thanks guys. i think i'll have to make a new tree brush that isn't transparent in the middle. After you pointed it out i had a look, and yeah. it is a bit annoying having a piece of beach in a tree haha.
and also, the mountains do indeed look somewhat like a rear. excellent spotting a lolling good sir.

EDIT: think i might blur the rivers by a couple of pixels to get rid of the harshness when it's scaled.