Terrance:
FWIW I found this on a website:
Donâ€[emoji]8482[/emoji]t use any wood from conifer trees, such as PINE, FIR, SPRUCE, REDWOOD, CEDAR, CYPRESS, etc.
There are many trees and shrubs in this world that contain chemicals toxic to humans–toxins that can even survive the burning process. Remember, you are going to eat the meat that you grill and the smoke particles and chemicals from the wood and what may be on or in the wood
are going to get on and in the meat. Use only wood for grilling that you are sure of.
If you have some wood and do not know what it is, DO NOT USE IT FOR COOKING FOOD. Burn it in your fireplace but not your smoker.
ELM and EUCALYPTUS wood is unsuitable for smoking, as is the wood from SASSAFRAS, SYCAMORE and LIQUID AMBER trees.