findings suggest the CO2 fertilization effect depends on the isohydric degree, which could be considered in future terrestrial ecosystem models.
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Affiliation(s)
- Wenzhi Wang
- The Key Laboratory of Mountain Environment Evolution and Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Nate G McDowell
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | - Xiaohong Liu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China
| | - Guobao Xu
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China
| | - Guoju Wu
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China
| | - Xiaomin Zeng
- School of Geography and Tourism, Shaanxi Normal University, Xi'an, Shaanxi 710119, China
| | - Genxu Wang
- The Key Laboratory of Mountain Environment Evolution and Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China
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18
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Beaulne J, Boucher É, Garneau M, Magnan G. Paludification reduces black spruce growth rate but does not alter tree water use efficiency in Canadian boreal forested peatlands. FOREST ECOSYSTEMS 2021; 8:28. [PMID: 34721933 PMCID: PMC8550502 DOI: 10.1186/s40663-021-00307-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 04/15/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Black spruce (Picea mariana (Mill.) BSP)-forested peatlands are widespread ecosystems in boreal North America in which peat accumulation, known as the paludification process, has been shown to induce forest growth decline. The continuously evolving environmental conditions (e.g., water table rise, increasing peat thickness) in paludified forests may require tree growth mechanism adjustments over time. In this study, we investigate tree ecophysiological mechanisms along a paludification gradient in a boreal forested peatland of eastern Canada by combining peat-based and tree-ring analyses. Carbon and oxygen stable isotopes in tree rings are used to document changes in carbon assimilation rates, stomatal conductance, and water use efficiency. In addition, paleohydrological analyses are performed to evaluate the dynamical ecophysiological adjustments of black spruce trees to site-specific water table variations. RESULTS Increasing peat accumulation considerably impacts forest growth, but no significant differences in tree water use efficiency (iWUE) are found between the study sites. Tree-ring isotopic analysis indicates no iWUE decrease over the last 100 years, but rather an important increase at each site up to the 1980s, before iWUE stabilized. Surprisingly, inferred basal area increments do not reflect such trends. Therefore, iWUE variations do not reflect tree ecophysiological adjustments required by changes in growing conditions. Local water table variations induce no changes in ecophysiological mechanisms, but a synchronous shift in iWUE is observed at all sites in the mid-1980s. CONCLUSIONS Our study shows that paludification induces black spruce growth decline without altering tree water use efficiency in boreal forested peatlands. These findings highlight that failing to account for paludification-related carbon use and allocation could result in the overestimation of aboveground biomass production in paludified sites. Further research on carbon allocation strategies is of utmost importance to understand the carbon sink capacity of these widespread ecosystems in the context of climate change, and to make appropriate forest management decisions in the boreal biome. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1186/s40663-021-00307-x.
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Affiliation(s)
- Joannie Beaulne
- Geotop Research Center, Université du Québec à Montréal, Montréal, Québec H3C 3P8 Canada
- Department of Geography, Université du Québec à Montréal, Montréal, Québec H3C 3P8 Canada
- GRIL-UQAM, Université du Québec à Montréal, Montréal, Québec H3C 3P8 Canada
| | - Étienne Boucher
- Geotop Research Center, Université du Québec à Montréal, Montréal, Québec H3C 3P8 Canada
- Department of Geography, Université du Québec à Montréal, Montréal, Québec H3C 3P8 Canada
- Centre d’études nordiques, Université Laval, Montréal, Québec G1V 0A6 Canada
| | - Michelle Garneau
- Geotop Research Center, Université du Québec à Montréal, Montréal, Québec H3C 3P8 Canada
- Department of Geography, Université du Québec à Montréal, Montréal, Québec H3C 3P8 Canada
- GRIL-UQAM, Université du Québec à Montréal, Montréal, Québec H3C 3P8 Canada
- Centre d’études nordiques, Université Laval, Montréal, Québec G1V 0A6 Canada
| | - Gabriel Magnan
- Geotop Research Center, Université du Québec à Montréal, Montréal, Québec H3C 3P8 Canada
- Department of Geography, Université du Québec à Montréal, Montréal, Québec H3C 3P8 Canada
- GRIL-UQAM, Université du Québec à Montréal, Montréal, Québec H3C 3P8 Canada
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19
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Sasani N, Pâques LE, Boulanger G, Singh AP, Gierlinger N, Rosner S, Brendel O. Physiological and anatomical responses to drought stress differ between two larch species and their hybrid. TREES (BERLIN, GERMANY : WEST) 2021; 35:1467-1484. [PMID: 34720435 PMCID: PMC8550302 DOI: 10.1007/s00468-021-02129-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 04/07/2021] [Indexed: 06/13/2023]
Abstract
KEY MESSAGE Hybrid saplings were more reactive to soil water deficit than Japanese and European larch. European larch had hydraulically safer wood and anisohydric behavior, Japanese and hybrid larch showed isohydric strategy. ABSTRACT Deciduous larch species could be an alternative to evergreen conifers in reforestation, but little is known about drought sensitivity of their saplings. The effect of an experimental drought on hydraulics and quantitative wood anatomy was tested on saplings of European larch (EL, Larix decidua), Japanese larch (JL, Larix kaempferi) and their hybrid (HL). Across species, biomass, transpiration rate and relative water content were higher in controls than in drought stressed trees, but transpiration efficiency was lower. JL had the highest transpiration efficiency under drought, and EL the lowest, coinciding with slower growth of EL. Wood of EL formed before drought was hydraulically safer as shown by higher wall/lumen ratio and lower pit cavity area. EL neither had a significant increase in transpiration efficiency nor a reduction in transpiration rate under drought, suggesting that the stomata remained open under soil water deficit. HL saplings were the most reactive to water shortage, indicated by intra-annual density fluctuations and a decrease in relative water content of the sapwood. Significant reduction in transpiration by HL suggested a higher stomatal sensitivity, while the same leaf surface area was maintained and radial growth was still similar to its best parent, the JL. The latter showed a significantly lower leaf surface area under drought than controls. EL, with its hydraulically safer wood, followed an anisohydric behavior, while JL and HL revealed an isohydric strategy. Altogether, our results suggest species dependent acclimations to drought stress, whereby HL followed the strategy of JL rather than that of EL. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s00468-021-02129-4.
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Affiliation(s)
- Nadia Sasani
- Institute of Biophysics, University of Natural Resources and Life Sciences, Vienna, Austria
| | | | - Guillaume Boulanger
- Université de Lorraine, AgroParisTech, INRAE, UMR Silva, 54000 Nancy, France
| | - Adya P. Singh
- Institute of Biophysics, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Notburga Gierlinger
- Institute of Biophysics, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Sabine Rosner
- Institute of Botany, University of Natural Resources and Life Sciences, Gregor Mendel Strasse 33, 1180 Vienna, Austria
| | - Oliver Brendel
- Université de Lorraine, AgroParisTech, INRAE, UMR Silva, 54000 Nancy, France
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20
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Beaulne J, Garneau M, Magnan G, Boucher É. Peat deposits store more carbon than trees in forested peatlands of the boreal biome. Sci Rep 2021; 11:2657. [PMID: 33514778 PMCID: PMC7846601 DOI: 10.1038/s41598-021-82004-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 01/12/2021] [Indexed: 01/30/2023] Open
Abstract
Peatlands are significant carbon (C) stores, playing a key role in nature-based climate change mitigation. While the effectiveness of non-forested peatlands as C reservoirs is increasingly recognized, the C sequestration function of forested peatlands remains poorly documented, despite their widespread distribution. Here, we evaluate the C sequestration potential of pristine boreal forested peatlands over both recent and millennial timescales. C stock estimates reveal that most of the carbon stored in these ecosystems is found in organic horizons (22.6-66.0 kg m-2), whereas tree C mass (2.8-5.7 kg m-2) decreases with thickening peat. For the first time, we compare the boreal C storage capacities of peat layers and tree biomass on the same timescale, showing that organic horizons (11.0-12.6 kg m-2) can store more carbon than tree aboveground and belowground biomass (2.8-5.7 kg m-2) even over a short time period (last 200 years). We also show that forested peatlands have similar recent rates of C accumulation to boreal non-forested peatlands but lower long-term rates, suggesting higher decay and more important peat layer combustion during fire events. Our findings highlight the significance of forested peatlands for C sequestration and suggest that greater consideration should be given to peat C stores in national greenhouse gas inventories and conservation policies.
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Affiliation(s)
- Joannie Beaulne
- Geotop Research Center, Université du Québec à Montréal, Montréal, QC, H3C 3P8, Canada.
- Department of Geography, Université du Québec à Montréal, Montréal, QC, H3C 3P8, Canada.
- GRIL-UQAM, Université du Québec à Montréal, Montréal, QC, H3C 3P8, Canada.
| | - Michelle Garneau
- Geotop Research Center, Université du Québec à Montréal, Montréal, QC, H3C 3P8, Canada.
- Department of Geography, Université du Québec à Montréal, Montréal, QC, H3C 3P8, Canada.
- GRIL-UQAM, Université du Québec à Montréal, Montréal, QC, H3C 3P8, Canada.
