What is the relationship between DBH and Dib?

What is the relationship between DBH and Dib?

• A. Dib is approximately 78% of DBH (Diameter at Breast Height).
• B. Dib is twice the DBH.
• C. DBH is 50% of Dib.
• D. There is no relation between Dib and DBH.

Answer: (A)

The key idea is that diameter inside the bark is smaller than diameter outside the bark, because the bark adds thickness around the trunk. At breast height, the outside diameter (with bark) is larger than the inside diameter (without bark). A commonly used approximation is that the inside-bark diameter is about 0.78 times the outside-bark diameter, so DIB is roughly 78% of DBH. This reflects the bark’s contribution to the total diameter, which varies somewhat by species and age but tends to keep the inside diameter noticeably smaller than the outside diameter. Therefore, the best answer is that DIB is approximately 78% of DBH. The other options imply impossible or inconsistent relationships (inside diameter larger than outside, or outside being only half of inside), and there’s always some bark thickness connecting the two.

The key idea is that diameter inside the bark is smaller than diameter outside the bark, because the bark adds thickness around the trunk. At breast height, the outside diameter (with bark) is larger than the inside diameter (without bark). A commonly used approximation is that the inside-bark diameter is about 0.78 times the outside-bark diameter, so DIB is roughly 78% of DBH. This reflects the bark’s contribution to the total diameter, which varies somewhat by species and age but tends to keep the inside diameter noticeably smaller than the outside diameter. Therefore, the best answer is that DIB is approximately 78% of DBH. The other options imply impossible or inconsistent relationships (inside diameter larger than outside, or outside being only half of inside), and there’s always some bark thickness connecting the two.