Possible Clues:

• Clearance of trees
• Core of students warning: stop environmental change
• Author filing first of reports on rank destruction of natural resources
• A root infested badly? It leads to many a tree being destroyed
• Change of trees into a wasteland, ultimately?
• Asteroid often crashed clearing a lot of trees
• To find a tree - so tricky when there's this?
• "Hazel" star Don once worked as a broadcaster in a clearing of trees.