Surprisingly, the main producer of walnuts in Brazil is not the country that gives it its name, but Bolivia. Brazil is only in second place, Ivory Coast and Peru complete the list of the only four walnut-producing countries in Brazil. No, Brazil nuts are not currently cultivated in the United States. Brazil's nut trees are native to the Amazon rainforest and need very specific conditions, such as a tropical climate and the right bee species to pollinate trees.
Brazil's walnut trees produce fruit almost exclusively in virgin forests, since altered forests lack large bees of the genera Bombus, Centris, Epicharis, Eulaema and Xylocopa, which are the only ones capable of pollinating the flowers of the tree, with different types of bees being the main pollinators in different areas and at different times of the year. Brazil nuts have been harvested on plantations, but production is low and is currently not economically viable. While some use equipment or shake trees by hand to release the nuts, most harvesters wait for the trees to drop theirs before picking them up. The fruit and its nut shell, which contains the edible Brazil nut, are relatively large and can weigh up to 2 kg (4 lb 7 oz) in total weight.
Walnuts, in and of themselves seeds, can be easily grown, but they take about 7 years to grow into trees that produce nuts. Hazelnuts, or more specifically Filberts, are mainly cultivated in Mediterranean climates, although warmer climates in other countries also produce them, including the United States and China. Like some of the other nuts, nuts are technically a fruit, but in cooking and food they are considered nuts. Bolivia is the main supplier and provides about 50% of the total Brazilian nuts imported to the United States.
Walnut wood from Brazil is prized for its quality in carpentry, flooring and heavy construction. Brazil is second only to the United States in beef exports, and the country's endless herds of cattle demand a lot of space, which has decimated the country's rainforest (almost 20% of the original forest so far). In several Spanish-speaking countries in South America, walnuts from Brazil are called chestnuts from Brazil, walnuts from Brazil, or chestnuts from Pará (or Para). Half of the world's Brazil nuts come from Bolivia, another 40% more or less come from Brazil and the other 10% from Peru.
The wood of walnut trees from Brazil (not to be confused with wood from Brazil) is of excellent quality and has a variety of uses, from floors to heavy buildings. Although originally discovered and produced in Australia, the macadamia nut is now produced in many countries around the world, South Africa is now the leading commercial producer, producing about a quarter of all world consumption. Brazil nuts are generally harvested from December to March, which is technically the fall season south of the equator. Brazil nuts grow wild on trees in the Amazon, but they can take up to 20 years to mature enough to start producing walnuts.
Not surprisingly, Brazil nuts didn't really take off until the Spanish and Portuguese made better forays into the jungles. The fruit itself is a large capsule 10 to 15 cm (4 to 6 inches) in diameter, similar in size to a coconut endocarp and weighing up to 2 kg (4 pounds 7 oz).