Tropical rainforests, also known as lowland equatorial evergreen rainforests, are those that grow in regions with a tropical rainforest climate, which means there is never a dry season and all months have an average precipitation of at least 60 mm. A subset of the tropical forest biome that occurs roughly within the 28-degree latitudes, true rainforests are often found between 10 degrees north and south of the equator (in the equatorial zone between the Tropic of Cancer and Tropic of Capricorn). Tropical rainforests are a kind of tropical moist broadleaf forest (also known as a tropical wet forest), which also includes the more extensive seasonal tropical forests. This article will explain to you about Tropical Rainforest Region which will be helpful in preparing the Environment Syllabus for the UPSC Civil Service exam.

Structure of a Rainforest

• The majority of rainforests are divided into four layers: emergent, canopy, understory, and forest floor.
• Each layer has distinct characteristics due to differences in water, sunlight, and air circulation.
• While each layer is distinct, they are interconnected: processes and species in one layer influence those in another.

Emergent Layer

• The top layer of the rainforest is the emergent layer. The skyline is dominated by trees up to 60 metres (200 feet) tall.
• The foliage on tree trunks is often sparse, but it spreads widely as the trees reach the sunny upper layer, where they photosynthesize the sun's rays.
• During long droughts or dry seasons, small, waxy leaves help trees in the emergent layer retain water.
• Strong winds carry lightweight seeds away from the parent plant.
• Animals frequently fly or glide through the emergent layer's unstable topmost branches.
• Animals that cannot fly or glide are usually quite small because they must be light enough to be supported by the slender uppermost layers of a tree.

Canopy Layer

• The canopy is a deep layer of vegetation about 6 metres (20 feet) thick that lies beneath the emergent layer.
• The dense network of leaves and branches of the canopy acts as a roof over the two remaining layers.
• Winds, rainfall, and sunlight are blocked by the canopy, resulting in a humid, still, and dark environment below.
• Trees have adapted to the wet conditions by producing glossy leaves with pointed tips that repel water.
• While trees in the emergent layer rely on wind to disperse their seeds, many canopy plants encase their seeds in fruit when there is no wind.
• The most familiar fruit tree in the canopy is the fig tree, which grows in most of the world's tropical rainforests.
• With so much food available, the canopy supports more animals than any other layer of the rainforest. Because the dense vegetation muffles sound, many—but not all—canopy dwellers are distinguished by their shrill or frequent vocalisation.
• The canopy is also home to tens of thousands of insect species.

Understory Layer

• The understory is a darker, stiller, and more humid environment located several metres below the canopy.
• Palms and philodendrons, for example, are much shorter and have larger leaves than plants that dominate the canopy.
• The large leaves of understory plants capture the little sunlight that reaches beyond the dense canopy.
• Understory plants, such as Heliconia, which is native to the Americas and the South Pacific, frequently produce large, visible flowers. Others, such as orchids, have a strong odour.
  • These characteristics attract pollinators even in low-light conditions in the understory.
• Many understory shrubs in temperate rainforests have edible fruit and seeds.
• Animals live in the understory for a variety of reasons. Many people use the dim lighting to their advantage for camouflage.
• Amphibians thrive in humidity because it keeps their skin moist, such as brilliantly coloured tree frogs.

Forest Floor Layer

• The forest floor is the darkest of all rainforest layers, making plant growth extremely difficult. Fallen leaves decompose quickly on the forest floor.
• On the forest floor, decomposers such as termites, slugs, scorpions, worms, and fungi thrive.
• Organic matter falls from trees and plants, and these organisms decompose it into nutrients.
• These nutrients are absorbed by the shallow roots of rainforest trees, and dozens of predators consume the decomposers.
• Rivers that flow through tropical rainforests create unique freshwater habitats on the forest floor.

What is a Tropical Rainforest?

