June–September temperature reconstruction in the Northern Caucasus based on blue intensity data

Dolgova, Ekaterina

doi:10.1016/j.dendro.2016.03.002

Cited by 55 publications

(37 citation statements)

References 31 publications

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“…LWB is closely related to MXD as they both measure similar wood properties (combined hemicellulose, cellulose, and lignin content related to cell wall thickness), and both are well correlated with warm-season temperatures (Campbell et al, 2007;Björklund et al, 2014;Rydval et al, 2014;Wilson et al, 2014). This correspondence between BI and temperature has recently been shown to hold true for several locations and tree species, including Scots pine (Pinus sylvestris) in Scotland, UK , and Sweden (Björklund et al, 2014(Björklund et al, , 2015; Caucasian fir (Abies nordmanniana) in the Northern Caucasus (Dolgova, 2016); Stone pine (Pinus cembra) in Austria ; Engelmann spruce (Picea engelmannii) from the Canadian Rockies, British Columbia, Canada . Although BI often requires larger sample sizes than MXD to improve signal strength , this is not a concern due to the low cost of the method.…”

Section: Introductionmentioning

confidence: 91%

Experiments based on blue intensity for reconstructing North Pacific temperatures along the Gulf of Alaska

et al. 2017

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Abstract. Ring-width (RW) records from the Gulf of Alaska (GOA) have yielded a valuable long-term perspective for North Pacific changes on decadal to longer timescales in prior studies but contain a broad winter to late summer seasonal climate response. Similar to the highly climatesensitive maximum latewood density (MXD) proxy, the blue intensity (BI) parameter has recently been shown to correlate well with year-to-year warm-season temperatures for a number of sites at northern latitudes. Since BI records are much less labour intensive and expensive to generate than MXD, such data hold great potential value for future treering studies in the GOA and other regions in mid-to high latitudes. Here we explore the potential for improving treering-based reconstructions using combinations of RW-and BI-related parameters (latewood BI and delta BI) from an experimental subset of samples at eight mountain hemlock (Tsuga mertensiana) sites along the GOA. This is the first study for the hemlock genus using BI data. We find that using either inverted latewood BI (LWB inv ) or delta BI (DB) can improve the amount of explained temperature variance by > 10 % compared to RW alone, although the optimal target season shrinks to June-September, which may have implications for studying ocean-atmosphere variability in the region. One challenge in building these BI records is that resin extraction did not remove colour differences between the heartwood and sapwood; thus, long term trend biases, expressed as relatively warm temperatures in the 18th century, were noted when using the LWB inv data. Using DB appeared to overcome these trend biases, resulting in a reconstruction expressing 18th-19th century temperatures ca. 0.5 • C cooler than the 20th-21st centuries. This cool period agrees well with previous dendroclimatic studies and the glacial advance record in the region. Continuing BI measurement in the GOA region must focus on sampling and measuring more trees per site (> 20) and compiling more sites to overcome site-specific factors affecting climate response and using subfossil material to extend the record. Although LWB inv captures the interannual climate signal more strongly than DB, DB appears to better capture long-term secular trends that agree with other proxy archives in the region. Great care is needed, however, when implementing different detrending options and more experimentation is necessary to assess the utility of DB for different conifer species around the Northern Hemisphere.

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Section: Introductionmentioning

confidence: 91%

Experiments based on blue intensity for reconstructing North Pacific temperatures along the Gulf of Alaska

et al. 2017

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“…Despite limitations, maximum BI has featured in a number of climate response and reconstruction studies (primarily summer temperature) that have been partly (or entirely) derived from this parameter, covering many regions, including northern (Björklund et al, ; Fuentes et al, ; Linderholm et al, ; McCarroll et al, ), northwest (Rydval, Gunnarson, et al, , Rydval, Loader, et al, ; Tene et al, ; Wilson et al, ), western (Trachsel et al, ), and eastern Europe (Kaczka et al, , ; Rydval et al, ), North America (Wilson et al, ; Wilson, D'Arrigo, et al, ), and the Caucasus (Dolgova, ). The parameter has also been included in large‐scale (hemispheric) reconstructions of temperature (Anchukaitis et al, ; Wilson et al, ) and the development of a temperature reconstruction in the tropics (Buckley et al, ).…”

