I'd never contadict Susan as far as cooking goes, but I've built a few fires in my day and I don't see any problem with burning pine in the bottom part of the wsm. The "gunk" that pine puts out will all go up in smoke. That's what you're smelling. Just make sure you clean out the ashes real good before you start a cook. Don't go crazy, just a good brushing out of the pit. Also, I wouldn't start a large fire using any kind of wood. A couple pieces at a time and you shouldn't do any damage to the pit. Also, keep the charcoal grate in it for air flow and so the heat doesn't build up right on the surface of the pit.