Marine5068,
In Ontario we only have two varieties of elm, American and Rock.
Both are great firewood and both hate cool fires, they tend to smolder in a cool fire.
I find here in Ontario it's about 2 American for every 1 rock elm so lots of American around these parts.
Well lots of dead and dying both all around.
White ash on most charts comes in at around 23.5 and American elm is all over the place for btu but IMO American I would say was about 24.5 burnt on a hot fire.
Lots of dead and dying white ash here also
Rock elm got to love living in an area that Rock elm is pretty easy to get and the reward for getting it is very toasty feet on a very cold night
Osage Orange actually is just slightly higher btu than Rock, I've burnt both and they are very different fires.
Rock burns longer and wants lots of air and Osage burns just a bit hotter but faster and likes normal air.
I bet I'm one of the very few that have burnt both since one grows in the south and one in the north.
I would be more than ok with more Osage deliveries LOL
Nothing compares to buckthorn in NA though for btu at 35 or same as coal and mahogany, more of a shrub than a tree and covered in thorns it's a workout just to get a face cord of it.
It's a serious weed here in Ontario and looks very similar to black cherry trees but smaller with lots of thorns and no black cherries.