The value defaults to 1 if there are no cohorts. I don't have any reason to believe this is affecting results. But I do see this as a code vulnerability. Obviously there are no canopy layers if there are no cohorts, and this would potentially affect logic and looping erroneously in various parts of the code.
See here where we calculate the number of canopy layers:
https://github.com/NGEET/fates/blob/main/biogeochem/EDCanopyStructureMod.F90#L2285
The value defaults to 1 if there are no cohorts. I don't have any reason to believe this is affecting results. But I do see this as a code vulnerability. Obviously there are no canopy layers if there are no cohorts, and this would potentially affect logic and looping erroneously in various parts of the code.