In "Bliss," what is the pear tree a symbol of, and how is it related to the main character, Bertha Young?

The pear tree represents transformation and change or the lack thereof. Bertha is on her way to transforming into a sexual being, but this change is arrested suddenly when she witnesses her spouse kissing another woman. She comes to the realization that she can no longer ignore problems and see her life as perfect. She rushes to the window and realizes that the pear tree is ‘‘as lovely as ever and as full of flower and as still.’’ This is symbolic of Bertha's inability to complete her transformation. She and the tree will remain exactly the same.