I think a stenciled design would work well here.

I don't want to hurt your feelings but, lose the desk and put a console table there, something smaller. The desk is not very attractive; it looks like it was salvaged from a fire. Sorry.

Casey, you do realize her wall is slanted and she had it custom made to fit, right?

c3110, do you use this as a desk? If not you could put some nice photos in frames on it in varying sizes. Or a computer screen if you do use the desk. I think something upright, but not too tall, may distract from the slant on the wall and desk. Or set it up as a bar with a nice tray, bottles and glassware on top. You could even lean a framed picture up against the wall. Just a few thoughts.

It is made from recycled barn wood and I do use it as a desk. It fits in with the rustic look of the tile floors. I have a console table on the other side of the room that I use as a wine rack so I wanted something different on this side.

I like it. Great rustic look and great use of space too.

You could add a bit of whimsy
1st pic painted birds on wallpaper
2nd pic repeat pattern of owls :-)
or something similar

Just wanted to add in regard to branches. You might look into using light branches that you could affix to the wall in a design you like as well. Some ideas re that:

http://www.brit.co/branch-decor/

Have you considered just wallpaper? It's been suggested above, So many options out there!