A girl with bark for skin and leaves for hair

As you walked down the trail, you noticed movement off in the woods. You glanced over, expecting to see a deer or a squirrel. Instead you saw... just trees? Oh, and a tree person.

Hold on, tree person?

You stared in disbelief as you saw a woman walking among the trees and looking like she was one of them. She was completely covered in smooth grey bark, like a beech tree, and a cascade of pale green leaves fell down her back like hair.

And she was completely naked.