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Abstract Southwestern North America has experienced significant temperature increases over the last century, leading to intensified droughts that significantly affect montane forests. Although tree‐ring data have provided long‐term context for this recent drought severity, the varying physiological responses of trees to climate variability make it challenging to disentangle the combined influence of temperature and soil moisture. Here we investigate complex climate‐growth relationships in Rocky Mountain bristlecone pine (Pinus aristata) at a low‐elevation and a high‐elevation site using quantitative wood anatomy (QWA). Significant correlations with climate were found for low‐elevation tree‐ring width (TRW) and earlywood chronologies, including positive correlations with spring and early summer precipitation and drought indices and negative correlations with spring and early summer maximum temperatures. At high elevations, TRW and earlywood chronologies show positive responses to summer moisture, whereas latewood chronologies correlate positively with August and September maximum temperatures and negatively with August precipitation. We leverage this differing seasonality of moisture and temperature signals and compare the QWA data to known droughts. The earlywood lumen area is found to be highly responsive to drought because of its physiological reliance on water availability for maintaining turgor pressure during cell enlargement. We also observed a decline in temperature sensitivity at the high elevation site, suggesting shifts in the dominance of limiting factors. Integrating QWA with traditional dendrochronology improves interpretations of tree‐ring data for use in climate reconstruction, offering detailed insights into tree physiological responses and the mix of environmental and developmental controls on cell growth.
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Resolution and Frequency‐Dependent Climate Signals in an Arctic Tree‐Ring Temperature Reconstruction of the Last Millennium
Paleoclimatology makes it possible to place recent climate changes in a longer‐term context than is available from the instrumental record. Tree‐ring reconstructions, often used to quantify temperature variations over the Common Era, contain multiple uncertainties that affect estimates of the magnitude of recent trends and past variability. The use of maximum latewood density (MXD) proxy mitigates many biases, but intra‐annual measurement resolution remains a limitation. We develop a quantitative wood anatomy (QWA)‐based temperature reconstruction from the Firth River in northeastern Alaska from 1150 CE to 2021 CE to improve regional past temperature estimates and to test the sensitivity of MXD‐based climate reconstructions to measurement constraints. We find that high‐resolution wood‐anatomy measurements reduce biological noise and enhance the representation of low‐frequency variability, resulting in stronger temperature signals and a larger magnitude of preindustrial to modern change. QWA data provide novel high‐resolution information that improves tree‐ring temperature reconstructions.
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- PAR ID:
- 10661557
- Publisher / Repository:
- American Geophysical Union
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 52
- Issue:
- 20
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1029/2025GL117846
