Bimodality for plant sizes and spatial pattern in cohorts: the role of competition and site conditions.

The well-known size bimodality in cohorts of plants is revisited with methods emphasizing generic modeling. A link between bimodality and interface growth in nonequilibrium statistical physics is emphasized: the development of bimodality is understood as a phase transition like interface roughening. A specific model is proposed, inspired by gap models. It is used to illustrate generic results, to understand the end point of mean field approximation and aggregation of variables, and to discuss the role of site and competition for the development of a social hierarchy within a forest stand, in a wider ecological context. Copyright 2001 Academic Press.