Moving air might be an issue in the basement. It is a large basement. Walk in on the back. Rough concrete floors. House is 90 years old so it certainly isn’t sealed in any sense of the word. Also, has original and very leaky metal duct work. This means it is a least partially climate controlled.

As far as the outdoor stacks (all pine at this point), it’s a catch-22. To avoid direct sunlight they’d have to be in the woods. If they are in the woods they won’t get as good air flow and they’ll get covered in leaves and pine needles.
Right now there is nothing precious on the outdoor stacks so I’ll give them time and see what happens.
I definitely need to get a moisture meter so that I’m not guessing.
Also, I may have misspoken about the mold. For what it’s worth it might be a sort of lichen. It is very very fine, somewhat rough sandy feeling to the touch and had a faint blue green tint to it. It does not brush or wipe off. Just the slightest skim with the planer takes it right off and the wood underneath looks fine. Whether it is an indication of moisture or not I do not know.
Anyway, if the basement is a bad idea and my outdoor stacks are wrong, I may have to build an open shed to dry the good stuff.
The last thing I need is another structure on the property!