Mapping of natural populations of Euterpe oleracea Mart., structure and estimates of fruit production at Araguari River, Eastern Amazon

This study aimed to identify the occurrence of natural populations of açaí palms in the low-land forest at Araguari River; to map the native açaí palm areas; to assess the structure of the açaí areas; to quantify the clumps of açaí palm trees and to estimate the fruit production. The study was conducted in the Araguari River Valley, state of Amapá, eastern Amazon, Brazil, covering the municipalities of Ferreira Gomes and Cutias, over a 68 km extension. For the sampling of the açaí palm area, we established 89 (10 m x 20 m) sampling plots, totaling a sample area of 1.78 ha. To measure the height and diameter of the palm trees, only palms with circumference at breast height (CBH) ≥ 20 cm were considered. The quantification of açaí fruits production was obtained through information provided by the owners who commercialize the fruit in the region. It was found that the açaí palm tree is present in the entire plantphysiognomy of the studied area. The high density and the high number of palms per clump shows that the açaí area is native and not managed. The average height of 16 m of the açaí palm indicates a need to reduce the dominant height of the palm trees in these places. The low estimate of açaí palm tree fruit production led us to conclude that the native açaí palm area of the Araguari River valley are of low production, although the areas are densely populated with açaí palm trees.