They're more artistic than mappy...but they sure are pretty. I especially like the dramatic lighting in the last village map. I want to see these in a post-apocalyptic ISO game. Maybe The Road.

Now, on to trees: I see what you've done with the trees and what you were going for. Cutting off the tops as you have, unfortunately, gives more an impression (to me anyway) that the vegetation is some sort of clumped vertical shrub thing than a collection of tops-removed-for-clarity trees. I'm not at all sure how to resolve the issue however. The only thing I can imagine is to somehow make the trees more distinct from the background so that you can really see the trunk clearly...and see the distinctive break at the top to know there was supposed to be more.

I'm sure I didn't manage to help but keep experimenting and I bet you'll get it down. In the meantime you're inventing a very nice ISO style all your own.
M