Nested array vs. tree

I'm currently writing on a paper about evaluation and comparison of Rich Internet Application technologies and am currently researching the effects of different data structures to store the data. I'm currently trying to compare nested arrays to trees and am having some doubts.

If we don't consider rectangular nested arrays but "jagged" nested arrays and compare them to trees, there basically is no difference, is there? Apart from the organization in memory of course, we could very well consider jagged nested array equal to trees and could implement a tree using nested arrays.

Have I missed something essential or should I consider them equal in my paper ?

A tree is an abstract data type. A nested array is a memory organization. So comparing them makes no sense, but implementing the former in terms of the latter does.

You should definitely not consider them equal.