good lining for cheese cave?

[Jen]

Greetings, fellow cheesy comestibles makers,

I'm in the process of making a small ice box/cheese cave.  It's going to be a wood frame, with cement/perlite walls for insulation.  I want to cover the walls with something.  My choices are fir, pine or plastic. I could also just leave the cement/perlite exposed too, which would have a humidifying effect, but I'm not sure how controllable it would be. The shelves can either be stainless steel wire racks or fir slats. I don't know if fir is a good idea or not. Any thoughts?