Since rainfall controls tropical vegetation in the tropics, rain forest types may be classified with reference to local climate. These include lowland, montane, subtropical, and temperate rain forests. Their common features are at least 1,500 millimeters (approximately 33 inches) of annual rainfall and evergreen vegetation with lianas and epiphytes. Most widespread are lowland tropical rain forests, accounting for less than one-third of the tropical land surface, growing in areas receiving between 2,000 to 5,000 millimeters of annual rainfall, with relatively high and constant air temperature (annual mean ±25°C) never below freezing point. They persist in Central America, the Amazon Basin, the Congo Basin, Southeast Asia, New Guinea, and northern Australia. Their canopy is often 25 to 45 meters or higher.

In the monsoonal tropics, characterized by similar total annual rainfall, but unevenly distributed between dry and wet seasons, a related type of lowland forest is found, which becomes partly leafless during the...