Which reference is cited for the derivation of the basal-area factor?

Which reference is cited for the derivation of the basal-area factor?

• A. Imaginary plot size
• B. Avery & Burkhart 1994
• C. Radius (ft)
• D. DBH

Answer: (B)

The concept being tested is how the basal-area factor is derived and where that derivation is documented. Basal-area factor serves as the conversion that lets you estimate basal area per acre from a count of trees sampled with a prism or angle gauge. It ties the individual tree’s basal area, calculated from its DBH as (π/4) × DBH^2, to a per-acre scale based on the sampling geometry. The standard, widely cited derivation and guidance for this factor appear in Avery & Burkhart (1994), a foundational forestry measurements text. They lay out the step-by-step relationship between DBH, the sampling method, and the resulting BAF, and show how to apply it for different plot or instrument setups. That’s why this reference is the correct one. The other options describe inputs or concepts used in the calculation (like DBH or radius) or aren’t sources for the derivation, so they don’t serve as the cited reference.

The concept being tested is how the basal-area factor is derived and where that derivation is documented. Basal-area factor serves as the conversion that lets you estimate basal area per acre from a count of trees sampled with a prism or angle gauge. It ties the individual tree’s basal area, calculated from its DBH as (π/4) × DBH^2, to a per-acre scale based on the sampling geometry. The standard, widely cited derivation and guidance for this factor appear in Avery & Burkhart (1994), a foundational forestry measurements text. They lay out the step-by-step relationship between DBH, the sampling method, and the resulting BAF, and show how to apply it for different plot or instrument setups. That’s why this reference is the correct one. The other options describe inputs or concepts used in the calculation (like DBH or radius) or aren’t sources for the derivation, so they don’t serve as the cited reference.