Based on the thickness & pattern of the bark along with the pics of the splits I'm guessing Cottonwood. I split some wood just like what you have last spring (looked exactly like your pics) - not 100% sure it was Cottonwood but from my research Cottonwood seemed like the closest match to what I had. Anyway it was pretty wet & slightly heavy when cut but dried very fast & ended-up being extremly light........burned very fast too.
One other indcator.....when freshly split does it smell a bit like Horse or Cat urine?? If it does I'd say Cottonwood for sure.
One other indcator.....when freshly split does it smell a bit like Horse or Cat urine?? If it does I'd say Cottonwood for sure.