We present a general stochastic forest-fire model which shows a variety of different structures depending on the parameter values. The model contains three possible states per site (tree, burning tree, empty site) and three parameters (tree growth probability p, lightning probability f, and...

A forest-fire model is introduced which contains a lightning probability f. This leads to a self-organized critical state in the limit f→0 provided that the time scales of free growth and burning down of forest clusters are separated. We derive scaling laws and calculate all critical...

We present a generalization of the forest-fire model of P. Bak et al. by including the immunity g which is the probability that a tree is not ignited although one of its neighbors is burning. When g reaches a critical value gc(p), which depends on the tree growth rate p, the fire cannot survive...

A model based on quantitative genetics for the coevolution of plants and their pollinators is proposed. The model is characterized by competition for resources and by a two-fold coupling between the two types of species: pollinators depend on plants for resources and plants on pollinators for...

We review properties of the self-organized critical (SOC) forest-fire model (FFM). Self-organized critical systems drive themselves into a critical state without fine-tuning of parameters. After an introduction, the rules of the model, and the conditions for spiral shaped and SOC large-scale...