Basal area (ft²/ac) is calculated how?

Basal area (ft²/ac) is calculated how?

• A. It is calculated based on the number of trees and their sizes within a plot.
• B. It is equal to the sum of tree heights.
• C. It is determined by the average diameter at breast height times plot area.
• D. It is derived from the volume per acre.

Answer: (A)

Basal area measures the cross-sectional area of all trees at breast height per unit land area. To get it, you determine each tree’s cross-sectional area at DBH (diameter at breast height) and sum these areas for the plot, then express the total per acre. Because a tree’s cross-sectional area is proportional to the square of its DBH, the total basal area depends on both how many trees there are and how large they are. Height doesn’t affect basal area, and volume is a separate metric, so options that use tree heights or volume don’t describe how basal area is calculated. This is why the method based on the number of trees and their sizes within the plot is the correct approach.

Basal area measures the cross-sectional area of all trees at breast height per unit land area. To get it, you determine each tree’s cross-sectional area at DBH (diameter at breast height) and sum these areas for the plot, then express the total per acre. Because a tree’s cross-sectional area is proportional to the square of its DBH, the total basal area depends on both how many trees there are and how large they are. Height doesn’t affect basal area, and volume is a separate metric, so options that use tree heights or volume don’t describe how basal area is calculated. This is why the method based on the number of trees and their sizes within the plot is the correct approach.