scholarly journals Chemical de-staining and the delta correction for blue intensity measurements of stained lake subfossil trees

2020 ◽  
Author(s):  
Feng Wang ◽  
Dominique Arseneault ◽  
Étienne Boucher ◽  
Shulong Yu ◽  
Steeven Ouellet ◽  
...  
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Black Spruce ◽  
Temperature Reconstruction ◽  
Sodium Dithionite ◽  
Sodium Ascorbate ◽  
Maximum Latewood Density ◽  
Intensity Measurements ◽  
Latewood Density ◽  
Canadian Boreal Forest ◽  
Blue Intensity

Abstract. The stain of wood samples from lake subfossil trees (LSTs) is challenging the wide application of the blue intensity (BI) technique for millennial dendroclimatic reconstructions. In this study, we used seven chemical de-staining reagents to treat samples of subfossil black spruce (Picea mariana (Mill.) B.S.P.)) trees from two lakes in the eastern Canadian boreal forest. We subsequently compared latewood BI (LBI) and delta BI (DBI) time series along with conventional maximum latewood density (MXD) measured from the stained and de-stained samples. Results show that the stain of our samples is most likely caused by post-sampling oxidation of dissolved ferrous iron in lake sediments that penetrated into wood. Three reagents (ascorbic acid, sodium ascorbate and sodium dithionite all mixed with ethylenediaminetetraacetic acid) could remove > 90 % of Fe. However, even for the best chemical protocol, a discrepancy of about +2 °C compared to MXD data remains in the LBI-based temperature reconstruction due to incomplete de-staining. On the contrary, the simple mathematical delta correction, DBI is unaffected by Fe stain and shows very similar results compared to MXD data (r > 0.82) from annual to centennial timescales over the past ~ 360 years. This study underlines the difficulty of completely de-staining lake subfossil samples, while confirming the robustness of the DBI approach. DBI data measured from stained LSTs can be used to perform robust millennial temperature reconstructions.

scholarly journals Chemical destaining and the delta correction for blue intensity measurements of stained lake subfossil trees

2020 ◽  
Vol 17 (18) ◽  
pp. 4559-4570 ◽  
Author(s):  
Feng Wang ◽  
Dominique Arseneault ◽  
Étienne Boucher ◽  
Shulong Yu ◽  
Steeven Ouellet ◽  
...  
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Black Spruce ◽  
Temperature Reconstruction ◽  
Sodium Dithionite ◽  
Sodium Ascorbate ◽  
Maximum Latewood Density ◽  
Intensity Measurements ◽  
Latewood Density ◽  
Canadian Boreal Forest ◽  
Blue Intensity

Abstract. The stain of wood samples from lake subfossil trees (LSTs) is challenging the wide application of the blue intensity (BI) technique for millennial dendroclimatic reconstructions. In this study, we used seven chemical destaining reagents to treat samples of subfossil black spruce (Picea mariana (Mill.) B.S.P.) trees from two lakes in the eastern Canadian boreal forest. We subsequently compared latewood BI (LBI) and delta BI (DBI) time series along with conventional maximum latewood density (MXD) measured from the stained and destained samples. Results showed that the stain of our samples is most likely caused by postsampling oxidation of dissolved ferrous iron in lake sediments that penetrated into wood. Three reagents (ascorbic acid, sodium ascorbate, and sodium dithionite all mixed with ethylenediaminetetraacetic acid) could remove >90 % of Fe. However, even for the best chemical protocol, a discrepancy of about +2 ∘C compared to MXD data remained in the LBI-based temperature reconstruction due to incomplete destaining. On the contrary, the simple mathematical delta correction, DBI, was unaffected by the Fe stain and showed very similar results compared to MXD data (r>0.82) from annual to centennial timescales over the past ∼360 years. This study underlines the difficulty of completely destaining lake subfossil samples while confirming the robustness of the DBI approach. DBI data measured from stained LSTs can be used to perform robust millennial temperature reconstructions.

