What is a tree?

I'm hoping someone here can put me out of my misery; I've been desperately trying to find a poem that I only have a vague memory of. I've checked all my books, and tried Google, but to no avail.

All I remember is the final line;

"What is a tree?" he said.

I think the poem was set in the (not so distant) future, and was about going to a zoo, and talking to a child and telling them about all the animals that had become extinct in the wild. I think the last verse was something about an animal that lived in trees, and it ended with the line above - the child asking 'what is a tree?'

Thanks in advance,

- Pixi

Oh! I have read this poem!! I loved it, my mom introduced me to it. Just one problem, she never told me the title! If I could help, I would, but sadly I cannot.

Could this be it? I came across it in a forum but do not know the author.

What is a tree? a planted seed?

An old soul growing all around me.

A hope, a plea

But what does it mean?

To live, to breathe

To cry, to grieve

Comfort & shelter, amongst the leaf