Tree Conservation Information Service
| Bertholletia excelsa
Lecythidaceae Brazil nut tree Distribution Bolivia, Brazil (Acre, Amapá, Amazonas, Maranháo, Mato Grosso, Pará, Rondônia), Colombia, French Guiana, Guyana, Peru, Suriname, Venezuela Habitat Tropical, lowland, moist, non-seasonal, closed forest. Trees grow best on deep well-drained alluvial soils on high ground not subject to flooding (Prance & Mori, 1979). Population Status and Trends A widely occurring emergent of Amazonian forest, the Brazil nut tree has experienced major declines in its population because of deforestation. One of the greatest concentrations of stands exists in Tocantins valley where various activities, from the construction of the Transamazon railway to the building of a reservoir, have brought about a shrinking in the gene pool (Smith et al., 1992). An area of 200,000ha in south Pará has been purchased by the government with the aim of settling landless farmers (Salamâo, 1991). There are also plans to establish a pig-iron smelter along the Carajás-Itaqui railway which is likely to result in the clearance of vast areas of forest to supply carbon (Smith et al., 1992). Trees remaining in the vast cattle ranches of Pará and Acre are neglected and dying (Clement, 1991). However, large natural stands still exist in northern Bolivia (Killeen, 1997). The species is locally abundant in Suriname, where Amerindians harvest the seeds (Werkhoven, 1997). Almost all Brazil nuts consumed around the world come from wild trees (Smith et al., 1992). Little is known about the impact of seed gathering on regeneration, but it clearly can be limited under certain exploitative regimes. Agoutis provide a vital function not only of dispersing the seed but of opening the pod, which if left closed generally imprisons the seeds until they rot. As part of some regimes agoutis may be hunted or driven away because of lack of food sources as a result of overextraction of Brazil nuts (Broekhoven, 1993). The sustainable harvesting of nuts by indigenous people in extractive forest reserves offers the most promising protection for remaining natural stands (Wickens, 1995). Role of species in the Ecosystem The seeds are encased in large pods of 0.5-0.75kg weight. The seeds are eaten by brocket deer (Mazama americana), the nocturnal paca (Agouti paca), other agoutis (Dasyprocta spp.) and squirrels. Agoutis and squirrels aid dispersal by caching the seeds. Macaws commonly damage the seeds and seed capsule before they have matured. The seeds have also played a significant role in the diets of numerous indigenous peoples. Flowers are pollinated by euglossine, anthophorid and apine bees in the genera Xylocopa, Bombus, Centris, Epicharis and Eulaema (Smith et al., 1992).
Threats Logging of the habitat, burning, increasing settlement and agriculture, infrastructural and industrial development (Pires O'Brien, 1996). Utilisation The seed provides a highly nutritious food, high in protein and unsaturated fatty acids. Seed oil can be used in cooking and soap-making, and the seed capsule is useful as a fuel or for craft-making (Wickens, 1995). The timber is excellent but living trees are considered more valuable as a source of nuts. It is used in the construction of ships, water tanks and railway ties but is not thought to have commercial value in the international market (Flynn, 1994). The bark is used for caulking ships (FAO, 1986). Trade Production of Brazil nuts for export is concentrated in north-west Amazonia and Acre in Brazil and the Pando/Beni region in Bolivia (Wickens, 1995). Pará is also a major area of production (Smith et al., 1992). At one time Brazil nuts were second only to rubber as an export crop from Amazonian Brazil (Wickens, 1995). Annual nut production decreased from 104,000 tonnes in 1970 to 50,000 tonnes in 1980 because of habitat loss (Mori et al., 1990). It continues to decrease at an average rate of 820 tonnes pa (Wickens, 1995). U.S.A, U.K. and Germany are the major importers (Wickens, 1995).
Source: La Fleur 1992 in Wickens, 1995 IUCN Conservation category VU A1acd+2cd according to the Americas Regional Workshop for the WCMC/SSC Conservation and sustainable management of trees project (WCMC, 1996). Conservation Measures It is illegal to fell trees in Brazil (Pires O'Brien, 1996). However, felling continues, particularly in southern Pará and northern Mato Grosso (Smith et al., 1992). Populations exist in various large protected areas and in places which are safe from logging and habitat clearance, such as corporate property, Companhia Vale do Rio Doce. A research programme on Brazil nut population biology and ecology is set up in north-east Bolivia by the University of Beni in Riberalta (IIFA), Utrecht University and the Netherlands Committee for IUCN. Forest Management and Silviculture Natural regeneration is rare in some areas. Trees can sprout from root systems of fallen trees. It is believed that many Brazil nut groves have been planted by indigenous people since the time when hunter gathers first colonised the rainforest (Smith et al., 1992). The pollinators' dependence on the availability of a variety of forest plants, including orchid species, as a source of food and chemical signals important in reproduction, has been thought to limit the establishment of plantations outside the rainforest. However, it is possible to obtain sizeable harvests from plantation sources given appropriate soil conditions and a well-defined dry season (Smith et al., 1992). Trees are 12-16 years old before fruiting, with maximum production at 25-30 years. Cultivated compact grafted trees may start production after 8 years. During a good year 100-120kg of unshelled seeds may be harvested from a single tree (Wickens, 1995). The Agricultural Research Centre of the Humid Tropics (CPATU-EMBRAPA) in Brazil are in the process of creating a clonal germplasm collection and providing clones for commercial plantations (Wickens, 1995). The species has been introduced to Malaysia, Sri Lanka, Java, Hawaii and the Caribbean (Wickens, 1995). References Broekhoven,
G. 1996. Non-timber forest products: ecological and economic aspects of
exploitation in Colombia, Ecuador and Bolivia. IUCN, Gland, Switzerland. |
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