Then a few years later my wife, Hannah, was executed under a tree. I can’t say what kind of tree that one was, I wasn’t there, I was just told about it, and I forgot to ask about the tree.
-- Narrator (chapter 1)

Importance: This quote reveals one of, and the most important, reason why the narrator is so concerned about trees. Despite him telling a story about surviving the Holocaust, the reader hears little about his perspective. This is one of the few facts the reader learns about his experience. The reader also knows that he is unmarried, likely because he has been unable to get over this tragic loss. It is reasonable to assume this is a large reason why he needs to tell the story, so that he can grief his wife’s passing and try to continue on with his life.

A mouse is what one ought to...
-- Narrator (chapter 1)