Survival and Growth of Brazil-Nut Seedlings in Tree-Fall Gaps and Forest Understory

This study aimed to evaluate the influence of canopy openness on the survival and growth of Bertholletia excelsa seedlings, through experimental plantings in tree-fall gaps and forest understory in Madre de Dios, Peru. Sixty-four seedlings were planted within the experimental design, with eight repetitions each with four seedlings in two treatments of canopy openness. Basal diameter, height, and incidences of seedlings mortality and regrowth were evaluated for twelve months. Survivorship, and the annual increase in height and diameter were significantly higher in gaps than in the understory (p < 0.05). Regression analysis showed a direct and highly significant relation between canopy openness and diameter increment (r² = 0.61), and between canopy openness and height increment (r² = 0.34). Due to the greater performance and high survival rate of Brazil-nut seedlings in the tree-fall gaps, we recommend enrichment planting in the clearings of natural forests in Madre de Dios.

Keywords:
Bertholletia excelsa Humb. & Bonp.; canopy openness; Madre de Dios; mortality