Possible Clues:

• Being so weak, the South appears to have been deforested
• No bones back there - and no conifers, either, in the end
• No trees like this at last for the invertebrates
• No backbone and no conifers at last
• Old Bob sleeps in? Terribly weak!
• Yielding
• 5 like crabs, worms and insects, say?
• Lily-livered
• Yellow, like tattered old book
• Lacking strength of character, unlike the porcupine