Software for spatially-explicit simulation of forest dynamics

Size Dependent Logistic Mortality

Size Dependent Logistic Mortality applies a mortality function that is a logistic function of tree size. Trees killed by this behavior will have a mortality reason code of "natural".

Parameters for this behavior

Parameter nameDescription
Max Mortality (0-1)Maximum mortality rate, as a value between 0 and 1.
X0Logistic function X0 parameter.
XbLogistic function Xb parameter.

How it works

For each tree to which this behavior is applied, the following function is evaluated:

  • p is the probability of mortality
  • X0 is the X0 parameter, representing the inflection point of the curve
  • Xb is the Xb parameter
  • diam is d10 for seedlings, and DBH for all other trees , in cm

The probability is compared to a random number to determine whether the individual tree will die.

How to apply it

This behavior may be applied to seedlings, saplings, and adults of any species.