According to BBQ Brothers in "7 Types of Wood for Smoking Meat," the wood from the Pecan tree is great for long barbecues, as it burns slowly, and gives meats a delicate flavor. Also a wonderful smoking wood -
Wisconsin Firewood explains: If you were to compare it to other types of firewood, the flavor profile of meat that has been smoked with pecan is only slightly stronger than if you had used wood from an apple or oak tree.
In addition, there’s very little chance that someone with a particular allergy to a crop would also have an allergic reaction to meat that was smoked with wood from the tree that produces their particular allergen.
The only smoking wood that could overpower any other flavors or smells present in your meat would be mesquite, a wood so potent that it’s in its own classification.