Current-Year Foliage Retention Percent

Audit independently established current-year needle inventory with observability bounds; older needle cohorts are not pooled and retention alone does not identify stress/disease.

Description

Current-year needle retention should use the corresponding expected cohort.

Current-year needle retention should use the corresponding expected cohort. Unassessable opportunities create bounds rather than automatic losses.^[1]

Audit independently established current-year needle inventory with observability bounds; older needle cohorts are not pooled and retention alone does not identify stress/disease.

When to use Current-Year Foliage Retention Percent

Use this tool to audit independently established current-year needle inventory with observability bounds; older needle cohorts are not pooled and retention alone does not identify stress/disease.

Gather the tree inventory, plot measurements or model parameters. Check diameter, area, time and moisture conventions; keep paired observations aligned.

How to use Current-Year Foliage Retention Percent and understand its results

Gather the tree inventory, plot measurements or model parameters. Check diameter, area, time and moisture conventions; keep paired observations aligned.
Enter expectedCurrentYearNeedleCounts, retainedCurrentYearNeedleCounts, unassessableExpectedCounts using the field table and calculation rules, then run the tool.
Read observableCurrentYearRetentionPercent, wholeExpectedRetentionPercentBounds. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
expectedCurrentYearNeedleCounts	Expected current year needle counts	list of number	Required
retainedCurrentYearNeedleCounts	Retained current year needle counts	list of number	Required
unassessableExpectedCounts	Unassessable expected counts	list of number	Required

Pair nonnegative integer expected, retained and unassessable counts. Require retained+unassessable≤expected per record, positive total expected and positive observable total. Return observed retention and whole-cohort bounds.

Paired lists must be nonempty and have equal lengths.

observable retention %=100retained/(expected−unassessable); whole bounds=100[retained,retained+unassessable]/expected

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
observableCurrentYearRetentionPercent	Observable current year retention percent	number
wholeExpectedRetentionPercentBounds	Whole expected retention percent bounds	list of number

json

{
  "input": {
    "expectedCurrentYearNeedleCounts": [
      100,
      200
    ],
    "retainedCurrentYearNeedleCounts": [
      80,
      100
    ],
    "unassessableExpectedCounts": [
      20,
      0
    ]
  },
  "output": {
    "observableCurrentYearRetentionPercent": 64.28571428571429,
    "wholeExpectedRetentionPercentBounds": [
      60,
      66.66666666666667
    ]
  }
}

Limitations and assumptions

Expected inventory must be independently established. Older cohorts, stress causes and disease diagnoses are excluded.

Numeric inputs and returned numeric values must be finite; an unrepresentable returned value produces an error. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Annual NDVI Change Defoliation Watch: Track paired annual NIR/red NDVI drops against caller screening threshold, retaining greening; unlike SWIR-based dNBR, input bands differ and neither index diagnoses defoliation agents. For a complementary task, use Deer Browse Leader Impact Percent: Summarize caller identified browsed leaders on observable opportunities with whole-inventory bounds for missing assessments; browse agents are not automatically attributed to deer.

References

Current-Year Foliage Retention Percent — tool.io

Similar or alternative tools

Annual NDVI Change Defoliation Watch
Track paired annual NIR/red NDVI drops against caller screening threshold, retaining greening; unlike SWIR-based dNBR, input bands differ and neither index diagnoses defoliation agents.
Deer Browse Leader Impact Percent
Summarize caller identified browsed leaders on observable opportunities with whole-inventory bounds for missing assessments; browse agents are not automatically attributed to deer.