RAINFOREST INFORMATION

A Place Out of Time: Tropical Rainforests and the Perils They Face - information on tropical forests, deforestation, and biodiversity

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BACKGROUND INFORMATION ON THE RAINFOREST

Rainforests are forest ecosystems characterized by high levels of rainfall, an enclosed canopy and high species diversity. While tropical rainforests are the best-known type of rainforest and the focus of this section of the web site, rainforests are actually found widely around the world, including temperate regions in Canada, the United States, and the former Soviet Union.

Tropical rainforests typically occur in the equatorial zone between the Tropic of Cancer and Tropic of Capricorn, latitudes that have warm temperatures and relatively constant year-round sunlight. Tropical rainforests merge into other types of forest depending on the altitude, latitude, and various soil, flooding, and climate conditions. These forest types form a mosaic of vegetation types which contribute to the incredible diversity of the tropics.

The bulk of the world's tropical rainforest occurs in the Amazon Basin in South America. The Congo Basin and Southeast Asia, respectively, have the second and third largest areas of tropical rainforest. Rainforests also exist on some the Caribbean islands, in Central America, in India, on scattered islands in the South Pacific, in Madagascar, in West and East Africa outside the Congo Basin, in Central America and Mexico, and in parts of South America outside the Amazon. Brazil has the largest extent of rainforest of any country on Earth.

Rainforests provide important ecological services, including storing hundreds of billions of tons of carbon, buffering against flood and drought, stabilizing soils, influencing rainfall patterns, and providing a home to wildlife and Indigenous people. Rainforests are also the source of many useful products upon which local communities depend.

While rainforests are critically important to humanity, they are rapidly being destroyed by human activities. The biggest cause of deforestation is conversion of forest land for agriculture. In the past subsistence agriculture was the primary driver of rainforest conversion, but today industrial agriculture — especially monoculture and livestock production — is the dominant driver of rainforest loss worldwide. Logging is the biggest cause of forest degradation and usually proceeds deforestation for agriculture.

Organization of this site

The rainforest section of Mongabay is divided into ten "chapters" (the original text for the site was a book, but has since been adapted for the web), with add-on content in the form of special focal sections (e.g. The Amazon, the Congo, REDD, New Guinea, Sulawesi, Forests in Brazil, etc), appendices, and other resources.

There is also a version of the site geared toward younger readers at kids.mongabay.com.

ABOUT THE RAINFOREST (SUMMARY)

RAINFOREST DISTRIBUTION AND CHARACTERISTICS

Each rainforest is unique, but there are certain features common to all tropical rainforests.

• Location: rainforests lie in the tropics.
• Rainfall: rainforests receive at least 80 inches (200 cm) of rain per year.
• Canopy: rainforests have a canopy, which is the layer of branches and leaves formed by closely spaced rainforest trees some 30 meters (100 feet) off the ground. A large proportion of the plants and animals in the rainforest live in the canopy.
• Biodiversity: rainforests have extraordinarily highs level of biological diversity or “biodiversity”. Scientists estimate that about half of Earth's terrestrial species live in rainforests.
• Ecosystem services: rainforests provide a critical ecosystem services at local, regional, and global scales, including producing oxygen (tropical forests are responsible for 25-30 percent of the world's oxygen turnover) and storing carbon (tropical forests store an estimated 229-247 billion tons of carbon) through photosynthesis; influencing precipitation patterns and weather; moderating flood and drought cycles; and facilitating nutrient cycling; among others.

The global distribution of tropical rainforests can be broken up into four biogeographical realms based roughly on four forested continental regions: the Afrotropical, the Australiasian, the Indomalayan/Asian, and the Neotropical. Just over half the world's rainforests lie in the Neotropical realm, roughly a quarter are in Africa, and a fifth in Asia.

