Modelling growth and primary production of the marine mangrove ( Rhizophora apiculata BL): A dynamic approach

Abstract

A mathematical model was developed to simulate the growth dynamics of monospecific stands of the marine mangroves ( Rhizophora apiculata), based on physiological and morphological processes. Six variables to describe the tree organs and three morphological variables to illustrate the growth pattern were selected and incorporated in the model. The growth pattern was described by using a series of mathematical relationships. Net tree growth was derived from the combined effect of photosynthesis, respiration, and mortality. Net primary production was allocated to the tree organs based on their allometric ratios. Coefficients reported in literature were used to simulate the life history and demographics of R. apiculata. Initial diameter at breast height ( DBH), daily global radiation and mean air temperature are some of the inputs that were used to calculate the biomass and demographic parameters, using daily time steps. The model was capable of simulating the growth dynamics of R. apiculata stands at lower latitudes, with reasonable accuracy ( R 2 ≥ 0.80). However, the predictions at higher latitudes exhibited unsatisfactory model fits. This discrepancy in observations at higher latitudes is probably due to other factors like rainfall distribution, soil structure, which were not incorporated in the model structure.