Hey now, why in the world are you trying to learn nature magic (also known as magic) but are not interested in things related to Wicca?
You speak and read English, so you’re already knee deep in the works of great druids and witches.
Anyhow, try approaching nature its self. Camp out as primative as you can. Start with empty hands and see if you can make fire. See if you can catch a fish or forage the right plants. Run in one direction as fast as you can then try to find your way back. The Forrest is a great teacher. I learned tons of magic as a Cub Scout.