COLUMBUS, Ohio, July 19 (UPI) -- A study of bottomland hardwood forests in the southeastern United States showed an unusual increased growth of vines during the past 20 years.
Ohio State University researchers charting the growth of vines in two South Carolina forests discovered a 10-fold increase in such vines as poison ivy, grapevines, trumpet vines and Virginia creeper.
"There are now so many vines that they're starting to change the makeup of the forest," said Bruce Allen, a recent Ohio State University doctoral graduate and the study's lead author. "It appears that as the number of vines increase, the density of small trees decreases at a fairly uniform rate."
The researchers said one of the possible mechanisms responsible for the enhanced growth might be increases in carbon dioxide concentrations.
"Collectively, we're talking about an increase of more than 500 vine stems in 27 acres of forest area that we studied," he said.
The study by Allen, Ohio State University Associate Professor P. Charles Goebel and Rebecca Sharitz, a senior research ecologist at the University of Georgia, was reported in a recent issue of the journal Forest Ecology and Management.