A two-dimensional (think about trees growing on a checker board) version of the model displays a much more dramatic connection between production and growth. In such a model there is a very dramatic change in production as growth rates are altered.6 In physics terms, such a dramatic change is known as a phase transition, and it can be shown (via percolation theory) that there is a “critical value” of g that results in the system going from a largely disconnected collection of trees to one in which all the trees are connected together as one.
