~ ~ ~ PURPOSE ~ ~ ~ this subroutine checks the dormant status of the different plant types
check for beginning of dormant season beginning of temperature based perennial dormant period - above ground senescence add dead stem mass to residue pool drop lai to minimum if not already compute leaf biomass drop add all seed/fruit mass to residue pool add all seed/fruit mass to residue pool beginning of cool season annual dormant period check if end of dormant period end of perennial dormant period end of cool season annual dormant period