What is a Rainforest?
A rainforest is described as tall, hot and dense forest near the equator and is believed to be the oldest living ecosystems on Earth which gets maximum amount of rainfall. As the name implies, rainforests are the forests that get very high amount of rainfall every year, more than the normal annual rainfall of 1750–2000 mm (68-78 inches). Most of the rainforests in this world are located around the middle of earth near the equator like South and Central America, Africa, Asia and Australia.
A rainforest is a densely wooded area that receives vast amounts of rainfall in a single year, 80 inches of rain to be exact. For a rainforest to exist, there must be a warm climate, which explains why a vast majority of tropical rainforest regions are situated on or near the equator. The countries taking the biggest share of rainforests include Brazil, Peru, Indonesia, Bolivia, Angola, Mexico, India, New Guinea, and Venezuela. Brazil claims the largest rain forest reserve on the entire globe, which is situated in the Amazon River basin.
There are places where rainforest cannot exist, for example, the desert due to unavailability of rainfall and the arctic regions due to freezing temperatures.
Rainforests cover about 6% of the total surface of the Earth and are home to more than half of the species of plants and animals of the world. At least two-thirds of the total plant species grows in the rainforests. The hot and humid climate of rainforest is very supportive to the growth of plants and animals. It is believed that there will be many millions of species of plants, insects and micro-organisms thriving in rainforest which have not been discovered still.
Importance of Rainforests
The main benefit of rainforests is that they supply much of the earth’s oxygen. They absorb carbon dioxide produced by man made activities and produce oxygen on which all humans and animals survive. They also contain millions of species of exotic plants and animals. Rainforest supplies many things essential for the survival of human and other living beings. Importance of rainforests can be derived from the items that they supply. Some of these are listed below:
- Natural medicines
- Oxygen production
- Spices such as coconut, vanilla, turmeric, ginger etc.
- Chocolates that come from cocoa which grow on trees in rainforests
Apart from this, they also:
- Stabilize world’s climate.
- Are an interesting place to visit.
- Maintain water cycle.
- Provide home to tribal people.
- House more than 1/2 of the world’s plant and animal species.
- Protect environment against soil erosion, floods and droughts.
A rainforest needs a adequate amount of rainfall and sunlight to grow tall and large. Areas near equator doesn’t have any seasons because neither it tilt towards or away from the sun. It remains warm (16 degrees Celsius) and receives more than 1000 centimeters of rainfall throughout the year. They cover only about 6% of the earth’s surface and more than 30 million species of plants and animals live in tropical rainforests. Many exotic species of plants and animals grow in rainforest.
Different Layers of Rainforest
A rainforest is divided into following 4 layers. Each layer has characteristic flora and fauna adapted for life in the particular surroundings.
1. The Emergent layer
The emergent layer is made up of the tallest trees, standing as high as 200 feet, towering above the canopy layer that features large mushroom shaped crowns. This layer is naturally inhabited by butterflies, bats and large birds of prey. Trees in the emergent layer enjoy the greatest possible quantity of sunshine, only they have to bear strong winds, extremely high temperatures, and low humidity. Eagles, bats, monkey and butterflies are main animals found here.
2. The Canopy layer
The canopy layer is the thickest layer of the rainforest consisting of the tops of most trees. The trees have smooth, oval leaves that form a dense maze, covering the other two layers as a wide roof. The canopy layer harbors most birds and animals that are able to navigate to the emergent layer to seek the bright light. The branches of trees in the canopy layer are typically wrapped with other plant species and joined with vines.
3. The Understory layer
It forms the middle layer of the rainforest located between the canopy and the ground. It’s home to snakes, big cats, and lizards. This layer only receives 2 to 15 percent of the sun’s rays that hit the canopy. It’s a very dark section of the rainforest. This layer is considerably open and teems with leafy herbaceous plants and young trees that are able to survive on minimum light. Most popular houseplants originate from this layer.
4. The Forest Floor
The forest floor completes the layers of a rainforest. This layer gets well below 2% of sunlight. Many animals that live in the forest layer survive by consuming dead animal and plant matter.
Types of Rainforests
1. Tropical rainforests are warm and wet, characterized by mean monthly temperatures of more than 180C (64OF) around the year and average annual rainfall of about 400 inches. These are located in the monsoon trough, between the Tropic of Cancer and Tropic of Capricorn. They have thousands of broad-based leaves aged between 50-100 years old. Diverse variety of plants and animals occupy tropical plants. Decomposition occurs at a very fast rate in tropical rainforests. These are also known as ‘Earth’s lungs’ because they contribute oxygen to the atmosphere. Most of the world’s tropical rainforests are present in – Southeast Asia, Sri Lanka, sub-Saharan Africa, South America, Central America and Pacific Islands.
These kinds of forests thrive in locations with equatorial climate, also known as tropical rainforest climate. Equatorial climate is a rainforest climate occurring along or near the equator. Tropical rainforest climates have no dry spells. The average precipitation in tropical rainforests is at least 60 mm.