These realms can be further divided into major tropical forest regions based on biodiversity hotspots, including:

1. Amazon: Includes parts of Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, Venezuela
2. Congo: Includes parts of Cameroon, Central African Republic, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Republic of Congo
3. Australiasia: Includes parts of Australia, Indonesian half of New Guinea, Papua New Guinea
4. Sundaland: Includes parts of Brunei, Indonesia, Malaysia, Singapore
5. Indo-Burma: Includes parts of Bangladesh, Cambodia, China, India, Laos, Myanmar, Thailand, Vietnam
6. Mesoamerica: Includes parts of Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama
7. Wallacea: Sulawesi and the Maluku islands in Indonesia
8. West Africa: Includes parts of Benin, Cameroon, Côte d'Ivoire, Ghana, Guinea, Liberia, Nigeria, Sierra Leone, Togo
9. Atlantic forest: Includes parts of Argentina, Brazil, Paraguay
10. Choco: Includes parts of Colombia, Ecuador, Panama

Other countries that have large areas of rainforest include Bolivia, Cameroon, Central African Republic, Ecuador, Gabon, Guyana, India, Laos, Malaysia, Mexico, Myanmar, Papua New Guinea, Republic of Congo, Suriname, and Venezuela.

Cover and loss by rainforest region

RAINFOREST STRUCTURE

Rainforests are characterized by a unique vegetative structure consisting of several vertical layers including the overstory, canopy, understory, shrub layer, and ground level. The canopy refers to the dense ceiling of leaves and tree branches formed by closely spaced forest trees. The upper canopy is 100-130 feet above the forest floor, penetrated by scattered emergent trees, 130 feet or higher, that make up the level known as the overstory. Below the canopy ceiling are multiple leaf and branch levels known collectively as the understory. The lowest part of the understory, 5-20 feet (1.5-6 meters) above the floor, is known as the shrub layer, made up of shrubby plants and tree saplings.

RAINFOREST BIODIVERSITY

Tropical rainforests support the greatest diversity of living organisms on Earth. Although they cover less than 2 percent of Earth’s surface, rainforests house more than 50 percent of the plants and animals on the planet.

THE RAINFOREST CANOPY

In the rainforest most plant and animal life is not found on the forest floor, but in the leafy world known as the canopy. The canopy, which may be over 100 feet (30 m) above the ground, is made up of the overlapping branches and leaves of rainforest trees. Scientists estimate that more than half of life in the rainforest is found in the trees, making this the richest habitat for plant and animal life.

The conditions of the canopy are markedly different from the conditions of the forest floor. During the day, the canopy is drier and hotter than other parts of the forest, and the plants and animals that live there have adapted accordingly. For example, because the amount of leaves in the canopy can make it difficult to see more than a few feet, many canopy animals rely on loud calls or lyrical songs for communication. Gaps between trees mean that some canopy animals fly, glide, or jump to move about in the treetops. Meanwhile plants have evolved water-retention mechanisms like waxy leaves.

Scientists have long been interested in studying the canopy, but the height of trees made research difficult until recently. Today the canopy is commonly accessed using climbing gear, rope bridges, ladders, and towers. Researchers are even using model airplanes and quadcopters outfitted with special sensors — conservation drones — to study the canopy.

The rainforest floor

The rainforest floor is often dark and humid due to constant shade from the leaves of canopy trees. The canopy not only blocks out sunlight, but dampens wind and rain, and limits shrub growth.

Despite its constant shade, the ground floor of the rainforest is the site for important interactions and complex relationships. The forest floor is one of the principal sites of decomposition, a process paramount for the continuance of the forest as a whole. It provides support for trees responsible for the formation of the canopy and is also home to some of the rainforest's best-known species, including gorillas, tigers, tapirs, and elephants, among others.

Rainforest waters

Tropical rainforests support some of the largest rivers in the world, like the Amazon, Mekong, Negro, Orinoco, and Congo. These mega-rivers are fed by countless smaller tributaries, streams, and creeks. For example, the Amazon alone has some 1,100 tributaries, 17 of which are over 1,000 miles long. Although large tropical rivers are fairly uniform in appearance and water composition, their tributaries vary greatly.

Rainforest waters are home to a wealth of wildlife that is nearly as diverse as the biota on land. For example, more than 5,600 species of fish have been identified in the Amazon Basin alone.

