Resumen El objetivo del estudio fue determinar y comparar el coeficiente mórfico (CM) y modelos alométricos para estimar volumen fustal de Apuleia leiocarpa en dos tipos de bosque en la Amazonía de Madre de Dios, Perú. Se utilizó un tamaño de muestra de 42 árboles talados de A. leiocarpa: 22 en bosques de colina baja y 20 en bosque de terraza baja. De cada individuo se midió su diámetro a la altura del pecho (DAP) y la altura del fuste, y se realizaron mediciones de diámetro a lo largo del fuste cada 2 m. Por tipo de bosque se determinó el coeficiente mórfico y se evaluaron 11 modelos no lineales para el volumen fustal comercial. El CM en el bosque de colina baja es significativamente superior al calculado en el bosque de terraza baja (t-Student, p<0.01). El ANCOVA mostró que el CM varía significativamente entre los dos tipos bosque. El DAP no influyó de forma significativa en el CM (p>0.05), aunque sí la interacción entre bosque × DAP (p<0.05). El mejor modelo alométrico para estimar el volumen varía según el tipo de bosque, en el bosque de colina baja fue el modelo de Takata y en el bosque de terraza baja fue el modelo de Spurr con término independiente.

Abstract The objective of the study was to determine and compare the morphic coefficient (MC) and allometric models in order to estimate the forest volume of Apuleia leiocarpa in two forest types in the Madre de Dios region of the Peruvian Amazonia. A sample size of 42 felled A. leiocarpa trees was used: 22 in low-hill forest, and 20 in low-terrace forest. The diameter at breast height (DBH) and the stem height of each individual were measured, and diameter measurements were taken along the stem every 2 m. The morphic coefficient was determined by forest type, and 11 nonlinear models were assessed for determining the merchantable forest volume. The MC in the low-ill forest is significantly higher than that calculated in the low-terrace forest (t-Student, p<0.01). The ANCOVA showed that the MC varied significantly between the two forest types. The DBH did not exert a significant influence on the MC (p>0.05); however, the interaction between the forest type and the DBH was significant (p<0.05). The best allometric model for estimating the merchantable forest volume was Takata's model for the low-hill forest, while Spurr's model with independent term was the best for the low-terrace forest.

Abstract Madre de Dios is one of the most diverse and best-conserved natural forests in Amazonia. However, this mega-diversity is threatened by illegal gold mining. The present study aimed to analyze the diversity, forest structure, and aboveground biomass in 3 sites reforested 20 years ago at Huepetuhe, southeast of Peruvian Amazon. Reforestation was carried out to recover abandoned mined areas using mainly exotic species. Three plots of 20 m × 20 m per site were used, where all individuals with diameter > 2.5 cm were inventoried. Twenty-five tree species were registered; only 3 were planted at the beginning of the reforestation (Tachigali sp. 1., Senna reticulata and Acacia mangium). The tree layer is dominated by spontaneous vegetation as Vismia baccifera, Cinchona micrantha, and Miconia poepigii and an exotic species (Tachigali sp. 1). We found M. poepigii trees with more than 20 cm of diameter and 18 m of height. Spontaneous species represent more than 80% of the species. The forest stored between 30 to 69% less biomass than secondary forests stands of similar age. Future projects should consider these native species for the ecological restoration of areas degraded by mining.

Resumen Madre de Dios es uno de los bosques naturales más diversos y mejor conservados de la Amazonía. Sin embargo, esta mega diversidad está amenazada por la minería ilegal de oro. El objetivo del presente estudio fue analizar la diversidad, estructura y biomasa aérea en 3 sitios reforestados hace 20 años en Huepetuhe, sureste de la Amazonía peruana. La reforestación se realizó para recuperar áreas abandonadas por minería, utilizando principalmente especies exóticas. Se utilizaron 3 parcelas de 20 m × 20 m por sitio, donde se inventariaron todos los individuos con un diámetro > 2.5 cm. Se registraron 25 especies arbóreas, solo 3 de estas se plantaron al inicio de la reforestación (Tachigali sp. 1, Senna reticulata y Acacia mangium). El estrato arbóreo está dominado por vegetación espontánea como Vismia baccifera, Cinchona micrantha y Miconia poepigii y una especie exótica (Tachigali sp. 1). Encontramos árboles de M. poepigii con más de 20 cm de diámetro y 18 m de altura. Las especies espontáneas representan más del 80% del total. El bosque almacenó entre 30-69% menos biomasa que bosques secundarios de edad similar. Los proyectos futuros deberían considerar estas especies nativas para la restauración ecológica de áreas degradadas por minería.

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. 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.