 "Music for Wilderness Lake" is a documentary film which traces the development and performance of a piece of  environmental music  written by Canadian composer, R. Murray Schafer. Twelve trombonists station themselves around the shores of an unpopulated lake, and play meditative music across the water to one another, at two particular times of day - dusk and dawn. The music is cued by Mr. Schafer, himself, from a raft in the middle of the lake, while the natural inhabitants of the surrounding landscapes respond and contribute to the music in their own peculiar way.