Should you use firewood??

[ecto1]

Sure looks like oak to me. 

 

[cliffcarter]

Oak, except for the one piece with the distinctly different bark. If you can post a pic or two of that one by itself maybe someone will recognize it.

The bark on your splits indicates that the wood came from a younger tree or a branch of an older one. Maple wood has brown heartwood, I don't see that on your splits.

 

[smokeamotive]

Looks like red oak to me, except the one piece- looks like what we call shagbark hickory around here. which is all good for smoking. Too yellow for birch and not red enough to be cedar. But if in doubt throw out the one piece, not worth worrying about.

 

[venture]

In my area folks burn a lot of pine and cedar which you don't want to smoke with.  I would use only wood that I could clearly identify.

A guide from the Wiki:

http://www.smokingmeatforums.com/wiki/guide-for-woods-used-to-smoke-food

Good luck and good smoking.