Ice Storm Canopy Retained Severity Percent

Audit measured retained live crown volume after storm against matched prestorm inventory and caller loss cutoff; canopy volume differs from shade/cover and observations do not establish future tree survival.

Description

Retained live crown volume after a storm is different from canopy cover or shade.

Retained live crown volume after a storm is different from canopy cover or shade. Local loss fractions can be audited alongside pooled retention.^[1]

When to use Ice Storm Canopy Retained Severity Percent

Use this tool to audit measured retained live crown volume after storm against matched prestorm inventory and caller loss cutoff; canopy volume differs from shade/cover and observations do not establish future tree survival.

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

How to use Ice Storm Canopy Retained Severity 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 preStormLiveCrownVolumesM3, retainedLiveCrownVolumesM3, callerMaximumLossFraction using the field table and calculation rules, then run the tool.
Read perTreeCrownLossFractions, pooledRetainedCrownPercent, aboveCallerLossFlags. 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
preStormLiveCrownVolumesM3	Pre storm live crown volumes m3	list of number	Required
retainedLiveCrownVolumesM3	Retained live crown volumes m3	list of number	Required
callerMaximumLossFraction	Caller maximum loss fraction	number	Required

Pair positive prestorm m³ and nonnegative retained volumes no greater than original; use a maximum loss fraction in [0,1]. Return local losses, pooled retained crown percent and strict above-loss flags.

Paired lists must be nonempty and have equal lengths.

loss=1−retained crown volume/prestorm volume

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

Output field	Meaning	Value type
perTreeCrownLossFractions	Per tree crown loss fractions	list of number
pooledRetainedCrownPercent	Pooled retained crown percent	number
aboveCallerLossFlags	Above caller loss flags	list of number

json

{
  "input": {
    "preStormLiveCrownVolumesM3": [
      10,
      20
    ],
    "retainedLiveCrownVolumesM3": [
      8,
      10
    ],
    "callerMaximumLossFraction": 0.3
  },
  "output": {
    "perTreeCrownLossFractions": [
      0.19999999999999996,
      0.5
    ],
    "pooledRetainedCrownPercent": 60,
    "aboveCallerLossFlags": [
      0,
      1
    ]
  }
}

Limitations and assumptions

Volume estimates and thresholds are supplied. Future survival and structural safety are not established.

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 Snow Load Stem Bending Stress Breakage Checker: Screen circular intact stem cantilever bending under caller transverse snow-weight lever arms and material stress limits; this elementary idealization does not predict tree breakage or certify public/work safety. For a complementary task, use Residual Stand Damage Percent Basal Area: Compare caller observed damaged residual basal area with assessable residual inventory and bounds for unassessable area; no diagnosis from raw stem count or assumed health of unexamined trees.

References

Ice Storm Canopy Retained Severity Percent — tool.io

Similar or alternative tools

Snow Load Stem Bending Stress Breakage Checker
Screen circular intact stem cantilever bending under caller transverse snow-weight lever arms and material stress limits; this elementary idealization does not predict tree breakage or certify public/work safety.
Residual Stand Damage Percent Basal Area
Compare caller observed damaged residual basal area with assessable residual inventory and bounds for unassessable area; no diagnosis from raw stem count or assumed health of unexamined trees.