I been thinking about this since the We Are Both episode. From the last season, we saw Regina's apple tree dying and it was because of the curse I agree to that but also think it means Regina doesn't have any of her magic left because she use it all. Now going into season 2, in the episode we see Regina using the book to regain her magic but also we see her apple trees come back to life in which help my theory more of Regina's apple trees are like being use to watch how much magic she have or something like that. I am still pondering on this still about Regina's apple trees and how it connected to her magic powers beside being the apples to put anyone to sleep. So there a connection there between Regina and her apple trees.