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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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Badea SL, Botoran OR, Ionete RE. Recent Progresses in Stable Isotope Analysis of Cellulose Extracted from Tree Rings. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10122743. [PMID: 34961215 PMCID: PMC8706557 DOI: 10.3390/plants10122743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/05/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
In this work, the challenges and progression in stable isotope investigation, from the analytical tools and technical sample preparation procedures to the dendroclimatological experiments, were reviewed in terms of their use to assess tree physiological responses to environmental changes. Since the isotope signature of whole wood is not always a reliable tool in studying the climate changes, cellulose is often preferred as the study material in paleoclimatic studies. Nevertheless, the isotope analysis of cellulose is challenging due to the difficulty to remove the other wood components (extractives, lignin, pectin, and hemicelluloses). Additionally, in the case of hydrogen isotope analysis, about 30% of the hydrogen atoms of cellulose are exchanged with the surrounding water, which complicates the isotope analysis. In recent years, more automated isotope analysis methods were developed based on high temperature pyrolysis of cellulose, followed by the chromatographic separation of H2 from CO and by their individual isotope analysis using isotope ratio mass spectrometry. When used to investigate climate factors, the combined isotope analysis δ13C and δ18O appears to be the most promising isotope tool. In contrast, the role of δ2H values is yet to be elucidated, together with the development of new methods for hydrogen isotope analysis.
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Climate-Sensitivity Comparisons for Whole Wood, Holocellulose, and α-Cellulose Carbon Isotope Series in Masson Pine. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2021. [DOI: 10.1007/s13369-020-04629-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Circumferential and Longitudinal δ13C Variability in a Larix decidua Trunk from the Swiss Alps. FORESTS 2020. [DOI: 10.3390/f11010117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tree-ring stable isotopes are insightful proxies providing information on pre-instrumental climate fluctuations, yet the variability of these data within a tree trunk has not been fully explored. Here, we analyze longitudinal and circumferential changes in tree-ring δ13C values from 1991–2010, considering seven height levels from 1 to 13 m above ground and six sampling directions (radii) separated by 60° around the stem. The disk samples were taken from a 360-year old European larch (Larix decidua Mill.) that grew at 1675 m above sea level in the Simplon Valley, Switzerland. Results show that the circumferential δ13C variability, defined as the difference between the minimum and maximum isotope values within a single ring at a certain height, ranges from 0.5 to 2.8‰. These differences appear substantial as they match the range of year-to-year variations retained in long tree-ring δ13C time series used for climate reconstruction. The assessment of longitudinal variability demonstrated a systematic change of ~0.1‰ m−1 towards isotopically heavier (less negative) δ13C values with increasing tree height, likely reflecting a vertical gradient towards isotopically heavier needle tissue due to changing microclimatic conditions and CO2 stratification within the canopy. Calibration against regional climate data indicates no substantial signal changes in δ13C values within the trunk. We conclude that the longitudinal isotope gradient adds uncertainty to long δ13C chronologies derived from subfossil material of unknown (and changing) sampling heights. The large circumferential variability recorded in the sub-alpine larch suggests that more than two cores are needed to analyze absolute δ13C values representative for each tree.
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Voelker SL, Meinzer FC, Lachenbruch B, Brooks JR, Guyette RP. Drivers of radial growth and carbon isotope discrimination of bur oak (Quercus macrocarpa Michx.) across continental gradients in precipitation, vapour pressure deficit and irradiance. PLANT, CELL & ENVIRONMENT 2014; 37:766-79. [PMID: 24004466 DOI: 10.1111/pce.12196] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 08/12/2013] [Accepted: 08/15/2013] [Indexed: 05/08/2023]
Abstract
Tree-ring characteristics are commonly used to reconstruct climate variables, but divergence from the assumption of a single biophysical control may reduce the accuracy of these reconstructions. Here, we present data from bur oaks (Quercus macrocarpa Michx.) sampled within and beyond the current species bioclimatic envelope to identify the primary environmental controls on ring-width indices (RWIs) and carbon stable isotope discrimination (Δ(13) C) in tree-ring cellulose. Variation in Δ(13) C and RWI was more strongly related to leaf-to-air vapour pressure deficit (VPD) at the centre and western edge of the range compared with the northern and wettest regions. Among regions, Δ(13) C of tree-ring cellulose was closely predicted by VPD and light responses of canopy-level Δ(13) C estimated using a model driven by eddy flux and meteorological measurements (R(2) = 0.96, P = 0.003). RWI and Δ(13) C were positively correlated in the drier regions, while they were negatively correlated in the wettest region. The strength and direction of the correlations scaled with regional VPD or the ratio of precipitation to evapotranspiration. Therefore, the correlation strength between RWI and Δ(13) C may be used to infer past wetness or aridity from paleo wood by determining the degree to which carbon gain and growth have been more limited by moisture or light.