Section: Primary and Currently Applied Microdensitometric Techniquesmentioning

confidence: 99%

Scientific Merits and Analytical Challenges of Tree‐Ring Densitometry

Björklund

Arx

Nievergelt

et al. 2019

Reviews of Geophysics

117

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X-ray microdensitometry on annually resolved tree-ring samples has gained an exceptional position in last-millennium paleoclimatology through the maximum latewood density (MXD) parameter, but also increasingly through other density parameters. For 50 years, X-ray based measurement techniques have been the de facto standard. However, studies report offsets in the mean levels for MXD measurements derived from different laboratories, indicating challenges of accuracy and precision. Moreover, reflected visible light-based techniques are becoming increasingly popular, and wood anatomical techniques are emerging as a potentially powerful pathway to extract density information at the highest resolution. Here we review the current understanding and merits of wood density for tree-ring research, associated microdensitometric techniques, and analytical measurement challenges. The review is further complemented with a careful comparison of new measurements derived at 17 laboratories, using several different techniques. The new experiment allowed us to corroborate and refresh "long-standing wisdom" but also provide new insights. Key outcomes include (i) a demonstration of the need for mass/volume-based recalibration to accurately estimate average ring density; (ii) a substantiation of systematic differences in MXD measurements that cautions for great care when combining density data sets for climate reconstructions; and (iii) insights into the relevance of analytical measurement resolution in signals derived from tree-ring density data. Finally, we provide recommendations expected to facilitate future inter-comparability and interpretations for global change research.Plain Language Summary Paleoclimatology, the study of how the climate has changed throughout earth history, is an important component of climate change research. The wood density of tree

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“…BI measurements, in general, reflect the combined hemi-cellulose, cellulose and lignin content in the latewood which are key components of relative density (Björklund et al, 2014;Rydval et al, 2014). The utility of LBi as a summer temperature proxy has been shown to improve climate reconstruction from multiple high elevation and high latitude sites (Björklund et al, 2014(Björklund et al, , 2015Campbell et al, 2007;Dolgova, 2016;Rydval et al, 2014Rydval et al, , 2017Wilson et al, 2014) and the use of dBi from the Gulf of Alaska (Wilson et al, 2017). Significantly, blue intensity is a much less expensive parameter to generate than MXD.…”

Section: Introductionmentioning

confidence: 99%

Yellow-cedar blue intensity tree-ring chronologies as records of climate in Juneau, Alaska, USA

et al. 2019

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This is the first study to generate and analyze the climate signal in blue intensity (BI) tree-ring chronologies from Alaska yellow-cedar (Callitropsis nootkatensis (D. Don) Oerst. ex D.P. Little). The latewood BI chronology shows a much stronger temperature sensitivity than ring width and can thus provide information on past climate. The well-replicated BI chronology exhibits a positive January–August mean maximum temperature signal for 1900–1975, after which it loses temperature sensitivity following the 1976–1977 shift in northeastern Pacific climate. The positive temperature response appears to recover and remains strong for the most recent decades, but the coming years will continue to test this observation. This temporary loss of temperature sensitivity from about 1976 to 1999 is not evident in ring width or in a change in forest health but is consistent with prior work linking cedar decline to warming. A confounding factor is the uncertain influence of a shift in color variation from the heartwood–sapwood boundary. Future expansion of the yellow-cedar BI network and further investigation of the influence of the heartwood–sapwood transitions in the BI signal will lead to a better understanding of the utility of this species as a climate proxy.

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June–September temperature reconstruction in the Northern Caucasus based on blue intensity data

Cited by 55 publications

References 31 publications

Experiments based on blue intensity for reconstructing North Pacific temperatures along the Gulf of Alaska

Experiments based on blue intensity for reconstructing North Pacific temperatures along the Gulf of Alaska

Scientific Merits and Analytical Challenges of Tree‐Ring Densitometry

Yellow-cedar blue intensity tree-ring chronologies as records of climate in Juneau, Alaska, USA

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