We burn elm here too. It’s usually a good burner. Oak we can load in the stove and it lasts for hours throwing off good heat.
The Elm around here will throw heat all night, get up in the morning there's still chunks in the stove putting off heat, stir it around, throw more in, it takes right back off. I almost never have to restart fires from scratch. I don't have a fancy stove either, just a old 70's earth stove, but it's pretty big (24x22x24 inside) so it takes a nice load, I fill it before bed.
I like siberian and chinese elm (they might be the same?) around here it grows straighter, not as many forks / branches until at the top, and the bark slides right off as you're cutting it. It only gets to about 18-22" My BIL calls it slippery bark Elm, since the bark slides off so easy.
The american elm around here, forks out a ton, it gets a lot bigger, I've seen some as big as 48-50" at the trunk. It holds it's bark forever. I've had some split & stacked two plus years later still holding it's bark on. I've noticed the american doesn't thrown heat like the other two flavors of Elm.
Last thought, the american seems to be more in peoples yards or near houses. Siberian and chinese are in wind rows or fence rows, exposed to the winds of the high plains. When I only split with a maul, some of the smaller flavors of Elm were like hitting rocks. I've had some siberian stall my 28-ton hydro splitter it's so hard and desne.
