If I were you I wouldn't use any trashbags, just purely random rubble and junk. FAR more interesting to look at.
Why do the mountains go light, dark, light into the horizon?
Bottom right trashbag is blocking too much view.
You might train the camera down a bit. That, or raise the tree.
Also, the tree is too typical. It's a wonder of the world. It's the future. Stylize that thing a little, make it alienish.
The surrounding flora takes away from tree's uniqueness. I say kill the grass and lose little shrubs scattered around and give all the element of life to the tree.
You might go for a duality concept - life and death. Death is the nasty junk yard, smog in the air, waste, excess, toxicity VS Life-one beautiful thriving tree in the midst of it all.