The role of Brazil nut trees in restoring degraded forest areas and as a source of food and income for northern Amazonian communities

Abstract

The role of Brasil nut in the restoring degraded Amazonian forest and supplementing local income - Brazil nut trees (Bertholletia excelsa H. & B. - Lecythidaceae) - are the largest girthed trees in Amazonian forests. Trees can range from 4.34 to 5.25 cm in dbh (diameter at breast high). There is evidence that some reproductive Brazil nut trees can be over 1,000 years old. The objectives of study is to examine the growth rate of Brazil nut trees in a multi-species reforestation system of areas degraded by mining activities and estimate the seed yield for local communities in the Sacará-Taqüera National Forest of Pará, Brazil. The study was carried out in an area of 19.4 ha being restored since 1994 with several species including 482 Brazil nut trees. To evaluate seed production, a pilot study will be used to quantify seed production from 2003 to 2007. The average for Brazil nut trees was 24,8 trees/ha. The lowest diameter was 2.1 cm and the largest was 61.6 cm (= 19.4 cm). This resulted in a mean increment of 0.11 to 3.24 cm/year. The variation in height ranged from 3m to 28m (= 14.7m) and height increment varied from 0.16 to 1.47m/year (= 0.77m/year). To estimate fruit production, 84 trees were selected at one site with a high tree density (= 14 trees/ha). In 2003, 74 trees produced fruits (= 29 fruits/tree) with a mean of 16 seeds per fruit. The mean production was 477 seeds per tree, which was considered low. Normally, the seed production in this region is 800 hectoliters (34,000 kg) which is equivalent to US$22,666.67. The total income derived from the seed harvest per individual is US$755.67 for a 3 month period or US$252/month, which was higher than the background average of US$100.00/month. The plantation of Brazil nut trees in a multi-species restoration system in Eastern Amazon is an excellent opportunity to both forest conservation and local revenues. The selection of highly productive trees can result in trees attaining 60 cm dbh and 28 m height in only 19 yrs. In the 2003, 74 trees in primary forest produced an average of 247 kg of seeds which is equivalent to US$164.72/tree in the local market