There are a long list of woods that give fabulous smoke flavor to BBQ and smoked meats, most notably hickory, oak, mesquite, apple, and pecan. But while they all may resemble each other (after all, they are all just hunks of wood), there are several wood types to avoid in BBQ and smoking. The resulting smoke from these woods may contain harmful tars or toxins that can penetrate the meat.
Use hardwood, not softwood. Just because it is wood doesn’t mean you can use it. Of the types below, some types may be toxic while others may impart a bad flavor to the meat.
Conifers and Oleander
Pine, cedar, fir, hemlock, cypress, and spruce are several to look out for and avoid. Avoid anything in the conifer family. You may have a whole pine stand in your back forty, but don’t use the wood for cooking. Same goes for the trimmed pieces of oleander that line your property. Cedar planks are different: they are used as a cooking vessel, not as a direct heat source or smoking wood.
Unknown Wood Scraps
If you didn’t cut it, then know your wood source. Avoid random wood piles or wood you are unsure about, or wood piles you aren’t positive what tree it came from (you can’t identify it).
Chemically Treated Wood
If you don’t know positively that the chemicals used are NOT poisonous or toxic, don’t use it. At all. Even if you think the chemicals are safe, the smoke produced will impart a negative, unpalatable flavor to the food.
Painted or Stained Wood
Same reasons as chemically treated wood. And some paints from older lumber may be lead-based.
Green wood is wood that isn’t seasoned or dried properly (or enough), or that is freshly cut. The smoke will taste different, and the wood contains more sap not found in seasoned wood of the same tree, which gives off more creosote.