Answer:
A nut cracker up in a tree.
This is needed both for courage and hardcover books.
Walk on the living, they donโt even mumble, Walk on the dead, they mutter and grumble. What are they?
The root tops the trunk on this backward thing, that grows in the winter and dies in the spring.
Although I'm not an insect, some people found me very difficult to exterminate. They called me something like 'insane priest.' The first half of my name means the same as 'scrape,' & my last three letters are a metal. Who am I?
Brings the sky a lot closer.