In a variable-radius plot with a BAF of 10, what is the limiting distance for a 20 inch tree?

In a variable-radius plot with a BAF of 10, what is the limiting distance for a 20 inch tree?

• A. 60 ft
• B. 55 ft
• C. 50 ft
• D. 65 ft

Answer: (B)

Limiting distance in Bitterlich variable-radius sampling is the distance from the observer at which a tree must lie to just meet the angular size corresponding to the chosen basal area factor (BAF). In this method, a tree is counted if it lies within that distance, because its bole subtends enough angular area to contribute the required basal area per acre. With a BAF of 10, the angular threshold is set so that a 20-inch tree will be included only if it is within about 55 feet. That means any 20-inch tree closer than roughly 55 feet will meet the criterion and be counted, while those farther away will not. Remember that increasing the BAF makes the inclusion zone smaller (limiting distance decreases), and increasing the tree’s DBH would increase the limiting distance.

Limiting distance in Bitterlich variable-radius sampling is the distance from the observer at which a tree must lie to just meet the angular size corresponding to the chosen basal area factor (BAF). In this method, a tree is counted if it lies within that distance, because its bole subtends enough angular area to contribute the required basal area per acre.

With a BAF of 10, the angular threshold is set so that a 20-inch tree will be included only if it is within about 55 feet. That means any 20-inch tree closer than roughly 55 feet will meet the criterion and be counted, while those farther away will not. Remember that increasing the BAF makes the inclusion zone smaller (limiting distance decreases), and increasing the tree’s DBH would increase the limiting distance.