An Etymological Dictionary of the German Language/Scheune
Scheune, f. (unknown to UpG.), ‘barn, shed,’ from the equiv. MidHG. schiune, f., which is derived by the loss of the g (equal to j?) from OHG. scugin, scugina, ‘barn.’ If the g is equal to j, Scheuer (MidHG. schiure) is closely allied. If this is not the case, No certain connecting link has been discovered.