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Effects of Poison Ivy and Global Warming

joycetheriot's picture

    P    What puts the ITCH in Poison Ivy?     p

The Allergy Chronicles (Source for Science Lesson Plans)

Pumped-up Poison Ivy

Leaves of three - let them be! Why? Urushiol a colorless, odorless oil (called resin) is contained in the leaves of the plants.

All Things Considered, May 30, 2006 · Global warming may spell bad times for polar bears but it seems to be a boon to poison ivy. A six-year experiment to find out how increased levels of carbon dioxide affect forests uncovered a surprising result: In the area used for the experiment, poison ivy grew like crazy. Melissa Block talks with ecologist Jacqueline Mohan is a scientist at the Ecosystems Center in Woods Hole, part of the Harvard Forest in central Massachusetts.

(Audio) is an Interview with scientist working on experiments using CO2 causing increased growth and toxicity of Poison Ivy.


The poison ivy plant (Toxicodendron radicans) has leaves grouped in three and can grow vine‑like up the trunks of trees. The leaves of the Western shrub‑like poison oak plant (Toxicodendron diversibolum) are also grouped in three but are shorter than poison ivy and are slightly lobed on the edge resembling oak‑shaped leaves.


Poison ivy sap causes an allergic reaction in humans. The active agent is secreted from broken resin ducts. Most plant parts contain a chemical that causes itching, swelling, rashes, and blisters. Plants are variously poisonous depending on the time of year and plant maturity, and people vary in susceptibility. In winter, theplant is leafless and dead looking but is actually alive and still very toxic.
Animals are generally not susceptible to the toxic chemical in poison ivy. A wide variety of birds consume the fruits. The leaves and fruits are some of the most important foods of white-tailed deer. The sap is used to make indelible ink and the plant is used to prevent erosion on sand dunes due to its tough root system.

Climbing Poison Ivy


Sometimes it's hard to tell poison ivy from the tree it's climbing on - it can branch out two or three feet.

When you cut down a tree for firewood you can get a good case of poison ivy from the vine stuck to the tree - even in winter.

And they say you can get VERY bad poison ivy from the smoke from burning wood with ivy vines on it. You get the problem in your lungs. You don't want that.

A CO2-driven vine also produces more of its rash-causing chemical, urushiol, conclude experiments conducted in a forest at Duke University where scientists increased carbon-dioxide levels to those expected in 2050. Compared to poison ivy grown in usual atmospheric conditions, those exposed to the extra-high carbon dioxide grew about three times larger — and produced more allergenic form of urushiol, scientists from Duke and Harvard University reported. Their study appears in this week’s Proceedings of the National Academy of Sciences. “The fertilization effect of rising CO2 on poison ivy ... and the shift toward a more allergenic form of urushiol have important implications for the future health of both humans and forests,” the study concludes.
About 80 percent of all people are allergic to poison ivy's sap or resin. Sufferers experience a red, bumpy, itchy, and sometimes blistering skin rash when they come into contact with urushiol—the plant's carbon-based active compound. Unfortunately, the study also found that carbon dioxide-enhanced poison ivy boasts a stronger strain of urushiol, which may prove even more poisonous to humans. "That was a bit of a surprise," said lead author Jacqueline Mohan, a postdoctoral scientist at the Ecosystems Center of the Marine Biological Laboratory in Woods Hole, Massachusetts. "It was not actually producing more of the carbon compounds but producing a more poisonous form."


Kyle Mundaye's picture

How to make poison ivy go away...

First thing you want to do is keep it open to the air. Many people are paranoid about how if it touches "air" it will "hop" onto a person near you. That is false. You cannot get poison ivy from touching another persons rash. The inflammatory area "the bubbles" needs to dry out. When it's dry, it WILL BE VERY ITCHY, but don't scratch it.

Second, buy Calamine lotion. You can find it just about any drugstore.

Third, be patient. Some rashes just need to run their course.


(1) I would not suggest trying this, because i did and it was very painful. Get it over and over again until your body "adapts" to it and is no longer dramatically harmed by it.

(2) Wear long sleeves and pants when walking/hiking in the woods.

(3) Avoid areas where there are vines on the trees that don't look "natural."