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

Deforestation notches up along logging roads on PNG’s New Britain Island (21 Oct 2021 06:53:16 +0000)
- Recent satellite data has shown a marked increase in the loss of tree cover in Papua New Guinea’s East New Britain province.
- Many of the alerts were near new or existing logging roads, indicating that the forest loss may be due to timber harvesting.
- Oil palm production is also growing, altering the face of a province that had more than 98% of its primary forest remaining less than a decade ago.
- The surge in land use changes has affected not only the environment in East New Britain, but also the lives of the members of the communities who depend on it.

Half-Earth, conservation, and hope: An interview with E.O. Wilson, Paula Ehrlich and Sir Tim Smit     (20 Oct 2021 20:02:09 +0000)
- E.O. Wilson is a scientist, naturalist, and author highly regarded for his theories of island biogeography and sociobiology, and for his writing that unites concepts in science and the humanities, winning him two Pulitzer Prizes in non-fiction, among other top recognitions.
- Wilson champions the goal of protecting half of the Earth, both land and sea, and makes the case that doing so would save more than 80% of all biodiversity. Biodiversity, he says, is “fundamental in continued human existence.”    
- On Oct. 22, Wilson will give a plenary speech at the Half-Earth Day virtual event, which brings together thought leaders, decision-makers and influencers such as Hindou Oumarou Ibrahim, Razan Al Mubarak, and Sir David Attenborough to discuss conservation in the areas of education, science, and technology.
- E.O. Wilson, Paula Ehrlich and Sir Tim Smit spoke with Mongabay staff writer Liz Kimbrough on Oct. 14, 2021 to discuss Half-Earth, hope and the need for a shift in consciousness.

Green groups call for scrapping of $300m loan offer for Borneo road project (20 Oct 2021 04:34:12 +0000)
- The Asian Development Bank is considering a $300 million loan proposal from the Indonesian government to fund a road project in Borneo.
- The 280-kilometer (170-mile) project across North and East Kalimantan provinces are designed to boost economic growth and further the integration of the Malaysian and Indonesian palm oil industries.
- Environmental groups around the world have urged the ADB to impose stricter environmental and social requirements for the project to reduce its expected impacts on the environment and the Indigenous communities living in the region.
- Indigenous peoples like the Dayak rely on the forests staying intact, as do critically endangered species such as Bornean orangutans.

Amazonian ecosystems and peoples on the brink – it is time for a new vision (commentary) (18 Oct 2021 21:07:33 +0000)
- Mercedes Bustamante — a Professor at the University of Brasilia, member of the Brazilian Academy of Sciences, and a lead scientist for the Science Panel for the Amazon — says the world needs to announce a “code red” for the Amazon due to increasing threats to the world’s largest rainforest.
- Bustamante cites evidence gathered in a new synthesis of the scientific knowledge on Amazonian socio-ecological systems, which “summarizes how ecosystems and human populations coevolved in this unique region and documents the unprecedented changes the Amazon has witnessed in recent years and their profound impacts on the continental and global environment.”
- “Saving existing forests from continued deforestation and degradation and restoring ecosystems is one of the most urgent tasks of our time to preserve the Amazon and its people and address the global risk and impacts of climate change,” Bustamante writes.
- This post is a commentary. The views expressed are those of the author, not necessarily Mongabay.

Math campus multiplies threats to Rio de Janeiro’s dwindling Atlantic Forest (15 Oct 2021 17:03:19 +0000)
- A plan to create a new mathematics campus with student accommodation in Rio de Janeiro is being challenged by residents as it calls for the removal of 255 trees in a patch of the already severely diminished Atlantic Forest.
- A study shows the construction site sits on a slope that poses a high geological risk, leaving residents worried about flooding and landslides in an area already affected by intense rainfall.
- Experts say there are irregularities in the licensing granted to the construction, and environmental laws are not being respected.
- The Institute for Pure and Applied Mathematics (IMPA), which is building the new campus, says all its licenses are in order, that it will reforest the area, and that the educational and social benefits will be worth it.

Guatemala tightens cattle ranching rules, but can they stop deforestation? (15 Oct 2021 14:18:52 +0000)
- Guatemala wants to continue to export cattle to Mexico but needs to regulate the industry to prevent the deforestation of the Mayan Biosphere Reserve and other protected forests.
- The government is constructing new cattle pen facilities on the border that could convince more ranchers to participate in a legal traceability system.
- However, even if the traceability system improves, deforestation caused by drug traffickers and other criminal actors will likely persist.

Malaysia’s Indigenous Penan block roads to stop logging in Borneo (14 Oct 2021 21:04:15 +0000)
- In an attempt to block logging operations by timber company Samling, Penan Indigenous tribespeople have erected two separate blockades in Malaysian Borneo’s Baram region.
- Penan activists allege Samling is encroaching on tribal land without their consent, and say they only put up the blockades after authorities failed to respond to their complaints.
- Samling, which has been granted a license to log in both contested areas, says the allegations that it has operated without consent on Penan land are “malicious and without any truth or basis.”
- One blockade, in the Long Ajeng area, has led to tensions between villagers opposed to Samling’s presence and those in favor of it, and has been dismantled and reinstalled multiple times.

