Modeling Tree Diameter Growth of Bertholletia excelsa Bonpl. in the Brazilian Amazon

Abstract

Modeling the growth of Bertholletia excelsa Bonpl. (B. excelsa) trees in natural forests is important for understanding the species’ ecology and for better defining site-specific management. In this sense, this study aimed to model the diameter growth rate of B. excelsa trees in contrasting forest environments in the Brazilian Amazon. This study was conducted in the Extractive Reserve Rio Cajari (RESEX Cajari). Growth models were fitted at species level to predict diameter growth rate in the two Amazonian forest environments. Subsequently, the age at which the B. excelsa tree in each forest environment reaches the minimum diameter for seed production was calculated by integrating the growth models. In each forest environment, the negative exponential behavior of the diametric growth rate of the tree species was fitted by an appropriate model. The time required for B. excelsa trees to reach the minimum diameter was shorter in the secondary forest environment when compared with that of the old growth terra firme forest (47 and 78 years to reach the diameter of 25 cm in the secondary and old growth terra firme forest, respectively). While the average growth pattern indicated higher diameter growth rates of B. excelsa in the secondary forest environment, the high level of uncertainty in the model’s estimation makes this inference complex. In conclusion, the secondary forest seems a favorable forest environment for the growth of B. excelsa trees, which may be an indicator of the potential for secondary forest environments to produce B. excelsa seeds in the future.