Sensitivity analysis of insect and disease model extensions

Most FVS insect and disease model extensions are a blend of process modeling and empirical relationships. Because of the process elements, insect and disease models can present unexpected results when simulated conditions are unlike those tested when the model was developed. Sensitivity analysis is a systematic procedure to test the model reaction to changes in inputs. It can expose a range of model problems, as well as indicate the level of precision the model can provide for changes in inputs. Statistical procedures have been employed for sensitivity analysis for FVS insect and disease models, including the annosus root disease model, western root disease model, and the dwarf mistletoe model. Graphical procedures have been used for the sensitivity analysis of the Westwide Pine Beetle Model and some aspects of the annosus root disease model. These analyses have produced useful information concerning both the construction and the operation of the models.