Deforestation threatens tree kangaroo habitat in Papua New Guinea (14 Oct 2021 11:18:56 +0000)
- A proposed conservation area in northwestern Papua New Guinea has experienced a substantial surge in deforestation-related alerts, according to satellite data from the University of Maryland.
- The still-unofficial Torricelli Mountain Range Conservation Area is home to critically endangered tree kangaroo species, along with a host of other biodiversity.
- In May 2021, communities voiced concern about road construction that was approaching the boundaries of the proposed conservation area and that the intended target may have been high-value timber species found within the region’s forests.
- Investment in local communities and the protection of the forests that these communities provide have led to an apparent rise in tree kangaroo populations, but logging and other potentially destructive land uses such as conversion to large-scale agriculture remain threats in the Torricellis and throughout Papua New Guinea.

Inland mangroves reveal a tumultuous climatic past — and hint at our future (14 Oct 2021 10:48:19 +0000)
- A new study concludes that the presence of inland mangroves along a river in southern Mexico was the result of climate change-driven sea level rise during the Pleistocene Epoch, some 115,000 to 130,000 years ago.
- The researchers’ analysis of the genetic history of the mangrove trees suggests that they are closely related to trees found on the coastline, and sediments nearby are similar to those found in ocean environments.
- Publishing their work Oct. 12 in Proceedings of the National Academy of Sciences, the team notes that their research highlights the impacts of global climate change.

Biosurveillance of markets and legal wildlife trade needed to curb pandemic risk: Experts (14 Oct 2021 09:30:41 +0000)
- Almost 90% of the 180 recognized RNA viruses that can harm humans are zoonotic in origin. But disease biosurveillance of the world’s wildlife markets and legal trade is largely absent, putting humanity at significant risk.
- The world needs a decentralized disease biosurveillance system, experts say, that would allow public health professionals and wildlife scientists in remote areas to test for pathogens year-round, at source, with modern mobile technologies in order to help facilitate a rapid response to emerging zoonotic disease outbreaks.
- Though conservation advocates have long argued for an end to the illegal wildlife trade (which does pose zoonotic disease risk), but the legal trade poses a much greater threat to human health, say experts.
- Governments around the world are calling for the World Health Organization to create a pandemic treaty. Wildlife groups are pushing for such an agreement to include greater at-source protections to prevent zoonotic spillover.

Fate of Malaysian forests stripped of protection points to conservation stakes (13 Oct 2021 19:30:33 +0000)
- In the seven years since Jemaluang and Tenggaroh were struck from Malaysia’s list of permanent forest reserves, the two forests in Johor state have experienced large-scale deforestation.
- The clearance is reportedly happening on land privately owned by the sultan of Johor, the head of the state, calling into question the effectiveness of the Central Forest Spine (CFS) Master Plan, a nationwide conservation initiative the two reserves had originally been part of.
- The CFS Master Plan is currently being revised, with experts seeing the review as a chance to change what has been a largely toothless program, beset by conflicts of interest between federal and state authorities.
- As the revision nears completion, Jemaluang and Tenggaroh highlight how much has been lost, but also what’s at stake for Malaysia’s forests, wildlife and residents.

‘Kew Declaration’ unites experts on reforestation, aims at policymakers ahead of COP26 (13 Oct 2021 06:24:43 +0000)
- More than 2,600 experts and concerned citizens from 113 countries signed the Kew Declaration on Reforestation for Biodiversity, Carbon Capture and Livelihoods.
- The declaration expresses the co-signatories’ concern over large-scale tree plantations of single species and/or non-native trees and proposes that forests be planted to reflect the diversity of natural ecosystems.
- The declaration specifically calls upon “policymakers, financiers and practitioners in countries that have made reforestation pledges” to work with Indigenous and local people and respect their land tenure rights. It also calls for funding and positive financial incentives to be targeted toward reforestation.
- Experts have noted that policies surrounding reforestation could be improved by increasing communication and involvement of people at all levels of projects, especially local communities, Indigenous people and landowners.

To predict forest loss in protected areas, look at nearby unprotected forest (13 Oct 2021 04:33:35 +0000)
- To predict deforestation risk in a protected area, look at the condition of its surrounding forests, according to a new study.
- The study, which analyzed satellite images of protected forests worldwide, found nearby forest loss to be a consistent early warning signal of future deforestation in protected areas.
- Researchers said national park agencies can use their proposed model to predict how vulnerable protected areas in their countries are to deforestation, and prioritize conservation efforts accordingly.
- But even as these agencies work to protect forests, they should take into account the needs of local communities living in the area, the researchers said.

Fire and forest loss ignite concern for Brazilian Amazon’s jaguars (12 Oct 2021 15:45:20 +0000)
- More than 1,400 jaguars died or were displaced in the Brazilian Amazon due to deforestation and fires over a recent three-year period, according to a recent study.
- The authors recommend “real-time satellite monitoring” of the Brazilian Amazon jaguar population to enable experts to monitor jaguar displacement due to habitat loss and help them to better target conservation efforts on the ground and to prioritize areas for enforcement action.
- Spatial monitoring will also enable identification of wildlife corridors to keep jaguar populations connected to ensure their long-term survival.

Indonesian park officials douse wildfire in Javan leopard habitat (12 Oct 2021 15:17:40 +0000)
- Authorities in Indonesia have put out the second major fire of the current dry season in Indonesia’s Bromo Tengger Semeru National Park, an area that’s home to rare leopards and eagles.
- The fire spread from nearby community lands on Oct. 9 and were put out by the next day.
- Burning is an annual problem in the park, with farmers in adjacent communities using fire to clear the land for planting, or tourists inside the park leaving behind lit campfires or discarding cigarette butts.
- The park is home to iconic wildlife like the Javan leopard and Javan hawk-eagle, and endangered plants like the Javan edelweiss.