Green Fire originated with the words of Aldo Leopold from his book A Sand County Almanac.
We reached the old wolf in time to watch a fierce green fire dying in her eyes. I realized then, and have known ever since, that there was something new to me in those eyes-something known only to her and to the mountain. I was young then, and full of trigger-itch; I thought that fewer wolves meant more deer, and that no wolves would mean hunters' paradise. But after seeing the green fire die, I sensed that neither the wolf nor the mountain agreed with such a view.