5 inch leaves sound about right. They are definitely not 8". I can pull a few down or collect a few off the ground next time I'm up there in two weeks.How big are the leaves... like 6-8 inches long?? Are they real rough on top... like 60 grit sandpaper?? That would be Red Elm.
However, that bark looks like Rock Elm, and so does the leaves... leaves would be 5 inches or less, and smooth, even shiny smooth.
If it's Rock Elm you've got some of the best firewood ever created by God.
Note... Siberian Elm leaves are small... like 2½ inches or less.
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Would growing in/near wet areas be an indicator of rock elm as well?