This model is a replication of that described by Peterson (2002) and illustrates the ‘spread’ feedback loop type described in Millington (2013). In spread feedback, spatial patterns influence spread processes which influence later spatial patterns and hence later spread processes. In ecology, this concept of processes being shaped by their history is known as the ‘memory’ of the process (Peterson 2002). For wildland fire, memory – and therefore feedbacks between spread and spatial pattern – has been conceptualized as being contained in vegetation flammability as a function of time since last the fire. In this model version red patches indicate areas burned in a given time step, green patches the length of time since the last fire at that location (lighter, fire more recently).