Temperature sensitivity of blue intensity, maximum latewood density, and ring width data of living black spruce trees in the eastern Canadian taiga

2020 ◽  
Vol 64 ◽  
pp. 125771
Author(s):  
Feng Wang ◽  
Dominique Arseneault ◽  
Étienne Boucher ◽  
Gabrielle Galipaud Gloaguen ◽  
Anne Deharte ◽  
...  
Keyword(s):  
Temperature Sensitivity ◽  
Black Spruce ◽  
Ring Width ◽  
Intensity Maximum ◽  
Maximum Latewood Density ◽  
Latewood Density ◽  
Blue Intensity

Different maximum latewood density and blue intensity measurements techniques reveal similar results

2018 ◽  
Vol 49 ◽  
pp. 94-101 ◽  
Author(s):  
Ryszard J. Kaczka ◽  
Barbara Spyt ◽  
Karolina Janecka ◽  
Ilka Beil ◽  
Ulf Büntgen ◽  
...  
Keyword(s):  
Maximum Latewood Density ◽  
Intensity Measurements ◽  
Latewood Density ◽  
Blue Intensity

Temperature reconstruction from tree-ring maximum latewood density of Qinghai spruce in middle Hexi Corridor, China

2011 ◽  
Vol 107 (3-4) ◽  
pp. 633-643 ◽  
Author(s):  
Feng Chen ◽  
Yu-jiang Yuan ◽  
Wen-shou Wei ◽  
Shu-long Yu ◽  
Zi-ang Fan ◽  
...  
Keyword(s):  
Tree Ring ◽  
Temperature Reconstruction ◽  
Hexi Corridor ◽  
Maximum Latewood Density ◽  
Latewood Density ◽  
Qinghai Spruce

Comparison between Blue Intensity (BI) and Maximum Latewood Density (MXD) tree-ring chronologies from the North American Boreal forests

2020 ◽  
Author(s):  
Laia Andreu-Hayles ◽  
Rosanne D'Arrigo ◽  
Rose Oelkers ◽  
Kevin Anchukaitis ◽  
Greg Wiles ◽  
...  
Keyword(s):  
High Resolution ◽  
North America ◽  
Tree Ring ◽  
Boreal Forests ◽  
Ring Width ◽  
Maximum Latewood Density ◽  
Latewood Density ◽  
Tree Ring Data ◽  
Summer Temperatures ◽  
Blue Intensity

<p>Tree ring-width (TRW) and Maximum Latewood Density (MXD) series have been largely used to develop high-resolution temperature reconstructions for the Northern Hemisphere. The divergence phenomenon, a weakening of the positive relationship between TRW and summer temperatures, has been observed particularly in northwestern North America chronologies. In contrast, MXD datasets have shown a more stable relationship with summer temperatures, but it is costly and labor-intensive to produce. Recently, methodological advances in image analyses have led to development of a less expensive and labor-intensive MXD proxy known as Blue Intensity (BI). Here, we compare 6 newly developed BI tree-ring chronologies of white spruce (<em>Picea glauca</em> [Moench] Voss) from high-latitude boreal forests in North America (Alaska in USA; Yukon and the Northwestern Territory in Canada), with MXD chronologies developed at the same sites. We assessed the quality of BI in relation to MXD based on mean correlation between trees, chronology reliability based on the Expressed Population Signal (EPS), spectral properties, and the strength and spatial extent of the temperature signal. Individual BI chronologies established significant correlations with summer temperatures showing a similar strength and spatial cover than MXD chronologies. Overall, the BI tree-ring data is emerging as a valuable proxy for generating high-resolution temperature spatial reconstructions over northwestern America.</p>

Blue Intensity for dendroclimatology: The BC blues: A case study from British Columbia, Canada

