Steve Dixon, from the rounds it kinda looks like Poplar or some sort but as said free is free & no danger of cutting down the tree and it falling on you.
My first glance is sweetgum maybe a few other small rounds from something else. Run a few splits through the splitter to give us an idea how the grain is.
Not only that if it’s falling off the round you can toss it on the ground and drive over it a bit. Breaks up in little chunks just like the stuff you buy in the bag LOL