The poem catches a funeral procession in a few quiet images. It begins bluntly, with a corpse heading to the grave, then turns to the living and how they look as they walk. The speaker seems to watch from a slight distance, noticing the mourners' movement more than any single face.
That movement is the heart of it. The people go "up and down / like a tress or vine," as if they were swaying plants, or hair moving in a breeze. It makes the procession feel organic and soft, even a little helpless. Then the last lines shift to "the ash of hands / so weary so long." Judging by the imagery, the hands are worn out, maybe from grief, carrying, or simply from the length of the walk, and "ash" links them to burning and loss.
The mood is hushed, tired, and observant. The speaker doesn't announce sorrow; the poem lets the weight of it show through the small details of bodies on the move.