Rainforests are areas with tall, dense, evergreen trees, high levels of humidity and rainfall, and a wide variety of wildlife. They have been around for the past 70 million years and are considered the planet’s oldest ecosystem.
There are two types of rainforests, temperate and tropical rainforests, distinguished by their locations. Rainforests are home to a wide variety of vegetation and wildlife.
A 10 square kilometer area of rainforest, which is equivalent to 4 square miles, contains around 1,500 flowering plants, 750 types of trees, 400 bird species, and 150 butterfly species.
Rainforests are the backbone of the ecology and are extremely essential for regulating the climate. Scientists use them for all forms of medications for diseases ranging from asthma to cancer.
In this post, we’ll have a look at what are rainforests, what are the types of rainforests, and why are rainforests important. Let’s get started!
What are Rainforests?
The rainforest is an area covered with tall, dense, and evergreen trees, and has a high amount of rainfall throughout the year.
Following are the main characteristics of a rainforest:
- Rainforests are the oldest ecosystems of the world, with some of them being present on the planet for at least 70 million years.
- They cover 6% of the Earth’s surface.
- They receive the highest precipitation of all the biomes, which ranges between 2,000 to 10,000 millimeters (79 to 394 inches) per year.
- Rainforests supply 40% of the Earth’s oxygen.
- They provide habitat to more than 50% of the Earth’s plants and animals.
- Rainforests are very dense. They can fit in 1,500 flowering plants, 750 tree species, 400 bird species, and 150 butterfly species in 10 square-kilometer, which is around 4 square miles.
- They are present on every continent except Antarctica.
- 70% of the plants used in cancer treatment are found in the rainforests.
Rainforest Structure
There are four layers of the rainforest structure: emergent, canopy, understory, and forest floor.
Emergent
The emergent level is the top-most level of the rainforest.
It starts at 60 meters or 200 feet above the ground level and contains the peak of the trees, specifically the Brazil nut tree and the kapok tree.
Common animal and bird species include white-tailed hawks, harpy eagles, pygmy gliders, and the Madagascan flying fox.
Canopy
As the name suggests, the canopy layer serves as a canopy as it blocks wind, rainfall, and sunlight.
This layer, which is just below the emergent layer, is made up of a dense network of leaves and branches and creates a dark, still, and humid environment.
It is around 6 meters or 20 feet thick and usually contains fig trees.
Due to the high availability of fruits and leaves in this layer, the highest percentage of animals in the rainforest live here. It is also the most suitable habitat for the insects of the forests.
Understory
The understory lies several meters below the canopy. It has wider leaves than the leaves in the upper layers. It has higher darkness, stillness, and humidity than the canopy.
The common plants include palms and philodendrons. Common flowers include heliconia and orchids. Animals that love to camouflage are usually found in this layer, for instance, the jaguar and the green mamba.
The understory, specifically in Central Africa, is home to some of the most endangered animals of the world, for instance, forest elephants, pythons, gorillas, and antelopes.
Forest Floor
As the name indicates, the forest floor is the floor of the rainforest. It is the darkest layer, making it very difficult for plants to grow.
This layer usually contains decomposers, such as termites, slugs, scorpions, worms, and fungi, who love to decompose the organic matter that falls from the trees.
Common animals found in this area include wild pigs, armadillos, anteaters, leopards, rats, and lowland pacas.
Many water bodies flow through the forest floor and are home to numerous water species. For instance, the Amazon River is home to the pink river dolphin (also termed as boto) and black caimans.
Types of Rainforests
There are two types of rainforests: tropical rainforest and temperate rainforest.
Tropical Rainforest
The tropical rainforests are the rainforests mainly located between the tropics, i.e., between the latitudes of 23.5°N (the Tropic of Cancer) and 23.5°S (the Tropic of Capricorn).
Tropical rainforests are found in:
- Central and South America
- Western and Central Africa
- Western India
- Southeast Asia
- Island of New Guinea
- Australia
Since the tropics are mainly in the middle of the globe, the sunlight hits the tropical forests directly, maintaining a temperature between 21° and 30°C (70° and 85°F).
Because of the regular high temperature, the humidity levels in the tropical rainforests are high, ranging between 77% and 88%, which results in extreme and frequent rainfall. The average yearly amount of rainfall in the tropical rainforest is between 200-1000 centimeters (80-400 inches).
