Updates to land use clearing logic

biogeochem/EDPatchDynamicsMod.F90

@@ -554,6 +554,7 @@ subroutine spawn_patches( currentSite, bc_in )
     integer  :: n_pfts_by_landuse
     integer  :: which_pft_allowed
     logical  :: buffer_patch_used
+    logical  :: clear_all
     !---------------------------------------------------------------------
 
     if (hlm_use_nocomp .eq. itrue) then
@@ -772,9 +773,17 @@ subroutine spawn_patches( currentSite, bc_in )
                                call mortality_litter_fluxes(currentSite, currentPatch, &
                                     newPatch, patch_site_areadis,bc_in)
                             case (dtype_ilandusechange)
+                               ! If we are clearing to make crops, then kill everything
+                               if (i_landusechange_receiverpatchlabel .eq. end_receiver_lulabel) then
+                                  clear_all = itrue
+                               else ! otherwise kill a fraction of the cohort determined by the clearing mortality param
+                                  clear_all = ifalse
+                               end if
+
                                call landusechange_litter_fluxes(currentSite, currentPatch, &
                                     newPatch, patch_site_areadis,bc_in, &
-                                    clearing_matrix(i_donorpatch_landuse_type,i_landusechange_receiverpatchlabel))
+                                    clearing_matrix(i_donorpatch_landuse_type,i_landusechange_receiverpatchlabel), &
+                                    clear_all)
 
                                ! if land use change, then may need to change nocomp pft, so tag as having transitioned LU
                                newPatch%changed_landuse_this_ts = .true.
@@ -1300,8 +1309,17 @@ subroutine spawn_patches( currentSite, bc_in )
 
                                   ! now apply survivorship based on the type of landuse transition
                                   if ( clearing_matrix(i_donorpatch_landuse_type,i_landusechange_receiverpatchlabel) ) then
-                                     ! kill everything
-                                     nc%n = 0._r8
+
+
+                                     ! If we are clearing for crops then kill everything
+                                     ! Note crops needs to be last lu class for this logic to work 
+                                     if (i_landusechange_receiverpatchlabel == end_receiver_lulabel ) then
+                                        nc%n = 0._r8
+                                     else
+                                        ! Otherwise kill some proportion of the PFT based on the PFT-level clearing mortality parameter
+                                        nc%n = nc%n * (1.0_r8 - EDPftvarcon_inst%landuse_clearing_mortality(currentCohort%pft) )
+                                     end if
+
                                   end if
 
                                case default
@@ -2615,12 +2633,15 @@ end subroutine mortality_litter_fluxes
 
   subroutine landusechange_litter_fluxes(currentSite, currentPatch, &
        newPatch, patch_site_areadis, bc_in,  &
-       clearing_matrix_element)
+       clearing_matrix_element, clear_all)
     !
     ! !DESCRIPTION:
     !  CWD pool from land use change.
     !  Carbon going from felled trees into CWD pool
-    !  Either kill everything or nothing on disturbed land, depending on clearing matrix
+    !  Whether or not to clear PFTs during transition from one land use class
+    !  to another is based on the clearing logic matrix. 
+    !  If clearing occurs, the fraction of the PFT killed depends on the
+    !  pft-level clearing mortality parameter
     !
     ! !USES:
     use SFParamsMod,          only : SF_VAL_CWD_FRAC
@@ -2632,7 +2653,8 @@ subroutine landusechange_litter_fluxes(currentSite, currentPatch, &
     real(r8)               , intent(in)            :: patch_site_areadis ! Area being donated
     type(bc_in_type)       , intent(in)            :: bc_in
     logical                , intent(in)            :: clearing_matrix_element ! whether or not to clear vegetation
-
+    logical                , intent(in)            :: clear_all ! should all vegetation be killed - applies to crops
+
     !
     ! !LOCAL VARIABLES:
 
