Mahogany grows to around 150m tall and 6m in diameter. It is a tropical hardwood, and mahogany timber comes from trees in a family called Meliaceae, in particular several closely related species in the genus Swietenia, such as Swietenia mahogonia and Swietenia macrophylla. It grows in the rainforests of South America and Asia. Mahogany is hard to grow on a commercial scale (in plantations) because it is vulnerable to an insect pest, a moth called Hypsipyla grandella. This means that mahogany timber comes from natural forests: rainforests. The mahogany timber trade is one of the main contributors to logging of rainforest timber and the consequent destruction and fragmentation of large areas of rainforest.