Brad,
I am not really worried to much about disease for my plants. I think you are right about them probably being OK that close together. I would like to transplant some to put them in a woods that would speed up their growth. Those pics show plants from seed I planted in the fall of 2009. So they range from 3 leaf to 3 prong but all so small due to either the soil or the canopy or both. The pic of the larger area above is just a snap shot of the hillside of one of my larger patches. I have thousands upon thousands of these little guys. I doubt they will be ready to harvest until they are 15 to 20 years old verses the 10 to 12 years I was hoping for. Always worried about germination rates, theft, disease etc and have not had any problems with this particular site. Never counted on the slow growth factor tho.
Latt