Answer:
A tree with 5 branches, no leaves and no fruits
In your fire you hear me scream, creaking and whining, yet I am dead before you lay me in your hearth.
Only two backbones and thousands of ribs.
I am nothing but holes tied to holes, yet am strong as iron.
This is in a realm of true and in a realm false, but you experience me as you turn and toss.
What is always coming but never arrives?