Illinois timber volume measurements are usually expressed in board feet/acre, but sometimes in cubic feet/acre or cords/acre.
Square feet/acre, however, is a forestry measurement usually reserved for describing basal area (BA), or the cross-sectional area of a tree(s) on an area basis (ex: 80 sq. ft/acre). Basal area is not a volume measurement, rather a measure of stocking (growing space relative to a pre-established standard).
Please verify whether a simple word-processor typo was made in your Forest Management Plan. I would contact the forester who wrote your management plan to verify the volume of merchantable timber, because timber volume is never expressed in square feet.
I certainly hope this helped!
