Question

In the Horizontal point sampling method, a total of 16 partially tallied trees and 10 fully tallied trees were recorded in a sweep of 360$^\circ$ with the help of a Wedge prism. If the calculated basal area per hectare is 72 m$^2$. The Basal Area Factor of the wedge prism is ______________.

• A. 4
• B. 6
• C. 5
• D. 3

Hint:

Remember that the "tally" in point sampling is simply the sum of trees counted, with borderline ones contributing half. The BAF is the constant that converts this count directly into m$^2$/ha.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
This question involves Horizontal Point Sampling (Bitterlich's Method), which uses a wedge prism to estimate the stand basal area without measuring tree diameters or plot boundaries.

Step 2: Key Formula or Approach: 1. Calculated Tally ($n$) = (Number of full trees) + 0.5 $\times$ (Number of partial/borderline trees).
2. Basal Area per hectare ($G$) = $n \times$ BAF.
where BAF is the Basal Area Factor of the instrument.

Step 3: Detailed Explanation:

• First, determine the effective tree count (tally) from the raw data. Full trees count as 1, while partially tallied (borderline) trees count as 0.5.
\[ n = 10 + (0.5 \times 16) \]
\[ n = 10 + 8 = 18 \]

• Given that the total calculated Basal Area ($G$) is 72 m$^2$/ha.

• Using the formula \( G = n \times \text{BAF} \):
\[ 72 = 18 \times \text{BAF} \]

• Solving for BAF:
\[ \text{BAF} = \frac{72}{18} \]
\[ \text{BAF} = 4 \]

Step 4: Final Answer:
The Basal Area Factor (BAF) of the wedge prism is 4.