If DBH is 15 inches, what is the approximate Dib?

If DBH is 15 inches, what is the approximate Dib?

• A. 11.7 inches
• B. 12.0 inches
• C. 13.2 inches
• D. 9.8 inches

Answer: (A)

Diameter inside bark is smaller than DBH because bark adds to the outside diameter. To estimate DIB, subtract the bark thickness on both sides of the tree, since DBH = DIB + 2 × (radial bark thickness). If DBH is 15 inches and we use a typical approximate bark thickness of about 1.65 inches (radial), then DIB ≈ 15 − 2 × 1.65 = 11.7 inches. This yields a reasonable estimate across many species, though actual bark thickness varies with species, age, and site.

Diameter inside bark is smaller than DBH because bark adds to the outside diameter. To estimate DIB, subtract the bark thickness on both sides of the tree, since DBH = DIB + 2 × (radial bark thickness).

If DBH is 15 inches and we use a typical approximate bark thickness of about 1.65 inches (radial), then DIB ≈ 15 − 2 × 1.65 = 11.7 inches. This yields a reasonable estimate across many species, though actual bark thickness varies with species, age, and site.