Just posted a tutorial on how to model a tree:
http://www.lemiere.com/html/tutorials/tree/tree.html
It takes a manual approach, and is based on the idea of fractal recursion. Instead of using a formula based plugin, branches are cloned and reconnected, resulting in a more characteristic tree.
The article is part of a project of 3d landscapes that I’m working on at the moment. Thought I would post my research online, and share some of my ideas.