The influence of decision-making in tree ring-based climate reconstructions

AbstractTree-ring chronologies underpin the majority of annually-resolved reconstructions of Common Era climate. However, they are derived using different datasets and techniques, the ramifications of which have hitherto been little explored. Here, we report the results of a double-blind experiment that yielded 15 Northern Hemisphere summer temperature reconstructions from a common network of regional tree-ring width datasets. Taken together as an ensemble, the Common Era reconstruction mean correlates with instrumental temperatures from 1794–2016 CE at 0.79 (p < 0.001), reveals summer cooling in the years following large volcanic eruptions, and exhibits strong warming since the 1980s. Differing in their mean, variance, amplitude, sensitivity, and persistence, the ensemble members demonstrate the influence of subjectivity in the reconstruction process. We therefore recommend the routine use of ensemble reconstruction approaches to provide a more consensual picture of past climate variability.

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A Norway spruce tree-ring width chronology for the Common Era from the Central Scandinavian Mountains

Dendrochronologia ◽

10.1016/j.dendro.2021.125896 ◽

2021 ◽

pp. 125896

Author(s):

Eva Rocha ◽

Björn Gunnarson ◽

Jesper Björklund ◽

Peng Zhang ◽

Hans W. Linderholm

Keyword(s):

Norway Spruce ◽

Tree Ring ◽

Ring Width ◽

Tree Ring Width ◽

The Common ◽

Common Era

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Heterogeneous response of Siberian tree-ring and stable isotope proxies to the largest Common Era volcanic eruptions

10.5194/cp-2018-70 ◽

2018 ◽

Cited By ~ 1

Author(s):

Olga V. Churakova ◽

Marina V. Fonti ◽

Matthias Saurer ◽

Sébastien Guillet ◽

Christophe Corona ◽

...

Keyword(s):

Tree Ring ◽

Climate Models ◽

Global Climate ◽

Sunshine Duration ◽

Ring Width ◽

Volcanic Eruptions ◽

Global Climate Models ◽

Spatial And Temporal Scales ◽

Latewood Density ◽

Common Era

Abstract. Stratospheric volcanic eruptions have far-reaching impacts on global climate and society. Tree rings can provide valuable climatic information on these impacts across different spatial and temporal scales. Here we explore the suitability of tree-ring width (TRW), maximum latewood density (MXD), cell wall thickness (CWT), and δ13C and δ18O in tree-ring cellulose for the detection of climatic changes in northeastern Yakutia (YAK), eastern Taimyr (TAY) and Russian Altai (ALT) sites caused by six largest Common Era stratospheric volcanic eruptions (535, 540, 1257, 1640, 1815 and 1991). Our findings suggest that TRW, MXD, and CWT show strong summer air temperature anomalies in 536, 541–542, 1258–1259 at all study sites. However, they do not reveal distinct and coherent fingerprints after other eruptions. Based on δ13C data, 536 was extremely humid in YAK and TAY, whereas 541 and 542 were humid years in TAY and ALT. In contrast, the 1257 eruption of Samalas likely triggered a sequence of at least two dry summers across all three Siberian sites. No further extreme hydro-climatic anomalies occurred at Siberian sites in the aftermath of the 1991 eruption. Summer sunshine duration decreased significantly in 536, 541–542, 1258–1259 in YAK, and 536 in ALT. Conversely, 1991 was very sunny in YAK. Since climatic responses to large volcanic eruptions are different, and thus affect ecosystem functioning and productivity differently in space and time, a combined assessment of multiple tree-ring parameters is needed to provide a more complete picture of past climate dynamics, which in turns appears fundamental to validate global climate models.

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Is temperature still the most limiting factor for growth in northern boreal forests?

