Dendro Master Curve Match Checker

Scan all whole-ring offsets using signed Pearson correlation on supplied sequences, first offset breaking ties; candidate correlations and a caller cutoff are not a statistically validated dendro date.

Description

Dendrochronological curve matching compares ring-width patterns at possible whole-ring offsets.

Dendrochronological curve matching compares ring-width patterns at possible whole-ring offsets. Signed Pearson correlation distinguishes similar patterns from inverted ones, but a high correlation alone is not validated dating.^[1]

When to use Dendro Master Curve Match Checker

Use this tool to scan all whole-ring offsets using signed Pearson correlation on supplied sequences, first offset breaking ties; candidate correlations and a caller cutoff are not a statistically validated dendro date.

Prepare the artifact, site or survey measurements and any independently established calibration or model choices. Keep paired observations aligned and confirm units and coordinate conventions.

How to use Dendro Master Curve Match Checker and understand its results

Prepare the artifact, site or survey measurements and any independently established calibration or model choices. Keep paired observations aligned and confirm units and coordinate conventions.
Enter sampleRingWidthsMm, masterRingWidthsMm, masterFirstCalendarYear, callerMinimumCorrelation using the field table and calculation rules, then run the tool.
Read candidateStartYears, candidateCorrelations, bestCandidateStartYear, bestCorrelation, aboveCallerMatchThreshold. 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
sampleRingWidthsMm	Sample ring widths mm	list of number	Required
masterRingWidthsMm	Master ring widths mm	list of number	Required
masterFirstCalendarYear	Master first calendar year	number	Required
callerMinimumCorrelation	Caller minimum correlation	number	Required

Enter positive ring widths with at least three sample rings and a master no shorter than the sample, a finite master-first year and cutoff in [−1,1]. Require nonconstant sample and every compared master window; master length times sample length may not exceed 1,000,000. Scan all offsets, return years and correlations, retain the first maximum and flag correlation at least the cutoff.

Sample variance requires at least two samples and uses the n−1 denominator. The least-squares fit needs at least two aligned observations and a varying independent variable. Where R² is returned, the helper assigns 1 for a constant dependent variable.

candidate r = covariance(sample,masterWindow)/(sampleSD × windowSD)

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

Output field	Meaning	Value type
candidateStartYears	Candidate start years	list of number
candidateCorrelations	Candidate correlations	list of number
bestCandidateStartYear	Best candidate start year	number
bestCorrelation	Best correlation	number
aboveCallerMatchThreshold	Above caller match threshold	boolean

json

{
  "input": {
    "sampleRingWidthsMm": [
      1,
      2,
      3
    ],
    "masterRingWidthsMm": [
      4,
      1,
      2,
      3,
      1
    ],
    "masterFirstCalendarYear": 1900,
    "callerMinimumCorrelation": 0.99
  },
  "output": {
    "candidateStartYears": [
      1900,
      1901,
      1902
    ],
    "candidateCorrelations": [
      -0.6546536707079771,
      1,
      -0.5
    ],
    "bestCandidateStartYear": 1901,
    "bestCorrelation": 1,
    "aboveCallerMatchThreshold": true
  }
}

Limitations and assumptions

Constant master windows reject the calculation. No multiple-testing adjustment, detrending or independent chronological validation is performed; the cutoff is supplied policy.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. 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. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use Dendro Ring Count Tool: Count measured dendro rings with explicit inferred missing-ring and outer-loss assumptions; calendar anchors are supplied, not independently dated by counting. For a complementary task, use Average Tree Ring Width: Calculate mean measured radial growth per represented year including multi-year measurements; not an unweighted width mean when measurements cover unequal time.

References

Dendro Master Curve Match Checker — tool.io

Similar or alternative tools

Dendro Ring Count Tool
Count measured dendro rings with explicit inferred missing-ring and outer-loss assumptions; calendar anchors are supplied, not independently dated by counting.
Average Tree Ring Width
Calculate mean measured radial growth per represented year including multi-year measurements; not an unweighted width mean when measurements cover unequal time.