I first thought elm from the bark alone but when I saw the end grains I thought mulberry. Give it a fresh cut or split. If it's bright yellow, it's mulberry for sure.
Dark color on the end looks like Mulberry to me. Bark is a perfect match, too. Like others have said....get into fresh wood and it will be a yellow color.
Siberian elm, worst crap i have ever burned. i see the tell tale ,dead rotten limb wood laying there. it burns like rotten wood and leaves a ton of ash behind. I cut a huge live one down and split it up, have burned about half. I told the neighbor he can use the rest in his firepit.