A quick google search found posts on BBQ-Brethren and Smoking Meat Forums and other forums that all say dogwood is ok to smoke with. Best check with a local Ag extension office to be sure your species of trees are ok though.
My test is to chip off the smallest piece possible (or use your name brand reciprocating saw ) and light it. If the smoke smells good to me, I'll maybe give it a shot. Try this and form your own opinion.
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