Your Bright Baby Blues by Jackson Browne. Nothing to do with nature but it sure is melancholy! By the time Lowell George hits the first note of his slide solo I'm nearly in tears
The Last Resort by the Eagles is partly about the (loss of) nature, and is plenty sad, as well.
If you hunt around in Van Morrison's catalog you'll find some pretty deep and introspective stuff. It occurs to me I'm showing my age here, most of this stuff is 40 years old!
If you're not an old geezer like me check out Jason Isbell-- Cover Me Up comes to mind.