Sensitivity and uncertainty analysis of an individual plant model and performance of its reduced form versions: A case study of TREGRO

Concern about the impact of environmental change on ecosystems has motivated the development of physiological response models of individual trees. This paper reports on two exercises using an advanced physiological model, TREGRO. The first exercise is systematic sensitivity and uncertainty analysis of the empirical parameters in model inputs and structure. The results identify the key sensitivities and uncertainties in predicting future plant response to climate change. The second exercise is a quantification of the loss in the predictive performance of the model as the simulation time step is increased and tree compartments are aggregated. These two sets of information are critical to the development of advanced stand models utilizing reduced form representations of individual tree responses.