Just saw the Seasons and Supernatural chat and yes you can have all Seasons or just the ones you want. You can set it to each Save of any world. I super look forward to playing this world in the all Winter setting as each Season has a festival to go with it, and a Holiday - the winter one has gift parties and I just see this world as perfect for it. So i am keeping my copy for sure. But yeah, I get what you are saying about the trees and such and I have no clue how the game snow will affect your trees and such. I do know plants outside look frozen and sort of like the ones in this world look. I'd say wait and see. I will definitely test it out for you with my copy if you like -(the good Lord willing as Seasons does come out after my tests and health scrutinizing thing - but I will try and promise to test it for you) but I see this world as perfect for an all snow/Winter world. Ice Station will work great too.
Especially during blizzard conditions - should look cool for sure.