Cassia lives in Mapletree Borough, a neighborhood lined with maple trees… That is, until the day she wakes up to the screaming sound of chainsaws cutting them all down. Why? Here's Cassia's assessment:
The maple trees have become too much of a problem. The leaves get too messy in the fall. They're not growing uniformly […] And some of them have diseases, so they all need to be chopped down. (23.14)
The maple trees represent disorder, something Society can't control—and any lack of uniformity or divergence from the norm is a threat to the system and must be crushed. Society's decision to chop them down—to violently tame them, if you will—clues us into just how attached this governing system is to obedience and containment, which doesn't bode well for Cassia and her family.