This behavior calculates the probability of mortality of an individual juvenile tree as a function of the density and mean diameter of the neighborhood trees. Only neighborhood seedlings and saplings are taken into account in this behavior.
Trees killed by this behavior will have a mortality reason code of "natural".
Parameter name | Description |
---|---|
Density Self-Thinning Asymptote (A) | The asymptote of the density self-thinning function. |
Density Self-Thinning Density Effect (S) | The parameter controlling the density effect of the density self-thinning function. |
Density Self-Thinning Diameter Effect (C) | The parameter controlling the effect of neighbor mean diameter of the density self-thinning function. |
Density Self-Thinning Minimum Density for Mortality (#/ha) | The minimum density of neighbors, in stems/ha, for density self-thinning mortality. A tree with a lower density of neighbors than this value will not die. |
Density Self-Thinning Neighborhood Radius, in m | The maximum radius, in m, within which to search for neighbors to calculate neighbor density for density self-thinning. |
The probability of mortality is calculated with a double Michaelis-Menton function:
where:
If the value of density is less than the value in the Density Self-Thinning Minimum Density for Mortality (#/ha) parameter, the tree does not die.
This behavior can be applied to seedlings and saplings of any species. It cannot be applied to adults. This behavior can only be applied with a one year timestep.