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Is it the same thing that's been sprouting up in my back yard?

Probably not, but anyway illustrates some taxonomical features.
-- The base of each leaf is pretty symmetrical - so I reckon it isn't any kind of elm, which I think have a fairly reliable tendency for the base of the leaf to run a little lower on its stem on one side than the other.
-- Where the leaf stem (or petiole) attaches to the main stem, there's often some kind of leafy structure (stipule), here narrow curly things. That's a good clue, and here it seems to match up with Corylus avellana, common hazel.


Dang squirrels.

Or it could be Ostrya virginiana, hop hornbeam.

University of Connecticut wrote: naturally occurs as an understory tree in dry woodlands

No stipules, if I am not mistaken.

Circular clump? Hazels I'm familiar with were trees also, but Cal Poly shows this form for Corylus americana

Wait, you have buffalo now?