PROCESSING NETWORK MODELS FOR FOREST MANAGEMENT

The Forest Management Problem of determining when and how much to plan t and harvest, to convert tree species, to spray pesticides, and to ta ke other silvicultural actions is a large scale optimization problem t hat is often formulated and solved as a linear program. Unfortunately, the algebraic representation of the model is often unintelligible to the practicing forest managers who ought to be able to manipulate the model in order to set up and examine various 'what-if' scenarios. We p ropose a solution to this communication problem: the time-expanded pro cessing network. The goal of the network diagram is to clearly convey the underlying structure, limitations, and assumptions to both mathema tical programming experts and nontechnical forest managers. The linear programming formulation then follows directly from the diagram. The p aper illustrates the model-building procedure by constructing processi ng network models for common forest behaviours including growth, fire, and pest infestation, and for common management actions including con version harvests, pest spraying, and nondeclining yield constraints.