- Centre d'études nordiques, Université Laval, Québec, QC, G1V 0A6, Canada.
| | - Gabriel Magnan
- Geotop Research Center, Université du Québec à Montréal, Montréal, QC, H3C 3P8, Canada
- GRIL-UQAM, Université du Québec à Montréal, Montréal, QC, H3C 3P8, Canada
| | - Étienne Boucher
- Geotop Research Center, Université du Québec à Montréal, Montréal, QC, H3C 3P8, Canada
- Department of Geography, Université du Québec à Montréal, Montréal, QC, H3C 3P8, Canada
- Centre d'études nordiques, Université Laval, Québec, QC, G1V 0A6, Canada
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21
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Driscoll AW, Bitter NQ, Ehleringer JR. Interactions among intrinsic water-use efficiency and climate influence growth and flowering in a common desert shrub. Oecologia 2021; 197:1027-1038. [PMID: 33387007 DOI: 10.1007/s00442-020-04825-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 12/05/2020] [Indexed: 12/16/2022]
Abstract
Plants make leaf-level trade-offs between photosynthetic carbon assimilation and water loss, and the optimal balance between the two is dependent, in part, on water availability. "Conservative" water-use strategies, in which minimizing water loss is prioritized over assimilating carbon, tend to be favored in arid environments, while "aggressive" water-use strategies, in which carbon assimilation is prioritized over water conservation, are often favored in mesic environments. When derived from foliar carbon isotope ratios, intrinsic water-use efficiency (iWUE) serves as a seasonally integrated indicator of the balance of carbon assimilation to water loss at the leaf level. Here, we used a multi-decadal record of annual iWUE, growth, and flowering from a single population of Encelia farinosa in the Mojave Desert to evaluate the effect of iWUE on plant performance across interannual fluctuations in water availability. We identified substantial variability in iWUE among individuals and found that iWUE interacted with water availability to significantly influence growth and flowering. However, the relationships between iWUE, water availability, and plant performance did not universally suggest that "conservative" water-use strategies were advantageous in dry years or that "aggressive" strategies were advantageous in wet years. iWUE was positively related to the odds of growth regardless of water availability and to the odds of flowering in dry years, but negatively related to growth rates in dry years. In addition, we found that leaf nitrogen content affected interannual plant performance and that an individual's iWUE plasticity in response to fluctuations in aridity was negatively related to early life drought survival and growth.
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Affiliation(s)
- Avery W Driscoll
- School of Biological Sciences, University of Utah, 257 S 1400 E, Salt Lake City, UT, 84112, USA.
| | - Nicholas Q Bitter
- School of Biological Sciences, University of Utah, 257 S 1400 E, Salt Lake City, UT, 84112, USA
| | - James R Ehleringer
- School of Biological Sciences, University of Utah, 257 S 1400 E, Salt Lake City, UT, 84112, USA
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22
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Rayback SA, Belmecheri S, Gagen MH, Lini A, Gregory R, Jenkins C. North American temperate conifer (Tsuga canadensis) reveals a complex physiological response to climatic and anthropogenic stressors. THE NEW PHYTOLOGIST 2020; 228:1781-1795. [PMID: 33439504 DOI: 10.1111/nph.16811] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 07/03/2020] [Indexed: 05/08/2023]
Abstract
Rising atmospheric CO2 (ca) is expected to promote tree growth and lower water loss via changes in leaf gas exchange. However, uncertainties remain if gas-exchange regulation strategies are homeostatic or dynamical in response to increasing ca, as well as evolving climate and pollution inputs. Using a suite of tree ring-based δ13C-derived physiological parameters (Δ13C, ci, iWUE) and tree growth from a mesic, low elevation stand of canopy-dominant Tsuga canadensis in north-eastern USA, we investigated the influence of rising ca, climate and pollution on, and characterised the dynamical regulation strategy of, leaf gas exchange at multidecadal scales. Isotopic and growth time series revealed an evolving physiological response in which the species shifted its leaf gas-exchange strategy dynamically (constant ci; constant ci/ca; constant ca - ci) in response to rising ca, moisture availability and site conditions over 111 yr. Tree iWUE plateaued after 1975, driven by greater moisture availability and a changing soil biogeochemistry that may have impaired a stomatal response. Results suggested that trees may exhibit more complex physiological responses to the changing environmental conditions over multidecadal periods, and complicating the parameterisation of Earth system models and the estimation of future carbon sink capacity and water balance in midlatitude forests and elsewhere.
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Affiliation(s)
- Shelly A Rayback
- Department of Geography, University of Vermont, 207 Old Mill Building, 94 University Place, Burlington, VT, 05405, USA
| | - Soumaya Belmecheri
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ, 85721, USA
| | - Mary H Gagen
- Department of Geography, Swansea University, Singleton Park, Swansea, SA2 8PP, UK
| | - Andrea Lini
- Department of Geology, University of Vermont, 319 Delehanty Hall, 180 Colchester Avenue, Burlington, VT, 05405, USA
| | - Rachel Gregory
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Catherine Jenkins
- School of Earth and Ocean Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
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23
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Impact of Recent Climate Change on Water-Use Efficiency Strategies of Larix sibirica in the Altai-Sayan Mountain Range. FORESTS 2020. [DOI: 10.3390/f11101103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A strong increase in the mean annual air temperature during the past 50 years by up to 0.54 °C was recorded in the Altai region (45°–52° N; 84°–99° E) compared to the global value of 0.07 °C over the period 1901–2008. The impact of the climatic changes on the hydrology are complex in these mountainous forest ecosystems and not fully understood. We aim to reveal differences in the intrinsic water-use efficiencies (iWUE) strategy by larch (Larix sibirica Ledeb.) derived from stable carbon isotopes at contrasting sites, ranging from the steppe (Ersin, Chadan) to high-elevation (Mongun, Koksu) sites of the Altai over the past century. The iWUE trends increased rapidly for all study sites except Chadan, where a decreasing trend after 2010 has been observed. This decline can be related to increased amount of precipitation compared to increased drought at the other sites. In general, the iWUE is increased up to 14% (1985–2019 compared to 1919–1984), which is lower compared to other studies across the globe likely due to harsh climatic conditions. Vapor pressure deficit and maximal air temperature are impacting Siberian larch significantly and affecting their iWUE differently at the high-elevated and steppe sites of the Altai over the past century.
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24
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Driscoll AW, Bitter NQ, Sandquist DR, Ehleringer JR. Multidecadal records of intrinsic water-use efficiency in the desert shrub Encelia farinosa reveal strong responses to climate change. Proc Natl Acad Sci U S A 2020; 117:18161-18168. [PMID: 32719142 PMCID: PMC7414048 DOI: 10.1073/pnas.2008345117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
While tree rings have enabled interannual examination of the influence of climate on trees, this is not possible for most shrubs. Here, we leverage a multidecadal record of annual foliar carbon isotope ratio collections coupled with 39 y of survey data from two populations of the drought-deciduous desert shrub Encelia farinosa to provide insight into water-use dynamics and climate. This carbon isotope record provides a unique opportunity to examine the response of desert shrubs to increasing temperature and water stress in a region where climate is changing rapidly. Population mean carbon isotope ratios fluctuated predictably in response to interannual variations in temperature, vapor pressure deficit, and precipitation, and responses were similar among individuals. We leveraged the well-established relationships between leaf carbon isotope ratios and the ratio of intracellular to ambient CO2 concentrations to calculate intrinsic water-use efficiency (iWUE) of the plants and to quantify plant responses to long-term environmental change. The population mean iWUE value increased by 53 to 58% over the study period, much more than the 20 to 30% increase that has been measured in forests [J. Peñuelas, J. G. Canadell, R. Ogaya, Glob. Ecol. Biogeogr. 20, 597-608 (2011)]. Changes were associated with both increased CO2 concentration and increased water stress. Individuals whose lifetimes spanned the entire study period exhibited increases in iWUE that were very similar to the population mean, suggesting that there was significant plasticity within individuals rather than selection at the population scale.
