Merge pull request #7 from rgknox/secondary_forest

Secondary forest

Author: ckoven

biogeochem/EDCanopyStructureMod.F90

@@ -13,6 +13,7 @@ module EDPatchDynamicsMod
   use EDTypesMod           , only : maxPatchesPerSite_by_disttype  
   use EDTypesMod           , only : ed_site_type, ed_patch_type, ed_cohort_type
   use EDTypesMod           , only : min_patch_area
+  use EDTypesMod           , only : min_patch_area_forced
   use EDTypesMod           , only : nclmax
   use EDTypesMod           , only : maxpft
   use EDTypesMod           , only : dtype_ifall
@@ -2058,16 +2059,28 @@ subroutine terminate_patches(currentSite)
     type(ed_patch_type), pointer :: currentPatch
     type(ed_patch_type), pointer :: olderPatch
     type(ed_patch_type), pointer :: youngerPatch
+    integer, parameter           :: max_cycles = 10  ! After 10 loops through
+                                                     ! You should had fused
+    integer                      :: count_cycles
 
     real(r8) areatot ! variable for checking whether the total patch area is wrong. 
     !---------------------------------------------------------------------
 
+    count_cycles = 0
+
     currentPatch => currentSite%youngest_patch
     do while(associated(currentPatch)) 
 
        if(currentPatch%area <= min_patch_area)then
 
-          if ( .not.associated(currentPatch,currentSite%youngest_patch) ) then
+          ! Even if the patch area is small, avoid fusing it into its neighbor
+          ! if it is the youngest of all patches. We do this in attempts to maintain
+          ! a discrete patch for very young patches
+          ! However, if the patch to be fused is excessivlely small, then fuse
+          ! at all costs.  If it is not fused, it will make
+
+          if ( .not.associated(currentPatch,currentSite%youngest_patch) .or. &
+               currentPatch%area <= min_patch_area_forced ) then
 
              if(associated(currentPatch%older) )then
 
@@ -2088,12 +2101,12 @@ subroutine terminate_patches(currentSite)
                 ! This logic checks to make sure that the younger patch is not the youngest
                 ! patch. As mentioned earlier, we try not to fuse it.
 
-             elseif( .not. associated(currentPatch%younger,currentSite%youngest_patch) ) then
+             elseif( associated(currentPatch%younger) ) then
 
                 if(debug) &
                       write(fates_log(),*) 'fusing to younger patch because oldest one is too small', &
                       currentPatch%area
-                
+
                 youngerPatch => currentPatch%younger
                 call fuse_2_patches(currentSite, youngerPatch, currentPatch)
 
@@ -2102,22 +2115,44 @@ subroutine terminate_patches(currentSite)
              endif
           endif
        endif
-          
-       currentPatch => currentPatch%older
 
+       ! It is possible that an incredibly small patch just fused into another incredibly
+       ! small patch, resulting in an incredibly small patch.  It is also possible that this
+       ! resulting incredibly small patch is the oldest patch.  If this was true than
+       ! we would had been at the end of the loop, and left with an incredibly small patch.
+       ! Think this is impossible? No, this really happens, especially when we have fires.
+       ! So, we don't move forward until we have merged enough area into this thing.
+
+       if(currentPatch%area > min_patch_area_forced)then
+          currentPatch => currentPatch%older
+          count_cycles = 0
+       else
+          count_cycles = count_cycles + 1
+       end if
+
+       if(count_cycles > max_cycles) then
+          write(fates_log(),*) 'FATES is having difficulties fusing very small patches.'
+          write(fates_log(),*) 'It is possible that a either a secondary or primary'
+          write(fates_log(),*) 'patch has become the only patch of its kind, and it is'
+          write(fates_log(),*) 'is very very small. You can test your luck by'
+          write(fates_log(),*) 'disabling the endrun statement following this message.'
+          write(fates_log(),*) 'FATES may or may not continue to operate within error'
+          write(fates_log(),*) 'tolerances, but will generate another fail if it does not.' 
+          call endrun(msg=errMsg(sourcefile, __LINE__))
+          
+          ! Note to user. If you DO decide to remove the end-run above this line
+          ! Make sure that you keep the pointer below this line, or you will get
+          ! an infinite loop.
+          currentPatch => currentPatch%older
+          count_cycles = 0
+       end if
+
     enddo
 
     !check area is not exceeded
-    areatot = 0._r8
-    currentPatch => currentSite%oldest_patch
-    do while(associated(currentPatch))
-       areatot = areatot + currentPatch%area
-       currentPatch => currentPatch%younger
-       if((areatot-area) > 0.0000001_r8)then
-          write(fates_log(),*) 'ED: areatot too large. end terminate', areatot
-       endif
-    enddo
+    call check_patch_area( currentSite )
 
+    return
   end subroutine terminate_patches
 
   ! =====================================================================================

biogeochem/EDCohortDynamicsMod.F90

@@ -60,7 +60,6 @@ module EDPhysiologyMod
   use FatesAllometryMod  , only : bbgw_allom
   use FatesAllometryMod  , only : carea_allom
   use FatesAllometryMod  , only : CheckIntegratedAllometries
-  use FatesAllometryMod  , only : StructureResetOfDH
 
   use PRTGenericMod, only : prt_carbon_allom_hyp
   use PRTGenericMod, only : leaf_organ
@@ -259,7 +258,8 @@ subroutine trim_canopy( currentSite )
 
           currentCohort%treesai = tree_sai(currentCohort%pft, currentCohort%dbh, currentCohort%canopy_trim, &
                                            currentCohort%c_area, currentCohort%n, currentCohort%canopy_layer, &
-                                           currentPatch%canopy_layer_tlai, currentCohort%treelai,currentCohort%vcmax25top )  
+                                           currentPatch%canopy_layer_tlai, currentCohort%treelai, &
+                                           currentCohort%vcmax25top,0 )  
 
           currentCohort%nv      = ceiling((currentCohort%treelai+currentCohort%treesai)/dinc_ed)