I read that poem again and again, and all I can say about it is that Dylan Thomas had a very unhealthy preoccupation with death. Abbadon is, according to Hutchinsons' on-line encyclopaedia:
In the Old Testament, a synonym for Sheol (Hades) and death. In the New Testament, in Revelation 9, it is the name of the angel (devil) of the bottomless pit, perhaps Hell personified.
There's a nice cheery thought for the day.
I, on the other hand, am fascinated by the landscape, and what grows on it and in it. Here are some notes taken on a journey to Brecon on the 6th January 2008. Discovered, with others, whilst searching for that elusive passport (I've given up now!) I may turn them into a bit of poetry some day. May . . .
Bare, sheep-freckled hillsides, the soft green of a mistletoe leaf, blasted by the winter winds. Paths, crooked fingers of sage green, poke through the dead bracken, stunted thorns snuggled into the hillslopes. Black thickets of thorn and sloe in the gulleys, holding fast to russet flocks of leaves, which fret and sidle at their feet, hand-fasted by winter. A golden beam of light illuminating a mountain manuscript of rocky crag and foothill. The moss-nibbled castle tump, home now to the shallow-rooted, silver barked beech.
Reading that, I know exactly which bit of the A40 we were driving along. The castle tumps are at Trecastle.