I've cut and burned Siberian Elm.
It's not a tree I would target for my firewood... but I wouldn't toss it in the brush pile with the Box Elder either. I see, or find it in fence-lines, along edges of woodlots and such. Standing-dead and bark-less it's difficult to distinguish from American Elm until you learn the subtle differences in structure... so I've probably burned more of it than I think I have. "White" elm get its own stacks in my world, I'm guessin' I've mixed Siberian with American many times without really knowing it. The stuff I know was Siberian Elm didn't burn as well, or have the same heat output as the stuff I know was American Elm... but it ain't all that far off.
Cutting "green" Siberian Elm is something I'd just-as-soon avoid... stuff stinks, gums up the saw, plugs the clutch cover, is way too wet and heavy (hard work) for the BTU's it provides later. Splitting "green" Siberian Elm is a lesson in frustration... between the stringiness and sliminess... No thank you, I'll pass. I don't think it smells different than American Elm when burning, just a stronger version of the same smell. We had a huge Siberian Elm in the front yard when I moved in this place (around 3 ft DBH) that died from DED within a couple years. I got tired of picking up all the branches and twigs and finally took it down after it had been standing-dead for two years. Damn thing was still green, even the upper branches, and I don't believe I've ever worked so hard for 3 cords of firewood in my life... and then all the bark released while it was in the stacks and left a huge mess to clean-up.
Anymore, if I have to cut "green" elm of any sort to make a fall zone, I'll buck it to length and stack or pile the rounds in the woodlot... and leave 'em there for a year. When I go back the next year to split, the bark will fall off in sheets (still have the slime though) so I leave the mess in the woodlot... and I stack the stuff downwind from the house. White elm should be cut when standing-dead and bark-less... easy work, clean work, and (mostly) ready to burn... otherwise it's hardly worth the frustration.