Basal area per acre is most closely associated with:

Basal area per acre is most closely associated with:

• A. The sum of trunk diameters in the plot.
• B. The average trunk diameter times the plot area.
• C. The aggregated cross-sectional trunk area per unit land.
• D. The total height of all trees.

Answer: (C)

Basal area per acre represents the cross-sectional area of all tree boles at a standard height summed across the stand and expressed per unit land area. In practice, you add up each trunk’s cross-sectional area, which is pi times the radius squared (or pi times (DBH/2) squared), for all trees in the plot, and then report that total per acre. This makes it a measure of how much trunk area is present per acre, reflecting stand density and composition. The other ideas don’t match this concept: simply summing diameters ignores the area relationship that grows with diameter squared; multiplying an average diameter by the plot area estimates something different than the actual summed cross-sectional area of all trees; and total height has no bearing on basal area, which is about cross-sectional area, not height.

Basal area per acre represents the cross-sectional area of all tree boles at a standard height summed across the stand and expressed per unit land area. In practice, you add up each trunk’s cross-sectional area, which is pi times the radius squared (or pi times (DBH/2) squared), for all trees in the plot, and then report that total per acre. This makes it a measure of how much trunk area is present per acre, reflecting stand density and composition.

The other ideas don’t match this concept: simply summing diameters ignores the area relationship that grows with diameter squared; multiplying an average diameter by the plot area estimates something different than the actual summed cross-sectional area of all trees; and total height has no bearing on basal area, which is about cross-sectional area, not height.