4/4 you can get away with alot more. personally i haven't air dried 4/4 quatersawn w.oak but,we air dry alot of a thin 6/4 w.oak qtrsawn and have real good luck doing so.
keep in mind i believe our "northern"hardwoods have a tighter growth ring.its real common to get 16 rings per inch. southern hardwoods will probably handle being dried faster.
red oak drying schedule here says 28 days from green to dry.i have done several loads in 16-18 days with no noticeable drying defects. drying qtrsawn w.oak i can dry from green in 15 days,there again no noticeable drying defects.... all this being 4/4 material.
air drying hardwoods should be done in a shaded area with reduced air flow. not in a building but alittle shelter is good. two things speed the drying process.heat and wind. the heat makes the water release from the wood and the wind helps remove the water trapped in between the stickered layers,and air drying you can't really control either one. that makes shade and alittle shelter move obvious as there importance.
i hope this makes some sense to you
