Is this cottonwood?

No,looks like tree of heaven. AKA. Ailanthus Altissma,
not very good fire wood.
Not sure but it might be better than Cottonwood/Poplar/Aspen.

I have been around cottonwood my whole life. The bark is very thick and deeply ridged. I have never cut it for firewood.

Yep, Tree of Heaven. Usually light as a feather. Wood think it burns super fast. Kevin

I really don't mind cottonwood. I got a couple face cords of it last season from my Uncle who had it seasoned for probably about 5 years. Big splits, pretty light weight yet kept a decent fire going for a while without throwing crazy heat. Use it during shoulder seasons and it should work fine.

Saturday I cut up some small fallen stuff at a local business that I had seen awhile ago, and in quick passing by I thought some was Poplar and figured it would be okay for kindling and small splits, but when I was cutting it I knew right away it wasn't Poplar, I thought maybe some sort of Sumac but when I was unloading it from the truck at home I knew it was Ailanthus and split a round just to make sure, and sure enough it looked like the big piles of it where I work, no one wants it! I kept the split round and will use it next year but the rest went up to the compost site and I'm sure someone probably took it, but I left there with some Black Locust and a bit of Cherry so as my neighbor said "you traded up" lol!