The Holocene ◽  
2014 ◽  
Vol 24 (11) ◽  
pp. 1428-1438 ◽  
Author(s):  
Rob Wilson ◽  
Rohit Rao ◽  
Miloš Rydval ◽  
Cheryl Wood ◽  
Lars-Åke Larsson ◽  
...  
Keyword(s):  
British Columbia ◽  
Tree Ring ◽  
Large Scale ◽  
Ring Width ◽  
Frequency Information ◽  
Maximum Latewood Density ◽  
Latewood Density ◽  
Summer Temperatures ◽  
Two Parameters ◽  
Blue Intensity

Maximum latewood density (MXD) is a strong proxy of summer temperatures. Despite this, there is a paucity of long MXD chronologies in the Northern Hemisphere, which limits large-scale tree-ring-based reconstructions of past temperature which are dominated by ring-width (RW) data – a weaker temperature proxy at inter-annual time-scales. This paucity likely results from the relative expense of measuring MXD and the lack of laboratories with the facilities to measure it. Herein, we test the ability of a relatively new, less expensive, tree-ring parameter, Blue Intensity (BI), to act as a surrogate parameter for MXD. BI was measured on Engelmann spruce samples from British Columbia where MXD had previously been measured to allow direct comparison between the two parameters. Signal strength analyses indicate that 8 MXD series were needed to acquire a robust mean chronology while BI needed 14. Utilising different detrending methods and parameter choices (RW + MXD vs RW + BI), a suite of reconstruction variants was developed. The explained variance from the regression modelling (1901–1995) of May–August maximum temperatures ranged from 52% to 55%. Validation tests over the earlier 1870–1900 period could not statistically distinguish between the different variants, although spectral analysis identified more lower frequency information extant in the MXD-based reconstructions – although this result was sensitive to the detrending method used. Ultimately, despite the MXD-based reconstruction explaining slightly more of the climatic variance, statistically robust reconstructions of past summer temperatures were also derived using BI. These results suggest that there is great potential in utilising BI for dendroclimatology in place of MXD data. However, more experimentation is needed to understand (1) how well BI can capture centennial and lower frequency information and (2) what biases may result from wood discolouration, either from species showing a distinct heartwood/sapwood boundary or from partly decayed sub-fossil samples.

scholarly journals Is blue intensity ready to replace maximum latewood density as a strong temperature proxy? A tree-ring case study on Scots pine from northern Sweden

2013 ◽  
Vol 9 (5) ◽  
pp. 5227-5261 ◽  
Author(s):  
J. A. Björklund ◽  
B. E. Gunnarson ◽  
K. Seftigen ◽  
J. Esper ◽  
H. W. Linderholm
Keyword(s):  
Image Data ◽  
Base Line ◽  
Sample Treatment ◽  
X Ray ◽  
Maximum Latewood Density ◽  
Latewood Density ◽  
Climate Signals ◽  
Temperature Proxy ◽  
Annual Scale ◽  
Blue Intensity

Abstract. At high latitudes, where low temperatures mainly limit tree-growth, measurements of wood density (e.g. Maximum Latewood Density, MXD) using the X-Ray methodology provide a temperature proxy that is superior to that of TRW. Density measurements are however costly and time consuming and have lead to experimentation with optical flatbed scanners to produce Maximum Blue Intensity (BImax). BImax is an excellent proxy for density on annual scale but very limited in skill on centennial scale. Discolouration between samples is limiting BImax where specific brightnesses can have different densities. To overcome this, the new un-exploited parameter Δ blue intensity (ΔBI) was constructed by using the brightness in the earlywood (BIEW) as background, (BImax − BIEW = ΔBI). This parameter was tested on X-Ray material (MXD − earlywood density = ΔMXD) and showed great potential both as a quality control and as a booster of climate signals. Unfortunately since the relationship between grey scale and density is not linear, and between-sample brightness can differ tremendously for similar densities, ΔBI cannot fully match ΔMXD in skill as climate proxy on centennial scale. For ΔBI to stand alone, the range of brightness/density offset must be reduced. Further studies are needed to evaluate this possibility, and solutions might include heavier sample treatment (reflux with chemicals) or image-data treatment (digitally manipulating base-line levels of brightness).

