The Kind of Misery Itched in Memory

By Lori Aratani
Washington Post Staff Writer
Saturday, August 23, 2008

There are things about summer -- long days, shaved ice, fresh-off-the-tree-peaches -- that we love. And then there are those things we simply tolerate because, well, the pessimist in us says that life can't possibly be that perfect, so we must suffer, just a bit.

Well, it appears we could be suffering a bit more in coming days.

Polar bears might be endangered because global warming is melting their homes on arctic ice shelves, but one species is thriving: poison ivy.

A growing body of research shows that in controlled experiments, poison ivy goes crazy in an atmosphere rich in carbon dioxide. Many plants grow better when they get extra carbon dioxide, but researchers were surprised to learn how well poison ivy did.

"It isn't that other plants can't grow as well, it's just that poison ivy grows so much more," said Lewis H. Ziska, a plant physiologist who specializes in crop systems and global change for the U.S. Department of Agriculture's Agricultural Research Service in Beltsville. One theory is that poison ivy, and vines in general, don't have to invest as much of their carbon (obtained from carbon dioxide) in trunks and branches as trees do.

And that just scratches the surface.

"It's going to be like a one-two punch: more poison ivy and more poisonous poison ivy," said Xianzhong Wang, a professor of biology at Indiana University-Purdue University Indianapolis, who studies the effect of carbon dioxide on plant growth.

Isn't it just our luck that among its leafy green counterparts, poison ivy would be the class overachiever?

This is not what Rachel Caspi wants to hear. She had a run-in with the vine earlier this summer.

"Oh, it was awful," said Caspi, an immunologist at the National Institutes of Health who ran into a cluster of poison ivy along a trail in Rock Creek Park. It was Father's Day, and Caspi was running along the paved path, as she often does, when she brushed against a cluster of green leaves.

"It was unavoidable," the Bethesda resident said, an indignant tone in her voice. "It was right there, right up along the path."

By late that evening, her legs were red and itchy.

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