How does the voice of the poem suggest the passing of time in "The Flower-fed Buffaloes" by Vachel Lindsay?FLOWER FED BUFFALOES by Vachel Lindsay...

This is one of my favorite poems. There is certainly a
melancholy mood established as the writer reminisces about the decline and virtual
disappearance of the buffalo. Lindsay uses the word "spring" to signify the buffalo in
their prime, ranging far and wide freely without restraint. Those times were "sweet" for
the buffalo before the arrival of the white man, who transformed the wide, open ranges
to wheat fields; and the appearance of the railroad, whose workers feasted on buffalo
meat as the tracks extended westward. Lindsay also repeats the words "long ago" several
times, suggesting both a passage of time and a wishful remembrance of better days.
"Lying low" suggests the interment of both the buffalo and the Pawnee, both residing in
graves on the land they once shared.