Evil-Ville: That is sick.
The last tree:

Is it the humans' purgatory, living in a world graced with only a single, small tree?
Or is it the tree's purgatory, existing in a realm where it is the last of its kind, knowing that, when it dies, it will be forgotten?
Perhaps it's the bird's purgatory, who lives surrounded by human children who torment it with their constant attention; knowing that this is the only place in the world where it is able to live as it should.
Maybe the purgatory is the dog's. So close to the tree...so full a bladder.
It could just as well be the man's purgatory; his dog refuses to walk in front and on the right side of him. (I know how annoying that can be.)
You decide.