Answer:
Its days are numbered.
What has roots that nobody sees, and is taller than trees. Up, up it goes, and yet it never grows.
What has a head and a tail but no body?
Sometimes it's silver but also gold. Printed on paper it's a treasure to hold. What is it?
Tickle with your fingers and a song it will sing. Be careful, though, you may break a string. What is it?
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.