• Tropical rainforests are primarily found between the latitudes of 23.5°N (the Tropic of Cancer) and 23.5°S (the Tropic of Capricorn).
• Tropical rainforests can be found in Central and South America, western and central Africa, western India, Southeast Asia, New Guinea, and Australia.
• The sun almost directly strikes the tropics, producing intense solar energy that keeps temperatures high, ranging between 21° and 30° C (70° and 85° F).
• With an average humidity of 77% to 88%, high temperatures keep the air warm and moist.
• Extreme and frequent rainfall, ranging from 200-1000 centimetres (80-400 inches) per year, is caused by such humid air.
• Because tropical rainforests are so warm and moist, they generate up to 75% of their own rain through evaporation and transpiration.
• Tropical rainforests are the world's most biologically diverse terrestrial ecosystems.
• The Amazon rainforest is the largest tropical rainforest on the planet. It is home to approximately 40,000 plant species, nearly 1,300 bird species, 3,000 different types of fish, 427 different mammal species, and 2.5 million different insects.

Tropical Rainforest Region - Distribution

• Except for Antarctica, rain forests thrive on every continent.
• The Amazon River in South America and the Congo River in Africa are surrounded by the world's largest rainforests.
• Dense rainforest habitats can be found on Southeast Asia's tropical islands and in parts of Australia.
• Even the cool evergreen forests of North America's Pacific Northwest and the Northern Europe are a type of rainforest.
• Southeast Asia, Hawaii, and the Caribbean Islands all have tropical rainforests.
• South America's Amazon rainforest is the world's largest, occupying an area almost two-thirds the size of the continental United States.

Distribution of Tropical Rain Forests

Tropical Rainforest Region - Temperature

• The average temperature in tropical rainforest regions is between 20 and 29 degrees Celsius, with no month having a temperature below 18 degrees Celsius.
• As the altitude rises, temperatures become more critical.
• For every 100 meters climbed in the humid tropics, temperatures drop by roughly 0.5 degrees Celsius.
• Despite the fact that the climate that supports tropical rainforests is always hot, temperatures never reach the extremes seen in drier areas to the north and south of the equatorial belt.

Tropical Rainforest Region - Precipitation

• With a warm summer rainfall and a cooler winter dry season, moist seasonal tropical forests receive a lot of rain.
• Annual rainfall ranges between 1,800 to 2,500 mm.
• Due to the loss of soluble nutrients from the ground, this large number of precipitation frequently results in poor soils.

Tropical Rainforest Region - Soil

• Tropical rainforest soils are often deep but not particularly fertile.
• This is partly due to the fact that huge amounts of some mineral nutrients are tied up inside the vegetation rather than being free in the soil at any given time.
• Tropical red regions of the world are formed when moist, hot climatic circumstances cause deep weathering of rock and the formation of deep, typically reddish soil profiles rich in insoluble sesquioxides of iron and aluminum.
• Because precipitation in tropical rainforest regions almost always exceeds evapotranspiration, there is a near-permanent surplus of water in the soil, which travels downward through the soil into valley-floor streams and rivers.
• The soil gets depleted of nutrients as a result of this process, leaving it generally infertile.

Tropical Rainforest Region - Flora

• Angiosperms are the most diverse of the higher autotrophs. Every year, new plant species, even ones as huge as trees, are identified.
• Ferns, mosses, liverworts, lichens, and algae are likewise abundant and diverse, though they have not been examined or cataloged as well as higher plants.
• Many are epiphytic, meaning they attach themselves to the stems and occasionally the leaves of larger plants, particularly in the wettest and most humid environments.
• Similarly, fungi and other saprophytic plants (those that thrive on dead or decaying substances) are diverse.
• Some play an important role in decomposing dead organic debris on the forest floor, releasing mineral nutrients that are then available to roots in the top layers of the soil.
• Other fungi form symbiotic relationships with tree roots (mycorrhizae).
• The Nilgiris have extensive grasslands interspersed with densely forested gorges of evergreen vegetation known as sholas (an offshoot of Western ghats). Sholas can also be found in the Aanaimalai and Palani hills.
• The Western Ghats rain forests are dense and lofty, with a wide variety of species.
• Mosses, ferns, epiphytes, orchids, lianas and vines, herbs, and shrubs all contribute to the diversity of habitat.
• These forests are dominated by ebony trees.
• There are numerous tropical orchids to be found.

