There are folks that use green hickory, pecan and even mesquite, you have to have a very hot fire, and a large cooker helps. The trick is to build a clean hot fire with seasoned wood or charcoal, them add just enough green wood to ignite and burn.
"perhaps...but then again...maybe not..."
careful there son, those ribs are boiling hot...
(='.'=) Here there be bunnies...
Pacific Rim BBQ
Bob's Brew and Que