So It Isn't My Imagination

As I have been out walking this past spring, I thought that the amount of poison ivy that I was seeing seemed to have increased from previous years. But then again, I also thought it might be just that I am now so much more aware of it since I am so allergic to it. I have gotten really good at dressing appropriately in long pants and scrubbing with Technu when I get back to my car after a walk and so far this year I have been fortunate that I have not yet gotten the nasty rash. Bill had told me that he saw a news article that global warming has increased the amount and the intensity of poison plants and I felt that I was truly witnessing it. Our local paper published the following article yesterday as even more proof that we are definitely in the midst of a poison ivy boom.

7/5/2007

A rash of poison ivy

The wild plant, which often grows on the edges of fields, and most vegetation are thriving because of increased carbon dioxide in the atmosphere, scientists say.

By Jason Brudereck

Reading Eagle

Berks County, PA - Poison ivy seems to be hardier and may be more potent than ever in Berks County and other areas in the East.
“In the last several years, there are more vines and they’re more vibrant,” said Dan Hewko, manager of the 665-acre Nolde Forest Environmental Education Center in Cumru Township.
This year at Reading Hospital, the emergency department is treating more cases of poison ivy-related contact dermatitis, or rashes, than in other recent years, said Dr. Charles F. Barbera, chairman of emergency medicine.
Exact figures weren’t available.
Barbera said he doesn’t know why the number of cases has increased.
But a scientist for the U.S. Department of Agriculture thinks he knows why.
A higher concentration of carbon dioxide in the atmosphere may have improved the health and potency of the plant, said Dr. Lewis H. Ziska, a plant physiologist in Beltsville, Md.
Ziska conducted a study that grew the ivy under two different conditions.
One set of plants was exposed to air that contained 300 parts per million of carbon dioxide, which is roughly the equivalent of the amount in the atmosphere 50 years ago.
Another set of plants was exposed to air that contained 400 parts per million of carbon dioxide, which is the level found in the atmosphere today.
The plants grown at today’s carbon dioxide levels were as much as 75 percent larger and had about the same increase in the amount of rash-causing oil they produced, Ziska said.
For plants to thrive, they need carbon dioxide, light, water and nutrients, he said.
“If you change any one of the four, plants are affected, but it doesn’t affect all plants the same way,” he said. “We’re trying to find wheat and rice and good plants that can adapt to this additional carbon in the atmosphere.
“That’s the good side of the coin. The bad side of the coin is things like poison ivy and ragweed and all sorts of things you don’t want to have around do well under those conditions.
An earlier study Ziska helped produce showed ragweed, which torment many of those who suffer from allergies, produces 131 percent more pollen than it did during pre-industrial times.

In 2006, the National Arbor Day Foundation updated its plant hardiness map for the first time in 15 years.
New data moved part of Berks into a warmer zone and the nonprofit organization attributed that change to global warming.
Some people who spend a lot of time in the woods have noticed all plants, not just poison ivy, are thriving.
“I live out in the country and poison ivy is all over the place, but a lot of plants are abundant this year,” said Karl Gardner, a member of the Berks Community Hiking Club who lives in Rockland Township.
But Gardner said the amount of poison ivy doesn’t seem unusual.
And the supposed increase of poison ivy isn’t to the point that it’s scaring off hikers.
“If you know when you’re looking at poison ivy, it wouldn’t keep you from going into the woods,” Hewko said.
He also pointed out that many plants, not just those that are poisonous, are doing better with the higher concentrations of carbon dioxide.
Dr. Susan Munch, a biologist and botanist at Albright College, also noted that all plants would improve with higher levels of carbon dioxide.
She added that another reason poison ivy may appear to be thriving is because development increases the amount of area that skirts the edges of woodlands.
Poison ivy grows well along those edges where there is plenty of light, she said.
“It does better there than in the depths of the forest,” she said. “And I certainly haven’t seen any decrease in the amount of poison ivy.”

•Contact reporter Jason Brudereck at 610-371-5044 or jbrudereck@readingeagle.com.