Caddy smells like trees.

Benjy remarks several times throughout his section that Caddy smells like trees or leaves. Caddy is Benjy’s only mother figure and source of affection when he is young, and she provides the cornerstone of comfort and order in Benjy’s mind. Benjy has relied heavily on his sister, and her absence plunges him into chaos. In his earliest memories of Caddy, Benjy pleasantly associates her youthful innocence with the smell of the trees in which they used to play.

When Caddy becomes sexually active, Benjy notices the change she has undergone. The troubling realization corrupts his sense of order. Caddy knows Benjy is upset and begins to avoid him. Benjy laments this new distance between himself and his sister by saying that Caddy suddenly does not smell like trees. Trees are a pleasant memory associated with the affection and repose that Caddy has brought to Benjy’s life, and when that order disappears, Benjy ceases to associate Caddy with that memory.