[Haskell-cafe] Pruned Sparks in Original Strategies

Dear List, I am trying to parallelize some number of codes with using Haskell's original and second generation strategies in order to be able to compare them. As far as I understood, in original strategies, ROOT garbage collection mechanism is used which does not allow any spark to be pruned. Since, they do not return any information back to its caller. (a type of void reference making fizzling of a spark impossible, is returned), However, in most of my measurements, spraks are being pruned. I wonder the reasons why this incident occurs? Do you have any idea? Many thanks, Burak.