In order to better describe and classify these rainforests, botanists have come with a set of guidelines for determining a tropical rainforest. There are many different types of forest that make up a tropical rainforests, one of which is lowland tropical rainforest.
Lowland tropical rainforests have been defined as areas of rainforest that lie within the Tropic of Cancer and the Tropic of Capricorn. To be categorized as lowland tropical rainforest, they must have at least a mean annual temperature of 75° F (24°C) and receive 80 inches (203 cm) of rain per year. These tropical rainforests are characterized by an abundance of vines and epiphytes, a closed canopy formed by broadleaf evergreen trees, a relatively open forest floor, and many thousands of species of flora and fauna. Lowland tropical rainforests also average a relative humidity of about 85%.
The boundaries between this type of rainforest and other types of tropical rainforest are often hard to determine, because the change from one rainforest to the next occurs gradually over a large area. A cloud forest, for example, is a type of tropical rainforest that merges with lowland tropical rainforests at higher altitudes. Seasonal tropical forests have been found to merge with lowland tropical forests in areas of less rainfall and mangroves merge into lowland tropical rainforests near the coast.
There are also rainforests that lie outside of the tropics which are known as temperate rainforests. Temperate rainforests are usually found in higher-latitude regions having wet, maritime climates, such as those on the northwest coast of North America, southern Chile, parts of southeastern Australia and New Zealand. These rainforests are home to many species of plant and animal, though the species are less diverse than those found in the tropical rainforests.