Jan - it freaked me out the first time I cut away all that lower branching. But it makes sense that each plant has a finite amount of energy reserves. There have been times when I've cut away what I thought was the entire node, only to find two weeks later that it was busy repairing the partial damage I created and growing new pistils. I think our plants maintain an inventory or awareness of their active growth sites...they certainly seem to. They can marshal resources at will, so it makes sense to me to strip everything below the very bottom of the canopy to focus what's left of its remaining energy on the sites that are bathed in light.