Why is Devon described so carefully in the beginning of Knowles book A Separate Peace?

Thomas Wolfe wrote a novel entitled You Can't Go
Home Again in which he writes of his main character that he learned through
hardship that you can't go home to someone who will ease your burden and save
you:

For he
had learned some of the things that every man must find out for himself, and he had
found out about them as one has to find out--through error and through trial, through
fantasy and illusion, through falsehood and his own foolishness, through being mistake
and wrong and an idiot and egotistical and aspiring and hopeful and believing and
confused....And, at the end of it [self-appraisal], he knew that....you can't go home
again....back home to a young man's dream of glory,...back home to someone who can help
you, save you, ease the
burden....

Gene Forrester
attempts to go "back home again" to Devon School in an effort to find the clue to his
actions of the summer of 1942, back to Devon School to relive those terrible moments and
gain some understanding of what he has done, to find that something that will "save
him."  Indeed, it is ironic that Gene walks through the portal of the First Academy
Building that reads "Here Boys Come to be Made Men" in an effort to acquire an
understanding of what happened to incite him to kill his best friend.  On his second
tour through the campus where he finds the infamous tree, Gene realizes that "it was
what you had in your heart that counted."  And, he knows that he can never go back again
even though he can reencounter the tree that has "loomed in [his] memory as a huge lone
spike dominating the riverbank." For,

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Nothing endures, not a tree, not love, not even a
death by violence.

Gene
encounters the "fearful sites" of the campus that he is now able to identify and deal
with as he perceives the selfishness of that summer so long ago as a somewhat detached
narrator who arrives at self-knowledge.