Explain: "time held me green and dying / though i sang in my chains like the sea."

These are the final lines of Dylan Thomas's poem Fern Hill. The poem is a subtle reworking of the Romantic (especially) topos of childhood and a pure world of nature where divine communion is felt. Thomas evokes a quasi-Wordsworthian journey into the past through the device of memory. But it is a movement that takes one back to a point 'below time' where the adult poetic consciousness, while reflecting back upon the apparently pristine days of childhood, can only figure out the anticipatory signs of a disaster,then  tunfathomed.

What Thomas fundamentally wants to show as a critique and subversion of the Wordsworthian temporal backtracking is that there is always an interpenetration at work in memory and the process is never capable of a true return but only a reconstitution of the past in terms of the present consciousness.

This interpenetrational irony is apparent in these lines. The two lines combine what the poet as a little boy had felt in the soon to be destroyed Fern Hill (in course of German Blitz) and what the mature creative consciousness underscores as the then unacknowledged undercurrent of time and its flux. The process of maturation is also a process towards the inevitable; thus the paradoxical coupling of 'green' and 'dying'. Time kept gnawing from within, a process to which the little boy was hardly sensitive as he kept articulating his absolute freedom, another illusion for he was singing like the roaring sea (another symbol of the flux) but only in chains. These chains of time that constitute the sea of its own self embody mortality and it is this very site that ironically becomes the space for the paradoxical exercise of human freedom.