Comparison of stable carbon and oxygen isotopes in Picea glauca tree rings and Sphagnum fuscum moss remains from subarctic Canada

AbstractStable isotope ratios from tree rings and peatland mosses have become important proxies of past climate variations. We here compare recent stable carbon and oxygen isotope ratios in cellulose of tree rings from white spruce (Picea glauca), growing near the arctic tree line; and cellulose of Sphagnum fuscum stems, growing in a hummock of a subarctic peatland, in west-central Canada. Results show that carbon isotopes in S. fuscum correlate significantly with July temperatures over the past ~20 yr. The oxygen isotopes correlate with both summer temperature and precipitation. Analyses of the tree-ring isotopes revealed summer temperatures to be the main controlling factor for carbon isotope variations, whereas tree-ring oxygen isotope ratios are controlled by a combination of spring temperatures and precipitation totals. We also explore the potential of combining high-frequency (annual) climate signals derived from long tree-ring series with low-frequency (decadal to centennial) climate signals derived from the moss remains in peat deposits. This cross-archive comparison revealed no association between the oxygen isotopes, which likely results from the varying sensitivity of the archives to different seasons. For the carbon isotopes, common variance could be achieved through adjustments of the Sphagnum age model within dating error.

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Climate signals in carbon and oxygen isotope ratios of Pinus cembra tree‐ring cellulose from the Călimani Mountains, Romania

International Journal of Climatology ◽

10.1002/joc.6349 ◽

2020 ◽

Vol 40 (5) ◽

pp. 2539-2556 ◽

Cited By ~ 5

Author(s):

Viorica Nagavciuc ◽

Zoltán Kern ◽

Monica Ionita ◽

Claudia Hartl ◽

Oliver Konter ◽

...

Keyword(s):

Oxygen Isotope ◽

Tree Ring ◽

Isotope Ratios ◽

Pinus Cembra ◽

Oxygen Isotope Ratios ◽

Carbon And Oxygen Isotope ◽

Climate Signals ◽

Tree Ring Cellulose

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Simulating oxygen isotope ratios in tree ring cellulose using a dynamic global vegetation model

Biogeosciences ◽

10.5194/bg-13-3869-2016 ◽

2016 ◽

Vol 13 (13) ◽

pp. 3869-3886 ◽

Cited By ~ 15

Author(s):

Sonja G. Keel ◽

Fortunat Joos ◽

Renato Spahni ◽

Matthias Saurer ◽

Rosemarie B. Weigt ◽

...

Keyword(s):

Oxygen Isotope ◽

Tree Ring ◽

Tree Rings ◽

Isotope Ratios ◽

Dynamic Global Vegetation Model ◽

Stable Oxygen Isotope ◽

Oxygen Isotope Ratios ◽

Stable Oxygen ◽

Global Vegetation ◽

Tree Ring Cellulose

Abstract. Records of stable oxygen isotope ratios in tree rings are valuable tools to reconstruct past climatic conditions and investigate the response of trees to those conditions. So far the use of stable oxygen isotope signatures of tree rings has not been systematically evaluated in dynamic global vegetation models (DGVMs). DGVMs integrate many hydrological and physiological processes and their application could improve proxy-model comparisons and the interpretation of oxygen isotope records. Here we present an approach to simulate leaf water and stem cellulose δ18O of trees using the LPX-Bern DGVM (LPX-Bern). Our results lie within a few per mil of measured tree ring δ18O of 31 different forest stands mainly located in Europe. Temporal means over the last 5 decades as well as interannual variations for a subset of sites in Switzerland are captured. A sensitivity analysis reveals that relative humidity, temperature, and the water isotope boundary conditions have the largest influence on simulated stem cellulose δ18O, followed by all climatic factors combined, whereas increasing atmospheric CO2 and nitrogen deposition exert no impact. We conclude that simulations with LPX-Bern are useful for investigating large-scale oxygen isotope patterns of tree ring cellulose to elucidate the importance of different environmental factors on isotope variations and therefore help to reduce uncertainties in the interpretation of δ18O of tree rings.

