DYNAMICS OF DENSE TROPICAL RAIN-FOREST CO MMUNITIES - OUTLINE OF A SINGLE TREE MODEL IN PARACOU (FRENCH-GUIANA)

A distance dependent single tree modelling project for tropical rain f orest dynamics is presented. Data are from the Paracou experimental de sign in French Guiana. As a first step, different species will not be distinguished in the model. Deterministic and random models are combin ed to simulate tree growth. A POTENTIAL REDUCER equation is used to model the deterministic part of individual tree diameter growth. POTEN TIAL is potential increment without competition (in this case, maximal diameters increments observed) and is fitted by a Korf model. REDUCER is a multilinear function of competition indices which takes into acc ount the number and size of neighbouring trees to reduce the potential growth of a subject. This deterministic model accounts for at most 15 .6% of the observed variance. Density dependent mortality will be desc ribed by a logistic model taking into account the tree features and ne ighbourhood. Tree falls will be simulated at random. Natural regenerat ion modelling will involve small discrete unit areas, as in gap models , where each height stratum demography will depend on upper strata. Se ed dispersal and tree fall range will account for spatial relationship s within unit areas. At that time, the mortality and regeneration data still have to be analysed.