Tropical Rainforest Region - Fauna

• Any tropical rainforest can expect to find a range of fruit-eating parrots, pigeons, and seed-eating weevil beetles.
• Monkeys are found in both the New and Old World's tropical rainforests, but they are completely missing from New Guinea and the territories to its east and south.
• Tree kangaroos and birds of paradise are both limited to tropical rainforest canopies found only in Australia and New Guinea.
• Monkeys, deer, pigs, cats, elephants, and rhinoceroses live in the rainforests to the west, while marsupial mammals such as opossums, cuscuses, dasyurids, tree kangaroos, and bandicoots live in the rainforests to the east.
• Only a few animal species, such as bats and rodents, have crossed the border and grown prevalent in both areas.
• Across the same division, similar disparities can be detected in many other animal and plant groups, albeit they are less prominent.
• Macaque, Assamese Macaque, slow Loris, capped Langurs, pig-tailed Macaque, stump-tailed Macaque, and Hoolock Gibbons.
• Elephants, gaurs, and other large animals find refuge in the Indian tropical rain forests.
• Aside from tigers, other animals found in these mangrove forests include spotted deer, pigs, rhesus monkeys, lizards, water monitors, crocodiles, crabs, and fish.

Tropical Rainforests in India

• The Indian tropical rain forests are dense, warm, and wet, and they support a diverse range of plant and animal species.
• These types of forests are mostly found in areas with plenty of rainfall and sunshine all year.
• Because of the heavy rainfall, the Indian tropical rain forests are primarily found in the states of Arunachal Pradesh, Assam, Meghalaya, Nagaland, Tripura, the Western Ghats, West Bengal, and the Andaman and Nicobar Islands.
• Because the area is warm and wet all year, trees in Indian tropical forests do not have a specific season for dropping their leaves.
• Tree growth is usually at its best when rainfall exceeds 200 cm and there is a short dry season. As a result, these forests are also known as archetypal rain forests.
• Trees grow quickly in these forests, reaching sublime heights of 60 metres and higher.

Regions of Tropical Rainforests in India

Different types of Tropical Rain Forest can be found in various parts of India. It is most common in three locations: Assam, the Western Ghats, and the Andaman Islands.

1) Andaman and Nicobar Islands

• The forests of the Andaman and Nicobar islands are located in the equatorial belt of tropical rain forests and are among the most beautiful in the world.
• Andaman and Nicobar Islands have some of India's most beautiful tropical rainforests. It has a wide range of fauna and flora species.
• The area is unique in that it is home to many exotic and rare animal and plant species.
• The animals come from Thailand, Bangladesh, Myanmar, and other places.

2) North Eastern Region

• The North East region of India is known for its tropical rain forests that have not been impacted by human population or commercialization. However, the woods are mostly concentrated in Assam's northern region.
• However, a few patches can be found in neighbouring states such as Tripura, Mizoram, Manipur, and Nagaland.
• The Indian tropical rain forests in Arunachal Pradesh are endowed with an abundance of wildlife and forested land.

3) Western Ghats

• The Western Ghats cover approximately 30,000 square kilometres of tropical rain forest.
• It is a dense forest that stretches from the southwest of Maharashtra to Karnataka in South India.
• It is home to over 1000 different species of animals and has a diverse wildlife.
• The most concerning factor, however, is the loss of forest cover as a result of commercialization and high urbanisation.

