SENSITIVITY AND UNCERTAINTY ANALYSIS OF AN INDIVIDUAL PLANT-MODEL ANDPERFORMANCE OF ITS REDUCED FORM VERSIONS - A CASE-STUDY OF TREGRO

Concern about the impact of environmental change on ecosystems has mot ivated the development of physiological response models of individual trees. This paper reports on two exercises using an advanced physiolog ical model, TREGRO. The first exercise is systematic sensitivity and u ncertainty analysis of the empirical parameters in model inputs and st ructure. The results identify the key sensitivities and uncertainties in predicting future plant response to climate change. The second exer cise is a quantification of the loss in the predictive performance of the model as the simulation time step is increased and tree compartmen ts are aggregated. These two sets of information are critical to the d evelopment of advanced stand models utilizing reduced form representat ions of individual tree responses.