Role and examples of irony and symbols in Miller's All My Sons?

Irony AND symbolism in how the Apple tree falls down. Keller says, "he'd been 27 this month. And his tree blows down." Ironic how it means so little to Keller. He reads the newspaper while saying, "Isn't it awful? The wind must've got it last night. You heard the wind, didn't you?" The falling symbolises that Larry is indeed missing or dead.