In the 3D-CMCC-FEM three different mortality are simulated within different routines acting at different spatial and temporal scales.
One, a ‘background’ mortality, which stochastically accounts for the age-dependent probability for a tree to die-off which increases based on species-specific maximum age in a logistic regression form.
The second ’mortality’ considers the annual balance between depletion of non-structural carbohydrates through substrate-dependant maintenance respiration and its accrual through NPP; when, all over the simulation period, NSC pool is fully depleted (i.e. carbon starvation), the model removes such trees (or cohorts).
The third is a crowding competition (e.g. self-thinning) mortality function based on dbh-crown increases.
The second and the latter mortality are iteratively solved and computed on a daily and monthly scale and represent the ‘physiological-environmental’ and ‘physiological-structural’ mortality into the model, respectively.