Acorns of red oaks (Quercus spp; Subgenus Erythrobalanus) are important forage for wildlife and seed for oak regeneration. I estimated production of viable acorns by red oaks in 5 forests in the Mississippi Alluvial Valley (MAV) and 2 greentree reservoirs (GTRs) in Mississippi. Mean acorn production in the MAV was 439 kg(dry)/ha of red oak crown (CV = 29%) during autumn-winter 2009-2010 and 794 kg/ha (CV = 19%) in GTRs during autumn-winters 2008-2010. I recommend researchers sample acorn production in the MAV for ≥5 years to improve precision of estimates (i.e., CV ≤ 15%). I estimated mass and gross energy (GE) of viable red oak acorns after 90 days in unflooded and flooded hardwood bottomlands in Mississippi. Within species, mass loss of acorns was <8.4% and variation in GE ≤0.08 kcal(dry)/g. Winter decomposition of intact viable red oak acorns would have minimal effect on wildlife carrying capacity of hardwood bottomlands.