Land never ends.
- What I mean:
When you make your land, go far out.
And I'm not sure if it was intentional to not shade, so I'll leave that.
And use light yellows and dark yellows (not too dark) for the sun. So it'll have more detail.
And technically you can never see the roots of a tree, so try to let them out. ^-^
It's a pretty picture though, I can't lie. :K