Well I'm gonna "stir the pot" up again as this isn't sitting well with me; I just was right next door staring at my neighbor's Tulip Poplar and yes I KNOW that's what it is; then I stared at the bark on the rounds of Hickory I have in next years pile and again I know that's what it is and I can't believe that what is pictured is not Hickory...the bark on the Tulip next door has more deeper ridges in it, no size or part of that tree has the tight bark on it like the OP pictured, but the Hickory has supertight bark with those lines on it. And looking at the way that the grain has those little "strands" that you can grab and peel off are just like Hickory I've had in the past. Sorry guys and you may still prove me wrong but I still say that is Hickory.
Original poster, again what does it smell like? Hickory has a faint almost manure-like smell. Better yet take a piece of it to someone local who knows firewood and ask them what it is. And I STILL see some variances from picture-to-picture; are you sure that this is all from the same tree?
I wish I could get my hands on it and feel it and smell it as I'd know instantly what it is....