The Holocene ◽

10.1177/09596836211011661 ◽

2021 ◽

pp. 095968362110116

Author(s):

Jeroen DM Schreel

Keyword(s):

Tree Ring ◽

Boreal Forests ◽

Ring Width ◽

Temperature Fluctuations ◽

Limiting Factor ◽

Tree Ring Width ◽

Climate Reconstructions ◽

Latewood Density

Over the last few decades – at a range of northern sites – changes in tree-ring width and latewood density have not followed mean summertime temperature fluctuations. This discrepancy sharply contrasts an earlier correlation between those variables. As the origin of this inconsistency has not been fully deciphered, questions have emerged regarding the use of tree-ring width and latewood density as a proxy in dendrochronological climate reconstructions. I suggest that temperature is no longer the most limiting factor in certain boreal areas, which might explain the observed divergence.

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Bristlecone pine tree rings and volcanic eruptions over the last 5000 yr

Quaternary Research ◽

10.1016/j.yqres.2006.07.004 ◽

2007 ◽

Vol 67 (1) ◽

pp. 57-68 ◽

Cited By ~ 116

Author(s):

Matthew W. Salzer ◽

Malcolm K. Hughes

Keyword(s):

Tree Ring ◽

Ice Core ◽

Ring Width ◽

Volcanic Eruptions ◽

Pine Tree ◽

Tree Ring Data ◽

Pinus Longaeva ◽

Bristlecone Pine ◽

Ice Core Record ◽

Pinus Aristata

AbstractMany years of low growth identified in a western USA regional chronology of upper forest border bristlecone pine (Pinus longaeva and Pinus aristata) over the last 5000 yr coincide with known large explosive volcanic eruptions and/or ice core signals of past eruptions. Over the last millennium the agreement between the tree-ring data and volcano/ice-core data is high: years of ring-width minima can be matched with known volcanic eruptions or ice-core volcanic signals in 86% of cases. In previous millennia, while there is substantial concurrence, the agreement decreases with increasing antiquity. Many of the bristlecone pine ring-width minima occurred at the same time as ring-width minima in high latitude trees from northwestern Siberia and/or northern Finland over the past 4000–5000 yr, suggesting climatically-effective events of at least hemispheric scale. In contrast with the ice-core records, the agreement between widely separated tree-ring records does not decrease with increasing antiquity. These data suggest specific intervals when the climate system was or was not particularly sensitive enough to volcanic forcing to affect the trees, and they augment the ice core record in a number of ways: by providing confirmation from an alternative proxy record for volcanic signals, by suggesting alternative dates for eruptions, and by adding to the list of years when volcanic events of global significance were likely, including the mid-2nd-millennium BC eruption of Thera.

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Siberian tree-ring and stable isotope proxies as indicators of temperature and moisture changes after major stratospheric volcanic eruptions

Climate of the Past ◽

10.5194/cp-15-685-2019 ◽

2019 ◽

Vol 15 (2) ◽

pp. 685-700 ◽

Cited By ~ 7

Author(s):

Olga V. Churakova (Sidorova) ◽

Marina V. Fonti ◽

Matthias Saurer ◽

Sébastien Guillet ◽

Christophe Corona ◽

...

Keyword(s):

