Rain forests; broad-leaved, mainly evergreen forests found in the tropics, sub-tropics and some temperate regions where moisture is abundant all year round. Tropical rain forests are best developed 10 degree north and south of the equator in the Amazon and Congo basins, West and parts of south-east Asia. Outside of that band, temperature and rainfall are sufficiently high to allow rainforests to flourish in areas such as Central America, Bangaladesh, Burma and north-eastern Australlia. Tropical rainforests cover some 12 million sequare kilometer and represent nearly one-third of the world's forests. Temperature rainforests exists in the coastal regions of western Canada, the United States Pacific north-west and New Zealand, where the prevailing westerlies provide enough moisture to maintain the rainforests ecosystem. Rainforests are arguably the most persistent, most stable and most complex of the earth's ecosystems. Tropical rainforests alone contain as many as 30 million species of plants and animals.