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NOTE 23.04.1985 english version 22.11.1985
note forest management model
note
note wood standing within the forest
l wood.k=wood.j+dt*(woodgrowth.jk-harvest.jk)
n wood=startingwood
c startingwood=15000 m**3
r woodgrowth.kl=wood.k*stocksfactor*cultivationfactor.k
c stocksfactor=0.04 growth in % of wood
a cultivationfactor.k=tabhl(tclfactor,clstate.k,0,1,0.1)
t tclfactor=0/.1/.2/.3/.4/.5/.7/.95/1/1.05/1.2
r harvest.kl=wood.k*harvestpercent.k*0.1
a harvestpercent.k=tabhl(tharvestpercent,ratio1.k,0.8,1.2,0.1)
t tharvestpercent=0.1/0.3/0.35/0.4/0.6
a ratio1.k=wood.k/maxstock
c maxstock=16000
note
note resources
l resources.k=resources.j+dt*(income.jk-clexpense.jk-draw.jk)
n resources=startresources
c startresources=100000 money units
r income.kl=wood.k*harvestpercent.k*0.1*price
c price=190 money units per cubic m
r clexpense.kl=resources.k-constdraw
r draw.kl=constdraw
c constdraw=20000
note
note cultivationstate (clstate; dimensionless )
l clstate.k=clstate.j+dt*(clbetter.jk-clworse.jk)
n clstate=startclstate
c startclstate=0.8
r clbetter.kl=clbetterfactor.k*(1-clstate.k)
a clbetterfactor.k=tabhl(tclbetter,cultivationcost.k,80000,180000,100000)
t tclbetter=0.0/0.1
a cultivationcost.k=resources.k-constdraw
r clworse.kl=clworsefactor.k*clstate.k
a clworsefactor.k=tabhl(tclworse,cultivationcost.k,0,80000,80000)
t tclworse=0.2/0
note
note
print wood,resources,clstate
plot wood=w/resources=r/clstate=c(0,1)
c dt=1
c length=50
c prtper=1
c pltper=1
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