scholarly journals Testing long-term summer temperature reconstruction based on maximum density chronologies obtained by reanalysis of tree-ring datasets from northernmost Sweden and Finland

2013 ◽  
Vol 9 (5) ◽  
pp. 5659-5700
Author(s):  
V. V. Matskovsky ◽  
S. Helama
Keyword(s):  
Tree Ring ◽  
Low Frequency ◽  
Temperature Reconstruction ◽  
Summer Temperature ◽  
Temperature History ◽  
Maximum Latewood Density ◽  
Northern Fennoscandia ◽  
Latewood Density ◽  
Novel Method

Abstract. Here we analysed the maximum latewood density (MXD) chronologies of two published tree-ring datasets: from Torneträsk region in northernmost Sweden (TORN, Melvin et al., 2013) and from northern Fennoscandia (FENN, Esper et al., 2012). We paid particular attention to the MXD low-frequency variations to reconstruct long-term summer (June–August, JJA) temperature history. We used published methods of tree-ring standardization: regional curve (RC) standardization, combined with signal-free (SF) implementation. Comparisons with a single-RC (RC1) and multiple-RC (RC2) were also carried out. We develop a novel method of standardization, the correction (C) implementation to SF (hence, RC1SFC or RC2SFC), tailored for detection of pure low-frequency signal in tree-ring chronologies. In this method, the error in RC1SF (or RC2SF) chronology, is analytically assessed and extracted to produce a RC1SFC or RC2SFC chronology. In TORN, the RC1SF chronology shows higher correlation with summer temperature (JJA) than RC1SFC, whereas in FENN the temperature signals of RC1SF chronology is improved by correction implementation (RC1SFC). The highest correlation between differently standardized chronologies for two datasets is obtained using FENN-RC2SFC and TORN-RC1 chronologies. Focusing on lowest frequencies, the importance of correction becomes obvious as the chronologies become progressively more correlative with RC1SFC and RC2SFC implementations. Subsampling the FENN data (which presents a higher number of samples than TORN dataset) to the chronology sample size of TORN data shows that the chronologies consistently bifurcate during the 7th, 9th, 17th and 20th centuries. We used the two MXD datasets to reconstruct summer temperature variations over the period −48–2010 calendar years. Our new reconstruction shows multi-decadal to multi-centennial variability with changes in the amplitude of the summer temperature of 2.6 °C in average during the Common Era.

scholarly journals 1200 years of regular outbreaks in alpine insects

2006 ◽  
Vol 274 (1610) ◽  
pp. 671-679 ◽  
Author(s):  
Jan Esper ◽  
Ulf Büntgen ◽  
David C Frank ◽  
Daniel Nievergelt ◽  
Andrew Liebhold
Keyword(s):  
Population Cycles ◽  
Temperature Reconstruction ◽  
Ice Age ◽  
European Alps ◽  
Ecological Disturbance ◽  
Maximum Latewood Density ◽  
Latewood Density ◽  
History Of ◽  
Zeiraphera Diniana ◽  
The Impact

The long-term history of Zeiraphera diniana Gn. (the larch budmoth, LBM) outbreaks was reconstructed from tree rings of host subalpine larch in the European Alps. This record was derived from 47 513 maximum latewood density measurements, and highlights the impact of contemporary climate change on ecological disturbance regimes. With over 1000 generations represented, this is the longest annually resolved record of herbivore population dynamics, and our analysis demonstrates that remarkably regular LBM fluctuations persisted over the past 1173 years with population peaks averaging every 9.3 years. These regular abundance oscillations recurred until 1981, with the absence of peak events during recent decades. Comparison with an annually resolved, millennium-long temperature reconstruction representative for the European Alps ( r =0.72, correlation with instrumental data) demonstrates that regular insect population cycles continued despite major climatic changes related to warming during medieval times and cooling during the Little Ice Age. The late twentieth century absence of LBM outbreaks, however, corresponds to a period of regional warmth that is exceptional with respect to the last 1000+ years, suggesting vulnerability of an otherwise stable ecological system in a warming environment.

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