Experimenting with covers

The accompanying illustration is of a proposed cover for the CreateSpace paperback of Hang Fire, the fourth volume in the six-book Steve Martinez series.

I've pretty much settled on the text and illustration (of a Kentucky flintlock rifle), but I'm not so sure about the background. It does the job of setting off text and illustration, but will people recognize it as the bark of a pine tree?

I think I'll try another background, perhaps a thick copse of white birch saplings, and see how that goes.