Tree-Ring Stable Carbon Isotope as a Proxy for Hydroclimate Variations in Semi-Arid Regions of North-Central China
Carbon and oxygen isotope ratios (δ 13 C and δ 18 O) were measured in annual tree-ring cellulose samples dated from 1756 to 2015 CE. These samples were extracted from Chinese pine ( Pinus tabulaeformis Carr. ) trees located in a semi-arid region of north-central China. We found that tree-ring δ 13 C...
Published in: | Forests |
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Main Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
MDPI AG
2022
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Subjects: | |
Online Access: | https://doi.org/10.3390/f13040492 https://doaj.org/article/6ab8d5f4d8724bc7af5bf09bfb190662 |
Summary: | Carbon and oxygen isotope ratios (δ 13 C and δ 18 O) were measured in annual tree-ring cellulose samples dated from 1756 to 2015 CE. These samples were extracted from Chinese pine ( Pinus tabulaeformis Carr. ) trees located in a semi-arid region of north-central China. We found that tree-ring δ 13 C and δ 18 O values both recorded similar climatic signals (e.g., temperature and moisture changes), but found that tree-ring δ 13 C exhibited a stronger relationship with mean temperature, precipitation, average relative humidity, self-calibrating Palmer drought severity index (scPDSI), and standard precipitation evaporation index (SPEI) than δ 18 O during the period 1951–2015 CE. The strongest correlation observed was between tree-ring δ 13 C and scPDSI (previous June to current May), which explains ~43% of the variance. The resulting 130-year reconstruction reveals severe drought events in the 1920s and a sustained drying trend since the 1980s. This hydroclimate record based on tree-ring δ 13 C data also reveals similar dry and wet events to other proxy data (i.e., tree-ring width and historical documentation) that have allowed reconstructions to be made across the northern fringe of the Asian summer monsoon region. Our results suggest that both large-scale modes of climate variability (e.g., El Niño-Southern Oscillation, Pacific Decadal Oscillation, and North Atlantic Oscillation) and external forcing (e.g., solar variability) may have modulated moisture variability in this region. Our results imply that the relationship between tree-ring δ 18 O and local climate is less well-characterized when compared to δ 13 C and may be affected more strongly by the influences of these different atmospheric circulation patterns. In this semi-arid region, tree-ring δ 13 C appears to represent a better tool with which to investigate historical moisture changes (scPDSI). |
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