KillPlants – FEST

public subroutine KillPlants(dt, age, agemax, ms, mf, mr, wSx1000, dc, density, cc, ws, wr, wf, wtot)

the number of trees is updated considering the mortality of the plants. for each tree that dies, a fraction mi of the mean biomass three types of mortality are considered:

The first mortality is due to the self thinning (the one included in 3PG), which basically ensures that the mean single-tree stem biomass WS does not exceed the maximum permissible single-tree stem biomass WSx (kg·trees-1) (Sands, 2004). We assume the maximum target density is reached after 1 year
The second mortality is age dependent mortality following the approach of LPJ-GUESS (Smith et al., 2014), with aging the plants become more suceptible to the wind, diseases, etc.
the third mortality is the so called the "crowding competition function", this mortality insures that the % of cover of pixel do not exceed the 95%

References:

Sands P., “Adaptation of 3-PG to novel species: guidelines for data collection and parameter assignment”, Cooperative Research Center for Sustainable Production Forestry, 2004

Smith, B., Wårlind, D., Arneth, A., Hickler, T., Leadley, P., Siltberg, J., and Zaehle, S.: Implications of incorporating N cycling and N limitations on primary production in an individual-based dynamic vegetation model, Biogeosciences, 11, 2027–2054, https://doi.org/10.5194/bg-11-2027-2014, 2014.

Arguments

Type	Intent		Name
integer(kind=short),	intent(in)	::	dt	time step (s)
real(kind=float),	intent(in)	::	age	current tree age (year)
real(kind=float),	intent(in)	::	agemax	maximum age (year)
real(kind=float),	intent(in)	::	ms	Fraction of mean stem biomass pools per tree on each dying tree
real(kind=float),	intent(in)	::	mf	Fraction of mean follioge biomass pools per tree on each dying tree
real(kind=float),	intent(in)	::	mr	Fraction of mean roots biomass pools per tree on each dying tree
real(kind=float),	intent(in)	::	wSx1000	maximum permissible single-tree stem biomass (t)
real(kind=float),	intent(in)	::	dc	crown diameter (m)
real(kind=float),	intent(inout)	::	density	number of plants per hectar
real(kind=float),	intent(inout)	::	cc	canopy cover
real(kind=float),	intent(inout)	::	ws	stem biomass (t/ha)
real(kind=float),	intent(inout)	::	wr	roots biomass (t/ha)
real(kind=float),	intent(inout)	::	wf	folliage biomass (t/ha)
real(kind=float),	intent(inout)	::	wtot	total biomass (t/ha)

Variables

Type	Visibility		Name		Initial
real(kind=float),	public	::	CCmax	=	0.95	maximum target canopy cover
real(kind=float),	public	::	CCred			canopy cover reduction within time step
real(kind=float),	public	::	Dage			probabilistic function for age-dependent Mortality
real(kind=float),	public	::	Dselfthinning			probabilistic function for age-dependent Mortality
real(kind=float),	public	::	Dthinning			the trees number reduction after the first type of mortality
real(kind=float),	public	::	avStemMass
real(kind=float),	public	::	delStems			the number of dead trees
real(kind=float),	public	::	density_after			the updated number of the trees after considering the mortality
real(kind=float),	public	::	n
real(kind=float),	public	::	thinPower	=	3./2.
real(kind=float),	public	::	wSmax

Source Code

SUBROUTINE  KillPlants &
!
( dt, age, agemax, ms, mf, mr, wSx1000 , dc, density,  cc, ws, wr, wf, wtot ) 
    
IMPLICIT NONE

!arguments with intent(in):
INTEGER (KIND = short), INTENT(IN) :: dt !! time step (s)
REAL (KIND = float), INTENT(IN) :: age !! current tree age (year)
REAL (KIND = float), INTENT(IN) :: agemax !! maximum age (year)
REAL (KIND = float), INTENT(IN) :: ms !! Fraction of mean stem biomass pools per tree on each dying tree 
REAL (KIND = float), INTENT(IN) :: mf !! Fraction of mean follioge biomass pools per tree on each dying tree 
REAL (KIND = float), INTENT(IN) :: mr !!  Fraction of mean roots biomass pools per tree on each dying tree
REAL (KIND = float), INTENT(IN) :: wSx1000 !! maximum permissible single-tree stem biomass  (t) 
REAL (KIND = float), INTENT(IN) :: dc !! crown diameter (m)

