Acer pennsylvanicum

If this is growing wild there it is a special find that should be protected and encouraged.

Looks like Moosewood...nice, but not rare around here.

Hi,
Acer pennsylvanicum or Moosewood looks right to me. Thanks to all those that gave feedback. I sometimes run into a small patch of these and then wont see anymore for a while. I am in the Appalachians and although I wouldn't call them rare I wouldn't say they are all that common either.

Quite common in certain mountainous areas. Particularly like N or NW-facing slopes where the soil is cooler. Easy to transplant.

It is an understory tree, isn't it? What trees does it prefer to live beneath? And how much shadow can it handle?

It handles alot of shade -- even full shade. In fact, doesn't do so well in complete full sun (gets burned). It's sparse & small compared to most trees, so a single, isolated specimen won't make much impression.