I'm almost certain she was only visible to me.

Today I watched an old woman wander through a grove of trees in the autumn wind. She crept along the path at a very slow pace, then stopped next to a statue of the Virgin Mary, looked around in all directions, and then slowly turned around and went back the way she came. There was a hill between her and I, and as she walked away, I watched her until her head descended beneath the horizon of the hill. I'm pretty much positive that she was the spirit of the forest.