Analysis of Changed. (Birds Of Passage. Flight The Third)

From the outskirts of the town
Where of old the mile-stone stood,
Now a stranger, looking down
I behold the shadowy crown
Of the dark and haunted wood.

Is it changed, or am I changed?
Ah! the oaks are fresh and green,
But the friends with whom I ranged
Through their thickets are estranged
By the years that intervene.

Bright as ever flows the sea,
Bright as ever shines the sun,
But alas! they seem to me
Not the sun that used to be,
Not the tides that used to run.