Wow, I like this 
I agree with Skeddles for the trees, maybe you could add a color.
Keep going !
Hm. This perplexes me. Something about it is really unique and atmospheric.
There are some things that kind of bring it down, like the single color trees, I don't think those work. I think you've got something here though.
I dig the crude look of it but I would like to be able to view it at 1x instead of 4x, so when you upload prescaled at least give a link to a non-scaled version (also note that we have an inbuilt zoom feature).
The trees look a bit undefined compared to the rest. I would try to either add a bit more depth/details to them or give them a lower contrast to the rest of the pic so they fade into the background (tending more towards the first).
I'm also pretty sure that you could do a lot cluster optimisation without destroying this type of style.
You could shade the trees in the same style of rest. Great piece anyway.