Common Name: Brazil Nut

General Information

Brazil nut is a large evergreen tree with a globose crown, that can grow 25 - 56 metres tall. The straight, cylindrical bole can be 1 - 2 metres in diameter and is unbranched until near the top[, ].
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[].

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[].

Botanical References

Range

North and western S. America - Brazil, Venezuela, the Guyanas.

Habitat

Deep, rich, alluvial soils, on slightly raised ground that is not subject to regular or extensive flooding[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	40.00 m
Growth Rate	Medium
Pollinators	Bees
Self-fertile	No
Cultivation Status	Cultivated, Wild

Cultivation Details

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 Uses

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[].

Medicinal

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[].

Other Uses

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[].

Propagation

Seed - fresh seed germinates rapidly, often within 2 - 3 weeks, so long as a portion of the hard shell is cracked or carefully removed first in order to allow the entry of moisture[]. Otherwise seed can take 2 years to germinate[]. Seedlings probably need good light to grow away well[]. Seedling trees have borne a first crop at an age of 14 - 20 years[].
If the conditions are right, some of the seeds buried by rodents may germinate. Trees appear to depend on natural or artificial disturbance to reproduce. For example, they will be found in clearings in the forest created by humans, forest gaps created by tree fall, or sprouting from damaged mother roots. Trees take about 10 years to start reproducing; grafted material may begin to bear nuts within 4 years. Other than using a single clone, several selections are cloned and grafted onto stock to encourage cross-fertilization, which increases yield[].

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