Hardwood Stocking Charts

Relation of basal area, number of trees, and average tree diameter to stocking percent for upland central hardwoods. Tree-diameter range 7-15 (left), 3-7 (right). The area between curves A and B indicates the range of stocking where trees can fully utilize the site. Curve C shows the lower limit of stocking necessary to reach the B level in 10 years on average sites. (Average tree diameter is the diameter of the tree of average basal area.)

1. Use Prism to determine basal area on 5 to 10 sample points (or more if conditions are not uniform).
2. Ate each sample point, count all trees 2 inches DBH and over- using 1/20th acre plot (26 1/3 ft. radius).
3. Then, knowing the B.A. and the number of trees per acre, read the “average tree diameter” and the “stocking percent” directly from the charts.
4. Next, follow down the line of “Average Tree Diameter” (parallel to the nearest LOWER average diameter line) to line B; then follow the horizontal line from this point to find what the basal area should be for the stand (at intersection with B.A. Axis).

For a stand with B.A. of 90 and 220 trees per acre, the average DBH is about 8.7 inches and the stand is 81% stocked. The B-level B.A. is 65 and the C-level is 51.

if the B.A. of the stand exceeds C-level requirements, the stand is worth managing. If worth managing, deduct B-level B.A. from the total B.A. to find the sq.ft. that may be cut (25 sq. ft. for this stand). Let stand grow up to 85%-90% stocking, and thin again to near the B-level.
Foresters Field Handbook, North Carolina Forest Service, (Agriculture Handbook 355 Forest Service)