Tree Ring ◽

Global Climate ◽

Sunshine Duration ◽

Ring Width ◽

Volcanic Eruptions ◽

Climate Dynamics ◽

Global Climate Models ◽

Added Value ◽

Latewood Density ◽

The Impact

Abstract. Stratospheric volcanic eruptions have far-reaching impacts on global climate and society. Tree rings can provide valuable climatic information on these impacts across different spatial and temporal scales. To detect temperature and hydroclimatic changes after strong stratospheric Common Era (CE) volcanic eruptions for the last 1500 years (535 CE unknown, 540 CE unknown, 1257 CE Samalas, 1640 CE Parker, 1815 CE Tambora, and 1991 CE Pinatubo), we measured and analyzed tree-ring width (TRW), maximum latewood density (MXD), cell wall thickness (CWT), and δ13C and δ18O in tree-ring cellulose chronologies of climate-sensitive larch trees from three different Siberian regions (northeastern Yakutia – YAK, eastern Taimyr – TAY, and Russian Altai – ALT). All tree-ring proxies proved to encode a significant and specific climatic signal of the growing season. Our findings suggest that TRW, MXD, and CWT show strong negative summer air temperature anomalies in 536, 541–542, and 1258–1259 at all studied regions. Based on δ13C, 536 was extremely humid at YAK, as was 537–538 in TAY. No extreme hydroclimatic anomalies occurred in Siberia after the volcanic eruptions in 1640, 1815, and 1991, except for 1817 at ALT. The signal stored in δ18O indicated significantly lower summer sunshine duration in 542 and 1258–1259 at YAK and 536 at ALT. Our results show that trees growing at YAK and ALT mainly responded the first year after the eruptions, whereas at TAY, the growth response occurred after 2 years. The fact that differences exist in climate responses to volcanic eruptions – both in space and time – underlines the added value of a multiple tree-ring proxy assessment. As such, the various indicators used clearly help to provide a more realistic picture of the impact of volcanic eruption on past climate dynamics, which is fundamental for an improved understanding of climate dynamics, but also for the validation of global climate models.

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Northern European summer temperature variations over the Common Era from integrated tree-ring density records

Journal of Quaternary Science ◽

10.1002/jqs.2726 ◽

2014 ◽

Vol 29 (5) ◽

pp. 487-494 ◽

Cited By ~ 57

Author(s):

JAN ESPER ◽

ELISABETH DÜTHORN ◽

PAUL J. KRUSIC ◽

MAURI TIMONEN ◽

ULF BÜNTGEN

Keyword(s):

Tree Ring ◽

Summer Temperature ◽

Temperature Variations ◽

Ring Density ◽

Northern European ◽

The Common ◽

Common Era

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Climate Change Detection and Attribution using observed and simulated Tree-Ring Width

10.5194/cp-2021-80 ◽

2021 ◽

Author(s):

Jörg Franke ◽

Michael Neil Evans ◽

Andrew Schurer ◽

Gabriele Clarissa Hegerl

Keyword(s):

Tree Ring ◽

Radiative Forcing ◽

Ring Width ◽

Volcanic Eruptions ◽

Temperature Sensitive ◽

Tree Ring Width ◽

Spatially Resolved ◽

Detection And Attribution ◽

Climate Simulations ◽

First Time

Abstract. The detection and attribution (D&A) of paleoclimatic change to external radiative forcing relies on regression of statistical reconstructions on simulations. However, this procedure may be biased by assumptions of stationarity and univariate linear response of the underlying paleoclimatic observations. Here we perform a D&A study via regression of tree ring width (TRW) observations on TRW simulations which are forward modeled from climate simulations. Temperature and moisture-sensitive TRW simulations show distinct patterns in time and space. Temperature-sensitive TRW observations and simulations are significantly correlated for northern hemisphere averages, and their variation is attributed most closely to volcanically forced simulations. In decadally smoothed temporal fingerprints, we find the observed responses to be significantly larger and/or more persistent than the simulated responses. The pattern of simulated TRW of moisture-limited trees is consistent with the observed anomalies in the two years following major volcanic eruptions. We can for the first time attribute this spatiotemporal fingerprint in moisture limited tree-ring records to volcanic forcing. These results suggest that use of nonlinear and multivariate proxy system models in paleoclimatic detection and attribution studies may permit more realistic, spatially resolved and multivariate fingerprint detection studies, and evaluation of the climate sensitivity to external radiative forcing, than has previously been possible.