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Affiliation(s)
- Avery W Driscoll
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112
| | - Nicholas Q Bitter
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112
| | - Darren R Sandquist
- Department of Biological Science, California State University, Fullerton, CA 92834
| | - James R Ehleringer
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112;
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25
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Rahman M, Islam M, Gebrekirstos A, Bräuning A. Disentangling the effects of atmospheric CO2 and climate on intrinsic water-use efficiency in South Asian tropical moist forest trees. TREE PHYSIOLOGY 2020; 40:904-916. [PMID: 32268375 DOI: 10.1093/treephys/tpaa043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 02/13/2019] [Accepted: 03/25/2020] [Indexed: 06/11/2023]
Abstract
Due to the increase in atmospheric CO2 concentrations, the ratio of carbon fixed by assimilation to water lost by transpiration through stomatal conductance (intrinsic water-use efficiency, iWUE) shows a long-term increasing trend globally. However, the drivers of short-term (inter-annual) variability in iWUE of tropical trees are poorly understood. We studied the inter-annual variability in iWUE of three South Asian tropical moist forest tree species (Chukrasia tabularis A.Juss., Toona ciliata M. Roem. and Lagerstroemia speciosa L.) derived from tree-ring stable carbon isotope ratio (δ13C) in response to variations of environmental conditions. We found a significantly decreasing trend in carbon discrimination (Δ13C) and an increasing trend in iWUE in all the three species, with a species-specific long-term trend in intercellular CO2 concentration (Ci). Growing season temperatures were the main driver of inter-annual variability of iWUE in C. tabularis and L. speciosa, whereas previous year temperatures determined the iWUE variability in T. ciliata. Vapor pressure deficit was linked with iWUE only in C. tabularis. Differences in shade tolerance, tree stature and canopy position might have caused this species-specific variation in iWUE response to climate. Linear mixed effect modeling successfully simulated iWUE variability, explaining 41-51% of the total variance varying with species. Commonality analysis revealed that temperatures had a dominant influence on the inter-annual iWUE variability (64-77%) over precipitation (7-22%) and atmospheric CO2 concentration (3-6%). However, the long-term variations in iWUE were explicitly determined by the atmospheric CO2 increase (83-94%). Our results suggest that the elevated CO2 and concomitant global warming might have detrimental effects on gas exchange and other physiological processes in South Asian tropical moist forest trees.
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Affiliation(s)
- Mizanur Rahman
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Wetterkreuz 15, Erlangen 91058, Germany
- Department of Forestry and Environmental Science, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
| | - Mahmuda Islam
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Wetterkreuz 15, Erlangen 91058, Germany
- Department of Forestry and Environmental Science, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
| | - Aster Gebrekirstos
- World Agroforestry Centre (ICRAF), United Nations Avenue, PO Box 30677-00100, Nairobi, Kenya
| | - Achim Bräuning
- Institute of Geography, Friedrich-Alexander University Erlangen-Nuremberg, Wetterkreuz 15, Erlangen 91058, Germany
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26
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Retrospective Analysis of Tree Decline Based on Intrinsic Water-Use Efficiency in Semi-Arid Areas of North China. ATMOSPHERE 2020. [DOI: 10.3390/atmos11060577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Long-term tree growth is significantly affected by climate change, which have become a global concern. Tree-ring width and isotopic information can show how trees respond to climate change on a long-term scale and reveal some phenomena of tree decline or death. In this study, we used isotopic techniques and investigated annual changes in carbon isotope composition and tree-ring width of Populus simonii Carr. in Zhangbei, as well as trends in tree-ring carbon discrimination (Δ13C) and iWUE in normal, mildly declining and severely declining trees, in order to make a retrospective analysis and further understand the process of tree decline. We found that there were significant differences (p < 0.01 **) in δ13C, Δ13C, ci and iWUE at different decline stages, meaning that the δ13C and iWUE could be new indicators of tree health. The iWUE of all groups increased significantly, while the growth rate of declined P. simonii was much higher than that of normal growth P. simonii. According to the analysis, there may be a threshold of iWUE for healthy trees, which once the threshold value is exceeded, it indicates that trees are resistant to adversity and their growth is under stress. Similarly, the changing trend of BAI supports our conclusion with its changes showed that tree growth became slower and slower as degradation progressed. iWUE inferred from tree-ring stable carbon isotope composition is a strong modulator of adaptation capacity in response to environmental stressors under climate change. Elevated annual temperatures and increased groundwater depth are all contributing to the decline of P. simonii in north China.
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27
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Vadeboncoeur MA, Jennings KA, Ouimette AP, Asbjornsen H. Correcting tree-ring δ13C time series for tree-size effects in eight temperate tree species. TREE PHYSIOLOGY 2020; 40:333-349. [PMID: 31976526 DOI: 10.1093/treephys/tpz138] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 10/16/2019] [Accepted: 12/18/2019] [Indexed: 06/10/2023]
Abstract
Stable carbon isotope ratios (δ13C) in tree rings have been widely used to study changes in intrinsic water-use efficiency (iWUE), sometimes with limited consideration of how C-isotope discrimination is affected by tree height and canopy position. Our goals were to quantify the relationships between tree size or tree microenvironment and wood δ13C for eight functionally diverse temperate tree species in northern New England and to better understand the physical and physiological mechanisms underlying these differences. We collected short increment cores in closed-canopy stands and analyzed δ13C in the most recent 5 years of growth. We also sampled saplings in both shaded and sun-exposed environments. In closed-canopy stands, we found strong tree-size effects on δ13C, with 3.7-7.2‰ of difference explained by linear regression vs height (0.11-0.28‰ m-1), which in some cases is substantially stronger than the effect reported in previous studies. However, open-grown saplings were often isotopically more similar to large codominant trees than to shade-grown saplings, indicating that light exposure contributes more to the physiological and isotopic differences between small and large trees than does height. We found that in closed-canopy forests, δ13C correlations with diameter at breast height were nonlinear but also strong, allowing a straightforward procedure to correct tree- or stand-scale δ13C-based iWUE chronologies for changing tree size. We demonstrate how to use such data to correct and interpret multi-decadal composite isotope chronologies in both shade-regenerated and open-grown tree cohorts, and we highlight the importance of understanding site history when interpreting δ13C time series.
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Affiliation(s)
- Matthew A Vadeboncoeur
- Earth Systems Research Center, University of New Hampshire, 8 College Road, Durham, NH 03824, USA
| | - Katie A Jennings
- Earth Systems Research Center, University of New Hampshire, 8 College Road, Durham, NH 03824, USA
| | - Andrew P Ouimette
- Earth Systems Research Center, University of New Hampshire, 8 College Road, Durham, NH 03824, USA
| | - Heidi Asbjornsen
- Earth Systems Research Center, University of New Hampshire, 8 College Road, Durham, NH 03824, USA
- Department of Natural Resources and the Environment, University of New Hampshire, 56 College Road, Durham, NH 03824, USA
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28
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Panthi S, Fan ZX, van der Sleen P, Zuidema PA. Long-term physiological and growth responses of Himalayan fir to environmental change are mediated by mean climate. GLOBAL CHANGE BIOLOGY 2020; 26:1778-1794. [PMID: 31696994 DOI: 10.1111/gcb.14910] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 10/23/2019] [Indexed: 06/10/2023]
Abstract
High-elevation forests are experiencing high rates of warming, in combination with CO2 rise and (sometimes) drying trends. In these montane systems, the effects of environmental changes on tree growth are also modified by elevation itself, thus complicating our ability to predict effects of future climate change. Tree-ring analysis along an elevation gradient allows quantifying effects of gradual and annual environmental changes. Here, we study long-term physiological (ratio of internal to ambient CO2 , i.e., Ci /Ca and intrinsic water-use efficiency, iWUE) and growth responses (tree-ring width) of Himalayan fir (Abies spectabilis) trees in response to warming, drying, and CO2 rise. Our study was conducted along elevational gradients in a dry and a wet region in the central Himalaya. We combined dendrochronology and stable carbon isotopes (δ13 C) to quantify long-term trends in Ci /Ca ratio and iWUE (δ13 C-derived), growth (mixed-effects models), and evaluate climate sensitivity (correlations). We found that iWUE increased over time at all elevations, with stronger increase in the dry region. Climate-growth relations showed growth-limiting effects of spring moisture (dry region) and summer temperature (wet region), and negative effects of temperature (dry region). We found negative growth trends at lower elevations (dry and wet regions), suggesting that continental-scale warming and regional drying reduced tree growth. This interpretation is supported by δ13 C-derived long-term physiological responses, which are consistent with responses to reduced moisture and increased vapor pressure deficit. At high elevations (wet region), we found positive growth trends, suggesting that warming has favored tree growth in regions where temperature most strongly limits growth. At lower elevations (dry and wet regions), the positive effects of CO2 rise did not mitigate the negative effects of warming and drying on tree growth. Our results raise concerns on the productivity of Himalayan fir forests at low and middle (<3,300 m) elevations as climate change progresses.
