ON FOREST SPATIAL DYNAMICS WITH GAP FORMATION

In ''Forest Spatial Dynamics with Gap Expansion: Total Gap Area and Ga p Size Distribution'' by Kubo and co-workers, a cellular automata mode l of gap formation is introduced. The authors claim that their model i s able to recover some of the features of the real clearing dynamics, and apply their results to a plot of a tropical rainforest in Panama. Using an analytic approximation to the model, they are able to obtain two real observations that can be compared with real systems: the glob al density of gaps po and the local density of gaps q(0/0). Neverthele ss, the gap size distribution is in most cases well fit by an exponent ial function, although the real rainforest analysed fits clearly to a power-law. Some previous work introduced the Forest Game (FG), a model of rainforest dynamics that included gap formation. The FG has been t ested with a plot of gap patchiness in the same rainforest. The FG is able to account for the exact distribution that the map presented by K ubo and co-workers displays, and we show that their model may give com patible distributions under certain conditions. Some other comments ab out this paper and the two models might be relevant for the general di scussion about gap dynamics modelling. (C) 1997 Academic Press Limited .