SORTIEND
Software for spatiallyexplicit simulation of forest dynamics 

Logistic bilevel mortalityThis behavior calculates the probability of survival according to a logistic equation, with the possibility of two sets of parameters for each species: one for highlight conditions and one for lowlight conditions. This can also be used alone without the light levels. Trees killed by this behavior will have a mortality reason code of "natural". Parameters for this behavior
How it worksThe equation used by this behavior to calculate survival probability is: where
If the timestep length is not one year, the actual probability of survival for the timestep is calculated as p' = p^{ T}, where p is the annual probability of survival, p' is the timestep probability of survival, and T is the number of years per timestep. Once the survival probability for the timestep is known for a tree, then a random number is compared to this probability to determine if the tree lives or dies. Light levels come from the Storm Light grid produced by the Storm Light behavior. The threshold between the use of highlight and lowlight parameters is set in the Logistic BiLevel  HighLight Mortality Threshold (0100) parameter. This behavior can also be used without Storm Light. In this case, only the lowlight mortality parameters are used. How to apply itThis behavior can be applied to seedlings, saplings, and adults of any species. If you wish to use the lightlevel parameter switch, also use the Storm Light behavior. 

FAQ  Contact Us
