Pumped Up on Carbon Dioxide, Vines Strengthen Their Grip

By Elizabeth Williamson
Washington Post Staff Writer
Saturday, July 15, 2006; A01

Vines -- poison ivy, Japanese honeysuckle, kudzu -- snake through the back yard, girdling trees and strangling shrubs, thriving, scientists say, on the same pollution they blame for global warming.

From backyard gardens to the Amazon rain forest, vines are growing faster, stronger and, in the case of poison ivy, more poisonous on the heavy doses of carbon dioxide that come from burning such fossil fuels as gasoline and coal.

Complaints about vine infestation have increased tenfold in a decade, said Carole Bergmann, forest ecologist for the Maryland-National Capital Parks and Planning Commission, which serves Montgomery and Prince George's counties. Vines have choked gardens, ruined brickwork, disrupted bird habitat and clogged paths, ponds and air conditioning and electronic equipment.

"The woods they used to know have just changed character," Bergmann said. "They're covered with vines. The trees are being weakened and falling over - s have been increasing in abundance all over the planet [and] inhibiting the growth and regeneration of the forest," said Mohan, who released her findings last month.

"This work suggests that atmospheric carbon dioxide is at least partially responsible."

But the vines also hint at a tantalizing solution to global warming: Perhaps scientists can engineer a plant that would absorb extraordinary amounts of carbon dioxide and clean the air without throwing forests wildly off kilter.

"There's some reason for optimism that we could use vegetation to stave off global warming," said William H. Schlesinger, an expert on climate change and dean of the Nicholas School of the Environment and Earth Sciences at Duke University. "But there's no telling that the mix you come to is going to be stable or functional the way today's ecosystems are."

Trees and plants play a vital role in soaking up carbon dioxide that is released into the atmosphere. Scientists are trying to determine whether plants can keep pace with -- or perhaps even begin to reverse -- the rise in carbon dioxide.

For 20 years, Bert Drake has been exposing marsh grasses to twice as much carbon dioxide as normally found in the atmosphere. On a recent day, he strolled the wooden decking that winds through his laboratory, a swath of Chesapeake Bay marsh at the Smithsonian Environmental Research Center in Edgewater.

Drake said his research suggests that most plants grow faster on higher levels of carbon dioxide -- including plants already used as alternative fuels, such as switch grass. If burned instead of fossil fuels, these plants, the theory goes, could form a defense against climate change.

But whether every plant will grow faster in those conditions, or how fast, or at all, is maddeningly unpredictable.

At Edgewater, Drake found that most grasses grow about 35 pe onal problem, Bergmann, of the Parks and Planning Commission, founded Weed Warriors, volunteers who patrol the region, ripping out offenders. Now an army of 500, they can't keep up. Many of the vines -- English ivy, porcelain berry, winter creeper -- were planted by homeowners who prized them as fast-growing, attractive ground cover.

"Just not buying these would really help a lot," she said. "I'd rather see native trees doing well than have some robotic tree developed that a vine can live on and create a super-jungle." © ;2006 ;The Washington Post Company
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