Boulder, Colorado. I'm quite sure it's not native. Anyways, as luck would have it, I was able to get a rather grainy snap shot of the exact tree that I got the acorn from off of bing maps street view. The tree happened to be right next to the road. Here this might help: Here is a link that might be useful:

Northern Ontario is not tundra, well maybe much further north. Here we have trees and flowers and vegatable gardens. Our summer is a couple of weeks later then the southern part of Ontario but we get a decent summer.

I am gonna have to agree with Georgeinbandonoregon, It looks like my Red (Q. Rubra) or Q. Velutina (black oak). If your leaves are still as the picture shows, (GREEN and intact) if there is some small amount of fuzz under the leaves. just enough to feel when you rub the underleaf. It may be Q. Velutina. The Velutina (black oak) usually has crappy fall color compared to Red oak (Q. Rubra). But to tell you the truth, a tree I had long since ID'ed as Velutina has shown some reddish hues this fall. But, really we have only recently had a frost worth mentioning, last night actually. Trees that usually color intensly have been a big yawn, so far anyway. The Velutina is said to have some orange in the trunk color, but yours has "baby bark" and I'm assuming is not mature enough to help with the ID, unless someone knows something i don't.

Looks like swamp white oak, Q bicolor. It might be a grove of them from your last pic. You might mention, or better, update your personal info to include your location....