Mortality utility behaviors

In this document:


Mortality utility parameters
Dead tree remover
Mortality reporter

Mortality utility parameters

Dead tree remover

This behavior performs cleanup by removing dead trees from memory at the appropriate time. This function is very important - if it did not occur, then the model would slow exponentially as memory filled up and those behaviors that look at recently dead trees would start getting strange results.

How it works

This behavior looks for the death flag as set by the mortality behaviors. For each tree that it finds with that flag, it sends a request to the tree population to "kill" the tree. The reason code stored in the death flag is passed to the tree population. The tree population acts according to the tree type and mortality reason.

This behavior can also allow only a portion of trees dead in a given timestep to become snags, and the proportion allowed can vary by mortality reason (see parameters above). A randomly selected group of trees become snags according to this proportion. Trees that do not become snags are removed immediately. This only applies if a run is "snag aware". This may interfere or cancel out snag management activities by other behaviors, particularly disturbance behaviors. Carefully check the documentation for other behaviors in the run. Not all mortality reason codes may apply to a given run.

How to apply it

This behavior automatically applies itself to all trees that have a mortality behavior applied.

Mortality reporter

This behavior reports how many trees were killed in the previous time step, and why.

How it works

The behavior examines all trees in the tree population to see which ones are flagged as dead. For those trees that are dead, it counts them by life history stage and mortality reason code, and also totals the basal area for trees larger than seedlings. The total tree numbers and total basal area for the plot are reported in the Dead Trees grid. The values are not converted to per hectare amounts. Not all possible mortality reasons will necessarily be implemented in any given run.

Harvested trees are never reported by this behavior. They are reported separately by the Harvest behavior. If a Substrate behavior is enabled, it may remove dead trees before they can be counted by this behavior.

How to apply it

Add this behavior to your run. You do not need to apply it to individual tree types or species. It will automatically count all dead trees that it finds.


18-Nov-2010 12:38 PM