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Affiliation(s)
- Shankar Panthi
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, Mengla, Yunnan, China
- Center for Plant Ecology, Chinese Academy of Sciences, Xishuangbanna, China
| | - Ze-Xin Fan
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, Mengla, Yunnan, China
- Center for Plant Ecology, Chinese Academy of Sciences, Xishuangbanna, China
- Ailaoshan Station of Subtropical Forest Ecosystem Studies, Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, Jingdong, Yunnan, China
| | - Peter van der Sleen
- Department of Wetland Ecology, Karlsruhe Institute of Technology, Rastatt, Germany
| | - Pieter A Zuidema
- Forest Ecology & Forest Management Group, Wageningen University, Wageningen, The Netherlands
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29
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Fu L, Xu Y, Xu Z, Wu B, Zhao D. Tree water-use efficiency and growth dynamics in response to climatic and environmental changes in a temperate forest in Beijing, China. ENVIRONMENT INTERNATIONAL 2020; 134:105209. [PMID: 31677597 DOI: 10.1016/j.envint.2019.105209] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/11/2019] [Accepted: 09/21/2019] [Indexed: 06/10/2023]
Abstract
Understanding the responses of local forests to the gradually rising atmospheric CO2 concentrations (ca) and changing environment is critical for appropriate management activities. This work used tree ring width measures (i.e. basal areal increment, BAI) and carbon (C) and nitrogen (N) signals to explore the intrinsic water use efficiency (iWUE) and tree growth dynamics of three major tree species (Pinus massoniana, P.tabuliformis and Larix gmelinii) in the Miyun Reservae Basin (MRB) of Beijing. The results indicate that ca was a primary contributor to tree growths, especially at the remote site where rising ca accounted for 92% and 74% of BAI changes for P. tabuliformis and L. gmelinii, respectively. N deposition was found to have a positive effect on BAI at this site. The controlling effect of ca on tree growth at the close-to-city site was smaller (52% and 44% of the contributions for P. tabuliformis and P. massoniana, respectively), while the negative influences of N deposition on BAI tends to be intensified. iWUE showed consistent increase during the entire growth period at all sites. Quadratic relationships between iWUE and BAI were observed, which indicated that the rising ca stimulated photosynthesis, contributing to the initial BAI and iWUE increase. However, the intensified water stress resulting from reduced precipitation and increased temperature led to a reduction in tree stomatal conductance causing the subsequent increase in iWUE but decrease in BAI. Of the site- and species-related responses of tree growth to ca, climatic and environmental changes in the MRB, the site-related variation dominated. The non-linear relationship between BAI and ca combined with the quadratic relationship between BAI and iWUE indicate a decreased ability of forests to capture atmospheric CO2 once the CO2 tipping point has passed.
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Affiliation(s)
- Li Fu
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, QLD 4111, Australia; State Key Laboratory of Remote Sensing, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China
| | - Yan Xu
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, QLD 4111, Australia
| | - Zhihong Xu
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Nathan, QLD 4111, Australia.
| | - Bingfang Wu
- State Key Laboratory of Remote Sensing, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China.
| | - Dan Zhao
- State Key Laboratory of Remote Sensing, Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing 100101, China
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30
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El Masri B, Schwalm C, Huntzinger DN, Mao J, Shi X, Peng C, Fisher JB, Jain AK, Tian H, Poulter B, Michalak AM. Carbon and Water Use Efficiencies: A Comparative Analysis of Ten Terrestrial Ecosystem Models under Changing Climate. Sci Rep 2019; 9:14680. [PMID: 31604972 PMCID: PMC6789101 DOI: 10.1038/s41598-019-50808-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 09/12/2019] [Indexed: 11/08/2022] Open
Abstract
Terrestrial ecosystems carbon and water cycles are tightly coupled through photosynthesis and evapotranspiration processes. The ratios of carbon stored to carbon uptake and water loss to carbon gain are key ecophysiological indicators essential to assess the magnitude and response of the terrestrial plant to the changing climate. Here, we use estimates from 10 terrestrial ecosystem models to quantify the impacts of climate, atmospheric CO2 concentration, and nitrogen (N) deposition on water use efficiency (WUE), and carbon use efficiency (CUE). We find that across models, WUE increases over the 20th Century particularly due to CO2 fertilization and N deposition and compares favorably to experimental studies. Also, the results show a decrease in WUE with climate for the last 3 decades, in contrasts with up-scaled flux observations that demonstrate a constant WUE. Modeled WUE responds minimally to climate with modeled CUE exhibiting no clear trend across space and time. The divergence between simulated and observationally-constrained WUE and CUE is driven by modeled NPP and autotrophic respiration, nitrogen cycle, carbon allocation, and soil moisture dynamics in current ecosystem models. We suggest that carbon-modeling community needs to reexamine stomatal conductance schemes and the soil-vegetation interactions for more robust modeling of carbon and water cycles.
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Affiliation(s)
- Bassil El Masri
- Department of Earth and Environmental Sciences, Murray State University, Murray, KY, 42071, USA.
| | - Christopher Schwalm
- Woods Hole Research Center, Falmouth, MA, 02540, USA
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Deborah N Huntzinger
- School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, AZ, 86011, USA
| | - Jiafu Mao
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, 37831, TN, USA
| | - Xiaoying Shi
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, 37831, TN, USA
| | - Changhui Peng
- Department of Biological Sciences, University of Quebec at Montreal, Montréal, QC, H3C 3J7, Canada
| | - Joshua B Fisher
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 91109, USA
| | - Atul K Jain
- Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Hanqin Tian
- International Center for Climate and Global Change Research, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL, 36849, USA
| | | | - Anna M Michalak
- Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, 94305, USA
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31
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Interactions between Climate and Nutrient Cycles on Forest Response to Global Change: The Role of Mixed Forests. FORESTS 2019. [DOI: 10.3390/f10080609] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Forest ecosystems are undergoing unprecedented changes in environmental conditions due to global change impacts. Modification of global biogeochemical cycles of carbon and nitrogen, and the subsequent climate change are affecting forest functions at different scales, from physiology and growth of individual trees to cycling of nutrients. This review summarizes the present knowledge regarding the impact of global change on forest functioning not only with respect to climate change, which is the focus of most studies, but also the influence of altered nitrogen cycle and the interactions among them. The carbon dioxide (CO2) fertilization effect on tree growth is expected to be constrained by nutrient imbalances resulting from high N deposition rates and the counteractive effect of increasing water deficit, which interact in a complex way. At the community level, responses to global change are modified by species interactions that may lead to competition for resources and/or relaxation due to facilitation and resource partitioning processes. Thus, some species mixtures can be more resistant to drought than their respective pure forests, albeit it depends on environmental conditions and species’ functional traits. Climate change and nitrogen deposition have additional impacts on litterfall dynamics, and subsequent decomposition and nutrient mineralization processes. Elemental ratios (i.e., stoichiometry) are associated with important ecosystem traits, including trees’ adaptability to stress or decomposition rates. As stoichiometry of different ecosystem components are also influenced by global change, nutrient cycling in forests will be altered too. Therefore, a re-assessment of traditional forest management is needed in order to cope with global change. Proposed silvicultural systems emphasize the key role of diversity to assure multiple ecosystem services, and special attention has been paid to mixed-species forests. Finally, a summary of the patterns and underlying mechanisms governing the relationships between diversity and different ecosystems functions, such as productivity and stability, is provided.
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32
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Sand Dune Height Increases Water Use Efficiency at the Expense of Growth and Leaf Area in Mongolian Pine Growing in Hulunbeier Steppe, Inner Mongolia, China. FORESTS 2019. [DOI: 10.3390/f10070558] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Mongolian pine (Pinus sylvestris var. mongolica) is one of the most common tree species in semiarid and arid areas of China, especially in the sand dunes of the Hulunbeier steppe. This study addresses the morphological and physiological characteristics of the Mongolian pine according to sand dune height. Five sites were chosen with various sand dune heights (P1–P5). Nine years after planting, tree growth, leaf area, leaf mass per leaf unit area (LMA), diameter at breast height (DBH), tree height, diameter at root collar (DRC), longest shoot length, carbon isotope composition, and intrinsic water use efficiency (iWUE) were measured to explore the responses of Mongolian pine trees to drought. DBH, tree height, DRC, leaf area, leaf length, and longest shoot length significantly decreased with greater sand dune height (p < 0.05). However, the carbon isotope actually increased with dune height (p < 0.05). Conversely, the iWUE of current-year pine needles was significantly higher at measurement points P3 (132.29 μmol CO2 mol −1 H2O), P4 (132.96 μmol CO2 mol −1 H2O), and P5 (125.34 μmol CO2 mol −1 H2O) than at the lower points P1 (95.18 ± 9.87 μmol CO2 mol −1 H2O) and P2 (103.10 ± 11.12 μmol CO2 mol −1 H2O). Greater sand dune height increases the distance to groundwater, which in this study led to an increase in iWUE in the Mongolian pines, thus these trees appear to adapt to increased sand dune height by increasing their iWUE and decreasing their leaf area. However, prolonged periods characterized by such adaptations can lead to tree death. We expect these findings to be useful when selecting plantation sites for Mongolian pines in semiarid and arid climates.
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Arco Molina JG, Helle G, Hadad MA, Roig FA. Variations in the intrinsic water-use efficiency of north Patagonian forests under a present climate change scenario: tree age, site conditions and long-term environmental effects. TREE PHYSIOLOGY 2019; 39:661-678. [PMID: 30649565 DOI: 10.1093/treephys/tpy144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 11/23/2018] [Accepted: 12/17/2018] [Indexed: 06/09/2023]
Abstract
The carbon isotope composition (δ13C) in tree rings were used to derive the intrinsic water-use efficiency (iWUE) of Araucaria araucana trees of northern Patagonia along a strong precipitation gradient. It is well known that climatic and ontogenetic factors affect growth performance of this species but little is known about their influence in the physiological responses, as iWUE. Thus, the main objective of this study was to assess the physiological reactions of young and adult trees from two open xeric and two moderately dense mesic A. araucana forests to the increases in atmospheric CO2 (Ca) and air temperature during the 20th century, and to relate these responses with radial tree growth. The results indicated that the iWUE and the intercellular CO2 concentration (Ci) increased 33% and 32% in average during the last century, respectively, but carbon isotope discrimination (∆13C) was more variable between sites and age classes. Trees from xeric sites presented greater iWUE and lower ∆13C and Ci values than those from mesic sites. In general, iWUE was strongly related with Ca and was significantly affected by mean summer maximum temperature. ∆13C from mesic sites seemed to be mainly affected by summer maximum temperature, while trees from xeric conditions did not show any influence. Tree age also presented a significant effect on iWUE. Adult trees showed higher iWUE values than young trees, indicating an incidence of the tree age and/or height, mainly in closed mesic forests. Moreover, some trees presented positive relationships between iWUE and radial tree growth, while others presented negative or no relationships, indicating that other factors may negatively influence tree growth. Broadly, the results demonstrate the incidence of climatic, environmental and ontogenetic variability in the tree responses; however, more studies are needed to better understand which forests will be more affected by actual and future climate changes.
