Clearing Stage

Okay folks, quick question:

I’m relatively new to flash so Im cramming as many tutorials as possible. You all have been very helpful with your insight and wisdom thus far. I was reading the Chaos Tree tutorial by ilyas usal ( http://www.kirupa.com/developer/actionscript/chaos_fractal.htm ) and playing around with it. My problem is not directly with the content of the tutorial, but something I stumbled upon while playing with it. As you can see from the attatched files, I am trying to randomize the fractal tree, and include a button to ‘reperform’ the same action. My problem is I cant get the previously created tree to disapear, the fractals are just continued further as the tree gets more and more dense. Is there a ‘clear stage’ command I can use or maybe an alternate route I can take to completely clear the previously created fractal?