Ken Norris shoulders his newly purchased Christmas Tree during the first day of operation at Ted Drewes Christmas Trees in St. Louis on November 26, 2010. Drewes anticipates selling over 5500 trees this season. UPI/Bill Greenblatt | License Photo

Decorations for the approaching Chinese Lunar New Year are hung on trees in one of Beijing's main parks January 23, 2011. Cold temperatures and freezing rain could create major headaches for the energy sector in China, energy analysts said. UPI/Stephen Shaver | License Photo

A man stops to take pictures of the snow covered trees outside Tompkins Square Park after a major storm dumped around 15 inches of snow on January 27, 2011 in New York City. UPI/John Angelillo | License Photo

Blooming cherry blossom trees are seen during the National Cherry Blossom festival in Washington, April 3, 2011. This weekend was the peak bloom for this year's festival. UPI/Kevin Dietsch | License Photo

Trees are bare of leaves after tornado damage in Joplin, Missouri on May 23, 2011. UPI/Tom Uhlenbrock | License Photo

DURHAM, N.C., Oct. 31 (UPI) -- More than half of tree species in eastern U.S. forests aren't adapting to climate change as quickly or consistently as predicted, researchers said.

Nearly 59 percent of the species examined in a study by Duke University researchers showed signs that their geographic ranges are contracting from both the north and south, a Duke release said Monday.


"Many models have suggested that trees will migrate rapidly to higher latitudes and elevations in response to warming temperatures, but evidence for a consistent, climate-driven northward migration is essentially absent in this large analysis," James S. Clark, a professor of environment, said.

Fewer species -- only about 21 percent -- appeared to be shifting northward than predicted, the researchers said.

"Warm zones have shifted northward by up to 100 kilometers (62 miles) in some parts of the eastern United States, but our results do not inspire confidence that tree populations are tracking those changes," Clark said.

The concept of climate-driven migration assumes that as temperatures warm, the southern edge of some tree species' ranges would recede as adult trees die and seeds they leave can no longer sprout.

At the same time, the species could spread to higher latitudes as seedlings dispersed on their northern boundaries are able to take root in newly favorable climates.

The Duke study's findings show "a lack of evidence for climate-mediated migration, and should increase concern for the risks posed by climate change," Clark said.