But like rainforests, tropical ecosystems are also threatened. Dams, deforestation, channelization and dredging, pollution, mining, and overfishing are chief dangers.

Rainforest people

Tropical rainforests have long been home to tribal peoples who rely on their surroundings for food, shelter, and medicines. Today very few forest people live in traditional ways; most have been displaced by outside settlers, have been forced to give up their lifestyles by governments, or have chosen to adopt outside customs.

Of the remaining forest people, the Amazon supports the largest number of Indigenous people living in traditional ways, although these people, too, have been impacted by the modern world. Nonetheless, Indigenous peoples' knowledge of medicinal plants remains unmatched and they have a great understanding of the ecology of the Amazon rainforest.

In Africa there are native forest dwellers sometimes known as pygmies. The tallest of these people, also called the Mbuti, rarely exceed 5 feet in height. Their small size enables them to move about the forest more efficiently than taller people.

There are few forest peoples in Asia living in fully traditional ways. The last nomadic people in Borneo are thought to have settled in the late 2000's. New Guinea and the Andaman Islands are generally viewed as the last frontiers for forest people in Asia and the Pacific.

Deforestation

In recent decades there has been an important shift in deforestation trends. Today export-driven industries are driving a bigger share of deforestation than ever before, marking a shift from previous decades, when most tropical deforestation was the product of poor farmers trying to put food on the table for their families. There are important implications from this change. While companies have a greater capacity to chop down forests than small farmers, they are more sensitive to pressure from environmentalists. Thus in recent years, it has become easier—and more ethical—for green groups to go after corporations than after poor farmers.

Rainforests are also threatened by climate change, which is contributing to droughts in parts of the Amazon and Southeast Asia. Drought causes die-offs of trees and dries out leaf litter, increasing the risk of forest fires, which are often set by land developers, ranchers, plantation owners, and loggers.

Rainforest importance

While rainforests may seem like a distant concern, they are critically important for our well-being. Rainforests are often called the lungs of the planet for their role in absorbing carbon dioxide, a greenhouse gas, and producing oxygen, upon which all animals depend for survival. Rainforests also stabilize climate, house incredible amounts of plants and wildlife, and produce nourishing rainfall all around the planet.

Rainforests:

• Help stabilize the world’s climate: Rainforests help stabilize the world’s climate by absorbing carbon dioxide from the atmosphere. Scientists have shown that excess carbon dioxide in the atmosphere from human activities is contributing to climate change. Therefore, living rainforests have an important role in mitigating climate change, but when rainforests are chopped down and burned, the carbon stored in their wood and leaves is released into the atmosphere, contributing to climate change.
• Provide a home to many plants and animals: Rainforests are home to a large number of the world’s plant and animals species, including many endangered species. As forests are cut down, many species are doomed to extinction.
• Help maintain the water cycle: The role of rainforests in the water cycle is to add water to the atmosphere through the process of transpiration (in which plants release water from their leaves during photosynthesis). This moisture contributes to the formation of rain clouds, which release the water back onto the rainforest. In the Amazon, 50-80 percent of moisture remains in the ecosystem’s water cycle. When forests are cut down, less moisture goes into the atmosphere and rainfall declines, sometimes leading to drought. Rainforests also have a role in global weather patterns. For example researchers have shown that forests in South America affect rainfall in the United States, while forests in Southeast Asia influence rain patterns in southeastern Europe and China. Distant rainforests are therefore important to farmers everywhere.
• Protect against flood, drought, and erosion: Rainforests have been compared to natural sponges, moderating flood and drought cycles by slowing run-off and contributing moisture to the local atmosphere. Rainforests are also important in reducing soil erosion by anchoring the ground with their roots. When trees are cut down there is no longer anything to protect the ground, and soils are quickly washed away with rain. On steep hillsides, loss of forest can trigger landslides.
• Are a source for medicines and foods and support forest-dependent people: People have long used forests as a source of food, wood, medicine, and recreation. When forests are lost, they can no longer provide these resources. Instead people must find other places to get these goods and services. They also must find ways to pay for the things they once got for free from the forest.