2. Temperate rainforests are cool and wet, characterized by mean annual rainfall of 50-140 inches and average daily mean temperature of around 50-80 degrees. These are located in the temperate regions. They have evergreen trees aged between 500-1000 years old. The temperate rainforests possess seasonal climate, hence less diversity of flora and fauna. Trees generally have needle-like leaves. In temperate rainforest, decomposition occurs at comparatively slow rate. Temperate rainforest are commonly found in North America, East Asia, Europe, South America, Australia and New Zealand.
These kinds of forests are characterized by broadleaf and coniferous forests that thrive in the temperate zones, which receive a lot of rainfall. Coniferous forests are chiefly composed of cone-bearing trees. Temperate forest areas receive an average temperature of 40 to 55 degrees Fahrenheit. The main temperate rainforest areas in the world include the British aisle of Europe, the Pacific North West of the United States and some areas in Australia and New Zealand.
3. Montane forests are also known as cloud forests, located on mountains and containing shorter trees such as oaks, pines and rhododendrons.
4. Lowland rainforests possess consistent weather throughout the year with same rainfall and humidity every day. It has tall trees with great diversity of plants and animals.
5. Flooded rainforests are the ones that flood for short or long periods of time due to heavy rains. ‘Varzea’ refers to these forests that flood for short period of time with water levels as much as 10 meters while ‘Igapo’ means forests that flood for long period of time, up to 11 months, with water levels as much as 12 meters. Trees and fish adapt to survive in this environment – trees form strange shapes and freshwater fish enter into these flooded forests.
6. Mangrove forests are found on river banks and coasts. These consist of wetland plants which filter the water that flows through them. These trees reach a height of 24 meters and possess stilt-like roots to prevent decomposition in water. They can survive in salty environment with periods of drought in the dry season.
Various Benefits of Rainforests
Offer natural habitat for animals and plants
Statistics learn that tropical forests took well over 90 million years to evolve. They are also considered the oldest and most sophisticated land-based ecosystems on planet earth and harbor more than 30 million bird and animal species. That figure represents half of wildlife found on the entire globe.
Since almost all rainforests thrive in warm and steamy climates, it’s home to a wide range of plant life. To be specific, a single hectare of lowland forest could harbor more than one thousand trees and approximately 300 species. If you compare this figure with forests in countries like the United Kingdom, there is a stark difference. You’re likely to find only 5-10 species in a single hectare in U.K. forest.
These pants species are a source of food and shelter for the wide range of birds and animals living in this rainforest ecosystem. The interesting part is there are still plenty of rainforests across the globe that have not been discovered and explored.
2. Rainforests are great sources of medicine
Even with the huge potential of medicine in rainforests, humans have only managed to harness 1% leaving 99% untouched. The possibility of yielding even more powerful medicine if the remaining 99% is experimented is huge. Classic examples of rainforest plants used to cure diseases include:
Curare: This is obtained in the canopy of the South American forest. It was traditionally utilized by Indians of South America to create poison used in hunting wild animals in rainforests.
Cocoa tree: The cocoa tree has great medicinal properties. It produces over 155 chemicals extracted from it back, leaves, fruits, and seeds. These extracts are used to cure kidney stones, coughs, external cuts and bruises, fever and anxiety.
Guarana: This climbing plant originates from the Amazon basin. It’s commonly used in sports energy beverages; it reduces the pain of strained muscles and is a natural caffeine source.
There are literally thousands of medicines derived from rainforests.
3. Offer a home for indigenous people
When you brush up your history, you will find that indigenous people have been living in these rainforests for many years and in harmony with the plant, animal and bird species. They have relied on the rainforests for food, medicine, and shelter. The indigenous people only began to be threatened by logging and oil extraction activities.
As a result, oil and logging company workers introduced diseases that lacked resistance and threatened their survival. These commercial activities have even forced these indigenous communities to relocate and have also died as a result.
4. Rain forests help mitigate soil erosion
The shocking fact about soil in the rainforest is that it is less in nutrients. The reason is that a lot of nutrients in the rainforest are stored in the wide range of plants and trees. The soil in rainforests is held together by the vast network of tree roots. The soil is insulated from pounding rain by the canopy. If a tree dies and falls to the ground below, it decays, and the nutrients obtained recycled.
Nonetheless, if the logging companies cut down and remove the trees, the nutrients are carried along. The soil also loses the grip of the roots and the protection of the canopy. When heavy rain falls, the unprotected soil is easily washed away resulting in floods and blockages in downstream areas. This phenomenon could also render upland rivers dry.
5. Climate regulation
Rainforests are huge water storehouses. According to veritable statistics, the Amazon forests alone store up more than half of the entire planet’s rain water. It’s a cycle in which rainforest trees absorb water from the floor of the forest and emit it back to the atmosphere in the form of cloud and mist.
If rainforests were not available, then droughts would be prevalent because there would be no water stored to feed the rivers that lead to lakes and oceans. Trees also help to rid the atmosphere of dangerous gasses. Trees absorb carbon dioxide, which we breathe out and emit oxygen that we need when breathing in. Combustion of rainforests triggers the release of carbon dioxide, which greatly contributes to climate change and global warming.