I think taht when people think of open ends on teh tree they automatically think that the tree needs to have a huge opening hole on the bottom to stop from drag, or restriction. But if the slits have been cut correctly, the surface area of the cuts should surpass the surface area of hte upstem. So iin conclusion open ends do not flow any more than close ends if the cuts are done right. It is all in your head. The whole what weighs more a pound of brick or a pound of feathers. everyone is oging to look at open ends and assume that they flow more, but looks are decieving.