I'll second what Bubba said...........although my wife is from Michigan so I might be tainted. LOL
When you are getting around to using the wood, put the pieces you are planning to use on top of the firebox as you are cooking, before you throw them in the box, give them a whack on the ground or something and quite often the bark will fall right off.
From what I've read on another forum (I'm not cheating on you....just looking....I never touched!) the only time bark is really an issue is when the trees have been sprayed with pestasides; common with fruit wood. If you're sure they haven't, or the know the wood to be well seasoned, I'd leave it on. As far as flavor goes, I've tried it with and without and can't tell a difference. I'm sure the EPA would have a more strict line than mine.
I've long thought that bark added a bitter taste...particularly w mesquite...but it has recently dawned on me that bark falls off dry wood. I now wonder if it is the fact that the wood is not adequately dried, not the bark that causes bitterness.