Silvicultural management of Brazil nut trees for wood and fruit production in a commercial plantation in the Amazon

Roberval Monteiro Bezerra de Lima, Cintia Rodrigues de Souza, Zilza Thayane Matos Guimarães

Bertholletia excelsa; volume equation; Brazil nut production; multiple-use management.

Background: This study integrated rigorous stem volume measurements and reproductive monitoring to evaluate the management of commercial Brazil nut (Bertholletia excelsa Bonpl.) plantations in the Amazon. Wood productivity was assessed in 110 trees aged 9-23.5 years by fitting 23 equations for total volume over bark. Fruit production comprised six harvests (2013, 2016, 2020, 2024, 2025, and 2026), five clones, and individually identified trees. Materials and Methods: A total of 110 cubed trees aged 9-23.5 years were analyzed, and 23 equations for total volume over bark were fitted. Fruit production was evaluated over six harvests by clone and tree using descriptive statistics and a linear mixed-effects model with harvest as a fixed effect and clone and tree nested within clone as random effects. Pearson and Spearman correlations were used to explore associations with annual precipitation. Results: The double-entry Weibull model based on diameter at breast height (DBH) and total height showed the best volumetric performance (RMSE = 0.1006 m3; adjusted R2 = 0.9623; CV-RMSE = 0.1078 m3). Estimated mean volumes ranged from 0.254 to 0.640 m3 tree-1 across age strata. For reproductive production, clone m_pedro yielded 3,440 fruits, and tree m_pedro527 yielded 757 fruits over six harvests. Variance in transformed production was partitioned into 21.7% among clones, 26.7% among trees within clones, and 51.6% residual variance. Total production was not significantly associated with annual precipitation in the preceding year (r = -0.03; p = 0.900) or two years earlier (r = 0.24; p = 0.389). The results support inventories based on DBH and height, simultaneous selection at the clone and tree levels, and continued monitoring. Conclusion: The double-entry Weibull equation is recommended for local inventories within the sampled range. Selection of reproductive material should combine mean clone performance, individual superiority, and stability across multiple harvests. Future integration of growth and fruiting measurements on the same trees is required to define multiple-use management regimes.

Received: 18 Jul 2026, Received in revised form: 17 Aug 2026, Accepted: 21 Aug 2026, Available online: 29 Aug 2026

10.22161/ijaers.138.10