The pistachio a member of the cashew family, is a small tree originating from Central Asia and the Middle East. The tree produces seeds that are widely conumed as food.
Pistacia vera often is confused with other species in the genus Pistacia that are also known as pistachio. These other species can be distinguished by their geographic distributions (in the wild) and their seeds which are much smaller and have a soft shell.
The pistachio tree is long-lived, possibly up to 300 years. The trees are planted in orchards, and take approximately seven to ten years to reach significant production. Production is alternate-bearing or biennial-bearing, meaning the harvest is heavier in alternate years. Peak production is reached around 20 years. Trees are usually pruned to size to make the harvest easier. One male tree produces enough pollen for eight to twelve drupe-bearing females. Harvesting in the United States and in Greece is often accomplished using equipment to shake the drupes off the tree. After hulling and drying, pistachios are sorted according to open-mouth and closed-mouth shells, then roasted or processed by special machines to produce pistachio kernels.