Biomass and nutrients removed in a first thinning from a of Bertholletia excelsa Bonpl. plantation

Abstract

The quantification of biomass and nutrient exportation by thinning can be useful to define the desired strategy for forest plantation management. The main objective of this study was to investigate the exportation of biomass and nutrients of the different tree compartments of B. excelsa removed from the first thinning at an eight-years-old plantation. It was determined by the destructive method the stock of biomass and nutrients in 20 trees, distributed in four different diametric classes (I= 1.3-| 5.6 cm, II= 5.6-| 9.9 cm, III= 9.9-| 14.2 cm, IV=14.2-| 18.6 cm). The total biomass exported in the first thinning of B. excelsa was 16.1 Mg ha-1 represented. From this total, leaves, fine branches, and stem 10, 17 and 73% respectively. The greater concentration of the micro and macronutrients was observed in the crow (leaves and fine branches). The crown represents 57% the total of nutrient stock. It was not observed a significant pattern for the accumulation of macronutrients, however for the micronutrients it was observed greater values for Mn > Fe > Zn > Cu in the different tree compartments. The fact that the leaves and branches showed a significant contribution for the total nutrient stocks suggests the maintenance of these compartments on the plantation area during thinning procedures for this species.