Brazil nut tree

Appearance

The Brazil nut is a large tree, reaching 50 m tall and with a trunk 1 to 2 m 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 long, and 10–15 cm broad. The flowers are small, greenish-white, in panicles 5–10 cm long; each flower has a two-parted, deciduous calyx, six unequal cream-colored petals, and numerous stamens united into a broad, hood-shaped mass.

Naming

In various countries of South America, Brazil nuts are called or. In Brazil, they are more commonly called "", with other names used in remote and/or small localities.

In North America, as early as 1896, Brazil nuts were sometimes known by the slang term "nigger toes", a vulgarity that gradually fell out of use as the racial slur became socially unacceptable.

Habitat

Since most of the production for international trade is harvested in the wild, the business arrangement has been advanced as a model for generating income from a tropical forest without destroying it. The nuts are most often gathered by migrant workers known as "castañeros" or "castanheiros". Logging is a significant threat to the sustainability of the Brazil nut-harvesting industry.

Analysis of tree ages in areas that are harvested shows that moderate and intense gathering takes so many seeds that not enough are left to replace older trees as they die. Sites with light gathering activities had many young trees, while sites with intense gathering practices had nearly none.

Reproduction

Brazil nut trees produce fruit almost exclusively in pristine forests, as disturbed forests lack the large-bodied bees of the genera "Bombus", "Centris", "Epicharis", "Eulaema", and "Xylocopa", which are the only ones capable of pollinating the tree's flowers, with different bee genera being the primary pollinators in different areas, and different times of year. Brazil nuts have been harvested from plantations, but production is low and is currently not economically viable.

The fruit takes 14 months to mature after pollination of the flowers. The fruit itself is a large capsule 10–15 cm in diameter, resembling a coconut endocarp in size and weighing up to 2 kg. It has a hard, woody shell 8–12 mm thick, which contains eight to 24 wedge-shaped seeds 4–5 cm long 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.

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.

Defense

Since most of the production for international trade is harvested in the wild, the business arrangement has been advanced as a model for generating income from a tropical forest without destroying it. The nuts are most often gathered by migrant workers known as "castañeros" or "castanheiros". Logging is a significant threat to the sustainability of the Brazil nut-harvesting industry.

Analysis of tree ages in areas that are harvested shows that moderate and intense gathering takes so many seeds that not enough are left to replace older trees as they die. Sites with light gathering activities had many young trees, while sites with intense gathering practices had nearly none.

Uses

Brazil nut oil is used as a lubricant in clocks, in the manufacturing of paint, and in the cosmetics industry. Because of its hardness, the Brazil nutshell is often pulverized and used as an abrasive to polish materials such as metals and ceramics, in the same way jeweler's rouge is used.

Cultural

In Brazil, cutting down a Brazil nut tree is illegal, unless done with previous authorization from the Brazilian Institute of Environment and Renewable Natural Resources.