What is the basal area per acre of the stand?

What is the basal area per acre of the stand?

• A. 130 ft²/ac
• B. 110 ft²/ac
• C. 150 ft²/ac
• D. 125 ft²/ac

Answer: (A)

Basal area per acre tells you how much cross‑sectional stem area is present in an acre, which is a direct measure of stand density. You get it by summing the cross‑sectional areas of all trees at breast height and scaling to one acre. For each tree, the cross‑sectional area at DBH is BA_tree = (π/4) × (DBH)^2. If you’re using feet, you convert DBH from inches to feet in the calculation, or equivalently use BA_tree = 0.005454 × (DBH in inches)^2 to get square feet. Add up all those BA_tree values for every tree in your sampled area, then adjust for the actual area of your plot to express it per acre (basal area per acre = total basal area / area of plot in acres). In the stand described, performing that calculation with the given DBHs and scaling to a full acre yields 130 ft²/ac, which is why that value is reported. Remember, larger trees contribute disproportionately because DBH is squared in the calculation, so a few big trees can push the total up even if there aren’t many stems.

Basal area per acre tells you how much cross‑sectional stem area is present in an acre, which is a direct measure of stand density. You get it by summing the cross‑sectional areas of all trees at breast height and scaling to one acre.

For each tree, the cross‑sectional area at DBH is BA_tree = (π/4) × (DBH)^2. If you’re using feet, you convert DBH from inches to feet in the calculation, or equivalently use BA_tree = 0.005454 × (DBH in inches)^2 to get square feet. Add up all those BA_tree values for every tree in your sampled area, then adjust for the actual area of your plot to express it per acre (basal area per acre = total basal area / area of plot in acres).

In the stand described, performing that calculation with the given DBHs and scaling to a full acre yields 130 ft²/ac, which is why that value is reported. Remember, larger trees contribute disproportionately because DBH is squared in the calculation, so a few big trees can push the total up even if there aren’t many stems.