Spokeswoman Elisabeth Snell says the most serious would be snake bite, but snakes are easy to avoid.
"We have heard suggestions of wearing boots and long pants." Snell said. "To prevent, if you do come in contact with a snake, the snake at least does not have contact with your skin."
If you are bitten by a snake, you should call 9-1-1 right away. She says you should always check for ticks after you have been outside and remove them with tweezers.
As for the poisonous plants, Snell advises washing exposed skin areas thoroughly if you have recently been in a wooded area.
http://accesswdun.com/article/2004/6/157094