Barn siding, like the side of a barn = exterior siding???
You can use "any" wallpaper you like, it doesn't matter. You just have to be sure to "prep." the surface correctly and thoroughly. In your circumstance the best way to prep. the wall would be to apply a layer of drywall to the wall using screws, tape and joint compound and then use a good sizing/primer. Done!
I think that any method short of this will end up with an irregular surface that would show right through any wallpaper or similar.