User blog comment:TheLastLastDragonlord/Sacrifice?/@comment-4650675-20120602165644

Yes, but in medieval times theydid not know that plants and trees are life forms, so we cannot say for sure!

In addition, since for a life to be returned, a life has to be taken, maybe the life must be of equal value. Plants or animals probably were not equal to humans, so that would not work. It's only a guess though.

Nice post!