Tropical Rainforest Region - Significance

• Rainforests aid to balance the global climate.
  • Rainforests produce about 20% of our oxygen and store a massive amount of carbon dioxide, reducing the impact of greenhouse gas emissions significantly.
  • Massive amounts of solar radiation are absorbed, assisting in the regulation of global temperatures.
• They maintain the water cycle to protect against flood, drought, and erosion.
  • Evapotranspiration returns more than half of the precipitation that falls on a rainforest to the atmosphere, assisting in the regulation of healthy rainfall around the world.
  • Rainforests also store a significant portion of the world's freshwater, with the Amazon Basin alone accounting for one-fifth.
• Rainforests provide many products that we use on a daily basis.
  • Teak, balsa, rosewood, and mahogany are tropical woods that are used in flooring, doors, windows, boatbuilding, and cabinetry.
  • Raffia, bamboo, kapok, and rattan fibres are used to make furniture, baskets, insulation, and cord.
  • Cinnamon, vanilla, nutmeg, and ginger are just a few rainforest spices.
  • Fruits grown in the ecosystem include bananas, papayas, mangoes, cocoa, and coffee beans.
• Rainforests also provide numerous medicinal products.
  • According to the US National Cancer Institute, 70% of plants useful in cancer treatment are only found in rainforests.
  • Muscle relaxants, steroids, and insecticides are all made from rainforest plants.
  • They are prescribed to treat conditions such as asthma, arthritis, malaria, heart disease, and pneumonia.
• They provide a home for many plants and animals.
• They support tribal people.
• Rainforests in general are interesting places of tourist attraction.

Tropical Rainforest Region - Threats

• Rainforests are rapidly disappearing, owing largely to human development over the last few centuries.
• Rainforests once covered 14% of the Earth's land surface, but now only account for 6%.
• The total area of tropical rainforests has most likely been reduced by more than half since 1947, to approximately 6.2 to 7.8 million square kilometres (3 million square miles).

Mining and Drilling

• Underneath rainforests all over the world are deposits of fossil fuels (oil and natural gas), precious metals (gold, silver, coltan), and coltan.
• Since these resources are valuable to developed countries, attention is frequently given to their extraction in order to promote economic expansion.
• Large-scale land development may be necessary for mining and drilling, which directly contributes to deforestation.
• About 12% of the natural rainforest in Ghana, a country in West Africa, was unaltered by decades of mining operations.

Conversion to Agricultural Land

• With the development of agriculture, people were able to clear areas of the forest and turn them into open farmland.
• These people, however, supplement their diet by hunting and foraging in the forest and get their food mostly from farmland that has been cleared from the forest.
• The conflict is between the independent farmer's desire to provide for his family and the needs and desires of the entire world.
• Because no strategy has been devised to assist all parties, this situation hasn't improved much.

Climate Change

• The reduction of atmospheric carbon dioxide largely depends on the tropics.
• The tropics are referred to as carbon sinks, particularly the Amazon rainforest.
• Their destruction adds to an increase in the number of atmospheric gases that trap energy globally because they are important carbon reducers and carbon and soil methane storage.
• The degradation of the rainforests has made a significant contribution to climate change.

Declining Population

• In rainforests, some animal species like reptiles that prey on amphibians show a pattern of diminishing populations.
• The reproductive patterns of amphibians are influenced by the seasonality of rainforests, and this can have a direct impact on the kinds of reptiles that prey on these groups, especially those with specialized feeding since they are less likely to use alternate resources.

Conclusion

Many individuals, communities, governments, intergovernmental organisations, and conservation organisations are taking novel approaches to preserve and protect tropical rainforest regions. Finding sustainable management methods for those who live in tropical rainforests is one aspect of rigorous habitat protection in tropical rainforests. Reducing Emissions from Deforestation and Forest Degradation (REDD) is a market incentive program that has been established by international legislation to encourage businesses and governments to offset their carbon emissions through financial contributions to rainforest preservation.