It's early morning and a beam of light makes its way through the dense canopy of trees. A bird begins to sing, and a brightly colored butterfly flits its way through the warm air. A sloth slowly opens its eyes, and a jaguar prowls the land for its next meal. Another day begins in the lush, warm rainforest.
The rainforest biome is defined by four distinct characteristics: high average annual temperatures, high annual rainfall, poor nutrient soil, and a high level of biodiversity. How is it that an ecosystem with such nutrient-poor soil can have such a wide range of insects, animals, and plants? After all, the abundant plant life in the Amazon rainforest is responsible for 20 percent of the earth’s oxygen! 1
Tropical rainforests, unsurprisingly, are located in the “tropics." These lie between the Tropic of Capricorn and the Tropic of Cancer, where sunlight hits at almost exactly a 90-degree angle. The consistent levels of sunlight allow plants to thrive in this biome.
The main locations of tropical rainforests are Central and South America, Central Africa, and South and Southeast Asia. A small part of Northern Australia is also covered by rainforest. 2
Because tropical rainforests are located near the equator, they remain at consistently high temperatures throughout the year. On average, a typical day in the rainforest will be approximately 85 degrees Fahrenheit. In most rainforests, there is only a nine-degree difference between “summer” and “winter” temperatures. The high levels of humidity in the rainforest can make temperatures feel much hotter.
The term "rainforest" implies that this particular biome receives a significant amount of rainfall every year. The average amount of rainfall varies between location and years, but rainforests in South America typically get between 80 and 120 inches of rainfall a year.
Although most people picture rainforests as being constantly wet, some locations have dry seasons. Even so, the humidity level stays high: approximately 88 percent humidity in the wet season and 77 percent in the dry season. Even during short “dry” spells, the soil and foliage never completely dry out. Rainforests that lie close to the equator have almost no dry spells, but those that lie further away tend to have slightly less rainfall. 3
Deforestation can minimize the amount of rainfall a rainforest receives in any given year. In African rainforests, deforestation can reduce rainfall by up to 50 percent. Large rainforests and their humidity levels contribute to the formation of rain clouds and can generate up to 75 percent of their own rain.
Rainforests make up less than six percent of the world’s landmass, yet contain up to 50 percent of Earth’s land-based species. In the tropical rainforests of Borneo alone, more than 15,000 species of plants have been documented—including over 2,500 species of orchids. Although all rainforests share common characteristics, many species of plants or animals can only be found in one location.
Because of the rich diversity of life in rainforests, one would automatically assume that the soil is incredibly rich in nutrients. However, the high levels of rainfall mean that the soil doesn’t get the opportunity to store nutrients for long. Heavy rain washes away organic material from the soil, causing this material to be swept away before it can fully decompose and release all of its nutrients. The nutrients that are released into the soil are quickly absorbed by the surrounding plants.
The rainforest is made up of four different layers. The top layer is known as the emergent layer, consisting of the tall trees that rise above everything else. The second layer is the canopy, where all of the leaves and branches intertwine. The majority of the animals in the rainforest live in this second layer. The next layer is known as the understory, which doesn’t get a lot of light. The final layer is the forest floor, which is only home to a few plants that don’t require a lot of sunlight. 4
Most of the plants and animals that thrive in the tropical rainforest rely on each other for survival; the rainforest is home to a wide range of beautiful symbiotic relationships. Many plants rely on animals as pollinators, while animals rely on the plants for food.
For instance, plants known as epiphytes grow on canopy trees yet do not deplete these trees of nutrients. They simply use this host tree for support and better access to sunlight. Instead of relying on soil for nutrients, epiphytes gather nutrients from the air around them.
Another common type of plant in the rainforest is known as a liana, which is a woody vine that begins on the forest floor and makes its way towards the sunlight by latching onto canopy trees. Another type of plant, hemiepiphyte, begins in the canopy and grows roots that eventually reach the forest floor.
Approximately half of the world’s animals live in the rainforest. The stunning blue morpho butterfly lives in the tropical rainforests of South America, along with vampire bats, and anacondas. Asia’s diverse rainforests house orangutans, Bengal tigers, and proboscis monkeys.
Chimpanzees, gorillas, and elephants call the rainforests of Africa home. Cassowaries thrive in the Daintree Rainforest of Australia and are referred to as the “world’s most dangerous bird." Although dangerous, these birds are beautiful and almost resemble dinosaurs more than birds. Many of the animals that live in rainforests rely on this unique ecosystem and cannot survive anywhere else.
Benefits of the Rainforest
Rainforests are sometimes referred to as the “lungs of the planet." They help absorb carbon dioxide and produce oxygen, stabilize the climate, provide a home for plants and animals, and are a source of a staggering amount of medicinal plants. In fact, approximately 25 percent of all natural medicines have been discovered in rainforests, and about 70 percent of the plants used in the treatment of cancer by the U.S. National Cancer Institute are endemic to rainforests. 5
Considering a large number of plants that call the rainforest biome their home, there are likely thousands more medicinal plants that have yet to be discovered or studied. With the rapid depletion of rainforests across the globe, beneficial species could go extinct before they can even be discovered.
The healing properties of the rainforest are not restricted to natural medicines. Simply taking a walk through this incredible environment can expose you to a wide variety of beneficial terpenes that can benefit both your mental and physical health. If you can visit these rainforests in person, you're in for an amazing, once-in-a-lifetime treat.Photo credits: Tisha85/shutterstock.com, Zulashai/shutterstock.com, worldclassphoto/shutterstock.com