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

Endangered seabirds return to Pacific island after century-long absence (Dec 14 2024)
- Endangered Polynesian storm petrels have returned to Kamaka Island in French Polynesia for the first time in more than 100 years, after conservationists used drones to remove the invasive rats eating the birds’ eggs and chicks.
- Scientists attracted the birds back to the island using solar-powered speakers playing bird calls recorded from a neighboring island, with monitoring cameras showing regular visits, though nesting has not yet been confirmed.
- The project demonstrates successful collaboration between international conservation groups and local communities, with the local Mangareva community’s knowledge and support proving crucial to the operation’s success.
- The birds’ return could benefit the entire island ecosystem, as seabirds bring nutrients from the ocean that help sustain both terrestrial and marine life around the island.

Study looks for success factors in African projects that heal land and help people (Dec 13 2024)
- Land degradation across Africa impacts the lives of rural Africans, who depend heavily on natural resources.
- Reversing land degradation while improving livelihoods can be tricky, and not all initiatives succeed.
- A recent Sustainability Science study examined 17 initiatives in 13 African nations to tease out what factors contribute to success or failure.
- The study finds that tapping into social relationships, providing adequate incentives to overcome risk-adverse behaviors, and maintaining momentum over the long term emerged as key factors in an initiative’s success.

Illegal cockfighting threatens endangered sea turtles across Central America (Dec 13 2024)
- The hawksbill sea turtle (Eretmochelys imbricata), a critically endangered species, has long been exploited for its shell, used in a wide range of ornaments, including, in Costa Rica, the deadly spurs used in illegal cockfighting.
- Cockfighting is banned in Costa Rica, but the tradition persists underground, with authorities increasing their efforts to seize hawksbill spurs.
- Conservationists are also helping to train inspection officers to identify hawksbill products brought into Costa Rica from neighboring countries.
- When poachers harvest hawksbills, they’re not targeting them specifically for spurs but also for other products, which often find their way into tourist shops and online markets worldwide.

Direct air capture climate solution faces harsh criticism, steep challenges (Dec 13 2024)
- Direct air capture — geoengineering technology that draws carbon dioxide from the air, allowing it to be stored in geologic formations or used by industry — is being heavily hyped as a climate solution.
- But as direct air capture (DAC) pilot projects an startups grow in number around the world, fueled by investment and government funding in the U.S. and elsewhere, this proposed climate solution is becoming ever more divisive.
- Critics paint DAC as a costly, ineffective distraction from drastically slashing fossil fuel extraction and emissions. The use of captured carbon by the fossil fuel industry to squeeze ever more oil from wells comes in for particularly sharp criticism.
- Though carbon dioxide removal (CDR) may be needed to help limit the worst impacts of global warming, experts say betting on direct air capture is riddled with challenges of cost and scale. Two hurdles: sourcing sufficient renewables to power DAC facilities, and minimizing carbon-intensive DAC infrastructure.

Recycling gold can tackle illegal mining in the Amazon, but is no silver bullet (Dec 13 2024)
- Artisanal and small-scale gold mining in Brazil’s Tapajós River Basin emits 16 metric tons of CO2 per kilo of gold produced, and 2.5 metric tons of mercury annually, a study has found.
- Researchers suggest that recycling gold could dramatically reduce harmful emissions, along with other solutions such as formalizing mining, adopting clean technologies, and improving gold supply chain transparency.
- Economic dependence, mercury accessibility, and a demand for gold sustain small-scale gold mining, while enforcement risks pushing miners into ecologically sensitive areas.
- In November, Brazil launched a federal operation in the Tapajós Basin to expel illegal gold miners from the Munduruku Indigenous Territory, imposing millions of reais in fines to curb the damage caused by gold mining.

Climate change fuels African floods that hit harder in vulnerable regions (Dec 13 2024)
- Extreme rainfall and flooding across Sudan, Cameroon, Niger, Nigeria and Chad this year led to thousands of deaths and millions of displacements, mirroring what occurred in the region in 2022.
- Research by World Weather Attribution shows that such extreme floods, linked to anthropogenic climate change, are likely to become more intense and frequent in the future.
- Existing conflicts, poverty, aging infrastructure and socioeconomic inequalities further exacerbate the exposure of vulnerable communities to extreme floods; local leaders and experts call for improved sanitation and urban development policies as well as adaptation strategies in preparation for future floods.

Vietnam’s mammals need conservation within and outside their range: Study (Dec 13 2024)
- Vietnam is a treasure trove of mammalian diversity: it’s home to the highest number of primate species in mainland Southeast Asia and a host of unique species found nowhere else on the planet.
- However, a new study reveals more than one-third of Vietnam’s mammal species are threatened with extinction at a national level.
- The researchers advocate combining field-based and ex-situ conservation measures to recover the country’s mammal populations.
- They recommend conservation managers focus on establishing captive-breeding populations of key conservation species, as well as strengthening protection of habitats and creating wildlife corridors.

