It's been a long time since I've been able to work on the core of Umbraco version 4 as it's been extremely busy here. I've been meaning to post this document up for some time but just never got around it. Some umbracians were asking about trees in version 4:

http://forum.umbraco.org/yaf_postst5259_Fun-with-Trees--New-patch-released.aspx

I've attached the file that describes the version 4 tree api. This was an initial document created for the Umbraco core team. It is probably close to 100% accurate but i know there's been some minor changes to the tree api since i wrote this.

Hope this helps some of you!

Umbraco_Trees_v1.doc (246.00 kb)