Anyone know what this is?

One possibility.....

It does resemble Red Buckeye:
https://www.flickr.com/photos/...
http://www.zugerzeitung.ch/sto...

Agreed, it immediately struck me as a buckeye.
Really interesting form, it looks like a flower.

Thanks everyone.
It ended up being identified as a Hickory, it also looks like the Buckeye, but the Buckeye doesn't grow up here in NE Wisconsin.
All the years I spent picking up hickory nuts in the wild, I never once ever looked at a hickory tree breaking dormancy before.
Ed

What type?
I'm only familiar with shag bark and shell bark, both are very green when they emerge...

*edit*
Just found a few pics that seem to confirm it is a shag bark, the pic shows extremely red bud scales, just like yours does, and it's a site based in Wisconsin...
Maybe genetic variety, maybe lots of sun.
Nice job!