Weddingbee boards

Have you thought about hanging lanterns? You could do them in a pretty green color to add a little color to the tent.

Take a look at Mrs. Tiramisu's post: http://www.weddingbee.com/2009/03/16/tents-and-lanterns-and-layouts-oh-my/

And look at some of the inspiration pictures Mrs. Penguin posted. They aren't in green, but can give you a good idea of the impact of paper lanterns.  http://www.weddingbee.com/2008/03/13/paper-lantern-inspiration/

Also, consider using accent napkins in green, or even green candles on the table. I think that people will be wowed by the overall look of the area, not just the tent itself.