20.500.12556/DiRROS-23767 Effects of soil and atmospheric drought on intra-annual δ13C patterns in tree rings None declared.Conflict of interestHigh-resolution carbon isotope ratio (δ13C) measurements of tree rings have the potential to provide seasonal environmental information. However, due to the complexity of the wood formation processes, the reliability of this method for intra-seasonal reconstruction of growing conditions remains unclear. We, therefore, investigated the intra-annual variation of δ13C in tree rings of three conifer species (Pinus sylvestris, Picea abies, Abies alba) across sites from the Swiss Alps to assess their response to seasonal variation of soil water potential (SWP) and vapour pressure deficit (VPD). Intra-annual δ13C values at a resolution of 10 points per year were assessed using laser-ablation isotope-ratio mass spectrometry. Seasonal δ13C patterns were analyzed for synchronicity across trees and species, and their correlation with on-site environmental variables was used to determine the driving factors of δ13C, to reconstruct growing season dynamics, and to estimate timings of the growth dynamics and allocation of carbon to xylem formation. The δ13C patterns showed high synchronicity between species, with characteristic maxima in wet and dry years occurring in the middle of the ring and at the end of the ring, respectively. Seasonal δ13C variations reliably reflected atmospheric dryness. Higher than normal soil dryness hindered integration of further fresh assimilates into the xylem, thus allowing the identification of species- and site-specific threshold conditions that disrupt wood formation. The δ13C of Scots pine shows the strongest correlations with VPD and SWP, making it an excellent indicator of environmental variability. Silver fir appears to integrate carbon into xylem structural material over a longer season than the other conifers, whilst Norway spruce shows more plastic site-specific responses to environmental conditions. In conclusion, we identify how atmospheric and soil drought jointly impact tree growth and intra-annual δ13C patterns across conifer species, offering valuable insights for climate reconstructions and wider applications on forest dynamics. water availability annual growth laser ablation tree-ring isotopes carbon isotopes razpoložljivost vode letna rast laserska ablacija izotopi drevesnih obročev izotopi ogljika true false true Angleški jezik Slovenski jezik Znanstveno delo 2025-10-01 13:55:31 2025-10-01 13:55:31 2026-01-27 03:53:57 0000-00-00 00:00:00 2025 0 0 Nasl. z nasl. zaslona; Opis vira z dne 1. 10. 2025; str. 1-17 iss. 11 Vol. 45 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 630*8 1758-4469 10.1093/treephys/tpaf120 251302659 https://academic.oup.com/treephys/advance-article/doi/10.1093/treephys/tpaf120/8266807 1 89bf88cb-9ebd-11f0-9bb7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=35235 tpaf120.pdf tpaf120.pdf 1 94542D3E1146D6AE0249B5AF5F2E8275 29272b73806d05c73510951f6de5ec7fdeedab929917f934d50a1941dc4d1cf5 8afdb217-faaf-11f0-a15d-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=38907 Gozdarski inštitut Slovenije 0 0 0