Crown Competition Factor

Sum caller open-grown potential crown areas under represented stem densities, allowing CCF above 100%; unlike measured canopy union cover, crowns may overlap and widths require independent calibration.

Description

Potential open-grown crown areas can overlap when assigned to a stand inventory.

Potential open-grown crown areas can overlap when assigned to a stand inventory. Crown competition factor therefore differs from a union canopy-cover percentage.^[1]

When to use Crown Competition Factor

Use this tool to sum caller open-grown potential crown areas under represented stem densities, allowing CCF above 100%; unlike measured canopy union cover, crowns may overlap and widths require independent calibration.

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

How to use Crown Competition Factor 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 openGrownCrownDiametersM, representedStemsPerHa using the field table and calculation rules, then run the tool.
Read potentialOpenGrownCrownAreaM2PerHa, crownCompetitionFactorPercent. 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
openGrownCrownDiametersM	Open grown crown diameters m	list of number	Required
representedStemsPerHa	Represented stems per ha	list of number	Required

Pair nonnegative calibrated open-grown crown diameters with nonnegative represented stems/ha. Sum circular potential areas and return that m²/ha total and CCF percentage, retaining values above 100%.

Paired lists must be nonempty and have equal lengths.

potential area=Σπdiameter²/4 × stems/ha; CCF %=potential m²/ha divided by 100

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

Output field	Meaning	Value type
potentialOpenGrownCrownAreaM2PerHa	Potential open grown crown area m2 per ha	number
crownCompetitionFactorPercent	Crown competition factor percent	number

json

{
  "input": {
    "openGrownCrownDiametersM": [
      2,
      4
    ],
    "representedStemsPerHa": [
      100,
      50
    ]
  },
  "output": {
    "potentialOpenGrownCrownAreaM2PerHa": 942.4777960769379,
    "crownCompetitionFactorPercent": 9.42477796076938
  }
}

Limitations and assumptions

Crown widths require independent calibration. No measured union cover or competition outcome is inferred.

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 Understory Cover Percentage: Aggregate area-weighted understory point-layer cover, preserving overlapping layer totals separately from the union; unlike an existing single canopy-area percentage, multiple cover layers are not double counted in union. For a complementary task, use Thinning Q-Factor Diameter Step: Normalize caller descending geometric q targets over equally spaced diameter classes, conserving supplied total density; these are continuous planning targets, not actual integer trees or an ecological prescription.

References

Crown Competition Factor — tool.io

Similar or alternative tools

Understory Cover Percentage
Aggregate area-weighted understory point-layer cover, preserving overlapping layer totals separately from the union; unlike an existing single canopy-area percentage, multiple cover layers are not double counted in union.
Thinning Q-Factor Diameter Step
Normalize caller descending geometric q targets over equally spaced diameter classes, conserving supplied total density; these are continuous planning targets, not actual integer trees or an ecological prescription.