actually pakled, the tutorials I've run into all start not by making tree but by experimenting with the app by makinf abstract shapes and there is a ton you can in fact do. Didn't have the demo long enough to get into that before it timed out as I found the tute the day before it did, but XFROG does indeed do cool abstracts.
@ spidergod....I'd recommend dl ing the demo and trying some out...it's good for a month I think. Can't remember or find the .pdf  but I know it's out there.. ...

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again