The plants commonly known as poison ivy, poison oak and poison sumac are all assigned to the botanical genus
Toxicodendron, which is a member of the sumac family. The three biggies are poison ivy, a common plant in the Midwest and eastern U.S., found mainly in woodlands. Poison oak is common along the Pacific coast, especially in California, and poison sumac is relatively rare, normally found in marshy or swampy areas, and much less often encountered by humans. Which is good, because allegedly it is the most virulent of the three. There are other members of the genus, but these are the three major ones. My recollection is that poison ivy leaves turn red in the fall, not yellow.
I know this for two reasons: 1. I have some botanical knowledge as an offshoot of my professional work. 2. I am allergic as hell to these things.
One of the big problems with them is that, counterintuitively, a person doesn't develop any resistance or immunity to them through repeated exposure. The opposite tends to be true. The more times you are exposed, the easier it gets to be affected, and the worse the rashes get. Fortunately, where I live now (Alaska), none of these plants grow. But I've needed serious medical treatment for the allergic reaction in the past, and it can take weeks to clear up. It's not an insignificant problem.
You absolutely do NOT want to burn these things, for danger of inhaling the smoke, which remains toxic and can cause serious internal problems. And I've read that no human is truly 100% resistant to their effects.
Not all members of the sumac family are toxic to the touch. Normal staghorn sumac is a shrub or small tree that is ubiquitous through much of the central and eastern U.S., usually as a woodland margin plant, often in roadside ditches. Its leaves turn fire-engine red in the fall, and it is easily identified. No toxicity.
Wikipedia has a decent straightforward article on them:
http://en.wikipedia.org/wiki/Toxicodendron