Question

Calculate the Normal Growing Stock (NGS) of a Eucalyptus plantation worked on 10 year rotation on 10 ha area, one ha under each gradation with the volume of 10 year gradation being 500 m$^3$

• A. 2150 m$^3$
• B. 2050 m$^3$
• C. 2500 m$^3$
• D. 3500 m$^3$

Hint:

For a normal forest with equal area gradations, the normal growing stock is always equal to half of the total volume that would be produced if the entire forest area were occupied by mature stands of the rotation age.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Normal Growing Stock (NGS) is the total volume of standing trees in a normal forest that has a normal distribution of age classes, normal stocking, and a normal increment rate.
In a normal forest with equal areas under each age class (gradation), the growing stock is distributed in a linear progression from young seedlings to mature trees.
Key Formula or Approach:
For a forest with a rotation period of \(R\) years and equal areas under each age gradation, the Normal Growing Stock (\(G_n\)) can be calculated using the standard formula:
\[ G_n = \frac{V_R \times R}{2} \]
where:
- \(V_R\) is the volume per unit area at the rotation age \(R\) (mature volume).
- \(R\) is the rotation period in years.

Step 2: Detailed Explation:
Let us plug the given values into the formula:
- The rotation period (\(R\)) is given as 10 years.
- The total area of the plantation is 10 ha, with exactly 1 ha under each of the 10 age gradations.
- The volume of the 10-year gradation (mature volume \(V_R\)) is given as \(500\text{ m}^3\).
Applying the formula:
\[ G_n = \frac{500\text{ m}^3 \times 10\text{ years}}{2} \]
\[ G_n = \frac{5000}{2} = 2500\text{ m}^3 \]
This represents the theoretical normal growing stock present in the plantation at the middle of the growing season.

Step 3: Fil Answer:
The calculated Normal Growing Stock of the Eucalyptus plantation is \(2500\text{ m}^3\).
Hence, the correct option is (C).