and never seen in flashback.

Kate refuses to accept or acknowledge that Larry has died. Despite all evidence to the contrary, she holds on to the unrealistic view that Larry is missing in action and will return to his family one day. The other characters know how unlikely this is and perhaps Kate knows, as well, deep down but if she openly acknowledges that Larry is gone, it will be almost as if she is being disrespectful to his memory.

When Larry's tree in the Keller's yard falls, it is almost as if fate takes the decision out of Kate's hands whether or not to accept that he is not going to return. The fallen tree is a symbol. It represents the fallen man who was a soldier, brother and, most importantly to the play, a son.

When Frank asks Joe what happened to the tree, both men immediately think of Kate and what her reaction will be. Yet, the tree—and what it symbolizes in terms of the memory of Larry—also is a catalyst that contributes to the growing guilt Joe will feel about his actions during the war.

Arthur Miller’s play All My Sons is about the willful blindness and deceptions that destroy a family. Joe Keller is a successful businessman whose World War II-era contracts with the War Department enriched him while also contributing to the deaths of American servicemen, including, it is revealed, his own son Larry. Larry was a casualty of war, but not in the sense of having been killed in combat. Rather, he killed himself rather than live with the lies surrounding his family resulting from Joe’s provision of faulty engine parts and Joe’s partner’s conviction and imprisonment. Contributing to the complexity of the Keller household is Larry’s brother Chris Keller’s relationship with Ann, Larry’s girlfriend before the war. In memory of Larry, the details of whose death are shaded by the clouds hanging over Joe’s head, the Keller family had planted an apple tree. When Miller’s play begins, the tree has been destroyed by a storm.

The significance of the apple tree lies in its representation of Larry, and its destruction is symbolic of the destruction of the myth surrounding him and of the cloak of deception that Joe had constructed around himself and his family. Throughout the play, Miller’s narrative repeatedly returns to the broken tree sitting in the Keller's yard. Its significance is suggested by the following exchange between Chris and Ann’s brother George:

George: The trees got thick, didn't they? (points to stump) What's that?

Chris: Blew down last night. We had it there for Larry. You know.

George: Why, afraid you'll forget him?

Chris: (starts for George) What kind of remark is that?

George and Ann, of course, are the children of Joe’s former business partner, who rots away in prison while Joe continues to prosper. Joe’s façade and his framing of his now-imprisoned partner Steve for the deaths of the pilots caused by the faulty engine parts is beginning to crumble under the weight of his guilt. Later in the play, Joe’s wife Kate, who is cognizant of her husband’s misdeeds and who remains forever hopeful of Larry’s eventual return, provides a telling indication of the significance of the tree’s destruction for the family’s future:

Mother: (at last confessing the tension) Why should he argue? (she goes to him. With desperation and compassion, stroking his hair) Georgie and us have no argument. How could we have an argument, Georgie? We all got hit by the same lightning, how can you . . . ? Did you see what happened to Larry's tree, Georgie? (She has taken his arm, and unwillingly he moves across the stage with her.) Imagine? While I was dreaming of him in the middle of the night, the wind came along and . . .

The destruction of the tree by strong winds concurrent with Kate’s dream about her lost son symbolizes not only the beginning of the end of Joe’s deceptions, but the realization as well that Larry will not return home.

Larry's tree falling is directly related to the confirmation of his death.  The tree falls in the month of his birth, August.  It falls when Ann, Larry's fiance, is sleeping in his room, having come for a visit to the Kellers' home.

Additionally, the fallen tree sits in the middle of the backyard, as a symbol of the presence of Larry in the middle of this play.  Larry is present in the action in the presence of this tree.  The characters, Joe, Kate, Chris and the neighbors have no choice but to talk about Larry. 

So the tree acts as a catalyst for a deeper, more meaningful discussion of Larry and his fate.  It precipitates Frank getting the horoscope for Larry in order to confirm if Larry is dead.  So it is intrinsically related to the revelation that Joe Keller sent faulty parts to the military and is responsible for many deaths.  The sad reality of Larry's suicide is linked to the falling of the tree.