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

Matthew W. Salzer, Malcolm K. Hughes, Andrew G. Bunn, and Kurt F. Kipfmueller
PNAS published ahead of print November 16, 2009 https://doi.org/10.1073/pnas.0903029106

  1. Edited by Harold A. Mooney, Stanford University, Stanford, CA, and approved September 28, 2009 (received for review March 19, 2009)

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 CO2 fertilization. The growth surge has occurred only in a limited elevational band within ≈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.

Footnotes

  • 1To whom correspondence should be addressed. E-mail: msalzer{at}ltrr.arizona.edu

  • Author contributions : M.W.S. and M.K.H. designed research; M.W.S., M.K.H., and A.G.B. performed research; M.W.S., M.K.H., A.G.B., and K.F.K. analyzed data; and M.W.S., M.K.H., A.G.B., and K.F.K. wrote the paper.

  • The authors declare no conflict of interest.

  • This article is a PNAS Direct Submission.

Back to top
Article Alerts
Email Article
Citation Tools
Request Permissions
Recent unprecedented tree-ring growth in bristlecone pine at the highest elevations and possible causes
Matthew W. Salzer, Malcolm K. Hughes, Andrew G. Bunn, Kurt F. Kipfmueller
Proceedings of the National Academy of Sciences Nov 2009, pnas.0903029106; DOI: 10.1073/pnas.0903029106
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
Proceedings of the National Academy of Sciences: 116 (8)
Current Issue

Submit

Jump to section

You May Also be Interested in

Nonmonogamous strawberry poison frog (Oophaga pumilio). Image courtesy of Yusan Yang (University of Pittsburgh, Pittsburgh).
Putative signature of monogamy
A study suggests a putative gene-expression hallmark common to monogamous male vertebrates of some species, namely cichlid fishes, dendrobatid frogs, passeroid songbirds, common voles, and deer mice, and identifies 24 candidate genes potentially associated with monogamy.
Image courtesy of Yusan Yang (University of Pittsburgh, Pittsburgh).
Active lifestyles. Image courtesy of Pixabay/MabelAmber.
Meaningful life tied to healthy aging
Physical and social well-being in old age are linked to self-assessments of life worth, and a spectrum of behavioral, economic, health, and social variables may influence whether aging individuals believe they are leading meaningful lives.
Image courtesy of Pixabay/MabelAmber.