@@ -2679,7 +2701,13 @@ subroutine landusechange_litter_fluxes(currentSite, currentPatch, &
        if (hlm_use_planthydro == itrue) then
           currentCohort => currentPatch%shortest
           do while(associated(currentCohort))
-             num_dead_trees  = (currentCohort%n*patch_site_areadis/currentPatch%area)
+
+             if (clear_all) then
+                num_dead_trees = (currentCohort%n * patch_site_areadis/currentPatch%area)
+             else
+                num_dead_trees  = (currentCohort%n*patch_site_areadis/currentPatch%area) * &
+                     EDPftvarcon_inst%landuse_clearing_mortality(currentCohort%pft)
+             end if
              call AccumulateMortalityWaterStorage(currentSite,currentCohort,num_dead_trees)
              currentCohort => currentCohort%taller
           end do
@@ -2750,8 +2778,15 @@ subroutine landusechange_litter_fluxes(currentSite, currentPatch, &
 
 
              ! Absolute number of dead trees being transfered in with the donated area
-             num_dead_trees = (currentCohort%n * &
-                  patch_site_areadis/currentPatch%area)
+
+             if (clear_all) then
+                num_dead_trees = (currentCohort%n * &
+                     patch_site_areadis/currentPatch%area)
+             else
+                num_dead_trees = (currentCohort%n * &
+                     patch_site_areadis/currentPatch%area) * &
+                     EDPftvarcon_inst%landuse_clearing_mortality(pft)
+             end if
 
              ! Contribution of dead trees to leaf litter
              donatable_mass = num_dead_trees * (leaf_m+repro_m) * &

biogeochem/FatesLandUseChangeMod.F90

@@ -16,6 +16,7 @@ module FatesLandUseChangeMod
   use FatesInterfaceTypesMod    , only : hlm_num_luh2_states
   use FatesInterfaceTypesMod    , only : hlm_num_luh2_transitions
   use FatesInterfaceTypesMod    , only : hlm_use_potentialveg
+  use FatesInterfaceTypesMod    , only : hlm_lu_transition_logic 
   use FatesUtilsMod             , only : FindIndex
   use EDTypesMod                , only : area_site => area
 
@@ -178,13 +179,19 @@ subroutine GetLanduseChangeRules(clearing_matrix)
     ! the purpose of this is to define a ruleset for when to clear the vegetation in transitioning
     ! from one land use type to another
 
+
     logical, intent(out) :: clearing_matrix(n_landuse_cats,n_landuse_cats)
+
+    ! local variables
+    integer :: ruleset
 
     ! default value of ruleset 4 above means that plants are not cleared during land use change
     ! transitions to rangeland, whereas plants are cleared in transitions to pasturelands and croplands.
-    integer, parameter    :: ruleset = 4   ! ruleset to apply from table 1 of Ma et al (2020)
-    ! https://doi.org/10.5194/gmd-13-3203-2020
 
+    ! ruleset to apply from table 1 of Ma et al (2020)
+    ! https://doi.org/10.5194/gmd-13-3203-2020
+    ruleset = hlm_lu_transition_logic
+
     ! clearing matrix applies from the donor to the receiver land use type of the newly-transferred
     ! patch area values of clearing matrix: false => do not clear; true => clear
 

main/EDPftvarcon.F90

@@ -266,6 +266,9 @@ module EDPftvarcon
      ! Grazing
      real(r8), allocatable :: landuse_grazing_palatability(:) ! Relative intensity of leaf grazing/browsing per PFT (unitless 0-1)
 
+     ! Clearing mortality rate
+     real(r8), allocatable :: landuse_clearing_mortality(:) ! Fraction of cohort killed when patch is cleared during land use transitions
+
    contains
      procedure, public :: Init => EDpftconInit
      procedure, public :: Register
@@ -738,6 +741,10 @@ subroutine Register_PFT(this, fates_params)
          dimension_names=dim_names, lower_bounds=dim_lower_bound)
 
     name = 'fates_landuse_grazing_palatability'
+    call fates_params%RegisterParameter(name=name, dimension_shape=dimension_shape_1d, &
+         dimension_names=dim_names, lower_bounds=dim_lower_bound)
+
+        name = 'fates_landuse_clearing_mortality'
     call fates_params%RegisterParameter(name=name, dimension_shape=dimension_shape_1d, &
          dimension_names=dim_names, lower_bounds=dim_lower_bound)
 