Rainforest conservation

Rainforests are disappearing very quickly. The good news is there are a lot of people who want to save rainforests. The bad news is that saving rainforests will be a challenge as it means humanity will need to shift away from business-as-usual practices by developing new policies and economic measures to creative incentives for preserving forests as healthy and productive ecosystems.

Over the past decade there has been considerable progress on several conservation fronts. Policymakers and companies are increasingly valuing rainforests for the services they afford, setting aside large blocks of forests in protected areas and setting up new financial mechanisms that compensate communities, state and local governments, and countries for conserving forests. Meanwhile, forest-dependent people are gaining more management control over the forests they have long stewarded. Large international companies are finally establishing policies that exclude materials sourced via deforestation. People are abandoning rural areas, leading to forest recovery in some planes.

But the battle is far from over. Growing population and consumption means that rainforests will continue to face intense pressures. At the same time, climate change threatens to dramatically alter temperatures and precipitation patterns, potentially pushing some forests toward critical tipping points.

Thus the future of the world's rainforests in very much in our hands. The actions we take in the next 20 years will determine whether rainforests, as we currently know them, are around to sustain and nourish future generations of people and wildlife.

The Latest News on Rainforests

Ecuador court upholds ‘rights of nature,’ blocks Intag Valley copper mine (Mar 31 2023)
- Community members in Ecuador’s Intag Valley have won a court case to stop the Llurimagua copper mining project, with the court ordering the revocation of mining licenses from Chile’s Codelco and Ecuador’s ENAMI EP.
- The Llurimagua mining concession is in the Tropical Andes, the world’s most biodiverse hotspot, home to dozens of threatened and endemic species, including two near-extinct frog species.
- A provincial court recognized that the mining companies violated the communities’ constitutional right to consultation and the rights of nature guaranteed by Ecuador’s Constitution since 2008.
- The decision is a significant win for the Intag communities, who have resisted mining for nearly 30 years, and sets an important precedent for protecting constitutional and environmental rights, as well as sends a message to investors that Ecuador is not a safe bet for mining operations.

Reconnecting ‘island habitat’ with wild corridors in Brazil’s Atlantic Forest (Mar 30 2023)
- This three-part Mongabay mini-series examines grassroots forest restoration projects carried out within isolated island ecosystems — whether those islands are surrounded by ocean as on the Big Island of Hawai‘i, or cloud forest mountaintop habitat encircled by lowlands in Costa Rica, or forest patches hemmed in by human development in Brazil.
- Reforestation of degraded island habitat is a first step toward restoring biodiversity made rare by isolation, and to mitigating climate threats. Though limited in size, island habitats can be prime candidates for reforestation because extinctions are typically much higher on isolated habitat islands than in more extensive ecosystems.
- Scientists mostly agree that the larger the forest island habitat, the greater its biodiversity, and the more resilient that forest system will be against climate change. Forests also store more carbon than degraded lands, and add moisture to soil and the atmosphere as a hedge against warming-intensified drought.
- The projects featured in this series are small in size, but if scaled up could become big forest nature-based climate solutions. In this third story, the NGO Saving Nature works to create wild corridors to reconnect fragmented patches of Brazil’s Atlantic Forest.

In central Brazil, mining company ignores Quilombola concerns over gold project (Mar 29 2023)
- Canadian mining company Aura Minerals plans to establish a major gold extraction project in Brazil’s Tocantins state without hearing the Quilombola (slave descendant) community that will be affected by the operations, thus violating their right to free, prior and informed consultation.
- So far, the company has not been transparent toward the community and has not described the potential impacts.
- Meanwhile, Aura Minerals has seen its value rise nearly 700% on the Toronto Stock Exchange between 2019 and 2022 — the best performance among 3,500 listed companies.
- The Quilombola estimate that, in the event of an accident with the company’s dam, the Baião community would be instantly engulfed and would disappear completely, with no chance to react.

