MAI Culmination Calculator

Observed MAI culmination among actual age/volume inventory points, ties retained; not continuous optimum rotation forecast or species yield curve.

Description

Mean annual increment divides standing volume by age at each observation.

Mean annual increment divides standing volume by age at each observation.^[1]

This tool identifies every sampled age attaining the largest observed ratio without forecasting a continuous optimum rotation.

When to use MAI Culmination Calculator

Use this tool to identify every sampled age attaining the largest observed ratio without forecasting a continuous optimum rotation.

How to use MAI Culmination Calculator and how it works

Prepare actualInventoryAgesYears, actualInventoryStandingVolumes, with the units, conventions and assumptions below.
Enter the required fields and run MAI Culmination Calculator.
Read result.observedMaiMaximizingAgesYears, result.observedMaximumMai using the output definitions below.
Correct any rejected inputs and rerun; interpret the result within the stated model and its assumptions.

Input field	Meaning	Value type	Requirement
actualInventoryAgesYears	Actual Inventory Ages Years. Use the units and matching context stated in the calculation below.	array of number	Required; other constraints below
actualInventoryStandingVolumes	Actual Inventory Standing Volumes. Use the units and matching context stated in the calculation below.	array of number	Required; other constraints below

Require aligned nonempty finite age and volume arrays, with positive strictly increasing ages and nonnegative cumulative volumes. Compute volume/age for every observation, find the largest rate, and return that rate plus all ages whose computed rates equal it exactly. This finds the sampled maximum, not an interpolated or biologically fitted culmination age.

MAI_i=volume_i/age_i; maximum=max(MAI_i); ages=all exact maximizing sampled ages

Apply the input ordering, units and branch conditions stated above.

Output field	Meaning	Value type
result	Object containing the calculated or selected fields below.	object
result.observedMaiMaximizingAgesYears	All sampled ages in years whose computed volume/age rate equals the maximum.	array of number
result.observedMaximumMai	Maximum sampled volume/year rate in the supplied volume unit per year.	number

json

{
  "input": {
    "actualInventoryAgesYears": [
      10,
      20,
      30
    ],
    "actualInventoryStandingVolumes": [
      20,
      60,
      60
    ]
  },
  "output": {
    "result": {
      "observedMaiMaximizingAgesYears": [
        20
      ],
      "observedMaximumMai": 3
    }
  }
}

Limitations and assumptions

The calculation uses the supplied observations and model inputs. It does not collect measurements, select a reference population or coefficient, or establish that the model applies to the actual case. The stated branch conditions and output units remain part of the result.

All fields require explicit values. Unexpected fields, wrong types, nonfinite numbers and sparse arrays are rejected. Alignment, bounds and supported-token rules are explained above; extremely large inputs or nonfinite results can also fail. Input errors differ from successful false comparisons, unavailable-domain flags and empty match lists.

Alternative or Complementary methods

Use Relative Frequency Calculator for a complementary operation: Relative frequency compares a species' frequency with the sum of all species frequencies on the same sampling basis.

Use Relative Dominance Calculator for a complementary operation: Relative dominance can express a species' basal area as a share of all-species basal area.

References

MAI Culmination Calculator — tool.io

Similar or alternative tools

Relative Frequency Calculator
Relative frequency compares a species' frequency with the sum of all species frequencies on the same sampling basis.
Relative Dominance Calculator
Relative dominance can express a species' basal area as a share of all-species basal area.