Codebook spans for lumber sheathing are;
24"=5/8" min thickness
48"-1.5" Fb270 E.34
60"-1.5" Fb420 E.66
72"-1.5" Fb600 E1.15

Off the top of my head #2 Eastern White Pine runs about Fb575 and E.9 So for 48" it doesn't take much but it does need some thickness.