Health Hazards - Poisonous Plants

The most common thing that can spoil a visit to the Forest is not an encounters with bears or snakes. For those that frequent the Forest often, the most difficult thing to avoid are the "poison" plants. The rashes and discomfort can certainly ruin a visit to the Forest.

The Itch that Sticks

There are certain plants in this area that can cause skin rashes and irritations lasting a week or more. Most humans react to these plants, and sensitivity in individuals changes over time. People who have never had a reaction in the past should still avoid these plants, since toxins can build up in an immune system, and after a certain level cause a reaction. These plants have oils which cause these reactions in humans. The oil is in the stems, leaves, and berries of the plants and can be transmitted by brushing against the plant, or from secondary contact with animals or clothing. When building fires in the forest with downed wood, be careful not to use wood that has vines on it. The smoke from burning poison ivy can cause serious respiratory problems in some individuals.

Poison Ivy (Toxicodendron radicans)

Found: along trails, roadsides and woodlands

Appearance: trailing, perennial vine. Can also appear as a small bush or as a groundcover.

Things to Look For: Three leaflets which alternate up the stem. Young leaves have a reddish tint and may have either smooth or jagged edges. Old vines are very hairy. In late summer and fall it will have green to white berries on the vines. A verse learned by many children to help them remember poison ivy is: "Leaves of three, let it be; berries white, poison in sight." In the fall this vine turns brilliant red. A similar-looking common vine is Virginia Creeper, but Virginia Creeper has five fan-shaped leaflets.

Treatment if Exposed: Rinse area as soon as possible with lots of cool water and soap. Avoid hot water since it opens the skin's pores more. Do not scrub the area as this will also allow the toxin to get in the pores. Generally a rash appears 12-24 hours after exposure.

Poison Oak (Toxicodendron rydbergii)

Poison Oak is a mostly western U.S. species found in open sunny habitats.

Poison Sumac (Toxicodendron vernix)

Found: Swamps or very wet areas. Usually in the shade.

Appearance: Shrub or small tree from 6.5 feet to 23 feet tall.

Things to Look For: Shrub with compound leaves and grayish-white berry clusters in swamps. Appears similiar to the fragrant sumac found along roadsides which has fuzzy red berries.

Treatment if Exposed: Rinse area as soon as possible with lots of cool water and soap. Skin rash and irritation will occur upon contact and can last a week or more.

Wood Nettle (Laportea canadensis) and Stinging Nettle (Urtica dioica)

Found: Bottomlands and along streams in shady areas.

Appearance: Perennial herb up to two feet tall with stiff hairs on the stem.

Things to Look For: Stiff hairs on the plant's stem. Each tiny hair on the stems and leaves is hollow with a jagged point at the end. A bump against the stiff hair squeezes an irritating acidic chemical through the hair and onto a passing person's skin, much like a hypodermic needle.

The acid in the hairs, formic acid, is the same substance that many ants secrete to protect themselves from predators. In the Stinging Nettle, it's pressurized so that it bursts out the instant the sharp hairs make contact with skin. The acid quickly spreads into the nearby human skin cells, causing them to swell. A rash appears on the surface of the skin and small white spots develop.

Treatment if Exposed: Apply lotions with an anti-inflammatory and cooling effects (talc, calamine). Home remedies include to rub the irritated area with juice of dock (Rumex spp.) or Jewelweed (Impatiens capensis). Since the source of the irritation is an acid, it can also be neutralized by applying a base. Baking soda mixed with water works particularly well.

Human Reaction: Rash and dermatitis with an intense burning sensation due to allergic reaction.