When one is attempting to simulate the dynamic response of the vegetation over short timescales (days to as long as years), it is efficacious to ignore the change in the vertical and the horizontal structure of natural vegetation. At longer timescales, for example, the timescales associated with monitoring and predicting interannual variation in the vegetation, structural dynamics can strongly alter the process-based predictions of such features as ecosystem productivity. There are ecosystem models that have the capability of simulating structural change, and these models have been tested to some degree using large-scale remotely sensed information. This paper reviews types of ecological modeling approaches used for evaluations of terrestrial vegetation change at large-area and longer-than-annual timescale. It then provides examples of results from models that simulate structural change. Finally, examples of ecosystem dynamics that change with spatial scale are presented. ¿ 2000 American Geophysical Union