B.F. Bachelor of Forestry Bachelor of Forestry Forest Mensuration 3 — Questions and Answers
Question 1: The 'growing stock' of a forest refers to:
- The annual growth increment only
- The total volume of live trees in a defined area (Correct answer)
- The number of seedlings planted per year
- The amount of timber harvested annually
Correct answer: The total volume of live trees in a defined area
Growing stock is the standing volume of all live trees (above a minimum size) within a defined forest area at a given point in time.
Question 2: When using a Bitterlich angle gauge (wedge prism) with a basal area factor (BAF) of 10, each 'in' tree represents how many square feet of basal area per acre?
- 5 sq ft/acre
- 10 sq ft/acre (Correct answer)
- 20 sq ft/acre
- 1 sq ft/acre
Correct answer: 10 sq ft/acre
Each tree tallied as 'in' using a BAF 10 prism contributes 10 square feet of basal area per acre to the stand estimate.
Question 3: What is the primary difference between 'net volume' and 'gross volume' of a log?
- Net volume includes bark; gross volume does not
- Gross volume is total wood including defects; net volume excludes defects (Correct answer)
- Net volume is measured in board feet; gross volume in cubic feet
- They are equivalent terms for the same measurement
Correct answer: Gross volume is total wood including defects; net volume excludes defects
Gross volume includes all wood regardless of quality, while net volume subtracts defect deductions to reflect merchantable wood only.
Question 4: An increment core extracted from a tree is used to determine:
- The tree's moisture content
- The tree's age and radial growth rate (Correct answer)
- The tree's root volume
- The tree's crown ratio
Correct answer: The tree's age and radial growth rate
An increment core contains annual rings that reveal the tree's age and the rate of radial (diameter) growth over time.
Question 5: Which of the following best describes 'stand density index' (SDI)?
- The ratio of crown area to stand area
- A measure of stocking based on number of trees and their average diameter (Correct answer)
- The total basal area divided by number of plots
- The annual volume increment per unit area
Correct answer: A measure of stocking based on number of trees and their average diameter
SDI (Reineke's SDI) relates the number of trees per acre to the quadratic mean diameter to quantify stand density relative to maximum capacity.
Question 6: The 'Doyle log rule' tends to underestimate volume for logs with a small end diameter of less than:
- 6 inches
- 10 inches
- 16 inches (Correct answer)
- 28 inches
Correct answer: 16 inches
The Doyle rule significantly underestimates board-foot volume for logs smaller than about 16 inches in small-end diameter due to formula limitations.
Question 7: In forest inventory, a 'two-stage sampling' design involves:
- Sampling trees in two seasons — spring and fall
- First selecting primary sampling units (PSUs), then selecting secondary units within each PSU (Correct answer)
- Measuring trees twice for accuracy verification
- Using two different plot sizes simultaneously
Correct answer: First selecting primary sampling units (PSUs), then selecting secondary units within each PSU
Two-stage sampling selects primary units (e.g., stands or large plots) first, then subsamples within those units to reduce travel costs while maintaining accuracy.
B.F. Bachelor of Forestry Bachelor of Forestry Forest Mensuration 3
The 'growing stock' of a forest refers to: