Format

Send to

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 2009 Dec 1;106(48):20348-53. doi: 10.1073/pnas.0903029106. Epub 2009 Nov 16.

Recent unprecedented tree-ring growth in bristlecone pine at the highest elevations and possible causes.

Author information

1
Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721, USA. msalzer@ltrr.arizona.edu

Abstract

Great Basin bristlecone pine (Pinus longaeva) at 3 sites in western North America near the upper elevation limit of tree growth showed ring growth in the second half of the 20th century that was greater than during any other 50-year period in the last 3,700 years. The accelerated growth is suggestive of an environmental change unprecedented in millennia. The high growth is not overestimated because of standardization techniques, and it is unlikely that it is a result of a change in tree growth form or that it is predominantly caused by CO(2) fertilization. The growth surge has occurred only in a limited elevational band within approximately 150 m of upper treeline, regardless of treeline elevation. Both an independent proxy record of temperature and high-elevation meteorological temperature data are positively and significantly correlated with upper-treeline ring width both before and during the high-growth interval. Increasing temperature at high elevations is likely a prominent factor in the modern unprecedented level of growth for Pinus longaeva at these sites.

PMID:
19918054
PMCID:
PMC2777957
DOI:
10.1073/pnas.0903029106
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center