Question

The value of m.a.i is never zero and in no circumstances it is _______ like the c.a.i.

• A. Negative
• B. Positive
• C. Optimistic
• D. Constant

Hint:

Remember that the MAI curve and CAI curve intersect at the point of maximum MAI, which represents the rotation age that maximizes volume production (biological rotation).

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Forest growth is evaluated using Mean Annual Increment (MAI) and Current Annual Increment (CAI).

Step 2: Detailed Explanation:
- Mean Annual Increment (MAI) is the average growth rate per year of a forest stand up to a specific age: \[ MAI = \frac{\text{Total Volume at age } t}{t} \] Since the total volume accumulated over time is always positive, MAI can never be zero or negative during the life of a living stand.
- Current Annual Increment (CAI) is the growth increment achieved in a single specific year.
- In overmature or degrading stands, mortality, decay, and windthrow can exceed new wood growth.
- Consequently, CAI can become negative, whereas MAI remains positive because it averages out the total accumulated volume over the entire lifespan of the stand.

Step 3: Final Answer:
Therefore, MAI is never negative, unlike CAI.