!arguments with intent(inout):
REAL (KIND = float), INTENT(INOUT) :: density !! number of plants per hectar
REAL (KIND = float), INTENT(INOUT) :: cc !! canopy cover
REAL (KIND = float), INTENT(INOUT) :: ws !! stem biomass (t/ha)
REAL (KIND = float), INTENT(INOUT) :: wr !! roots biomass (t/ha)
REAL (KIND = float), INTENT(INOUT) :: wf !! folliage biomass (t/ha)
REAL (KIND = float), INTENT(INOUT) :: wtot !! total biomass (t/ha)



REAL (KIND = float) :: density_after !! the updated number of the trees after considering the mortality 
REAL (KIND = float) :: CCmax = 0.95 !! maximum target canopy cover 
REAL (KIND = float) :: CCred !!canopy cover reduction within time step

! Fractions of mean foliage, root and stem biomass pools per tree on each dying tree 
! 1- the first mortality, the need for this mortality should be checked at the end of each time step 
!local declarations:

!INTEGER (KIND = short) :: i
REAL (KIND = float) :: n
!REAL (KIND = float) :: X1
!REAL (KIND = float) :: X2
!REAL (KIND = float) :: dfN
!REAL (KIND = float) :: dN
!REAL (KIND = float) :: fN
REAL (KIND = float) :: Dthinning !! the trees number reduction after the first type of mortality
REAL (KIND = float) :: Dselfthinning !! probabilistic function for age-dependent Mortality
REAL (KIND = float) :: Dage !! probabilistic function for age-dependent Mortality
! variables required for the update of the biomass 
REAL (KIND = float) :: delStems !! the number of dead trees 

!DEBUG
REAL (KIND = float) :: wSmax
REAL (KIND = float) :: thinPower = 3./2.
REAL (KIND = float) :: avStemMass

!---------------------------end of declarations--------------------------------


! 1- the first type of mortality

!max stem mass
wSmax = wSx1000 * (1000 / density) ** thinPower 

!current average stem mass
avStemMass = ws / density


IF ( wSmax < avStemMass ) THEN !compute self thinning
    
    !compte maximum target density
    n = 1000. / ( avStemMass / wSx1000 ) ** (2./3.)
    
    !compute number of trees to kill
    IF (dt <  10 * year) THEN
        Dthinning = (density - n) * dt /  ( 10 * year) 
    ELSE
         Dthinning = density - n
    END IF

ELSE
        Dthinning = 0.
END IF
Dthinning = 0. !DEBUG tolgo questa mortalità, da indagare

 
!  2- the second mortality 
Dage = - 3. * lOG10 (0.001/agemax) * (age/agemax)**2  * dt / ( 10 * year)  !DEBUG lascio solo la mortalità per età


! 3- the third mortality 
IF ( cc <= CCmax) THEN !low density
    Dselfthinning = 0.
ELSE ! high density
     CCred = (cc - CCmax) * dt / ( 30 * year )
     n = 4. * (cc - CCred) * hectare / (Pi * dc**2.) 
     Dselfthinning = (density - n )
END IF
Dselfthinning = 0.  !DEBUG tolgo questa mortalità, da indagare


! UPDATE  the number of the trees after the mortality 
Density_after = density - ( density * DAGE + Dselfthinning + Dthinning )


! update the biomass pools according to the mortality of the trees

delStems= density - Density_after
wf = wf - mf * delStems * (WF / density)
wr = wr - mr * delStems * (WR / density)
ws = ws - ms * delStems * (WS / density)
wtot = wf + wr + ws

!update density
density = density_after

!update canopy cover
cc = CanopyCover (dc, density)

RETURN
END SUBROUTINE KillPlants

KillPlants Subroutine

Contents

Variables

Source Code

public subroutine KillPlants(dt, age, agemax, ms, mf, mr, wSx1000, dc, density, cc, ws, wr, wf, wtot)

Arguments

Variables

Source Code