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Stratospheric residence time and the lifetime of volcanic aerosol

10.5194/egusphere-egu21-12131 ◽

2021 ◽

Author(s):

Matthew Toohey ◽

Yue Jia ◽

Susann Tegetmeier

Keyword(s):

Residence Time ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Volcanic Aerosol ◽

Aerosol Forcing ◽

Radiative Impact ◽

The Common ◽

The Impact ◽

The Relationship ◽

Common Era

<p>The cumulative radiative impact of major volcanic eruptions depends strongly on the length of time volcanic sulfate aerosol remains in the stratosphere. Observations of aerosol from recent eruptions have been used to suggest that residence time depends on the latitude of the volcanic eruption, with tropical eruptions producing aerosol loading that persists longer than that from extratropical eruptions. However, the limited number of eruptions observed make it difficult to disentangle the roles of latitude and injection height in controlling aerosol lifetime. Here we use satellite observations and model experiments to explore the relationship between eruption latitude, injection height and resulting residence time of stratospheric aerosol. We find that contrary to earlier interpretations of observations, the residence time of aerosol from major tropical eruptions like Pinatubo (1991) is on the order of 24 months. Model results suggest that the residence time is greatly sensitive to the height of the sulfur injection, especially within the lowest few kilometers of the stratosphere. As injection heights and latitudes are unknown for the majority of eruptions over the common era, we estimate the impact of this uncertainty on volcanic aerosol forcing reconstructions.&#160;</p>

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Progress in Dendroclimatic Studies of Mountain Pine in Northern Thailand

IAWA Journal ◽

10.1163/22941932-90001508 ◽

1997 ◽

Vol 18 (4) ◽

pp. 433-444 ◽

Cited By ~ 26

Author(s):

Rosanne D'Arrigo ◽

Michael Barbett ◽

Manas Watanasak ◽

Brendan Buckley ◽

Paul Krusic ◽

...

Keyword(s):

Tree Ring ◽

Ring Width ◽

Drought Severity ◽

Wet Season ◽

North Central ◽

Pinus Kesiya ◽

Mountain Pine ◽

Average Rainfall ◽

The Common ◽

Central Thailand

New data added to the existing tree-ring width chronologies of mountain pine (Pinus kesiya and Pinus merkusii) result in a total of seven chronologies for these species for Thailand. The oldest (1647-1993) is from a P. merkusii site at Phu Kradung, north central Thailand. An analysis of the three longest P. kesiya chronologies, from north central Thailand, with Phetchabun rainfall (1951-1992) reveals correspondence between years oflow growth and below average rainfall (drought) during the wet season (July-November). The lowest growth year averaged over these three sites during the period of rainfall data (1951-1992) occurred in 1979, coinciding with the lowest wet season rainfall on record. For the common period of tree-ring record prior to 1951 (1830-1950), the level of drought severity in 1979 appears to have been exceeded only twice previously, in 1832 and 1894. A P. merkusii record from Thung Salaeng Luang is most significantly correlated with temperatures during May-June, considered a critical period for the subsequent evolution of the Asian monsoon.

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Temperature variability of the Iberian Range since 1602 inferred from tree-ring records

10.5194/cp-2016-9 ◽

2016 ◽

Cited By ~ 2

Author(s):

E. Tejedor ◽

M. A. Saz ◽

J. M. Cuadrat ◽

J. Esper ◽

M. de Luis

Keyword(s):

Tree Ring ◽

Full Range ◽

Ring Width ◽

Low Frequency ◽

Basal Area ◽

Volcanic Eruptions ◽

Temperature Variability ◽

Iberian Range ◽

Cambial Age ◽

Low Frequency Variability

Abstract. Tree-rings are an important proxy to understand the natural drivers of climate variability in the Mediterranean basin and hence to improve future climate scenarios in a vulnerable region. Here, we compile 316 tree-ring width series from 11 conifer sites in the western Iberian Range. We apply a new standardization method based on the trunk basal area instead of the tree cambial age to develop a regional chronology which preserves high to low frequency variability. A new reconstruction for the 1602–2012 period correlates at −0.78 with observational September temperatures with a cumulative mean of the 21 previous months over the 1945–2012 calibration period. The new IR2Tmax reconstruction is spatially representative for the Iberian Peninsula and captures the full range of past Iberian Range temperature variability. Reconstructed long-term temperature variations match reasonably well with solar irradiance changes since warm and cold phases correspond with high and low solar activity, respectively. In addition, some annual temperatures downturns coincide with volcanic eruptions with a three year lag.

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