Then you are not presenting an argument. You don't know what all of Skyrim looks like anyway, or have an intricate knowledge of how, where and when what plants may grow on Nirn.
I have, however, been following what Todd says about Skyrim. So far, everything points towards a scandinavian environment instead of a canadian envorinment. Canada is more like the home of wood elves now that i think about it.
Besides, the warm and cold areas in Skyrim are not from being north or south, but how far up they are. That is why it would be plausible for the screenshot big trees you showed to exist in low-land places. Ofcourse it is nirn, do put pink flying elephants there, how do we know they are not there.