SORTIE-ND

Software for spatially-explicit simulation of forest dynamics

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NCI infection effects

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.

Infection effect

Parameters

Infection Effect "a"	The "a" parameter for the infection effect.
Infection Effect "b"	The "b" parameter for the infection effect.

How it works

Infection Effect is calculated as:

Infection Effect = a * ln(T) + b

where:

a is the Infection Effect "a" parameter
b is the Infection Effect "b" parameter
T is the time infested

Time infested comes from either the Density Dependent Infestation or Insect Infestation behaviors. Trees to which this behavior is applied must have one of these two behaviors also applied.

If a tree is not infested, there is no effect.

NCI infection effects

Size Dependent Infection effect

Parameters

Infection Effect "a"	The "a" parameter for the infection effect.
Infection Effect "b"	The "b" parameter for the infection effect.
Infection Effect "X0"	The "X0" parameter for the infection effect.
Infection Effect "Xb"	The "Xb" parameter for the infection effect.
Infection Effect "Xp"	The "Xp" parameter for the infection effect.

How it works

Infection Effect is a function of the size of the tree and the time since infested. It is calculated as:

where:

a is the Infection Effect "a" parameter
b is the Infection Effect "b" parameter
X0 is the Infection Effect "X0" parameter
Xb is the Infection Effect "Xb" parameter
Xp is the Infection Effect "Xp" parameter
diam is the diameter of the tree: diam10 if a seedling, DBH for all others
T is the time infested

Time infested comes from either the Density Dependent Infestation or Insect Infestation behaviors. Trees to which this behavior is applied must have one of these two behaviors also applied.

If a tree is not infested, there is no effect.