What does yellow leaf that Jacob sees suspended in air represent in the novel, When the English Fall?

The yellow leaf that Jacob sees suspended in air represents hope. When he sees it he rationalizes that it is probably floating because it is attached to a piece of a spider's web that he cannot see, but he discards this explanation and instead decides to believe that it is magic instead. When Sadie comes outside he shows her the leaf, because he knows she will appreciate it. It is Sadie who labels the leaf, "hope" (95). It looks like it must fall, and yet it does not, which is the perfect symbol of hope for a peaceful people caught in a violent world.