Triple-isotope evidence for distinct physiological strategies of larch and cembra pine across the Holocene
Year: 2025
Type: article
Abstract: Stable isotopes of carbon, oxygen and hydrogen in tree rings provide a record of plant physiological processes and environmental variability. Although an increasing number of studies now apply triple-isotope approaches, no investigation has yet tested their temporal stability over millennial timescales or assessed the relative impacts of physiology versus climate on long-term isotopic signals. Here, we used 9000 years of multi-isotope records from co-occurring deciduous larch (Larix decidua) and evergreen cembra pine (Pinus cembra) at the Alpine treeline. We found a high interspecies coherence for δ18O throughout the Holocene with a robust summer hydroclimate sensitivity, confirming its dominance by environmental drivers. In contrast, δ13C and δ2H show weaker and less stable coherence, reflecting species-specific physiology. Larch exhibits tight δ2H-δ18O and δ2H-δ13C correlations and stronger climate sensitivity, consistent with its reliance on freshly assimilated carbon. Pine, by contrast, shows weaker δ2H-climate relationships and frequent decoupling from δ13C and δ18O, reflecting potential storage use and metabolic fractionations. Thus, inter-isotope relationships reveal that δ18O is a robust long-term climate proxy, while δ13C and δ2H encode contrasting carbon-use strategies and metabolic processes across species that may vary over time. Together, these findings demonstrate that multi-isotope, multi-species approaches not only strengthen climate reconstructions but also provide a physiological dimension to long-term isotope records.
Source: Tree Physiology
Language: English
Topic: Tree-ring climate responses
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: hybrid
Estimated APC paid: $4,253
Awards: IN SItu tracking of water fluxes in Forest ecosystems through novel high-resolution monitoring of stable water isotopes (INSIghtForest), Climate and Environmental Physics: Isotopes in Earth System Science (isoCEP), Holocene Hydrogen isotopes in Tree-rings for Paleoclimate and Physiology -HHTPP, Alpine Holocene tree ring isotope records, Unraveling interactions of climate and N dynamics in European forest ecosystems (UnICaN)
OpenAlex ID: W7117366045
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