Characterizing a forest mosaic and its dynamics in an evergreen tropical rainforest

Using a 0.78 ha transect in an undisturbed forest in French Guiana, we sought a typology of forest mosaic units (5 x 5 m quadrats) based on diameter distribution with three main classes of trees greater than or equal to 5 cm DBH. We identified nine basic structural types corresponding to potential stages of a sequence of development from colonization of gaps to filling of the vertical space among three layers. Two enumerations made over a 10-year interval (1981 and 1991), enabled a transition matrix to be estimated. This summarizes movement between structural types over the period and enables ideas on dynamics to be discussed.