Thanks for your comments.
I added LOD and uploaded a new video showing it in action.
http://www.youtube.com/watch?v=CVD6lhFPcuM

These are 50 trees, running with about 80fps.
It´s possible to change the distances for the different LOD stages and the refreshrate (every 20 frames in this video which was slown down by fraps to 25fps).


PS: Happy birthday frazzle

Lite-C Tut. 1 Lite-C Tut. 2 Lite-C Tut. 3 (en)
Shader Tutorial (ger)

http://www.slindev.com