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Recent unprecedented tree-ring growth in bristlecone pine at the highest elevations and possible causes
Matthew W Salzer1, Malcolm K Hughes, Andrew G Bunn
1Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721, USA. msalzer@ltrr.arizona.edu
Summary
Great Basin bristlecone pines experienced unprecedented growth in the late 20th century, exceeding any 50-year period in 3,700 years. This accelerated tree growth is linked to rising high-elevation temperatures.
Area of Science:
- Dendrochronology
- Climate Science
- Ecology
Background:
- Great Basin bristlecone pine (Pinus longaeva) are long-lived trees providing valuable climate records.
- Tree growth near the upper elevation limit is sensitive to environmental changes.
Purpose of the Study:
- To investigate the unprecedented ring growth observed in Great Basin bristlecone pines during the latter half of the 20th century.
- To identify potential environmental drivers of this accelerated growth.
Main Methods:
- Analysis of tree ring width from Pinus longaeva at three high-elevation sites in western North America.
- Comparison of recent growth rates with a 3,700-year record.
- Correlation analysis with independent temperature proxy records and meteorological data.
Main Results:
- Ring growth in the second half of the 20th century was greater than any other 50-year period in the last 3,700 years.
- The accelerated growth was confined to a narrow elevational band near the upper treeline.
- High-elevation temperature data showed a significant positive correlation with tree ring width.
Conclusions:
- The unprecedented growth surge in Pinus longaeva is likely driven by increasing high-elevation temperatures.
- This phenomenon suggests an environmental change unprecedented in millennia, impacting treeline ecosystems.
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