B.F. Bachelor of Forestry Bachelor of Forestry Forest Mensuration 2 — Questions and Answers
Question 1: Which formula is used to calculate the volume of a tree using the Smalian's method?
- V = L × (Ab + At) / 2 (Correct answer)
- V = L × (Ab + 4Am + At) / 6
- V = L × Ab
- V = L × At / 3
Correct answer: V = L × (Ab + At) / 2
Smalian's method calculates log volume as the average of the basal areas of both ends multiplied by the log length.
Question 2: The Prismatic compass is primarily used in forest mensuration for:
- Measuring tree height
- Measuring horizontal distances
- Running compass traverses and measuring bearing angles (Correct answer)
- Estimating crown density
Correct answer: Running compass traverses and measuring bearing angles
A prismatic compass is used to measure magnetic bearings during traverse surveys in forest areas.
Question 3: What does 'form quotient' represent in tree measurement?
- Ratio of crown width to tree height
- Ratio of diameter at mid-height to DBH (Correct answer)
- Ratio of merchantable height to total height
- Ratio of volume to basal area
Correct answer: Ratio of diameter at mid-height to DBH
Form quotient is the ratio of the diameter at mid-height (or upper stem) to the diameter at breast height, indicating stem taper.
Question 4: A timber cruise using systematic sampling with a fixed-area plot requires the cruiser to:
- Measure every tree in the forest
- Measure trees within randomly located circular or rectangular plots (Correct answer)
- Use a relascope to tally trees by species only
- Count stumps rather than live trees
Correct answer: Measure trees within randomly located circular or rectangular plots
Fixed-area plot cruising involves establishing sample plots at systematic intervals and measuring all trees within each plot.
Question 5: The ocular estimate of crown closure in a stand is typically expressed as:
- Cubic feet per acre
- Percentage of ground covered by tree crowns (Correct answer)
- Number of trees per hectare
- Basal area per hectare
Correct answer: Percentage of ground covered by tree crowns
Crown closure (or canopy cover) is expressed as the percentage of the ground area covered by vertical projection of tree crowns.
Question 6: In log scaling, what is the purpose of deducting for defects?
- To account for the weight of bark
- To adjust volume estimates to reflect only sound, usable wood (Correct answer)
- To add a safety factor for transportation
- To convert log volumes to board feet automatically
Correct answer: To adjust volume estimates to reflect only sound, usable wood
Defect deductions reduce the gross scale to a net scale that reflects only the merchantable, sound wood in the log.
Question 7: Which instrument measures tree height using the principle of trigonometry based on horizontal distance and vertical angles?
- Biltmore stick
- Diameter tape
- Hypsometer (Correct answer)
- Increment borer
Correct answer: Hypsometer
A hypsometer uses trigonometric relationships between the observer's horizontal distance and measured vertical angles to calculate tree height.
B.F. Bachelor of Forestry Bachelor of Forestry Forest Mensuration 2
Which formula is used to calculate the volume of a tree using the Smalian's method?