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Affiliation(s)
- Steven L Voelker
- Biology Department, Southern Oregon University, 1250 Siskiyou Blvd., Ashland, OR, 97520, USA
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Environmental information from13C/12C Ratios of Wood. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm078p0325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Leavitt SW. Tree-ring C-H-O isotope variability and sampling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2010; 408:5244-5253. [PMID: 20719360 DOI: 10.1016/j.scitotenv.2010.07.057] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 07/20/2010] [Accepted: 07/20/2010] [Indexed: 05/29/2023]
Abstract
In light of the proliferation of tree-ring isotope studies, the magnitude and cause of variability of tree-ring δ(13)C, δ(18)O and δ(2)H within individual trees (circumferential) and among trees at a site is examined in reference to field and laboratory sampling requirements and strategies. Within this framework, this paper provides a state-of-knowledge summary of the influence of "juvenile" isotope effects, ageing effects, and genetic effects, as well as the interchangeability of species, choice of ring segment to analyze (whole ring, earlywood or latewood), and the option of sample pooling. The range of isotopic composition of the same ring among trees at a site is ca. 1-3‰ for δ(13)C, 1-4‰ δ(18)O, and 5-30‰ for δ(2)H, whereas the circumferential variability within a tree is lower. A standard prescription for sampling and analysis does not exist because of differences in field environmental circumstances and mixed findings represented in relevant published literature. Decisions in this regard will usually be tightly constrained by goals of the study and project resources. Sampling 4-6 trees at a site while avoiding juvenile effects in rings near the pith seems to be the most commonly used methodology, and although there are some reasoned arguments for analyzing only latewood and developing separate isotope records from each tree, the existence of some contradictory findings together with efforts to reduce cost and effort have prompted alternate strategies (e.g., most years pooled with occasional analysis of rings in the sequence separately for each tree) that have produced useful results in many studies.
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Affiliation(s)
- Steven W Leavitt
- Lab. of Tree-Ring Research, University of Arizona, Tucson, AZ 85721, USA.
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Keel SG, Siegwolf RTW, Jäggi M, Körner C. Rapid mixing between old and new C pools in the canopy of mature forest trees. PLANT, CELL & ENVIRONMENT 2007; 30:963-72. [PMID: 17617824 DOI: 10.1111/j.1365-3040.2007.01688.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Stable C isotope signals in plant tissues became a key tool in explaining growth responses to the environment. The technique is based on the fundamental assumption that the isotopic composition of a given unit of tissue (e.g. a tree ring) reflects the specific C uptake conditions in the leaf at a given time. Beyond the methodological implications of any deviation from this assumption, it is of physiological interest whether new C is transferred directly from sources (a photosynthesizing leaf) to structural sinks (e.g. adjacent stem tissue), or inherently passes through existing (mobile) C pools, which may be of variable (older) age. Here, we explore the fate of (13)C-labelled photosynthates in the crowns of a 30-35 m tall, mixed forest using a canopy crane. In all nine study species labelled C reached woody tissue within 2-9 h after labelling. Four months later, very small signals were left in branch wood of Tilia suggesting that low mixing of new, labelled C with old C had taken place. In contrast, signals in Fagus and Quercus had increased, indicating more intense mixing. This species-specific mixing of new with old C pools is likely to mask year- or season-specific linkages between tree ring formation and climate and has considerable implications for climate reconstruction using stable isotopes as proxies for past climatic conditions.
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Affiliation(s)
- Sonja G Keel
- Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
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Long ES, Sweitzer RA, Diefenbach DR, Ben-David M. Controlling for anthropogenically induced atmospheric variation in stable carbon isotope studies. Oecologia 2005; 146:148-56. [PMID: 16082561 DOI: 10.1007/s00442-005-0181-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Accepted: 06/07/2005] [Indexed: 10/25/2022]
Abstract
Increased use of stable isotope analysis to examine food-web dynamics, migration, transfer of nutrients, and behavior will likely result in expansion of stable isotope studies investigating human-induced global changes. Recent elevation of atmospheric CO2 concentration, related primarily to fossil fuel combustion, has reduced atmospheric CO2 delta13C (13C/12C), and this change in isotopic baseline has, in turn, reduced plant and animal tissue delta13C of terrestrial and aquatic organisms. Such depletion in CO2 delta13C and its effects on tissue delta13C may introduce bias into delta13C investigations, and if this variation is not controlled, may confound interpretation of results obtained from tissue samples collected over a temporal span. To control for this source of variation, we used a high-precision record of atmospheric CO2 delta13C from ice cores and direct atmospheric measurements to model modern change in CO2 delta13C. From this model, we estimated a correction factor that controls for atmospheric change; this correction reduces bias associated with changes in atmospheric isotopic baseline and facilitates comparison of tissue delta13C collected over multiple years. To exemplify the importance of accounting for atmospheric CO2 delta13C depletion, we applied the correction to a dataset of collagen delta13C obtained from mountain lion (Puma concolor) bone samples collected in California between 1893 and 1995. Before correction, in three of four ecoregions collagen delta13C decreased significantly concurrent with depletion of atmospheric CO2 delta13C (n > or = 32, P < or = 0.01). Application of the correction to collagen delta13C data removed trends from regions demonstrating significant declines, and measurement error associated with the correction did not add substantial variation to adjusted estimates. Controlling for long-term atmospheric variation and correcting tissue samples for changes in isotopic baseline facilitate analysis of samples that span a large temporal range.