Because of the high temperature, humidity, and moisture, 75% of the rainfall in the tropical rainforests is produced by themselves through evaporation and transpiration.
The high temperature and moisture of the tropical rainforests provide an excellent environment for a diverse range of flora and fauna to flourish. As a result, around 50% of the world’s species thrive in these forests, with somewhere between 40 to 100, and sometimes, even more, species of trees per hectare.
Therefore, tropical rainforests are the most biologically diverse terrestrial ecosystems (dryland ecosystems) on Earth.
Common animals found in the tropical rainforest include okapi, tapir, Sumatran rhinoceros, western lowland gorilla, jaguar, poison dart frog, south-American coati, boa constrictor, African gray parrot, keel-billed toucan, spider monkey, three-toed sloth, great hornbill, kinkajou, crowned eagle, king colobus, and the large flying fox.
The common examples of tropical rainforests are the Amazon rainforest in South America and the Congo rainforest in Africa.
Temperate Rainforest
The temperate rainforests are located in the mid-latitudes, mostly in coastal and mountainous regions.
Since the rainforests are located in the mid-latitudes, they receive less sunlight in comparison to the tropical rainforests, and thus, have milder temperatures, averaging between 10° and 21°C (50° and 70°F).
Because of their mountainous and coastal locations, they receive high rainfall. i.e., between 150-500 centimeters (60-200 inches) per year. They receive warm and moist air from the coast, which gets trapped between mountains, and produces rain.
Temperate rainforests are found in the following locations:
- Pacific Northwest Coasts in North America
- Chile
- United Kingdom
- Norway
- Japan
- New Zealand
- Southern Australia
In terms of biological diversity, temperate rainforests lose against their tropical cousins, however, they have significantly higher biological productivity, which ranges from 500-2000 metric tons of storage of leaves, wood, and other organic matter per hectare (202-809 metric tons per acre).
Because of the stable climate, this organic matter doesn’t decompose rapidly and piles up on the forest floor. As a result, temperate rainforests are home to some of the world’s oldest and largest tree species.
For instance, the temperate rainforests in the Pacific Northwest produce three times the biomass of tropical rainforests, which Is basically living or once-living organic matter.
Common temperate rainforest animals include crossbill, mule deer, red tree vole, porcupine, snowshoe hare, black bear, deer mice, Townsend’s chipmunk, bobcat, great horned owl, mountain beaver, mountain lion, Pacific giant salamander, pine siskin, raccoon, shrew, and mink.
The most famous temperate rainforest include Pacific temperate rainforests, the Tongass national forest, the Appalachian temperate rainforest, the Valdivian rainforest, and the Taiheiyo temperate rainforest.
Difference Between Tropical and Temperate Rainforests
In addition to the location, the two main types of rainforests have numerous other differences as well. What are they?! Let’s find out!
Location
The tropical rainforests are the rainforests mainly located between the tropics, i.e., between the latitudes of 23.5°N (the Tropic of Cancer) and 23.5°S (the Tropic of Capricorn), whereas, the temperate rainforests are located in the mid-latitudes, mostly in coastal and mountainous regions.
Climate
Tropical rainforests are warmer than temperate rainforests. They have a temperature between 21° and 30°C (70° and 85°F), humidity between 77% and 88%, and yearly rainfall between 200-1000 centimeters (80-400 inches).
Temperate rainforests are cooler than tropical rainforests. They have a temperature between 10° and 21°C (50° and 70°F) and yearly rainfall between 150-500 centimeters (60-200 inches).
Precipitation
Tropical rainforests have higher rainfall than temperate rainforests. In tropical rainforests, the yearly precipitation is between 200-1000 centimeters (80-400 inches), whereas, in temperate rainforests, it is between 150-500 centimeters (60-200 inches).
Why are Rainforests Important?
We need rainforests to survive. Here’s why:
They are the Backbone of Ecology
Do you know that the Amazon rainforest alone contains 10% of the world’s species?!
This shows how much we rely on the rainforests for the planet’s survival.
Some scientists call rainforests the ‘Earth’s thermostat‘, and they are quite on point because the tropical rainforests alone have dense vegetation spread over 1.2 billion hectares (3 billion acres).
