In the MAI formula MAI = Ya / a, what does Ya represent?

In the MAI formula MAI = Ya / a, what does Ya represent?

• A. Yield at a given age.
• B. Age.
• C. Mean annual increment.
• D. Total height.

Answer: (A)

In this formula, the numerator must be the total yield accumulated up to that age per unit area. That quantity is the yield at age a, meaning the cumulative yield by age a. So Ya represents the total yield achieved by age a, not the age itself, not height, and not the mean annual increment (which is the MAI value itself after division). For example, if a stand has produced 400 units per hectare by age 20, the MAI would be 400 divided by 20, i.e., 20 units per hectare per year.

In this formula, the numerator must be the total yield accumulated up to that age per unit area. That quantity is the yield at age a, meaning the cumulative yield by age a. So Ya represents the total yield achieved by age a, not the age itself, not height, and not the mean annual increment (which is the MAI value itself after division). For example, if a stand has produced 400 units per hectare by age 20, the MAI would be 400 divided by 20, i.e., 20 units per hectare per year.