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Affiliation(s)
- Eric S Long
- Department of Biology, University of North Dakota, Grand Forks, ND, 58202, USA.
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Adams HD, Kolb TE. Drought responses of conifers in ecotone forests of northern Arizona: tree ring growth and leaf δ13C. Oecologia 2004; 140:217-25. [PMID: 15148600 DOI: 10.1007/s00442-004-1585-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2003] [Accepted: 04/07/2004] [Indexed: 10/26/2022]
Abstract
We sought to understand differences in tree response to meteorological drought among species and soil types at two ecotone forests in northern Arizona, the pinyon-juniper woodland/ponderosa pine ecotone, and the higher elevation, wetter, ponderosa pine/mixed conifer ecotone. We used two approaches that provide different information about drought response: the ratio of standardized radial growth in wet years to dry years (W:D) for the period between years 1950 and 2000 as a measure of growth response to drought, and delta13C in leaves formed in non-drought (2001) and drought (2002) years as a measure of change in water use efficiency (WUE) in response to drought. W:D and leaf delta13C response to drought for Pinus edulis and P. ponderosa did not differ for trees growing on coarse-texture soils derived from cinders compared with finer textured soils derived from flow basalts or sedimentary rocks. P. ponderosa growing near its low elevation range limit at the pinyon-juniper woodland/ponderosa pine ecotone had a greater growth response to drought (higher W:D) and a larger increase in WUE in response to drought than co-occurring P. edulis growing near its high elevation range limit. P. flexilis and Pseudotsuga menziesii growing near their low elevation range limit at the ponderosa pine/mixed conifer ecotone had a larger growth response to drought than co-occurring P. ponderosa growing near its high elevation range limit. Increases in WUE in response to drought were similar for all species at the ponderosa pine/mixed conifer ecotone. Low elevation populations of P. ponderosa had greater growth response to drought than high-elevation populations, whereas populations had a similar increase in WUE in response to drought. Our findings of different responses to drought among co-occurring tree species and between low- and high-elevation populations are interpreted in the context of drought impacts on montane coniferous forests of the southwestern USA.
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Affiliation(s)
- Henry D Adams
- School of Forestry, Northern Arizona University, Flagstaff, AZ, 86011-5018, USA
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Liu Y, Cai Q, Won-Kyu P, An Z, Ma L. Tree-ring precipitation records from Baiyinaobao, Inner Mongolia since A.D. 1838. ACTA ACUST UNITED AC 2003. [DOI: 10.1007/bf03185769] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Kagawa A. Effects of spatial and temporal variability in soil moisture on widths and δ13C values of eastern Siberian tree rings. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2002jd003019] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Borella S, Leuenberger M, Saurer M. Analysis of δ18O in tree rings: Wood-cellulose comparison and method dependent sensitivity. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1999jd900298] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Borella S, Leuenberger M, Saurer M, Siegwolf R. Reducing uncertainties in δ13C analysis of tree rings: Pooling, milling, and cellulose extraction. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98jd01169] [Citation(s) in RCA: 149] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bates AL, Spiker EC. Chemical changes and carbon isotope variations in a cross-section of a large Miocene gymnospermous log. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/0009-2541(92)90006-q] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Wefer G, Killingley JS. Carbon isotopes in organic matter from a benthic alga Halimeda incrassata (Bermuda): Effects of light intensity. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/0168-9622(86)90081-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Leavitt SW, Long A. Sampling strategy for stable carbon isotope analysis of tree rings in pine. Nature 1984. [DOI: 10.1038/311145a0] [Citation(s) in RCA: 156] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gleason JD, Kyser TK. Stable isotope compositions of gases and vegetation near naturally burning coal. Nature 1984. [DOI: 10.1038/307254a0] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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