Mountain islands: Restoring a transitional cloud forest in Costa Rica (Mar 29 2023)
- This three-part Mongabay mini-series examines grassroots forest restoration projects carried out within isolated island ecosystems — whether those islands are surrounded by ocean as on the Big Island of Hawai‘i, or cloud forest mountaintop habitat encircled by lowlands in Costa Rica, or forest patches hemmed in by human development in Brazil.
- Reforestation of degraded island habitat is a first step toward restoring biodiversity made rare by isolation, and to mitigating climate threats. Though limited in size, island habitats can be prime candidates for reforestation because extinctions are typically much higher on isolated habitat islands than in more extensive ecosystems.
- Scientists mostly agree that the larger the forest island habitat, and greater its biodiversity, and the more resilient that forest system will be against climate change. Forests also store more carbon than degraded agricultural lands, and add moisture to soil and the atmosphere as a hedge against global warming-intensified drought.
- The projects featured in this series are small in size, but if scaled up could become big forest nature-based climate solutions. In this second story, two tourists vacationing in Costa Rica and stunned by the deforestation they see, buy degraded land next to Chirripó National Park and restore a transitional cloud forest.

Mexico’s Tren Maya hotel construction clears forest reserve without permits (Mar 29 2023)
- The construction of a hotel in Mexico’s Calakmul Biosphere Reserve took many residents by surprise when bulldozers started clearing the forest in January.
- The hotel is part of the Tren Maya project, a controversial railway line that will move tourists and cargo throughout the Yucatán Peninsula and southern Mexico.
- Residents said they weren’t consulted and that the location of the project is dangerously close to Maya ruins and important sources of freshwater.

Can a new regional pact protect the Amazon from environmental crime? (commentary) (Mar 28 2023)
- Police, prosecutors, money-laundering experts and others convened last week in Brazil to tackle drug and environmental crimes like illegal mining and logging that are growing in scale across the Amazon.
- The group resolved to move law enforcement beyond occasional raids and periodic destruction of machinery used by organized crime syndicates and toward a concerted and pan-Amazonian push for local, regional and global cooperation on law enforcement.
- While acknowledging the increasing scale of these crimes, participants were optimistic: “We are living in a new moment to fight environmental crime and protect the Amazon,” said the newly appointed director for Amazon environmental crime with Brazil’s federal police, for example.
- This post is a commentary. The views expressed are those of the authors, not necessarily of Mongabay.

From ukuleles to reforestation: Regrowing a tropical forest in Hawai‘i (Mar 28 2023)
- This three-part Mongabay mini-series examines grassroots forest restoration projects carried out within isolated island ecosystems — whether those islands are surrounded by water as on the Big Island of Hawai‘i, or cloud forest mountaintop habitat encircled by lowlands in Costa Rica, or forest patches hemmed in by human development in Brazil.
- Reforestation of degraded island habitat is a first step toward restoring biodiversity made rare by isolation, and to mitigating climate threats. Though limited in size, island habitats can be prime candidates for reforestation because extinctions are typically much higher on isolated habitat islands than in more extensive ecosystems.
- Scientists mostly agree that the larger the forest island habitat, the greater its biodiversity, and the more resilient that forest system will be against climate change. Forests also store more carbon than degraded agricultural lands, and add moisture to soils and the atmosphere as a hedge against global warming-intensified drought.
- The projects featured in this series are small in size, but if scaled up could become big forest nature-based climate solutions. In this first story, two ukulele makers strive to save Hawai‘i’s koa tree, found nowhere else in the world. In the process they restore a biodiverse tropical forest on the slopes of the Big Island’s Mauna Loa volcano.

Tropical forest regeneration offsets 26% of carbon emissions from deforestation (Mar 23 2023)
- A new study published in the journal Nature analyzed satellite images from three major regions of tropical forest on Earth — Amazon, Central Africa and Borneo — and showed recovering forests offset just 26% of carbon emissions from new tropical deforestation and forest degradation in the past three decades.
- Secondary forests have a good potential to absorb carbon dioxide from the atmosphere and could be an ally in addressing the climate crisis, but emissions generated from deforestation and forests lost or damaged due to human activity currently far outpace regrowth.
- The study provides information to guide debates and decisions around the recovery of secondary forests and degraded areas of the Brazilian Amazon — around 17% of the ecosystem is in various stages of degradation and another 17% is already deforested.
- Since Brazil’s new President Luiz Inácio Lula da Silva took office, projects to curb deforestation are in place, but plans to protect recovering areas remain unclear.

