That's poison ivy, the "hairs" being the vines' aerial roots. As you can see in this picture of the vine climbing a tree, it can cling so tightly to the trunk of a tree as to seem a part of it. It's only the aerial roots that give its identity away in this picture.
Pictures of Poison Ivy - the Aerial Roots
"What Are Those Hairy Vines?"
Have you wondered what those hairy vines are climbing up trees...?
Poison ivy's aerial roots are what allow it to scale trees and other objects.
David Beaulieu