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Affiliation(s)
- J G Arco Molina
- Laboratorio de Dendrocronología e Historia Ambiental, IANIGLA-CCT CONICET-Mendoza, Av. Ruiz Leal s/n, Mendoza, Argentina
| | - G Helle
- Section 5.2 Climate Dynamics and Landscape Evolution, GFZ-German Research Centre for Geosciences, Telegrafenberg, Potsdam, Germany
| | - M A Hadad
- CIGEOBIO-CONICET-San Juan, Universidad Nacional de San Juan, Av. Ignacio de la Roza 5900 Oeste, San Juan, Argentina
| | - F A Roig
- Laboratorio de Dendrocronología e Historia Ambiental, IANIGLA-CCT CONICET-Mendoza, Av. Ruiz Leal s/n, Mendoza, Argentina
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Tree-ring isotopes capture interannual vegetation productivity dynamics at the biome scale. Nat Commun 2019; 10:742. [PMID: 30765694 PMCID: PMC6375978 DOI: 10.1038/s41467-019-08634-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 01/18/2019] [Indexed: 11/22/2022] Open
Abstract
Historical and future trends in net primary productivity (NPP) and its sensitivity to global change are largely unknown because of the lack of long-term, high-resolution data. Here we test whether annually resolved tree-ring stable carbon (δ13C) and oxygen (δ18O) isotopes can be used as proxies for reconstructing past NPP. Stable isotope chronologies from four sites within three distinct hydroclimatic environments in the eastern United States (US) were compared in time and space against satellite-derived NPP products, including the long-term Global Inventory Modeling and Mapping Studies (GIMMS3g) NPP (1982–2011), the newest high-resolution Landsat NPP (1986–2015), and the Moderate Resolution Imaging Spectroradiometer (MODIS, 2001–2015) NPP. We show that tree-ring isotopes, in particular δ18O, correlate strongly with satellite NPP estimates at both local and large geographical scales in the eastern US. These findings represent an important breakthrough for estimating interannual variability and long-term changes in terrestrial productivity at the biome scale. Historical and future trends in net primary productivity (NPP) and its sensitivity to global change are largely unknown because of the lack of long-term, high-resolution data. Here the authors show that tree-ring isotopes can be used for inferring interannual variability and long-term changes in NPP.
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Giguère-Croteau C, Boucher É, Bergeron Y, Girardin MP, Drobyshev I, Silva LCR, Hélie JF, Garneau M. North America's oldest boreal trees are more efficient water users due to increased [CO 2], but do not grow faster. Proc Natl Acad Sci U S A 2019; 116:2749-2754. [PMID: 30692257 PMCID: PMC6377478 DOI: 10.1073/pnas.1816686116] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Due to anthropogenic emissions and changes in land use, trees are now exposed to atmospheric levels of [[Formula: see text]] that are unprecedented for 650,000 y [Lüthi et al. (2008) Nature 453:379-382] (thousands of tree generations). Trees are expected to acclimate by modulating leaf-gas exchanges and alter water use efficiency which may result in forest productivity changes. Here, we present evidence of one of the strongest, nonlinear, and unequivocal postindustrial increases in intrinsic water use efficiency ([Formula: see text]) ever documented (+59%). A dual-isotope tree-ring analysis ([Formula: see text] and [Formula: see text]) covering 715 y of growth of North America's oldest boreal trees (Thuja occidentalis L.) revealed an unprecedented increase in [Formula: see text] that was directly linked to elevated assimilation rates of [Formula: see text] (A). However, limited nutrient availability, changes in carbon allocation strategies, and changes in stomatal density may have offset stem growth benefits awarded by the increased [Formula: see text] Our results demonstrate that even in scenarios where a positive [Formula: see text] fertilization effect is observed, other mechanisms may prevent trees from assimilating and storing supplementary anthropogenic emissions as above-ground biomass. In such cases, the sink capacity of forests in response to changing atmospheric conditions might be overestimated.
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Affiliation(s)
- Claudie Giguère-Croteau
- Department of Biology, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
- GEOTOP, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
- Centre d'Études sur la Forêt, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
| | - Étienne Boucher
- GEOTOP, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada;
- Department of Geography, Université du Québec à Montréal, Montréal, QC H2X 3R9, Canada
- Centre d'Études Nordiques, Université Laval, Québec, QC G1V 0A6, Canada
| | - Yves Bergeron
- Department of Biology, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
- Centre d'Études sur la Forêt, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
- Institut de Recherche sur les Forêts, Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, QC J9X 5E4, Canada
| | - Martin P Girardin
- Centre de Foresterie des Laurentides, Ressources Naturelles Canada, Sainte-Foy, QC G1V 4C7, Canada
| | - Igor Drobyshev
- Centre d'Études sur la Forêt, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
- Institut de Recherche sur les Forêts, Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, QC J9X 5E4, Canada
| | - Lucas C R Silva
- Environmental Studies Program, Department of Geography, Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403
| | - Jean-François Hélie
- GEOTOP, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
- Department of Earth and Atmosphere Sciences, Université du Québec à Montréal, Montréal, QC H2X 3Y7, Canada
| | - Michelle Garneau
- GEOTOP, Université du Québec à Montréal, Montréal, QC H2X 1Y4, Canada
- Department of Geography, Université du Québec à Montréal, Montréal, QC H2X 3R9, Canada
- Centre d'Études Nordiques, Université Laval, Québec, QC G1V 0A6, Canada
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Fatichi S, Pappas C, Zscheischler J, Leuzinger S. Modelling carbon sources and sinks in terrestrial vegetation. THE NEW PHYTOLOGIST 2019; 221:652-668. [PMID: 30339280 DOI: 10.1111/nph.15451] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 08/12/2018] [Indexed: 05/06/2023]
Abstract
Contents Summary 652 I. Introduction 652 II. Discrepancy in predicting the effects of rising [CO2 ] on the terrestrial C sink 655 III. Carbon and nutrient storage in plants and its modelling 656 IV. Modelling the source and the sink: a plant perspective 657 V. Plant-scale water and Carbon flux models 660 VI. Challenges for the future 662 Acknowledgements 663 Authors contributions 663 References 663 SUMMARY: The increase in atmospheric CO2 in the future is one of the most certain projections in environmental sciences. Understanding whether vegetation carbon assimilation, growth, and changes in vegetation carbon stocks are affected by higher atmospheric CO2 and translating this understanding in mechanistic vegetation models is of utmost importance. This is highlighted by inconsistencies between global-scale studies that attribute terrestrial carbon sinks to CO2 stimulation of gross and net primary production on the one hand, and forest inventories, tree-scale studies, and plant physiological evidence showing a much less pronounced CO2 fertilization effect on the other hand. Here, we review how plant carbon sources and sinks are currently described in terrestrial biosphere models. We highlight an uneven representation of complexity between the modelling of photosynthesis and other processes, such as plant respiration, direct carbon sinks, and carbon allocation, largely driven by available observations. Despite a general lack of data on carbon sink dynamics to drive model improvements, ways forward toward a mechanistic representation of plant carbon sinks are discussed, leveraging on results obtained from plant-scale models and on observations geared toward model developments.
