Stories about Fluttershy yearning to be a tree, or really, truly being a tree, or maybe somewhere in between.

(But she has to be wanting to be a tree, or being a tree, or something very tree-related. "It's about Fluttershy" isn't quite enough in itself. Sorry!)

Also, if a story only barely mentions Fluttershy wanting to be a tree, the story might better belong in "Borderline, or Trivially Tree."