Due to this vast dense vegetation, rainforests produce about 20% of our oxygen. In addition to this, they store a massive chunk of the carbon we produce from our insensitive industrial practices, assisting in reducing the impact of greenhouse gas emissions.
Amazon stores 25% of the 2.4 billion metric tons of carbon stored by forests each year.
The majority of the animals found in the rainforests have special adaptations to their environment and don’t survive outside of it. Examples include toucans, lemurs, sloths, and gorillas.
Unfortunately, due to excessive human activity, many of the rainforest species are going down in numbers. Endangered rainforest species include:
- Bengal Tiger – less than 2,000
- Chimpanzee – 150,000 to 250,000
- Golden Lion Tamarin Monkey – around 2,500
- Gorilla – 100,000 to 200,000
- Harpy Eagle – around 20,000 to 49,999
- Hyacinth Macaw – about 2,000 to 6,500
- Manatee – about 13,000
- Orang-utan – Bornean (104,700) and Sumatran (7,500)
- Three-toed Sloth – around 48
To learn about the 5 most endangered animals of the world head over to our post ‘The 5 Most Endangered Animals in 2022‘.
Climate Regulation
Rainforests play an important role in maintaining our planet’s climate by reducing the impact of GHGs. Also, they absorb massive amounts of solar radiation, which regulates the temperature and helps fight global warming.
Rainforests are Earth’s largest terrestrial carbon sinks as their ecosystems absorb around 2 billion tons of CO2 every year. They then turn this carbon into biomass through photosynthesis, which mitigates climate change.
Rainforests are essential for maintaining our planet’s water cycle, as over 50% of the precipitation on them is turned back to the atmosphere through evapotranspiration, which assists in maintaining healthy rainfall throughout the world.
In addition to maintaining rainfall, they store a substantial percentage of the planet’s fresh water. For context, the Amazon Basin alone stores 20% of it.
In 2011, students from Yale discovered Pestalotiopsis microspora, a rare mushroom in Ecuador’s Amazon rainforest, which breaks down, digests, and turns polyurethane, a common type of plastic, into organic matter.
They are the Home of Indigenous Communities
Approximately 50 million people live in the rainforests, and it is expected that there are many more, but they are yet to be discovered, as they don’t like to expose their communities.
The Amazon alone is home to around 400 to 500 tribes, out of which 50 are disconnected from the outside world. Each of these tribes has its own customs and traditions, and none of them rely on everyday facilities, such as electricity to survive. Here are a few facts that you need to know about them:
- Indigenous tribes are the biggest barrier to deforestation. They survive without having any significant impact on the environment.
- Half of the Amazonian indigenous tribes live in Brazil.
- These tribes started settling in the Amazon around 10,000 years ago.
- Akuntsu is the smallest indigenous tribe with only 4 people left. Most of the members were killed by loggers and ranchers.
- Currently, there are a million indigenous people in the Amazon rainforest.
They are Essential for Medicines
Rainforests play a key role in numerous medical products. According to the US National Cancer Institute, approximately 70% of all the medications used for cancer treatment are extracted from the rainforests.
In addition to this, they are used in creating multiple other types of medicines, such as muscle relaxants, steroids, and insecticides. Rainforests play a key role in developing treatments for the following diseases:
- Asthma
- Arthritis
- Malaria
- Heart diseases
- Pneumonia
Now, this isn’t everything that rainforests do for the medical field, in fact, it’s just one percent because we are yet to conduct research on the 99% of rainforest species for their medicinal value.
Soil Erosion
Rainforest trees and vegetation hold onto the soil, which if washed off, known as soil erosion, poses the following threats:
- Flows into the waterways and makes them muddy, impacting marine habitats and water transportation. Examples include smothering of fish eggs, leading to lower hatch rates.
- Deforestation causes soil erosion leading to siltation in hydroelectric projects, which causes loss of productivity, and in a few cases, shuts them down due to lack of water.
- Siltation results in raised river beds, which causes flooding.
- Deforestation of rainforests causes the topsoil to wash away, which reduces crop yields, and forces farmers to use heavy chemical fertilizers.
We hope by now you would have understood what are rainforests, what are the types of rainforests, and why are rainforests important. Let us know in the comments below if you have ever experienced a rainforest and what was it like. Also, stay tuned for our next article on the indigenous people of the rainforests!