Featured Research

from universities, journals, and other organizations

Tree-ring data show history, pattern to droughts

Date:
February 17, 2013
Source:
University of Arkansas, Fayetteville
Summary:
Researchers used more than 1,400 climate-sensitive tree-ring chronologies from multiple tree species across North America to reconstruct the Palmer drought severity index (PDSI), a widely used soil moisture index.

For more than a decade, Distinguished Professor David Stahle has taken core samples from trees and examined the chronology of their rings to help explain the societal impact of drought and other climate changes.
Credit: Image courtesy of University of Arkansas, Fayetteville

Dendrochronologists have shown that tree-ring data produce a remarkably accurate history of droughts and other climate changes. Combined with reliable drought indices and historical descriptions of climate conditions, dendrochronology -- the technique of dating events and environmental change by relying on characteristic patterns of tree-ring growth -- can provide a climate perspective on important events such as large-scale human migration and even the rise and fall of entire civilizations.

Related Articles


A research team, including University of Arkansas Distinguished Professor and dendrochronologist David Stahle and Ewing Research Professor Edward Cook of Columbia University, used more than 1,400 climate-sensitive tree-ring chronologies from multiple tree species across North America to reconstruct the Palmer drought severity index (PDSI), a widely used soil moisture index. Stahle presented his research on Feb. 15, in a symposium on "U.S. Climate and Weather Extremes: Past, Present, and Future," during the American Association for the Advancement of Science annual meeting in Boston. He also participated in a panel discussion with other climate experts.

The Palmer drought severity index is based on instrumental temperature and precipitation data dating back to 1895. Stahle and his colleagues inserted the index between fixed points on a grid covering most of North America. Their tree-ring reconstructions cover the same geographic area but extend back to 800 A.D.

Stahle wanted to examine the reconstructed indices to test the accuracy of the records and to see if there were any patterns related to drought and other climate changes. The findings were dramatic.

"Comparisons of reconstructed PDSI with instrumentally measured PDSI during the 20th century document the remarkable accuracy with which the tree-ring data reproduce the spatial pattern and intensity of observed drought at annual and decadal time scales, including the Dust Bowl drought of the 1930s," Stahle said.

The data also confirmed historical descriptions of climate conditions prior to the modern era of instrumentation for weather and climate measurements. For these comparisons, the researchers relied on accounts from Zebulon Pike's 1806-1807 expedition and from Stephen H. Long's 1820 exploration. Both expeditions described extremely dry conditions across much of the Great Plains and Rocky Mountains.

The researchers analyzed the reconstructions and found a pattern of droughts over the past few centuries similar to the 2011 drought centered over Texas and the Southern Plains as well as the 2012 Corn Belt drought.

"Both of these droughts have precedents in the centuries-long tree-ring reconstructions," Stahle said. "In fact, the tree-ring data document drought anomalies in prehistory with a similar severity and spatial impact that persisted for two to three years. Severe drought over the Corn Belt and southern Great Plains are likely to recur, especially with continued warming over the United States."

The tree-ring reconstructions of the Palmer index indicated that the Great Pueblo Drought, which occurred from 1276 to 1297 and may have contributed to the abandonment of the northern Colorado Plateau by the ancient Pueblo, affected a larger geographic area than originally thought. The findings indicated that this drought covered the entire southwestern United States and included drought in both the winter and early growing season.

For more than a decade, Stahle has taken core samples from trees and examined the chronology of their rings to help explain the societal impact of drought and other climate changes. Specifically, his research has added rich information to explanations about the migration of North America's indigenous people and the demise of Mesoamerican civilization.

A recently published 1,238-year-long tree-ring chronology, the longest and most accurate of its kind for Mesoamerica, was the first to reconstruct the climate of pre-colonial Mexico on an annual basis for more than a millennium. That study identified four ancient megadroughts and their exact years. Previous research found large and epic droughts over North America during the 8th and 16th centuries.


Story Source:

The above story is based on materials provided by University of Arkansas, Fayetteville. Note: Materials may be edited for content and length.


Cite This Page:

University of Arkansas, Fayetteville. "Tree-ring data show history, pattern to droughts." ScienceDaily. ScienceDaily, 17 February 2013. <www.sciencedaily.com/releases/2013/02/130217083054.htm>.
University of Arkansas, Fayetteville. (2013, February 17). Tree-ring data show history, pattern to droughts. ScienceDaily. Retrieved October 26, 2014 from www.sciencedaily.com/releases/2013/02/130217083054.htm
University of Arkansas, Fayetteville. "Tree-ring data show history, pattern to droughts." ScienceDaily. www.sciencedaily.com/releases/2013/02/130217083054.htm (accessed October 26, 2014).

Share This



More Plants & Animals News

Sunday, October 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Black Bear Cub Goes Sunday Shopping

Black Bear Cub Goes Sunday Shopping

Reuters - Light News Video Online (Oct. 23, 2014) Price check on honey? Bear cub startles Oregon drugstore shoppers. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Dances With Wolves in China's Wild West

Dances With Wolves in China's Wild West

AFP (Oct. 23, 2014) One man is on a mission to boost the population of wolves in China's violence-wracked far west. The animal - symbol of the Uighur minority there - is under threat with a massive human resettlement program in the region. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
Breakfast Debate: To Eat Or Not To Eat?

Breakfast Debate: To Eat Or Not To Eat?

Newsy (Oct. 23, 2014) Conflicting studies published in the same week re-ignited the debate over whether we should be eating breakfast. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins