your post kind of intrigued me because believe it or not I've actually left a folded up piece of paper in a tree before.
Ok, ok, not exactly, it was just near a tree, let me explain.
About 8 years ago I went on a trip to England and Israel. My roommates friend was going to be working on a kibbutz a few months after me being there so I gathered materials from the different cities that I visited and when I was in Jerusalem I built a 8-10 inch well out of all of the materials that I had collected. I had rocks from the Meditarian, olive branches, palm leaves, bark from a tree by the Jordan River, etc. etc.
I wrote a little note, placed the folded up piece of paper in the well and hid them both in the Kidron Valley just outside of the city. It's on the mountain side of the Mount of Olives under a big tree in case you are in the area:) (my roommates friend never found it)
Why did I do all of this?
Because "What makes the desert beautiful," said the little prince, "is that somewhere it hides a well . . ."