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Backpacker Magazine – September 2007

Super Poison Ivy is Coming

More potent poison ivy is on the way, plus fast-growing weeds that will change the face of Eastern forests.

by: The Backpacker Editors

Picture poison ivy growing like it's jacked on steroids. Or kudzu sprouting like a mutant monstrosity in a Japanese horror flick, strangling the trees all around it. Sound far-fetched? Not if carbon dioxide levels keep rising. A sweeping prognosis for eastern woodlands can be tricky, but one important 2006 study hints at what could be in store.

Jacqueline Mohan, an ecologist with the Ecosystems Center at the Marine Biological Laboratory in Woods Hole, MA, used a duct network to boost CO2 levels in a North Carolina forest by 200 parts per million, 50 percent higher than present levels. Her goal was to mimic the concentration expected by the year 2050 if current emission rates continue worldwide.

In her study, poison ivy grew 150 percent faster and three times larger than normal, and its rash-causing oil, urushiol, increased in potency. And if that's not nightmarish enough, the evil weed grew five times faster than most of the area's trees. Kudzu (below) is another big winner in a CO2-dense forest. This exotic Japanese vine has already overgrown many Southeast forests, burying even tall trees under thick mounds of green and wreaking havoc for trail crews. Lacking a tree's trunk-and-branch network, the vines' carbon intake is spent mainly on growing new leaves, which collect yet more carbon and sunlight. Cold-sensitive kudzu has marched north with this advantage, following changing frost zones, and is now firmly entrenched as far north as Delaware.

"It's sobering that carbon dioxide increases can favor pests and weeds, those plants we'd least like to see succeed," comments ecologist Bruce Hungate of Northern Arizona University. The big worry for backpackers: that kudzu and other woody vines like English ivy will monopolize soil nutrients, choke out new tree growth, and alter Eastern forests forever.

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Star Star Star Star Star
Jun 02, 2013

leave my feet

Sep 10, 2008

Being the avid hiker that I am, I can't stand even the sight of poison ivy. I did see a truck though that interested me on the highway. The decal said so I went to the site, and it turns out that they come out to your yard or anywhere, and will kill poison ivy for you. Just wanted to share with everyone since they did a great job on my yard. Thanks.

Zach Greenwood
Aug 15, 2008

Working for my degree in forestry at a local college in western, Virginia. I have spent many hours in the forests. While carbon dioxide pollutes our air exchange, stomas within each leaf, will absorbs more carbon. This could be good for trees, the idea being trees will grow fat faster, providing more quality lumber. Instead clearing of forests gives exotic, invasive species an opportunity to invade.
While trees are trying to grow fat, vines can spread rapidly, anywhere and everywhere. There are no limits! Kudzu is here to stay. While American Chestnut, Castanea dentata, the former king of the Appalachian will remain a puny shrub :( I wonder what the deer think, Kudzu has to be worse than eating poison ivy


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