Spruce tree-ring proxy signals during cold and warm periods

Esper, Jan; Carnelli, Adriana L.; Kamenik, Christian; Filot, Marc; Leuenberger, Markus; Treydte, Kerstin (2017). Spruce tree-ring proxy signals during cold and warm periods. Dendrobiology, 77, pp. 3-18. Polish Academy of Sciences 10.12657/denbio.077.001

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The strength and temporal rigidity of climate signals are important characteristics of proxy data used to reconstruct climate variability over pre-instrumental periods. Here, we assess the performance of different tree-ring proxies, including ring width, maximum latewood density, δ¹³C, and δ¹⁸O, during exceptional cold (1800–1850) and warm periods (1946–2000). The analysis was conducted at a spruce (Picea abies) timberline site in the Swiss Alps in proximity to long homogenized instrumental records to support calibration tests against early temperature and precipitation data. In this cold environment, tree-ring width, maximum latewood density, and δ¹⁸O are mainly controlled by temperature variations. δ¹³C is influenced by various factors including temperature, precipitation, sunshine, and relative humidity. When comparing the response patterns during cold and warm periods, ring width and maximum latewood density revealed temporally stable temperature signals. In contrast, the association between the stable isotopes and climate changed considerably between the early 19th and late 20th centuries. The temperature signal in δ¹⁸O was stronger during the recent warm period, whereas the opposite is true for δ¹³C. In δ¹³C, the temperature signal weakened from the early 19th to the late 20th centuries, but an (inverse) precipitation signal evolved indicating that soil moisture conditions additionally limited recent carbon isotope ratios. An attempt to combine the tree-ring proxies in a multiple regression model did not substantially improve the strength of the dominating temperature signal retained in the latewood density data as this proxy already explained a significant fraction of summer temperature variability. Our findings underscore the importance of split calibration/verification approaches including cold and warm periods, and challenge transfer models based on only late 20th century observational data.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geography > Physical Geography > Unit Paleolimnology
08 Faculty of Science > Physics Institute > Climate and Environmental Physics
08 Faculty of Science > Institute of Geography
08 Faculty of Science > Institute of Geography > Physical Geography

UniBE Contributor:

Kamenik, Christian and Leuenberger, Markus

Subjects:

500 Science > 530 Physics
900 History > 910 Geography & travel

ISSN:

1641-1307

Publisher:

Polish Academy of Sciences

Language:

English

Submitter:

Monika Wälti-Stampfli

Date Deposited:

27 Jun 2017 13:44

Last Modified:

27 Jun 2017 13:44

Publisher DOI:

10.12657/denbio.077.001

Uncontrolled Keywords:

stable isotopes; maximum latewood density; reconstruction model; Picea abies; Engadin; Alps

BORIS DOI:

10.7892/boris.101204

URI:

https://boris.unibe.ch/id/eprint/101204

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