In cohort mode only, an average disturbance interval may be specified. This results in stochastic disturbances that recur with the specified expected frequency in each patch, destroying all biomass there. The default disturbance interval specified in the sample instruction file for cohort mode is 100 years, but this may be changed by modifying the following setting in the instruction file:
distinterval 100
Patch-destroying disturbances may also by switched off by specifying 0 instead of 1 in the setting:
ifdisturb 1
Note that when the disturbance interval is increased or disturbances are switched off, a longer initialisation (spin up) is required for vegetation to come to equilibrium with the long-term climate. The recommended length of the initialisation phase is five times the disturbance interval or at the most 1000 years. The length of the initialisation phase is specified when you create an environmental driver file with GetClim. Further advice is available here.