Peatland trees record strong and temporally stable hydroclimate information in tree-ring δ¹³C and δ¹⁸O

Summary, in English

Peatland trees are valuable archives of paleoclimatic information; however, gaps persist in understanding the relationships between tree growth, peatland hydrology, and hydroclimate variables. While previous research in peatlands has mainly focused on tree-ring widths (TRW), yielding inconclusive results, the potential of stable carbon (δ¹³C) and oxygen (δ¹⁸O) isotopes in tree rings remains unexplored. In this study, we develop TRW, δ¹³C, and δ¹⁸O chronologies of Scots pine trees located in a Swedish peatland and a reference site on bedrock with a mineral soil layer. We assess their responses to hydroclimate conditions and evaluate their potential for reconstructing hydroclimate variations. Our findings show significant differences in mean TRW and δ¹³C values between the peatland and reference sites. Moreover, while TRWs do not exhibit distinct common patterns between sites, both δ¹³C and δ¹⁸O site chronologies show uniform year-to-year variations across all sites. Some discrepancies for TRW and δ¹³C site chronologies emerge, however, regarding multi-decadal trends. While the climate sensitivity of TRW is weak and non-homogenous, the δ¹³C and δ¹⁸O peatland and reference chronologies contain robust and consistent signals, with a maximum sensitivity to water table, precipitation, and vapor pressure deficit (VPD) variations during summer. Both δ¹³C and δ¹⁸O chronologies show stable relationships with three key hydroclimate variables over time. In conclusion, while TRWs from living peatland pines at our sites have limited potential to record high-frequency hydroclimate information, δ¹³C and δ¹⁸O chronologies can serve as excellent proxies for the reconstruction of past hydroclimate changes.

• Author: Karolina Janecka; Kerstin Treydte; Silvia Piccinelli; Loïc Francon; Marçal Argelich Ninot; Johannes Edvardsson; Christophe Corona; Veiko Lehsten; Markus Stoffel
• Department/s: BECC: Biodiversity and Ecosystem services in a Changing Climate; Department of Geology; Dept of Physical Geography and Ecosystem Science; MERGE: ModElling the Regional and Global Earth system
• Publishing year: 2025-10
• Language: English
• Pages: 1679-1697
• Publication/Series: Climate of the Past
• Volume: 21
• Issue: 10
• Links: http://dx.doi.org/10.5194/cp-21-1679-2025
• Document type: Journal article
• Publisher: Copernicus GmbH
• Topic: Climate Science; Palaeontology and Palaeoecology
• Status: Published
• ISBN/ISSN/Other: ISSN: 1814-9324