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Simulating oxygen isotope ratios in tree ring cellulose using a dynamic global vegetation model

Biogeosciences Discussions ◽

10.5194/bgd-12-18463-2015 ◽

2015 ◽

Vol 12 (22) ◽

pp. 18463-18512

Author(s):

S. G. Keel ◽

F. Joos ◽

R. Spahni ◽

M. Saurer

Keyword(s):

Oxygen Isotope ◽

Tree Ring ◽

Tree Rings ◽

Climatic Factors ◽

Isotope Ratios ◽

Vegetation Model ◽

Dynamic Global Vegetation Model ◽

Oxygen Isotope Ratios ◽

Global Vegetation ◽

Tree Ring Cellulose

Abstract. Records of stable oxygen isotope ratios in tree rings are valuable tools to reconstruct past climatic conditions and the response of trees to those conditions. So far they have not been made use of in global dynamic vegetation models, which integrate many hydrological and physiological processes and could improve proxy-model comparisons. Here we present an approach to simulate stem cellulose δ18O of trees using the LPX-Bern Dynamic Global Vegetation Model (LPX-Bern). Our results compare well with measured tree ring δ18O of thirty-one different forest stands mainly located in Europe. Temporal means over the last five decades as well as inter-annual variations for a subset of sites in Switzerland are captured well. A sensitivity analysis reveals that relative humidity, temperature, and the water isotope boundary conditions have the largest influence on simulated stem cellulose δ18O, followed by all climatic factors combined, whereas increasing atmospheric CO2 and nitrogen deposition exert no impact. We conclude that simulations with LPX-Bern are useful to investigate large-scale oxygen isotope patterns of tree-ring cellulose, to elucidate the importance of different environmental factors on isotope variations and therefore help to reduce uncertainties in the interpretation of δ18O of tree-rings.

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Drought signals inferred from ring-width and stable carbon isotope chronologies from Thuja occidentalis trees growing at their northwestern distribution limit, central Canada

Canadian Journal of Forest Research ◽

10.1139/x2012-012 ◽

2012 ◽

Vol 42 (3) ◽

pp. 517-531 ◽

Cited By ~ 5

Author(s):

Robert Au ◽

Jacques C. Tardif

Keyword(s):

Tree Ring ◽

Tree Rings ◽

Stable Carbon Isotopes ◽

Stable Carbon Isotope ◽

Ring Width ◽

Ring Formation ◽

Moisture Regime ◽

Stable Carbon ◽

Thuja Occidentalis ◽

Central Canada

Stable carbon isotopes (δ13C) fixed in tree rings are dependent upon environmental conditions. Old northern white-cedar ( Thuja occidentalis L.) trees were sampled at their northwestern limit of distribution in central Canada. The objectives of the study were (i) to investigate the association between tree-ring δ13C values and radial growth in addition to the response of these variables to climate, (ii) to assess site differences between two sites varying in moisture regime, and (iii) to compare tree-ring δ13C of T. occidentalis with that of other boreal tree species growing at the northern limit of their distribution in central Canada. Over 2500 tree rings comprised of 15 T. occidentalis trees were analyzed for δ13C. Annually resolved δ13C (1650–2006) and ring-width (1542–2006) chronologies were developed. During the year of ring formation, ring width was associated with spring and early-summer conditions, whereas δ13C was more indicative of overall summer conditions. However, compared with δ13C values, ring width was more often associated with climate conditions in the year prior to ring formation. Conditions conducive to moisture stress were important for both parameters. Although ring width and δ13C corresponded to the drought intervals of the 1790s, 1840s, 1890s, 1930s, and 1960–1970, ring width may be more responsive to prolonged drought than δ13C. Tree-ring δ13C could, however, provide important information regarding physiological adaptations to drought.

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