Possible Clues:

• There's nothing brave in having the South deforested like this
• Being invertebrate, cut off the top to have it deforested
• Lacking (moral) courage
• Invertebrate
• Weak; invertebrate
• Not like Mrs Tiggy-Winkle to be so lily-livered!
• This invertebrate might end without a tree
• Can the South be lacking trees as well as bones?
• Lacking backbone, the South seems to have become quite deforested
• Vacillating invertebrate