Northern Light
Superstar
This is an interesting point. I've definitely absolved myself after buying/planting trees that aren't found in Ontario currently, but are found a climate zone or two south. With the exact reasoning you've given (eventually through natural or anthropogenic warming those trees will be found here). As long as the species are from this continent, I think it's okay.
Interesting you should use that criteria (from the same continent) so let's start there shall we?
Oriental Sweet Gum - native to Asia (China, Thailand, various others)
Willow-leafed Magnolia - native to Japan
Turkish Hazel - native to Turkey
Paulownia Tormentosa - Native to China (considered invasive in North America)
Magnolia (Saucer) - Hybrid created in France, both originating varietals are native to China
Plane - they didn't specify the species, but knowing landscape architects they're thinking London Plane - (see Bloor St., originally) (hybrid of American and S/E European/Asian species)
So...not so many native to North America, at least one invasive, and I'd be tempted to put Turkish Hazel in that category too, I've found it reproducing the ravines.
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True native (to Toronto-area)
Sugar Maple
American Elm
Red Oak
The south-of-here, (near native)
Could be argued for Pin Oak which is present in the Windsor area....
Tulip Tree......very borderline, but again exists from Windsor south
Pitch Pine.......very rare, maybe a few on the shores of the St. Lawrence, but really much more of a Appalachian and Coastal species in the US mostly well south of here.
I know why they want that one.....its A) very maleable (makes good Bonsai type tree) .... B) also puts up w/miserable conditions.