NCI precipitation effects

Precipitation effects adjust tree growth based on plot precipitation.

Note: If these effects are used with NCI Mortality, the time period unit for parameters must match the value specified in the NCI Parameter Period (years) parameter.

Weibull precipitation effect

Parameters

Weibull Precip Effect "A"	The A parameter for the precipitation effect. Units of precipitation are millimeters per year.
Weibull Precip Effect "B"	The B parameter for the precipitation effect. Units of precipitation are millimeters per year.
Weibull Precip Effect "C"	The C parameter for the precipitation effect. Units of precipitation are millimeters per year.
Precipitation Type to Use	Which precipitation variable should be used.

How it works

Precipitation Effect is calculated as:

PE =

Weibull climate growth precipitation effect equation

where:

A is the Weibull Precip Effect "A" parameter
B is the Weibull Precip Effect "B" parameter
C is the Weibull Precip Effect "C" parameter
P is one of the Plot's precipitation variables.

The desired precipitation variable is set in the Precipitation Type to Use variable.

Double logistic precipitation effect

Parameters

Double Logistic Precip Effect "al"	The a_l parameter for the precipitation effect.
Double Logistic Precip Effect "bl"	The b_l parameter for the precipitation effect.
Double Logistic Precip Effect "cl"	The c_l parameter for the precipitation effect.
Double Logistic Precip Effect "ah"	The a_h parameter for the precipitation effect.
Double Logistic Precip Effect "bh"	The b_h parameter for the precipitation effect.
Double Logistic Precip Effect "ch"	The c_h parameter for the precipitation effect.
Precipitation Type to Use	Which precipitation variable should be used.

How it works

Precipitation Effect is calculated as:

where:

a_l is the Double Logistic Precip Effect "al" parameter
b_l is the Double Logistic Precip Effect "bl" parameter
c_l is the Double Logistic Precip Effect "cl" parameter
a_h is the Double Logistic Precip Effect "ah" parameter
b_h is the Double Logistic Precip Effect "bh" parameter
c_h is the Double Logistic Precip Effect "ch" parameter
ppt is one of the Plot's precipitation variables.