Never used crab apple before, but I bet its a nice mild smoke like real apple is.
I have a crab apple that will be cut down next year. It's only about 3" in diameter now and I have plenty of wood on hand. I'll let you know how it is as soon as possible. When you use what you have let us know how it smokes.
I just did a search for Crab Apple Wood. All sources point to a go. Basically any hard wood tree that bears fruit or nuts will make a good smoking wood.
That's not entirely true......although black walnut is a nut-bearing tree......it contains too much oil to be a good smoking wood....it can be used as a "fuel" wood if it is dried and cured, but I wouldn't recommend it for a "flavor" wood while you are smoking meats.
Actually Eric, its not bad for smoking.
Sorta between Mesquite and Hickory.
Oiley yes, but most wood is until seasoned.
Reason you don't see it much is because us woodworkers hog it all up for projects!