SORTIE-ND
Software for spatially-explicit simulation of forest dynamics

Logistic growth

This behavior does either diameter or height growth as a function of GLI.

Parameters for this behavior

Parameter nameDescription
Logistic - Asymptotic Diam Growth - Full Light in mm/yr (a)Asymptotic annual growth at full light, in mm/yr, for diameter growth.
Logistic - Diam Shape Param 1 (b)Shape parameter 1, for diameter growth.
Logistic - Diam Shape Param 2 (c)Shape parameter 2, for diameter growth.
Logistic - Asymptotic Height Growth - Full Light in cm/yr (a)Asymptotic annual growth at full light, in cm/yr, for height growth.
Logistic - Height Shape Param 1 (b)Shape parameter 1, for height growth.
Logistic - Height Shape Param 2 (c)Shape parameter 2, for height growth.

How it works

The amount of diameter increase is calculated as:

where

• Y = amount of diameter increase, in mm, or the amount of height increase, in cm
• a = Logistic - Asymptotic Diam Growth - Full Light in mm/yr (a) parameter (for diameter growth) or the Logistic - Asymptotic Height Growth - Full Light in cm/yr (a) parameter (for height growth)
• b = Logistic - Diam Shape Param 1 (b) parameter (for diameter growth) or the Logistic - Height Shape Param 1 (b) parameter (for height growth)
• c = Logistic - Diam Shape Param 2 (c) parameter (for diameter growth) or the Logistic - Height Shape Param 2 (c) parameter (for height growth)
• GLI = global light index, as a percentage between 0 and 100, calculated by a light behavior
• T = number of years per timestep

How to apply it

This behavior can be applied to seedlings, saplings, and adults of any species. Any tree species/type combination to which it is applied must also have a light behavior applied. You can choose either a diam with auto height, diam only, or height only version.