The cashew, Anacardium occidentale, is a resilient and fast-growing evergreen tree that can grow to a height of 20 m (60 ft). It belongs to the family Anacardiaceae, which also contains poison ivy and the mango. Native to arid northeastern Brazil, the cashew was taken around the world by the Portuguese and Spanish who planted the trees in their colonies. The English name "cashew" is derived from the Portuguese "cajú" which came from the Tupi Indian "acaju" (Rosengarten, 1984). In Spanish it is known as "marañón" or "anacardo."
Cashew is an important nut crop that provides food, employment and hard currency to many in developing nations. Of all nuts, cashew is second only to the almond in commercial importance (Rosengarten, 1984). India, Mozambique, and Tanzania are the three biggest exporters of cashew nuts today. Although there are large commercial plantings of cashew, wild trees or those owned by small farmers account for 97% of cashew production (Rosengarten, 1984).
The plant produces not only the well-known nut, but also a pseudofruit known as the cashew "apple" and cashew nut shell liquid (CNSL) which is used for industrial and medicinal purposes.
The cashew tree has other uses as well. It is used for reforestation, in preventing desertification and as a roadside buffer tree. Cashew was planted in India in order to prevent erosion on the coast (Morton, 1960). The wood from the tree is used for carpentry, firewood, and charcoal. The tree exudes a gum called cashawa that can be used in varnishes or in place of gum arabic. Cashew bark is about 9% tannin, which is used in tanning leather.