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Affiliation(s)
- Simone Fatichi
- Institute of Environmental Engineering, ETH Zurich, Stefano Franscini Platz 5, 8093, Zurich, Switzerland
| | - Christoforos Pappas
- Département de géographie and Centre d'études nordiques, Université de Montréal, Montreal, QC, H2V 2B8, Canada
| | - Jakob Zscheischler
- Institute for Atmospheric and Climate Science, ETH Zurich, Universitätstrasse 16, 8092, Zurich, Switzerland
| | - Sebastian Leuzinger
- Institute for Applied Ecology New Zealand, School of Science, Auckland University of Technology, Wakefield Street 46, 1142, Auckland, New Zealand
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Thomas FM, Rzepecki A, Lücke A, Wiekenkamp I, Rabbel I, Pütz T, Neuwirth B. Growth and wood isotopic signature of Norway spruce (Picea abies) along a small-scale gradient of soil moisture. TREE PHYSIOLOGY 2018; 38:1855-1870. [PMID: 30265369 DOI: 10.1093/treephys/tpy100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 08/22/2018] [Indexed: 06/08/2023]
Abstract
Among the environmental factors that have an effect on the isotopic signature of tree rings, the specific impact of soil moisture on the Δ13C and, in particular, the δ18O ratios has scarcely been investigated. We studied the effects of soil type and soil moisture (from moderately moist [Cambisol] to wet [Gleysol]) on the growth and isotopic signature of tree rings of Norway spruce (Picea abies [L.] H. Karst.), a widely distributed forest tree species in Central Europe, at a small spatial scale in a typical mature forest plantation in the low mountain ranges of Western Germany. The δ18O ratios were lower in rings of trees growing at the wettest microsite (Gleysol) than in tree rings from the microsite with moderately moist soil (Cambisol). This indicates higher uptake rates of 18O-unenriched soil water at the Gleysol microsite and corresponds to less negative soil water potentials and higher transpiration rates on the Gleysol plots. Contrary to our expectations, the basal area increments, the Δ13C ratios and the intrinsic water-use efficiency (calculated on the basis of δ13C) did not differ significantly between the Cambisol and the Gleysol microsites. For average values of each microsite and year investigated, we found a significantly positive correlation between δ13C and δ18O, which indicates a consistent stomatal control over gas exchange along the soil moisture gradient at comparable relative air humidity in the stand. As δ18O ratios of tree rings integrate responses of wood formation to soil moisture over longer periods of time, they may help to identify microsites differing in soil water availability along small-scale gradients of soil moisture under homogeneous climatic conditions and to explain the occurrence of particular tree species along those gradients in forest stands.
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Affiliation(s)
- Frank M Thomas
- University of Trier, Faculty of Regional and Environmental Sciences, Geobotany, Behringstraße 21, Trier, Germany
| | - Andreas Rzepecki
- University of Trier, Faculty of Regional and Environmental Sciences, Geobotany, Behringstraße 21, Trier, Germany
- Rheinisches Landesmuseum Trier, Weimarer Allee 1, Trier, Germany
| | - Andreas Lücke
- Forschungszentrum Jülich, Institute of Bio- and Geosciences, Agrosphere (IBG-3), Wilhelm-Johnen-Straße, Jülich, Germany
| | - Inge Wiekenkamp
- Forschungszentrum Jülich, Institute of Bio- and Geosciences, Agrosphere (IBG-3), Wilhelm-Johnen-Straße, Jülich, Germany
| | - Inken Rabbel
- University of Bonn, Department of Geography, Meckenheimer Allee 166, Bonn, Germany
| | - Thomas Pütz
- Forschungszentrum Jülich, Institute of Bio- and Geosciences, Agrosphere (IBG-3), Wilhelm-Johnen-Straße, Jülich, Germany
| | - Burkhard Neuwirth
- Burkhard Neuwirth, DeLaWi Tree Ring Analyses, Preschlin-Allee 2, Windeck, Germany
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Disentangling Contributions of CO2 Concentration and Climate to Changes in Intrinsic Water-Use Efficiency in the Arid Boreal Forest in China’s Altay Mountains. FORESTS 2018. [DOI: 10.3390/f9100642] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Intrinsic water-use efficiency (iWUE) is affected by the balance of photosynthetic rate, stomatal conductance, and climate, along with many other exogenous factors, such as the CO2 concentration in the atmosphere (CO2atm), nutrients, and water holding capacity of the soil. The relative contributions of CO2atm and climate to iWUE are still incompletely understood, particularly for boreal forests where the climate is undergoing unprecedented warming. We combined δ13C and δ18O in tree rings from the Siberian larch (Larix sibirica Ledeb.) in Northwestern China’s Altay Mountains, which receives 190 mm in annual precipitation, to detect the drivers of long-term iWUE changes and their time-varying contributions over the past 222 years. A climate optimization approach was used to isolate the influence of climate from CO2atm influence on iWUE. We found that iWUE increased about 33.6% from 1790 to 2011, and rising CO2atm contributed 48.8% to this iWUE increase. The contributions of CO2atm and climate (drought conditions) varied during the study period 1790–2011. From 1790 to 1876, the climate was the most important factor contributing to the changes in iWUE. From 1877 to 1972, CO2atm was the main contributor; however, after 1973, the climate was again the dominant contributor to the increase in iWUE, especially during 1996–2011. During the period 1996–2011, climate substantially (83%) contributed to the iWUE increase. Our findings imply that, in the boreal forest in Northwestern China’s arid region, iWUE experienced three changes: (1) the climate dominating from 1790 to 1876; (2) CO2atm dominating from 1877 to 1972, and (3) climate dominating again during the past four decades. We observed that the relationships between iWUE and tree-ring width shifted from positive to negative from 1996 onwards. These relationship changes indicate that CO2atm-mediated effects of increasing iWUE on tree growth are counteracted by climatic drought stress and iWUE increase cannot counter the stress from drought on tree growth in China’s arid boreal forest.
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Drought-Affected Populus simonii Carr. Show Lower Growth and Long-Term Increases in Intrinsic Water-Use Efficiency Prior to Tree Mortality. FORESTS 2018. [DOI: 10.3390/f9090564] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The Three-North Shelter Forest (TNSF) is a critical ecological barrier against sandstorms in northern China, but has shown extensive decline and death in Populus simonii Carr. in the last decade. We investigated the characteristics—tree-ring width, basal area increment (BAI), carbon isotope signature (13Ccor), and intrinsic water-use efficiency (iWUE)—of now-dead, dieback, and non-dieback trees in TNSF shelterbelts of Zhangbei County. Results from the three groups were compared to understand the long-term process of preceding drought-induced death and to identify potential early-warning proxies of drought-triggered damage. The diameter at breast height (DBH) was found to decrease with the severity of dieback, showing an inverse relationship. In all three groups, both tree-ring width and BAI showed quadratic relationships with age, and peaks earlier in the now-dead and dieback groups than in the non-dieback group. The tree-ring width and BAI became significantly lower in the now-dead and dieback groups than in the non-dieback group from 17 to 26 years before death, thus, these parameters can serve as early-warning signals for future drought-induced death. The now-dead and dieback groups had significantly higher δ13Ccor and iWUEs than the non-dieback group at 7–16 years prior to the mortality, indicating a more conservative water-use strategy under drought stress compared with non-dieback trees, possibly at the cost of canopy defoliation and long-term shoot dieback. The iWUE became significantly higher in the now-dead group than in the dieback group at 0–7 years before death, about 10 years later than the divergence of BAI. After the iWUE became significantly different among the groups, the now-dead trees showed lower growth and died over the next few years. This indicates that, for the TNSF shelterbelts studied, an abrupt iWUE increase can be used as a warning signal for acceleration of impending drought-induced tree death. In general, we found that long-term drought decreased growth and increased iWUE of poplar tree. Successive droughts could drive dieback and now-dead trees to their physiological limits of drought tolerance, potentially leading to decline and mortality episodes.
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Reed CC, Ballantyne AP, Cooper LA, Sala A. Limited evidence for CO 2 -related growth enhancement in northern Rocky Mountain lodgepole pine populations across climate gradients. GLOBAL CHANGE BIOLOGY 2018; 24:3922-3937. [PMID: 29658158 DOI: 10.1111/gcb.14165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 03/08/2018] [Indexed: 06/08/2023]
Abstract
Forests sequester large amounts of carbon annually and are integral in buffering against effects of global change. Increasing atmospheric CO2 may enhance photosynthesis and/or decrease stomatal conductance (gs ) thereby enhancing intrinsic water-use efficiency (iWUE), having potential indirect and direct benefits to tree growth. While increasing iWUE has been observed in most trees globally, enhanced growth is not ubiquitous, possibly due to concurrent climatic constraints on growth. To investigate our incomplete understanding of interactions between climate and CO2 and their impacts on tree physiology and growth, we used an environmental gradient approach. We combined dendrochronology with carbon isotope analysis (δ13 C) to assess the covariation of basal area increment (BAI) and iWUE over time in lodgepole pine. Trees were sampled at 18 sites spanning two climatically distinct elevation transects on the lee and windward sides of the Continental Divide, encompassing the majority of lodgepole pine's northern Rocky Mountain elevational range. We analyzed BAI and iWUE from 1950 to 2015, and explored correlations with monthly climate variables. As expected, iWUE increased at all sites. However, concurrent growth trends depended on site climatic water deficit (CWD). Significant growth increases occurred only at the driest sites, where increases in iWUE were strongest, while growth decreases were greatest at sites where CWD has been historically lowest. Late summer drought of the previous year negatively affected growth across sites. These results suggest that increasing iWUE, if strong enough, may indirectly benefit growth at drier sites by effectively extending the growing season via reductions in gs . Strong growth decreases at high elevation windward sites may reflect increasing water stress as a result of decreasing snowpack, which was not offset by greater iWUE. Our results imply that increasing iWUE driven by decreasing gs may benefit tree growth in limited scenarios, having implications for future carbon uptake potential of semiarid ecosystems.
