Description
retainedFraction is their ratio; decayConstant = -ln(fraction)/years; halfLifeYears = ln(2)/decayConstant.
Phenological intervals and litter-loss summaries depend on a time origin, mass basis and decay convention. A two-point interval or exponential fit does not establish a universal seasonal or decomposition process.
retainedFraction is their ratio; decayConstant = -ln(fraction)/years; halfLifeYears = ln(2)/decayConstant.
When to use this tool
Use Litter Decay Rate Two Mass Term when checking a supplied ecological time or mass-loss relationship.
How to use the tool and how it works
- Enter initialMass, remainingMass, elapsedYears, initialAsh, remainingAsh. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read retainedFraction, decayConstant, halfLifeYears. Use the output convention below.
Require positive ash-free initial and remaining masses, with remaining ash-free mass strictly smaller, and positive elapsedYears. retainedFraction is their ratio; decayConstant = -ln(fraction)/years; halfLifeYears = ln(2)/decayConstant.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| initialMass | Initial Mass | Required. Finite number. |
| remainingMass | Remaining Mass | Required. Finite number. |
| elapsedYears | Elapsed Years | Required. Finite number; strictly above 0. |
| initialAsh | Initial Ash | Required. Finite number; minimum 0. |
| remainingAsh | Remaining Ash | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| retainedFraction | Retained Fraction | Required. Finite number. |
| decayConstant | Decay Constant | Required. Finite number. |
| halfLifeYears | Half Life Years | Required. Finite number. |
{
"input": {
"initialMass": 100,
"remainingMass": 55,
"elapsedYears": 1,
"initialAsh": 10,
"remainingAsh": 10
},
"output": {
"retainedFraction": 0.5,
"decayConstant": 0.6931471805599453,
"halfLifeYears": 1
}
}Limitations and assumptions
- Zero retention, no loss and mass gain are rejected. The two-point exponential model does not validate a constant decay rate, sampling design or causal decomposition process.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use appropriate observations and uncertainty analysis for seasonal inference and decomposition-rate estimation.
References
Similar or alternative tools
- Litter Mass Blank Loss Term
rawLoss = initialMass-remainingMass; correctedLoss = rawLoss-(blankInitial-blankRemaining).
- Leaflitter Decay Single Interval Factor Tool
Calculate a supplied litter dry-mass remaining fraction and apparent single-interval exponential decay constant, preserving negative values for mass gain.