I would not do a 'special' or 'fancy' border. I would do a basic either dark green or chocolate brown border to frame this great top. I think I might leave the triangle parts on the side and border around then and then have a straight border at top and bottom (still thinking about that). But, the goal would be to just let this work stand out, not compete with it. And perhaps use the aimal piece in the backing. I am really big on doing some sort of piecing to the backs of my quilts rather than plain backing fabric. This piece would look great as a large center panel with a couple wide borders around it - maybe a medium brown, medium green, then dark brown and dark green. Can't wait to see the pics of your choices.