Life in a Rainforest: Understanding This Fragile and Productive Ecosystem

Everything you need to know about the world's most diverse ecosystem

Kanchanaburi Waterfall Huay Mae Kamin, Thailand
Kanchanaburi Waterfall Huay Mae Kamin, Thailand (Photo: Piyaphon Phemtaweepon/Getty Images).

Can you guess what the defining characteristic of a rainforest is?  If you guessed rain, you would be correct.

Rainforests can be hot or cool. Their vegetation and diversity varies with their climate. Some are located along the equator, while others are found farther to the north or south. But one thing they all have in common is that they are home to large amounts of rainfall. The average annual rainfall amount in a rainforest is between 98 and 177 inches.


But what makes rainforests really unique is their lush abundant and diversity. These biomes make up just six percent of the Earth's surface, but they are home to more than one-half of the world's plant and animal species. In fact, many researchers believe that there are still huge numbers of plant and animal species living deep within the world's rainforests that have yet to be identified by humans. 

All of the plants living in a rainforest mean that rainforests are also responsible for almost one-third of the Earth's oxygen turnover - processing the greenhouse gas carbon dioxide through photosynthesis and releasing oxygen into the atmosphere.

For classification purposes, there are two types of rainforests on earth: Tropical Rainforests and Temperate Rainforests. Here's a closer look at each ecosystem:

Tropical Rainforests. These zones have been called the "world's largest pharmacy" as over one-quarter of our known natural medicines come from tropical rainforests.

Two-thirds of the world's flowering plants are found in tropical rainforests. They are also home to more types of trees than any other area in the world. 

They are characterized by the warm climate - with average annual temperatures usually around 64 °F or warmer all year long. Tropical rainforests are located in the equatorial zone - between the Tropic of Cancer and the Tropic of Capricorn.

They can be found in Southeast Asia (Burma, the Phillipines, Malaysia, Indonesia, Papua New Guinea, and northeastern Australia,) Sri Lanka, Sub-Saharan Africa, South America, Central America, and on many islands in the Pacific. 

Tropical rainforests can be further broken down into smaller biome categories:

  • Lowland equatorial evergreen rainforests. Receive some of the highest amounts of annual rainfall of all rainforests.
  • Moist deciduous forests. These forests are wet year-round with warmer temperatures in the summer and cooler temps in the winter.
  • Montane rainforests. These are also known as cloud forests because they receive most of their precipitation from the mist or fog that comes up from the lowlands.

Temperate Rainforests. Like their warmer cousins, temperate rainforests are characterized by the large amounts of rain they see each year. But these biomes exists farther north and south of the equator, making them cooler and subject to larger temperature fluctuations than tropical rainforests. The average annual temperature in a temperate rainforest is between freezing and 54 °F, thus the precipitation in these ecosystems can come in the form of rain, sleet, hail, or even snow.

Temperate rainforests can be found along the northwestern coast of North America from northern California though southern Alaska.

  There are also small pockets of these types of forests located in southern Chile, New Zealand, northwest Europe, and Australia.

Threats to Rainforests. Hot or cold, north or south, the greatest threat to the world's rainforests is habitat loss due to heavy logging and clearance for agricultural lands. Another factor affecting rainforests is the clearing of land for the expansion of cities. These types of habitat destruction affect not only the trees, but also the vast array of plants and animals that call rainforests home.