Question

A stand of Sal at the age of 50 years have volume of 2500 cft and at the age of 60 years 3500 cft and a thinning at the age of 55 years gave a volume of 300 cft, then the increment per cent (p) by Pressler's formula will be :

• A. 4.13
• B. 0
• C. 6.78
• D. 0

Hint:

Pressler's formula is highly robust because it uses the average of the initial and final volumes as the base, reducing calculation bias over longer growth periods.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
In forest mensuration, calculating the volume increment percent of a forest stand over a given period is essential for monitoring growth rates and planning harvesting cycles.
Pressler's formula is a standard method used to estimate this volume increment percent, accounting for any intermediate thinning volume removed during the period.
Key Formula or Approach:
Pressler's formula for the volume increment percent ($p$) is expressed as:
\[ p = \frac{V_2 - V_1 + T}{V_2 + V_1 + T} \times \frac{200}{n} \]
where:
- $V_1$ is the initial stand volume at the beginning of the period.
- $V_2$ is the final stand volume at the end of the period.
- $T$ is the volume of wood removed during intermediate thinning operations.
- $n$ is the length of the growth period in years.

Step 2: Detailed Explanation:
Let us extract the values from the problem statement:
- Initial volume at 50 years ($V_1$) = $2500 \text{ cft}$
- Final volume at 60 years ($V_2$) = $3500 \text{ cft}$
- Thinning volume removed at 55 years ($T$) = $300 \text{ cft}$
- Growth period in years ($n$) = $60 - 50 = 10 \text{ years}$
Now, substitute these values into Pressler's formula:
\[ p = \frac{3500 - 2500 + 300}{3500 + 2500 + 300} \times \frac{200}{10} \]
Simplify the numerator and denominator:
\[ p = \frac{1300}{6300} \times 20 \]
\[ p = \frac{13}{63} \times 20 \]
\[ p = \frac{260}{63} \approx 4.1269\% \]
Rounding to two decimal places, we get $4.13\%$.

Step 3: Final Answer:
The volume increment percent is $4.13\%$, corresponding to option (A).