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Affiliation(s)
- Charlotte C Reed
- Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana
| | - Ashley P Ballantyne
- Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana
| | - Leila Annie Cooper
- Ecosystem and Conservation Sciences, University of Montana, Missoula, Montana
| | - Anna Sala
- Division of Biological Sciences, University of Montana, Missoula, Montana
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Mathias JM, Thomas RB. Disentangling the effects of acidic air pollution, atmospheric CO 2 , and climate change on recent growth of red spruce trees in the Central Appalachian Mountains. GLOBAL CHANGE BIOLOGY 2018; 24:3938-3953. [PMID: 29781219 DOI: 10.1111/gcb.14273] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 05/24/2023]
Abstract
In the 45 years after legislation of the Clean Air Act, there has been tremendous progress in reducing acidic air pollutants in the eastern United States, yet limited evidence exists that cleaner air has improved forest health. Here, we investigate the influence of recent environmental changes on the growth and physiology of red spruce (Picea rubens Sarg.) trees, a key indicator species of forest health, spanning three locations along a 100 km transect in the Central Appalachian Mountains. We incorporated a multiproxy approach using 75-year tree ring chronologies of basal tree growth, carbon isotope discrimination (∆13 C, a proxy for leaf gas exchange), and δ15 N (a proxy for ecosystem N status) to examine tree and ecosystem level responses to environmental change. Results reveal the two most important factors driving increased tree growth since ca. 1989 are reductions in acidic sulfur pollution and increases in atmospheric CO2 , while reductions in pollutant emissions of NOx and warmer springs played smaller, but significant roles. Tree ring ∆13 C signatures increased significantly since 1989, concurrently with significant declines in tree ring δ15 N signatures. These isotope chronologies provide strong evidence that simultaneous changes in C and N cycling, including greater photosynthesis and stomatal conductance of trees and increases in ecosystem N retention, were related to recent increases in red spruce tree growth and are consequential to ecosystem recovery from acidic pollution. Intrinsic water use efficiency (iWUE) of the red spruce trees increased by ~51% across the 75-year chronology, and was driven by changes in atmospheric CO2 and acid pollution, but iWUE was not linked to recent increases in tree growth. This study documents the complex environmental interactions that have contributed to the recovery of red spruce forest ecosystems from pervasive acidic air pollution beginning in 1989, about 15 years after acidic pollutants started to decline in the United States.
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Affiliation(s)
- Justin M Mathias
- Department of Biology, West Virginia University, Morgantown, West Virginia
| | - Richard B Thomas
- Department of Biology, West Virginia University, Morgantown, West Virginia
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Forner A, Valladares F, Bonal D, Granier A, Grossiord C, Aranda I. Extreme droughts affecting Mediterranean tree species' growth and water-use efficiency: the importance of timing. TREE PHYSIOLOGY 2018; 38:1127-1137. [PMID: 29554342 DOI: 10.1093/treephys/tpy022] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 02/09/2018] [Indexed: 06/08/2023]
Abstract
It has been known for a long time that drought intensity is a critical variable in determining water stress of Mediterranean tree species. However, not as much attention has been paid to other drought characteristics, for example the timing of the dry periods. We investigated the impact of the timing and intensity of extreme droughts on growing season length, growth and water-use efficiency of three tree species, Pinus nigra ssp. Salzmannii J.F. Arnold, Quercus ilex ssp. ballota (Desf.) Samp. and Quercus faginea Lam. coexisting in a continental Mediterranean ecosystem. Over the study period (2009-13), intense droughts were observed at annual and seasonal scales, particularly during 2011 and 2012. In 2012, an atypically dry winter and spring was followed by an intense summer drought. Quercus faginea growth was affected more by drought timing than by drought intensity, probably because of its winter-deciduous leaf habit. Pinus nigra showed a lower decrease in secondary growth than observed in the two Quercus species in extremely dry years. Resilience to extreme droughts was different among species, with Q. faginea showing poorer recovery of growth after very dry years. The highest intra- and inter-annual plasticity in water-use efficiency was observed in P. nigra, which maintained a more water-saving strategy. Our results revealed that the timing of extreme drought events can affect tree function to a larger extent than drought intensity, especially in deciduous species. Legacy effects of drought over months and years significantly strengthened the impact of drought timing and intensity on tree function.
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Affiliation(s)
- Alicia Forner
- Laboratorio Internacional de Cambio Global (LINCGlobal), Departamento de Biogeografía y Cambio Global, Museo Nacional de Ciencias Naturales, MNCN, CSIC, Serrano 115 dpdo, Madrid, Spain
| | - Fernando Valladares
- Laboratorio Internacional de Cambio Global (LINCGlobal), Departamento de Biogeografía y Cambio Global, Museo Nacional de Ciencias Naturales, MNCN, CSIC, Serrano 115 dpdo, Madrid, Spain
- Departamento de Biología y Geología, Escuela Superior de Ciencias Experimentales y Tecnológicas, Universidad Rey Juan Carlos, c/ Tulipán s/n, Móstoles, Spain
| | - Damien Bonal
- INRA, Université de Lorraine, UMR 1137 Ecologie et Ecophysiologie Forestières, Champenoux, France
| | - André Granier
- INRA, Université de Lorraine, UMR 1137 Ecologie et Ecophysiologie Forestières, Champenoux, France
| | - Charlotte Grossiord
- Earth and Environmental Sciences, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Ismael Aranda
- Department of Forest Ecology and Genetics, INIA, Forest Research Centre, Avda. A Coruña km 7.5, Madrid, Spain
- INAGEA, Instituto de Investigaciones Agroambientales y de Economía del Agua, Palma de Mallorca, Islas Baleares, Spain
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Au RAD. Tree Rings of Pinus ponderosa and Juniperus virginiana Show Different Responses to Stand Density and Water Availability in the Nebraska Grasslands. AMERICAN MIDLAND NATURALIST 2018. [DOI: 10.1674/0003-0031-180.1.18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- R. Aus Der Au
- Department of Geography, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
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Weigt RB, Streit K, Saurer M, Siegwolf RTW. The influence of increasing temperature and CO2 concentration on recent growth of old-growth larch: contrasting responses at leaf and stem processes derived from tree-ring width and stable isotopes. TREE PHYSIOLOGY 2018; 38:706-720. [PMID: 29194509 DOI: 10.1093/treephys/tpx148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 11/03/2017] [Indexed: 06/07/2023]
Abstract
Time series of tree-ring growth show significant increases since the early 1970s at the alpine tree line, with simultaneously increasing temperatures and atmospheric CO2 concentration. For a comprehensive understanding of this growth change, the physiological response patterns at both the leaf and stem level need to be separately analyzed and identified, and can be retrieved from tree-ring growth and isotope (δ13C, δ18O) series. In this study, we assessed the relative contribution of environmental factors to interannual tree-ring variability by multivariate linear mixed-effects models and the dual isotope approach on a dataset of tree-ring records of ~400-year-old larch (Larix decidua Mill.) from a non-water-limited high-elevation site in the Swiss Alps. The models suggest that summer temperatures and the recent lack of larch budmoth outbreaks were most important for explaining growth variations and trends, while a significant direct effect of the continuously increasing CO2 concentration could not be confirmed. In contrast, δ13C and δ18O, which are strongly influenced by fractionation changes in the leaf, clearly reflected the impact of air humidity (precipitation and vapor pressure deficit) and CO2 concentration: the increase in (δ13C-derived) intrinsic water-use efficiency over the second half of the 20th century suggests an increase in carbon assimilation as a result of enhanced CO2 concentration. The tree-ring δ18O largely reflected recent precipitation as source water, thus indicating a low variability in stomatal conductance, which was confirmed by the dual isotope approach. These leaf-level effects were not reflected in stem growth as they may have been masked by the temperature-caused growth limitation controlling the allocation of increased amounts of photosynthates into wood growth. Our approach demonstrates that the identification of different roles of environmental factors on leaf and stem processes helps to improve the assessment of site-specific changes of carbon fluxes and growth performance under future environmental conditions.
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Affiliation(s)
- Rosemarie B Weigt
- Laboratory of Atmospheric Chemistry, Ecosystem Fluxes, Paul Scherrer Institute, 5232 Villigen, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Kathrin Streit
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Matthias Saurer
- Laboratory of Atmospheric Chemistry, Ecosystem Fluxes, Paul Scherrer Institute, 5232 Villigen, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
| | - Rolf T W Siegwolf
- Laboratory of Atmospheric Chemistry, Ecosystem Fluxes, Paul Scherrer Institute, 5232 Villigen, Switzerland
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Birmensdorf, Switzerland
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Martínez-Sancho E, Dorado-Liñán I, Gutiérrez Merino E, Matiu M, Helle G, Heinrich I, Menzel A. Increased water-use efficiency translates into contrasting growth patterns of Scots pine and sessile oak at their southern distribution limits. GLOBAL CHANGE BIOLOGY 2018; 24:1012-1028. [PMID: 29030903 DOI: 10.1111/gcb.13937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 08/26/2017] [Indexed: 05/08/2023]
Abstract
In forests, the increase in atmospheric CO2 concentrations (Ca ) has been related to enhanced tree growth and intrinsic water-use efficiency (iWUE). However, in drought-prone areas such as the Mediterranean Basin, it is not yet clear to what extent this "fertilizing" effect may compensate for drought-induced growth reduction. We investigated tree growth and physiological responses at five Scots pine (Pinus sylvestris L.) and five sessile oak (Quercus petraea (Matt.) Liebl.) sites located at their southernmost distribution limits in Europe for the period 1960-2012 using annually resolved tree-ring width and δ13 C data to track ecophysiological processes. Results indicated that all 10 natural stands significantly increased their leaf intercellular CO2 concentration (Ci ), and consequently iWUE. Different trends in the theoretical gas-exchange scenarios as a response to increasing Ca were found: generally, Ci tended to increase proportionally to Ca , except for trees at the driest sites in which Ci remained constant. Ci from the oak sites displaying higher water availability tended to increase at a comparable rate to Ca . Multiple linear models fitted at site level to predict basal area increment (BAI) using iWUE and climatic variables better explained tree growth in pines (31.9%-71.4%) than in oak stands (15.8%-46.8%). iWUE was negatively linked to pine growth, whereas its effect on growth of oak differed across sites. Tree growth in the western and central oak stands was negatively related to iWUE, whereas BAI from the easternmost stand was positively associated with iWUE. Thus, some Q. petraea stands might have partially benefited from the "fertilizing" effect of rising Ca , whereas P. sylvestris stands due to their strict closure of stomata did not profit from increased iWUE and consequently showed in general growth reductions across sites. Additionally, the inter-annual variability of BAI and iWUE displayed a geographical polarity in the Mediterranean.
