Perhaps you have noticed that even in the very lightest breeze you can hear the voice of the cottonwood tree; this we understand is its prayer to the Great Spirit, for not only men, but all things and all beings pray to Him continually in differing ways.
"The Sacred Pipe: Black Elk's Account of the Seven Rites of the Oglala Sioux". Book by Black Elk and Joseph Epes Brown, 1953.