Age-Related Climate Response of Tree-Ring delta C-13 and delta O-18 From Spruce in Northwestern China, With Implications for Relative Humidity Reconstructions
AffiliationUniv Arizona, Lab Tree Ring Res
stable carbon and oxygen isotopes
MetadataShow full item record
PublisherAMER GEOPHYSICAL UNION
CitationXu, G., Wu, G., Liu, X., Chen, T., Wang, B., Hudson, A., & Trouet, V. (2020). Age‐related climate response of tree‐ring δ13C and δ18O from spruce in northwestern China, with implications for relative humidity reconstructions. Journal of Geophysical Research: Biogeosciences, 124;e2019JG005513. https://doi.org/10.1029/2019JG005513
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AbstractUnderstanding varying climate responses in tree-ring data across tree ages is important, but little is known about tree-age effects on climate responses in tree-ring stable isotopes. To detect whether age differences in tree-ring delta C-13 and delta O-18 could lead to differing climate responses, we measured tree-ring cellulose delta C-13 and delta O-18 (1901-2010) from Schrenk spruce (Picea schrenkiana) trees in northwestern China with ages ranging from 110 to 470 years, which we binned into three age groups. Tree-ring delta C-13 (pin-corrected) and delta O-18 exhibited similar year-to-year variability between age groups and did not feature age-related trends. delta C-13 series from old trees (270-470 years) showed stronger legacy effects, reflecting influences from the antecedent period (due to carbohydrate reserves and climate), compared to young trees (110-125 years). Both tree-ring delta C-13 and delta O-18 values decreased with increasing relative humidity (RH) and precipitation and with decreasing mean and maximum temperatures during the main growing season (May-August). delta C-13 and delta O-18 exhibited age-dependent climate responses: Young trees had a stronger climate response in delta C-13 but a weaker or similar climate response in delta O-18 compared to old trees. We developed multiple growing-season RH reconstructions based on composite chronologies using delta C-13 and delta O-18 series from different age groups. In particular, we found that including delta C-13 from young trees improved the skill of RH reconstructions because of the age-specific mechanisms driving the delta C-13-climate relationship, but that caution is warranted with regard to extreme values. We therefore suggest that young trees should be considered when using stable isotopes, particularly in delta C-13, for climate reconstruction.
Note6 month embargo; first published: 25 April 2020
VersionFinal published version