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Affiliation(s)
- Elisabet Martínez-Sancho
- Ecoclimatology, Department of Ecology and Ecosystem Management, Technische Universität München, Freising, Germany
| | - Isabel Dorado-Liñán
- Departamento de Silvicultura y Gestión de los Sistemas Forestales, CIFOR-INIA, Madrid, Spain
| | - Emilia Gutiérrez Merino
- Departament of Biological Evolution, Ecology and Environmental Sciences, Universitat de Barcelona, Barcelona, Spain
| | - Michael Matiu
- Ecoclimatology, Department of Ecology and Ecosystem Management, Technische Universität München, Freising, Germany
| | - Gerhard Helle
- Climate Dynamics and Landscape Evolution, GFZ - German Research Centre for Geosciences, Potsdam, Germany
| | - Ingo Heinrich
- Climate Dynamics and Landscape Evolution, GFZ - German Research Centre for Geosciences, Potsdam, Germany
| | - Annette Menzel
- Ecoclimatology, Department of Ecology and Ecosystem Management, Technische Universität München, Freising, Germany
- Institute for Advanced Study, Technische Universität München, Garching, Germany
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Guerrieri R, Jennings K, Belmecheri S, Asbjornsen H, Ollinger S. Evaluating climate signal recorded in tree-ring δ 13 C and δ 18 O values from bulk wood and α-cellulose for six species across four sites in the northeastern US. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:2081-2091. [PMID: 28940773 DOI: 10.1002/rcm.7995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 05/08/2023]
Abstract
RATIONALE We evaluated the applicability of tree-ring δ13 C and δ18 O values in bulk wood - instead of the more time and lab-consuming α-cellulose δ13 C and δ18 O values, to assess climate and physiological signals across multiple sites and for six tree species along a latitudinal gradient (35°97'N to 45°20'N) of the northeastern United States. METHODS Wood cores (n = 4 per tree) were sampled from ten trees per species. Cores were cross-dated within and across trees at each site, and for the last 30 years. Seven years, including the driest on record, were selected for this study. The δ13 C and δ18 O values were measured on two of the ten trees from the bulk wood and the α-cellulose. The offsets between materials in δ13 C and δ18 O values were assessed. Correlation and multiple regression analyses were used to evaluate the strength of the climate signal across sites. Finally the relationship between δ13 C and δ18 O values in bulk wood vs α-cellulose was analyzed to assess the consistency of the interpretation, in terms of CO2 assimilation and stomatal conductance, from both materials. RESULTS We found offsets of 1.1‰ and 5.6‰ between bulk and α-cellulose for δ13 C and δ18 O values, respectively, consistent with offset values reported in the literature. Bulk wood showed similar or stronger correlations to climate parameters than α-cellulose for the investigated sites. In particular, temperature and vapor pressure deficit and standard precipitation-evaporation index (SPEI) were the most visible climate signals recorded in δ13 C and δ18 O values, respectively. For most of the species, there was no relationship between δ13 C and δ18 O values, regardless of the wood material considered. CONCLUSIONS Extraction of α-cellulose was not necessary to detect climate signals in tree rings across the four investigated sites. Furthermore, the physiological information inferred from the dual isotope approach was similar for most of the species regardless of the material considered.
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Affiliation(s)
- Rossella Guerrieri
- Earth Systems Research Center, University of New Hampshire, Durham, NH, 03824, USA
| | - Katie Jennings
- Earth Systems Research Center, University of New Hampshire, Durham, NH, 03824, USA
| | - Soumaya Belmecheri
- Laboratory of Tree Ring Research, University of Arizona, Tucson, AZ, 85721-0045, USA
| | - Heidi Asbjornsen
- Earth Systems Research Center, University of New Hampshire, Durham, NH, 03824, USA
| | - Scott Ollinger
- Earth Systems Research Center, University of New Hampshire, Durham, NH, 03824, USA
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Effects of Drought on Xylem Anatomy and Water-Use Efficiency of Two Co-Occurring Pine Species. FORESTS 2017. [DOI: 10.3390/f8090332] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ruzicka KJ, Puettmann KJ, Brooks JR. Cross-scale interactions affect tree growth and intrinsic water use efficiency and highlight the importance of spatial context in managing forests under global change. THE JOURNAL OF ECOLOGY 2017; 105:1425-1436. [PMID: 30220733 PMCID: PMC6134861 DOI: 10.1111/1365-2745.12749] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
1. We investigated the potential of cross-scale interactions to affect the outcome of density reduction in a large-scale silvicultural experiment to better understand options for managing forests under climate change. 2. We measured tree growth and intrinsic water-use efficiency (iWUE) based on stable carbon isotopes δ13C) to investigate impacts of density reduction across a range of progressively finer spatial scales: site, stand, hillslope position, and neighborhood. In particular, we focused on the influence of treatments beyond the boundaries of treated stands to include impacts on downslope and neighboring stands across sites varying in soil moisture. 3. Trees at the wet site responded with increased growth when compared with trees at the dry site. Additionally, trees in treated stands at the dry site responded with increased iWUE while trees at the wet site showed no difference in iWUE compared to untreated stands. 4. We hypothesized that water is not the primary limiting factor for growth at our sites, but that density reduction released other resources, such as growing space or nutrients to drive the growth response. At progressively finer spatial scales we found that tree responses were not driven by hillslope location (i.e., downslope of treatment) but to changes in local neighborhood tree density. 5. Synthesis. This study demonstrated that water can be viewed as an agent to investigate cross-scale interactions as it links processes operating at coarse to finer spatial scales and vice versa. Consequently, management prescriptions such as density reductions to increase resistance and resilience of trees to climate change, specifically to drought, need to consider cross-scale interactions as specific magnitude and mechanisms of growth responses can only be predicted when multiple scales are taken into account.
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Affiliation(s)
- Kenneth J Ruzicka
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, present address: US Department of Interior, Bureau of Land Management. Salem, Oregon
| | - Klaus J Puettmann
- Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331
| | - J Renée Brooks
- U.S. Environmental Protection Agency, Western Ecology Division, Corvallis, OR 97331
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Levesque M, Andreu-Hayles L, Pederson N. Water availability drives gas exchange and growth of trees in northeastern US, not elevated CO 2 and reduced acid deposition. Sci Rep 2017; 7:46158. [PMID: 28393872 PMCID: PMC5385545 DOI: 10.1038/srep46158] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/10/2017] [Indexed: 11/11/2022] Open
Abstract
Dynamic global vegetation models (DGVM) exhibit high uncertainty about how climate change, elevated atmospheric CO2 (atm. CO2) concentration, and atmospheric pollutants will impact carbon sequestration in forested ecosystems. Although the individual roles of these environmental factors on tree growth are understood, analyses examining their simultaneous effects are lacking. We used tree-ring isotopic data and structural equation modeling to examine the concurrent and interacting effects of water availability, atm. CO2 concentration, and SO4 and nitrogen deposition on two broadleaf tree species in a temperate mesic forest in the northeastern US. Water availability was the strongest driver of gas exchange and tree growth. Wetter conditions since the 1980s have enhanced stomatal conductance, photosynthetic assimilation rates and, to a lesser extent, tree radial growth. Increased water availability seemingly overrides responses to reduced acid deposition, CO2 fertilization, and nitrogen deposition. Our results indicate that water availability as a driver of ecosystem productivity in mesic temperate forests is not adequately represented in DGVMs, while CO2 fertilization is likely overrepresented. This study emphasizes the importance to simultaneously consider interacting climatic and biogeochemical drivers when assessing forest responses to global environmental changes.
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Affiliation(s)
- Mathieu Levesque
- Tree-Ring Laboratory, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA
| | - Laia Andreu-Hayles
- Tree-Ring Laboratory, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA
| | - Neil Pederson
- Harvard Forest, Harvard University, Petersham, MA 01366, USA
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