Zwerg 1

das wäre auch eine Möglichkeit, dann ist aber die schöne Baumstruktur mit Loch weg ;-)

I say landscape, but maybe another aspect ratio, like 5:4.

habe es mal als Notiz eingeblendet, gefällt mir, Sami!

That looks 3:2, not 5:4 ;-)

My point is this:
1) Choose 5:4.
2) Use golden sections to help with composition.
3) For example line up the right side of the foremost tree and gnome's nose onto composition guides.

You get just enough "loose space" removed especially from the left side.

I dared to add my suggestion on the notes. The little details on right are all important to keep. Twigs and green leaves on the top right section are cool! =)