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

Abstract

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. Sixtyfour 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 (r 2 = 0.61), and between canopy openness and height increment (r 2 = 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.

Growth and survival over ten years of Brazil-nut trees planted in three anthropogenic habitats in northern Amazonia

“…In an enrichment planting in a central Amazonian secondary forest, growth in height of B. excelsa was highest during the second year and responded positively to the exposure to light (Santos and Ferreira 2020). Similarly, in experimental plantings in tree-fall gaps and mature forest in the Peruvian Amazon, the annual increase in height and diameter of B. excelsa was significantly higher in gaps than in the understory forest (Garate-Quispe et al 2020). In a study in the state of Acre, in the southwestern Brazilian Amazon, Kainer et al (1998) compared the growth of B. excelsa seedlings during two years in pasture, secondary regrowth and forest gaps (71%, 64% and 21.5% sunlight incidence, respectively) and observed that seedlings grew twice as much in the secondary regrowth than in pasture.…”

“…The objective of this study was to evaluate the mediumterm (ten years) growth and survival of Brazil-nut tree seedlings planted under different ecological conditions mediated by canopy openness. Our study differs from other studies of B. excelsa experimental plantations (Kainer et al 1998;Peña-Claros et al 2002;Cotta et al 2008;Garate-Quispe et al, 2020) in that: (1) the tested light conditions were anthropogenic habitats resulting from usual activities of traditional Amazonian communities (crop field, shrub fallow and Brazil-nut forest (forest with B. excelsa stands), and, unlike Kainer et al (1998), who tested similar conditions in the southeastern Amazon, we used a crop field instead of pasture;…”

Efecto del espaciamiento de plantación en la morfometría de copa de Bertholletia excelsa Bonpl. (castaña) en la Amazonía Peruana

“…33 Nº 3 -2022 lo arboles en el Castañal se debería a que las plantaciones establecidas con espaciamiento reducido pueden generar elevados niveles de competición entre los árboles por recursos (luz, agua, etc. ), lo cual se reflejaría en bajas tasas de crecimiento (Machado et al, 2017;Garate-Quispe et al, 2020). Además, estudios recientes demostraron que en condiciones similares de plantación el principal factor de influencia en un mayor crecimiento es la incidencia de luz solar (Coelho et al, 2021;Scoles y Gribel, 2021).…”

“…A pesar su importancia económica, otros factores vienen afectando la producción de las poblaciones nativas de B. excelsa son: la deforestación y los incendios forestales (Guariguata et al, 2017). B. excelsa destaca por su elevado potencial en programas de reforestación (Garate-Quispe et al, 2020), recuperación de áreas degradadas (Brouwer et al, 2021) y enriquecimiento de bosques y plantaciones (Scoles y Gribel, 2021). Promover los establecimientos de plantaciones comerciales no maderables o en sistemas agroforestales son las opciones más viables para disminuir la deforestación y la presión sobre los bosques (Aguirre-Forero et al, 2021;Brouwer et al, 2021).…”