Lance- Actually if you go back and look at all the pictures, this is what it is.
Heavy feeders- all the new roots are relatively new and up in the air. and I do not see hardly any new roots other than a few on the neofenitia of the latter group. All others in this latter group have older roots from previous season (main cattleya types and others are buried in the semi hydro pot and can't see those).
If you look at those mounted orchids on the heavy feeder group, they are heavily covered with green stuff.
Plus, green stuff on the wood, little is still "existence" while your earlier claim was "no existence", which makes a huge difference to me and probably to a lot of other readers as well.
and who knows how old those woods are. Maybe the heavily greened up one might just have been around longer or something.
Lastly, by looking at the pictures, you still can't back your statement overgeneralizing organisms not being there.
The only thing you can see is the green you mention and they are present in both conditions as opposed to what you say.
There's a difference between the areas and the plants whether you can see the differences I point out or not I see them.