NOAA 2000-088
FOR IMMEDIATE RELEASE
Contact: Pat Viets
12/15/00

NEW TREE RING DATA PROVIDING CLUES TO TEMPERATURES IN ROCKIES FROM 1000 YEARS AGO, NOAA TELLS AGU

New Tree Ring Data Providing Clues to Temperatures in Rockies from 1000 Years Ago, NOAA Tells AGU

Tree rings are giving scientists new clues about the climate of the Central and Northern Rockies that existed over the past 1000 years, Connie Woodhouse of NOAA's Paleoclimatology Program told attendees of the American Geophysical Union's fall meeting in San Francisco today.

Newly developed tree-ring chronologies from sites in Colorado, Wyoming, Idaho, and Montana contain records of spring-summer temperatures. "This new collection of long chronologies that extend from 700 to over 1000 years fills in a gap between long, temperature-sensitive chronologies from the Great Basin and Sierra Nevada to the southwest and from the Canadian Rockies to the north," Woodhouse said.

The goal of this expanded network is to provide a more comprehensive picture of past temperature variability in western North America over the last 1000 or more years through analysis of tree ring widths, ring densities, and cell sizes from several species of trees.

Woodhouse and her colleagues, Peter Brown from Rocky Mountain Tree-Ring Research, Inc., and Malcolm Hughes from the Laboratory of Tree-ring Research at the University of Arizona, said that scientists have compared the new chronologies with existing chronologies. The comparisons show, among other things, several sustained cold events that are reflected in trees from the southwestern U.S. to the Canadian Rockies. The most notable of these events occurred in the mid-15th century.

More information is available at http://www.ngdc.noaa.gov/paleo/recons.html, http://www.rmtrr.org/ and http://www.LTRR.Arizona.EDU/