When reeds are dead and a straw to thatch the marshes,
 And feathered pampas-grass rides into the wind
 Like aged warriors westward, tragic, thinned
 Of half their tribe, and over the flattened rushes,
 Stripped of its secret, open, stark and bleak,
 Blackens afar the half-forgotten creek,—
 Then leans on me the weight of the year, and crushes
 My heart. I know that Beauty must ail and die,
 And will be born again,—but ah, to see
 Beauty stiffened, staring up at the sky!
 Oh, Autumn! Autumn!—What is the Spring to me?
 What is the central idea of this poem?
 I’m quite confuse .. any help?