Island looks great. Some really nice texturing. My only thing about the tree would be to maybe make the leaves a bit smaller (and have more of them to counter the thinning effect that will have, so you maintain the roundness). Are the bumps in the far background waves or a mainland (sorry - really crappy old monitor here - not great on colour distinction). If they're waves, they may be a bit too big compared to the height of the island (especially when allowing for perspective). Even so, looking real good so far.

Dreams are just nightmares on prozac...
Digital WasteLanD