Answer:
I am the kind of a tree that is carried in your hand. What am I?
What goes up and down but does not move?
Forward I am heavy backward I am not. What am I?
I have a little pool with two layers of wall around it. One white and soft and the other dark and hard. What am I?
There's not a kingdom on the earth I haven't traveled over and over and though I know not whence my birth yet when I come you know my roar. I through the town do take my flight and through the fields and meadows green and whether it be day or night I neither am nor can be seen.
No matter how little or how much you use me, you change me every month.