Hi Heat Stroke,
The background on the image isn't meant to be wood (Although now that Ii think about it, it does have a slight resemblance if you're not keen in the field of German Paratrooper uniforms).
It's meant to be a camouflaged paratrooper smock. Here's the piece I made for a back background (resized)
Considering most of it would be hidden, I didn't bother detailing it too much.
Here's one of the links I used as a reference for the smock:
http://www.germanmilitaria.com/Luftwaff ... 28161.html