Components of functional-structural tree models

We analyze functional-structural tree models (FMSs) that are an outgrowth o f developments in process-based models (PBMs) on the one hand, and morpholo gical models on the other. Existing morphological and functional-structural models are briefly reviewed. We introduce the idealized elementary unit (I EU) that can be used as the basic component of a FSM, and pinpoint the proc esses that have to be accounted for. The distribution of metabolites and gr owth is identified as one of the main focal points to be investigated in co njunction with FSMs, and the different approaches that can be applied in co nstructing the model component for this process are presented. Finally, we analyze the computational requirements of FSMs, discuss the challenges they pose, and assess their applicability in st number of different tasks.