By no means am I a master mapper, so take my opinion for what it is...

It looks like the trees are trying to climb up the sides of the cliff, which is good, but might could use a bit more detail. I wonder what it'd look like if you got rid of the ground level and expanded the water (and maybe the cliffs on the right side) so that the cliffs overlooked the water directly. I think the shadow that it casts on the water might have an interesting effect.

Look at this image to see what I mean: