Among all forest types on Earth, the greatest diversity of living organisms is found in the tropical rainforest. Also called tropical wet evergreen forest, this forest type occurs in those parts around the equator with over 2,000 millimetres of annual rainfall distributed over most of the year. Dry periods with less than 60 millimetres rainfall occur only for a few weeks at most. As a result, there is luxuriant
vegetation and most trees remain green year-round.