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Forestry Yield Cycle


The foryield model has the essence of a forest plantation and its interface with the economy which buys the wood products. The simulation plots the stock of money in the upper graph, and the stock of wood biomass and soil nutrients in the lower graph.


Plantation forests are found all over the world, using different species in different places depending on soil and climate. Species are selected for rapid net growth. The plantation species rarely develop as much gross production as a fully developed mature forest, but the higher net production of wood meets the needs of the human economy for wood for housing, paper, cooking and many other uses.



W = Wood biomass
SW = Soil nutrients
M = Money


G = K6*M/P3
DW = K1*R*SW*W - K2*W - X*K5*W
DS = K8*G - K3*R*SW*W - K4*SW
DM = X*K5*P1*W - X*K9*W*P2 - K9*M - L1*M - K6*M


The graph shows the changes of M(red), SW(green) and W(blue) over a time period.
Source code:

"What if" Experiments:

  • What happens to yield and money earned if the environmental inputs supporting the plantation increase?
  • For some purposes such as paper manufacture, trees do not have to be large, whereas larger trees are needed for telephone poles and construction. What happens in this model when the treshold for cutting is increased? Change values for TW.