This was explained in another topic which was back when the japanese releases came out, the white forest being in the black version is some kind of glitch with the save transfer.SeraphicSage said:Experiencing a strange error:
I used my japanese white save on a black eur game, and my black version now features the White Forest. Is anyone else having that problem or has white forest been switched to Pokemon Black for the european release? Interestingly I can not find Rufflet (when looking at the pokedex) which is exclusive to pokemon white. I don't know what that means about what data is included in the save or what.