I'm looking into decorative [Topiary](http://en.wikipedia.org/wiki/Topiary). In my studies I've come across a similar process called [Espalier](http://en.wikipedia.org/wiki/Espalier).

They're both shaped trees.

Here's my question: What is the difference between espalier and topiary? Is it plant species, shape or function? Obviously, I've wikied it and several difference are outlined:

* Topiary is rounder
* Espalier is flat
* Topiary is perenial with thick leaves or nestles
* Espalier is usually a fruit tree

What if I had a round (or even animal shaped) fruit tree. Would that be topiary or espalier?