Spatial considerations in physiological models of tree growth

To include competitive interactions in a physiologically-based model of mixed growth-form plant communities presents a major methodological problem. This paper outlines a two-step solution: (1) a spatial framework for calculating a continuous surface that depicts the magnitude of influences of crowns, roots. and sterns on resource availability, termed ECOLOGICAL FIELD THEORY (EFT), and (2) a mathematical technique for coupling water, light, and nutrients into a single growth equation using a physiologically-based continuous-time Markov approach, termed the CTM METHOD. Assumptions, limitations, and an application of the methodology to plant growth in a semiarid woodland community in Australia are presented.