After Dridon's recent post on trees, I thought I's post a link to a tutorial I wrote and put up at pbwiki back when I didn't know where to post stuff
Making Trees using POVRay, POVTree, and Photoshop (or GIMP)
It explains how to use free tools (well I did use photoshop at the time, but it could just have easily been GIMP) to make your own top-down view, detailed trees.
-Rob A>