T,I have to disagree with you about regen not happening in open canopies.I know quite a few areas in 2G that have excellant white oak growth in various stages which gets plenty of light.Nearby under the closed canopy there's hardly any new growth.
Tell you what,this area I'm talking about is alittle over a mile walk but I'll make it a point this summer to take pics and post on here.You'll see some great regen of white oaks in an opening of about 200 square yards.