What is the formula for calculating MAI?

What is the formula for calculating MAI?

• A. MAI = Ya * a
• B. MAI = Ya / a
• C. MAI = Ya - a
• D. MAI = a / Ya

Answer: (B)

Mean annual increment shows the average annual growth of a stand over its life up to a given age. It is found by dividing the total yield achieved by that age (Ya) by the age itself (a). So the formula is MAI = Ya / a, where Ya is the cumulative yield per hectare at age a and a is the age in years. For example, if Ya is 400 m3/ha at 20 years, MAI = 400/20 = 20 m3/ha per year. This metric helps compare growth over time and identify the rotation age where growth per year is highest. The other forms don’t represent an average annual rate: multiplying Ya by a scales with age squared, subtracting a mixes units of volume and years, and dividing a by Ya gives a rate with inappropriate units.

Mean annual increment shows the average annual growth of a stand over its life up to a given age. It is found by dividing the total yield achieved by that age (Ya) by the age itself (a). So the formula is MAI = Ya / a, where Ya is the cumulative yield per hectare at age a and a is the age in years. For example, if Ya is 400 m3/ha at 20 years, MAI = 400/20 = 20 m3/ha per year. This metric helps compare growth over time and identify the rotation age where growth per year is highest. The other forms don’t represent an average annual rate: multiplying Ya by a scales with age squared, subtracting a mixes units of volume and years, and dividing a by Ya gives a rate with inappropriate units.