Palm oil deforestation hits record high in Sumatra’s ‘orangutan capital’ (Mar 23 2023)
- Deforestation in a protected wildlife reserve known as the “orangutan capital of the world” hit a record high in 2022, according to various analyses.
- The forest loss was driven by clearing for oil palm plantations by well-connected local elites, rather than smallholders, according to advocacy group Rainforest Action Network (RAN).
- RAN’s investigation found that palm oil from these illegal plantations had wound up in the global supply chains of major brands like Procter & Gamble, Nestlé, PepsiCo and Unilever, among others.

Indonesian campaigns getting money from illegal logging, mining, watchdog says (Mar 21 2023)
- As Indonesia gears up for legislative and presidential elections in less than a year, authorities have warned of the pattern of dirty money from illegal logging, mining and fishing flowing into past campaigns.
- Experts say the practice of candidates taking this money from companies that exploit natural resources is common, given the high cost of running a campaign.
- This then perpetuates a tit-for-tat cycle that sees the winning candidate pay back their funders in the form of land concessions and favorable regulations.

Bearded pigs a ‘cultural keystone species’ for Borneo’s Indigenous groups: Study (Mar 20 2023)
- A recent study examined the impacts of ecological and sociocultural influences on bearded pig populations in Malaysian Borneo.
- The researchers found that the presence of pigs is “compatible” with Indigenous hunting in certain areas.
- The team’s findings point to the importance of a nuanced understanding of nearby human cultural values and local ecology in determining policies toward hunting.

Deforestation on the rise in Quintana Roo, Mexico, as Mennonite communities move in (Mar 15 2023)
- Mennonite families began to arrive in the southern Mexican municipality of Bacalar in 2001.
- They swiftly bought land, became members of the local ejido — an area of communally owned agricultural land — and then founded their own.
- Their presence in the region has continued to grow, along with the level of deforestation.
- Satellite imagery and field visits reveal vast swaths of rainforest have been cleared for large-scale agriculture.

Make it local: Deforestation link to less Amazon rainfall tips activism shift (Mar 14 2023)
- A new study supports mounting evidence that deforestation in the Amazon Rainforest correlates with a reduction in regional rainfall.
- Experts say this research reinforces the findings of other studies that claim the Amazon is leaning toward its “tipping point” and the southern regions are gradually becoming drier.
- Environmentalists see this research as an opportunity to reshape conservation activism and policy towards local communities.

Global ecosystems are at risk of losing carbon storage ability, study says (Mar 14 2023)
- Landscapes are showing signs of losing their ability to absorb the amount of carbon they once could, a new study revealed. That would pose serious obstacles to the fight against climate change.
- The study reviewed the productivity of carbon storage of different ecosystems between 1981 and 2018, finding that many fluctuated greatly and were at risk of turning into permanent scrubland.
- Researchers identified a concerning “spiraling” effect, in which landscapes absorb less carbon that in turn worsens climate change, which then destabilizes additional landscapes and puts them at higher risk of turning into scrubland.

Mobilizing Amazon societies to reduce forest carbon emissions and unlock the carbon market (commentary) (Mar 13 2023)
- Brazil could generate $10 billion or more from the global voluntary carbon market over the next four years through the sale of credits from Amazon states’ jurisdictional REDD+ programs; some states are already finalizing long-term purchase agreements.
- This funding would flow to those who are protecting the forest – Indigenous peoples and traditional communities, farmers, businesses, and government agencies – and the prospect of this funding could mobilize collective action to reduce emissions from illegal deforestation and degradation.
- Rapid progress in reducing emissions from Amazon deforestation and forest degradation – which represent half of Brazil’s nation-wide emissions – would also position Brazil to capture significant international funding for its national decarbonization process through the regulated carbon market that is under development through the UN Paris Agreement.
- This post is a commentary. The views expressed are those of the authors, not necessarily of Mongabay.