This seems to be a vision of "death's other kingdom," glimpsed from afar and brokenly. The details seem to originate in PURGATORIO xxviii-xxix, in the description of the Earthly Paradise: the birds and the breeze are singing in the trees, there is the sound of chanting and a light glows under the boughs. The star, (see line 28) here a "fading star," is used by Dante as an image of God or of Mary.