@CrimsonDev I'm thinking because she is a forest spirit, she can't leave without reprecussions. Unlike the other three, which have vast areas of influence, she likely got the most gutted when the Land of the Dead was formed.
Edit: yup, went back to see if they noted anything about the size, and yeah... Land of the dead takes up 2/3 of the continent they are on, so her sphere of influence got gutted.