@@ -1169,6 +1176,10 @@ subroutine Receive_PFT(this, fates_params)
     call fates_params%RetrieveParameterAllocate(name=name, &
          data=this%landuse_grazing_palatability)
 
+    name = 'fates_landuse_clearing_mortality'
+    call fates_params%RetrieveParameterAllocate(name=name, &
+         data=this%landuse_clearing_mortality)
+
   end subroutine Receive_PFT
 
   !-----------------------------------------------------------------------

main/FatesInterfaceMod.F90

@@ -1507,6 +1507,7 @@ subroutine set_fates_ctrlparms(tag,ival,rval,cval)
          hlm_num_lu_harvest_cats   = unset_int
          hlm_num_luh2_states       = unset_int
          hlm_num_luh2_transitions  = unset_int
+         hlm_lu_transition_logic = unset_int
          hlm_use_cohort_age_tracking = unset_int
          lb_params%dayl_switch = unset_int
          lb_params%photo_tempsens_model = unset_int
@@ -2056,7 +2057,13 @@ subroutine set_fates_ctrlparms(tag,ival,rval,cval)
                if (fates_global_verbose()) then
                   write(fates_log(),*) 'Transfering hlm_num_luh2_transitions= ',ival,' to FATES'
                end if
-
+
+            case('fates_lu_transition_logic')
+               hlm_lu_transition_logic = ival
+               if (fates_global_verbose()) then
+                  write(fates_log(),*) 'Transfering hlm_lu_transition_logic= ',ival,' to FATES'
+               end if
+
             case('use_cohort_age_tracking')
                hlm_use_cohort_age_tracking = ival
                if (fates_global_verbose()) then

main/FatesInterfaceTypesMod.F90

@@ -120,6 +120,10 @@ module FatesInterfaceTypesMod
                                                          ! If 1, it automatically sets
                                                          ! hlm_use_logging to 1
 
+   integer, public :: hlm_lu_transition_logic    ! This flag signals which logic to use in transitions between land use classes
+                                                 ! See the FATES user guide for full description of options
+
+
    integer, public :: hlm_num_lu_harvest_cats    ! number of hlm harvest categories (e.g. primary forest harvest, secondary young forest harvest, etc.)
                                                          ! this is the first dimension of:
                                                          ! harvest_rates in dynHarvestMod

parameter_files/fates_params_default.cdl

@@ -350,7 +350,10 @@ variables:
 		fates_hydro_vg_n_node:long_name = "(used if hydr_htftype_node = 2),n in van Genuchten 1980 model, pore size distribution parameter" ;
 	double fates_landuse_grazing_palatability(fates_pft) ;
 		fates_landuse_grazing_palatability:units = "unitless 0-1" ;
-		fates_landuse_grazing_palatability:long_name = "Relative intensity of leaf grazing/browsing per PFT" ;
+		fates_landuse_grazing_palatability:long_name = "Relative intensity of leaf grazing/browsing per PFT" ;	
+	double fates_landuse_clearing_mortality(fates_pft) ;
+		fates_landuse_clearing_mortality:units = "fraction" ;
+		fates_landuse_clearing_mortality:long_name = "Fraction of cohort killed during land use clearing" ;
 	double fates_landuse_harvest_pprod10(fates_pft) ;
 		fates_landuse_harvest_pprod10:units = "fraction" ;
 		fates_landuse_harvest_pprod10:long_name = "fraction of harvest wood product that goes to 10-year product pool (remainder goes to 100-year pool)" ;
@@ -1362,6 +1365,8 @@ data:
 
  fates_landuse_grazing_palatability = 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1 ;
 
+ fates_landuse_clearing_mortality = 0.8, 0.8, 0.8, 0.8, 0.8, 0.8, 1, 1, 1, 1, 1, 1, 1, 1 ;	
+
  fates_landuse_harvest_pprod10 = 1, 0.75, 0.75, 0.75, 1, 0.75, 1, 1, 1, 1, 1, 
     1, 1, 1 ;