Nice render - the grass, mountains and sky look awesome. In terms of composition I would have preferred to see more of the background instead of the central tree but I still like the feel of this picture.
Out of interest - how large was your scene in blender units?
Thanks for the input talebreeder! I can see how that tree is blocking a lot of the background. I think i will re render it to see how it looks with that tree moved way to the side.
the clipping on my camera was at like 4500 blender units, and the far mountains were just hitting the clipping plane.