Botanical Name: Bertholletia excelsa
Species: B. excelsa
Barthollesia excelsa, Silva Manso, Bertholletia nobilis Miers
Common Names: Brazil nut
Habitat: Bertholletia excelsa is native to North and western S. America – Brazil, Venezuela, the Guyanas. It grows in deep, rich, alluvial soils, on slightly raised ground that is not subject to regular or extensive flooding.
Bertholletia excelsa is a large evergreen tree, reaching 50 m (160 ft) tall and with a trunk 1 to 2 m (3 ft 3 in to 6 ft 7 in) in diameter, making it among the largest of trees in the Amazon rainforest. It may live for 500 years or more, and can often reach a thousand years of age. The stem is straight and commonly without branches for well over half the tree’s height, with a large emergent crown of long branches above the surrounding canopy of other trees.
The bark is grayish and smooth. The leaves are dry-season deciduous, alternate, simple, entire or crenate, oblong, 20–35 cm (8–14 in) long and 10–15 cm (4–6 in) broad. The flowers are small, greenish-white, in panicles 5–10 cm (2–4 in) long; each flower has a two-parted, deciduous calyx, six unequal cream-colored petals, and numerous stamens united into a broad, hood-shaped mass. The flowers are pollinated by Bees. The plant is self-fertile.
The fruit takes 14 months to mature after pollination of the flowers. The fruit itself is a large capsule 10–15 cm (4–6 in) in diameter, resembling a coconut endocarp in size and weighing up to 2 kg (4 lb 7 oz). It has a hard, woody shell 8–12 mm (3?8–1?2 in) thick, which contains eight to 24 wedge-shaped seeds 4–5 cm (1 1?2–2 in) long (the “Brazil nuts”) packed like the segments of an orange but not limited to one whorl of segments. Up to three whorls can be stacked onto each other, with the polar ends of the segments of the middle whorl nestling into the upper and lower whorls (see illustration from Scientific American above).
The capsule contains a small hole at one end, which enables large rodents like the agouti to gnaw it open. They then eat some of the seeds inside while burying others for later use; some of these are able to germinate into new Brazil nut trees. Most of the seeds are “planted” by the agoutis in caches during wet season, and the young saplings may have to wait years, in a state of dormancy, for a tree to fall and sunlight to reach it, when it starts growing again. Capuchin monkeys have been reported to open Brazil nuts using a stone as an anvil.
The seed is one of the most commonly consumed nuts in the world. The tree is not usually cultivated, the seed being gathered in large quantities from the wild and then exported from there to many other countries. The tree is also harvested from the wild for its wood and for local medicinal use. The tree has not as yet been much cultivated since it is abundant in the Amazon jungle, though some work on cultivating it has been carried out successfully in other humid tropical areas such as Malaya, Sri Lanka and the West Indies.
A plant of the lowland, tropical rain forests, where it is found at elevations up to 200 metres. It grows best in areas where annual daytime temperatures are within the range 20 – 36°c, but can tolerate 12 – 40°c. It prefers a mean annual rainfall in the range 2,400 – 2,800mm, but tolerates 1,400 – 3,500mm. In eastern Amazonia, in the lower limits of its climatic range, there can be 2 – 7 months where the monthly rainfall is less than 100 mm. A pronounced dry season is necessary for good fruit set. Requires a deep, well-drained but moisture retentive fertile, medium to heavy soil. Mature trees grow best in a sunny position, but young trees require shade for their first 5 – 7 years. Well adapted to heavy clay and low-fertility Oxisols but is not tolerant to waterlogging. Prefers a pH in the range 5.5 – 7, tolerating 4.5 – 8. Trees commence flowering when about 5 – 6 years old. Fruiting starts at 12 – 16 years in the forest and as early as 8 years if trees are well managed in the open. Mature nuts are produced approximately 15 months after fertilization. The seeds are borne in a large spherical wooden ‘fruit’ that is up to 15cm in diameter and can weight up to 2 kilos. Between 12 and 24 seeds are contained in each fruit and this falls intact from the tree when it is ripe. Since the fruits are only formed on the upper branches, and these can be 30 metres or more above ground level, this can make collecting the seeds a rather hazardous occupation. The nuts are normally extracted in situ from the ‘fruits’ and then shipped out of the jungle to be sold. Trees 16 years old produce 30 – 50 fruits, mature trees usually 200 – 400, and a yield of 1,000 fruits has been reported. Yields of up to 450 kilos of nuts can be obtained from the best trees
Edible portion: Nut, Oil, Flavouring. Seed – raw or cooked. A mild flavour, the nuts are a common item of food, eaten raw and also roasted, salted or used in ice cream etc. The nuts are very nutritious, containing roughly 66% fat or oil, 17% protein and 7% carbohydrate. The ripe fruit is a wooden capsule weighing up to 750g and containing 12 – 24 angular brown seed, each about 5cm long and 2.5cm wide. An oil is obtained from the seed. The fresh-pressed oil is pale yellow, almost odourless, with a pleasant nutty flavour. It is not unlike almond oil in composition. It can be used like olive oil. Nuts have a high level of selenium. They are also high in sulphur containing amino acids.
The bark of the tree is used as a treatment for liver problems. The sweet oil from the seeds is applied to burns. A tea made from the fruit is used as a treatment for gastralgia. Nuts have a high level of selenium. They are also high in sulphur containing amino acids.
The hard woody ‘fruit’ that contains the seeds is used as cups or other receptacles. It is also made into bracelets or carved to make other ornaments. Empty fruit capsules are used to carry small, smoky fires in order to discourage black flies (Simulium spp.) from attacking people working in the field during the rainy season. Open capsules are sometimes used to collect latex from rubber trees. The oil obtained from the seed has been used as an illuminant. The oil has also sometimes been used in perfumery, paint and soap making, and as a lubricant for watches and clocks. The woody ‘fruits’ make an excellent fuel. The nut, which has an elevated oil content of 63-69%, burns with a candle-like flame when lit . The bark has been used in remote regions for fibre production. It is used for caulking ships. The heartwood is light brown to reddish; it is not clearly demarcated from the 3 – 5cm wide band of sapwood. The texture is medium, the grain straight or interlocked; lustre is medium. The wood is moderately heavy, hard and moderately durable being moderately resistant to fungi and termites but susceptible to dry wood borers. Seasoning is fairly fast with only a slight risk of checking or distortion; once dry it is moderately stable in service. It works well with normal tools; nailing and screwing are good; gluing is correct for internal purposes only. The durable wood is sought by boat builders, and is also used for purposes such as interior joinery, cabinet making, high class furniture, construction, flooring, heavy carpentry and sliced veneer. The felling of the trees is discouraged because they are more valuable as a nut crop, however the wood is well suited to all manner of structural work. The charcoal from Brazil nut shells is good at purifying water.
Known Hazards: Nuts from trees growing on barium-rich soils can accumulate up to 0.29% barium and should be avoided due to danger of barium toxicity.
Disclaimer : The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplement, it is always advisable to consult with your own health care provider.