Foreign investor lawsuits impede Honduras human rights & environment protections (Dec 12 2024)
- Foreign investors in Honduras have “extraordinary privileges,” allowing them to sue the government for reforms that affect their investments, hindering public interest legislation, a recent report has found.
- Honduras faces billions of dollars in lawsuits from corporations, many tied to controversial investments made after the 2009 coup, creating a deterrent effect on the government’s ability to make sovereign decisions and making it the second-most-sued country in Latin America over the period of 2023 to August 2024, after Mexico.
- Some local communities in Honduras are divided over foreign investment projects, with several expressing resistance due to concerns about their impact on the environment and land rights.
- Honduras’ recent energy reforms and mining bans are facing backlash and legal challenges, as foreign corporations resist changes aimed at protecting natural resources and human rights.

Indonesian forests put at risk by South Korean and Japanese biomass subsidies (Dec 12 2024)
- Subsidies for forest biomass energy in Japan and South Korea are contributing to deforestation in Southeast Asia, according to an October 2024 report by environmental NGOs. The biomass industry is expanding especially quickly in Indonesia; the nation is exporting rapidly growing volumes of wood pellets, and is burning biomass at its domestic power plants.
- Japanese trading company Hanwa confirmed that rainforest is being cleared to establish an energy forest plantation for wood pellet production in Indonesia’s Sulawesi Island. Hanwa owns a stake in the project. The wood pellet mill uses cleared rainforest as a feedstock while the monoculture plantation is being established.
- A Hanwa representative defended the Sulawesi biomass project by claiming the area consists of previously logged secondary growth and that the energy plantation concession is not officially classified as “forest area.”
- The Japanese government is supporting biomass use across Southeast Asia through its Asia Zero Emission Community initiative, begun in 2023.

Peru’s modern history of migration and settlement (Dec 12 2024)
- Four roads with an enormous impact on rural Peru were built starting in the 1970s, incentivizing migration in the second half of the 20th century to the Amazonian lowlands from the Andean foothills.
- The largest single migratory destination in the Peruvian Amazon is landlocked Iquitos; immigrants arrived there in search of jobs in the oil industry. Currently counting more than 500,000 inhabitants, Iquitos is now the largest city in the Western Amazon.
- The cultivation of coca has had major impacts on the development of Peru’s Amazonian regions. Violent clashes between armed groups searching to dominate the activity have pushed as many as 450,000 people out of their homes.

Communities warn of threat to ecosystems from Brazil bridge project (Dec 12 2024)
- Islanders and experts have warned of widespread environmental and social impacts from the construction of a bridge linking the Brazilian city of Salvador with the island of Itaparica in Todos os Santos Bay.
- Critics say the project will devastate mangrove forests and coral reefs, leading to environmental imbalance, compromising fishing communities and threatening the survival of many marine species including humpback whales and sea turtles.
- Proponents say the bridge will boost development in the region, in particular transporting agricultural produce, but islanders say the anticipated population surge on Itaparica will create unsustainable pressure on public services as well as drastically change the dynamics of the community living there.
- Experts say the best solution for improving transportation links between Salvador and Itaparica is to invest in the existing ferry system, but this option wasn’t considered by planners.

Kenya embraces electric buses to combat air pollution (Dec 12 2024)
- The Kenyan capital Nairobi is slowly introducing electric buses into the fleet of notoriously noisy and polluting matatus that ply its streets.
- Drivers selected to operate these Chinese-made and locally assembled buses say passengers prefer them because they’re quieter, faster and more comfortable.
- The rollout is still on a small scale: the $200,000 price tag for an electric bus is prohibitive, but the manufacturer is leasing them to operators to make them more affordable.
- Charging is also an issue, with drivers reporting shorter ranges than advertised, and just three charging stations available in the city.

In 2024, Nepal’s elusive snow leopards pounce into spotlight (Dec 12 2024)
- The year 2024 marks significant milestones for snow leopard conservation in Nepal, one of the animal’s 12 range countries.
- A snow leopard was found roaming the country’s plains and provided a home in the country’s central zoo.
- With the launch of a new conservation action plan, the government has initiated a shift in its approach to save the animal.
- Snow leopards also found their way into the popular imagination of filmmakers and even cricket enthusiasts.

Wildlife conservation is a key climate change solution (commentary) (Dec 11 2024)
- It’s time for global leaders, funders, and policymakers to prioritize the inclusion of local conservationists in major climate discussions, a new op-ed argues.
- The effects of climate change, such as fires, droughts, and extreme weather events are not just environmental threats, but crises that directly impact human well-being and wildlife survival alike.
- “If we are serious about tackling climate change and preserving biodiversity, we must embrace holistic and inclusive approaches to conservation that integrate both wildlife and community needs,” two conservationists write.
- This article is a commentary. The views expressed are those of the authors, not necessarily Mongabay.

Brazil natural landscape degradation drives toxic metal buildup in bats (Dec 11 2024)
- Bats play a crucial role in tropical regions as pollinators, seed dispersers and agricultural pest controllers. But they are exposed to a wide range of threats, pollution among them.
- Two recent papers show how natural landscape transformation and degradation, due to pasture and crop monoculture creation and mining in Brazil’s Atlantic Forest, can increase bioaccumulation of toxins and heavy metals in bat populations, leading to potential health impacts.
- Over time, this toxic accumulation could increase the likelihood of local bat extinctions and the loss of vital ecosystem services. The toxic contamination of these landscapes also poses a concern for human health, researchers say.
- These findings are likely applicable to bats living in other highly disturbed tropical habitats around the world, researchers say.