I got a load of green white pine seats a few months ago and Seth and I stacked them for drying. Here’s what we did:
The pine on the trailer. These came from the sawmill with the ends sealed with end-grain sealer (a wax emulsion), but otherwise I would paint the ends myself. The sooner you paint them, the more effective the sealer is.
Minding the Base: We were using our brick patio to stack on for the first time, but you can also make piers out of cinder blocks or piles of wood. The piers need to be off the ground, completely straight and big enough that they won’t sink into the ground when you put a couple thousand pounds of wet wood on them.
Powder-post beetles love green wood, so I always spray my lumber with Tim-bor, a non-toxic borate pesticide. It only sits on the surface of the lumber, so if you have a live infestation use Bora-Care.
I brush the sawdust off the lumber, spray the Tim-bor on and then brush the lumber to even out the spray job. Make sure you flush the sprayer out when you are done or the Tim-bor will eat up the pump parts.
Beetles are especially attracted to the inner-bark, so I remove all signs of bark with a drawknife.
Use dry stickers of even thickness between each board (green stickers will cause mold and staining). Put stickers under your first board to promote airflow between your first board and the piers.
The dark lines in this board are pine pitch, which greatly adds to the weight of pine seats and can ooze though layers of paint and shellac. Sap and pitch are different: all trees have sap (water, sugar, minerals) but only some trees have pitch (resins).