Question

The volume at the age of 40 years is 4000 cft. and at the age of 50 years is 5000 cft. and a thinning carried out at the age of 45 years gave 1000 cft., then increment percent (p) by Pressler’s formula will be :

• A. 4.0
• B. 5.0
• C. 2.5
• D. 4.5

Hint:

Thinning ($t$) is always added to the final volume ($V_2$) because it was part of the growth produced by the forest during that period.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for the periodic annual increment percentage ($p$) using Pressler's formula. This formula is used to calculate the growth rate of a stand over a specific period, accounting for intermediate removals like thinnings.
Key Formula or Approach:
Pressler’s Formula for increment percent including thinning is: \[ p = \frac{(V_2 + t) - V_1}{(V_2 + t) + V_1} \times \frac{200}{n} \] Where: - \(V_1\) = Volume at the start of the period (at 40 yrs) = 4000 cft.
- \(V_2\) = Volume at the end of the period (at 50 yrs) = 5000 cft.
- \(t\) = Volume of thinning removed during the period = 1000 cft.
- \(n\) = Number of years in the period (50 - 40) = 10 years.

Step 2: Detailed Explanation:

• Calculation of numerator: \((V_2 + t) - V_1 = (5000 + 1000) - 4000 = 6000 - 4000 = 2000\).

• Calculation of denominator: \((V_2 + t) + V_1 = (5000 + 1000) + 4000 = 6000 + 4000 = 10000\).

• Plugging into the formula: \[ p = \frac{2000}{10000} \times \frac{200}{10} \] \[ p = 0.2 \times 20 \] \[ p = 4.0 \]

Step 3: Final Answer:
The increment percent by Pressler’s formula is 4.0.