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Rain Forests: What Are Rain Forests?

Rain Forests. Online ed. 2012. Lexile Measure: 760L.
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A rain forest is a biome. A biome is a large area where certain plants and animals have learned to live. The rain forest biome is one of the world’s oldest. It also used to be one of the world’s largest. Rain forests once covered more than 14 percent of the world’s land. Now, they cover only 5 percent. Many people want to save the rain forest. They joined together in a group. The group’s name is Replanting the Rainforests. They say: “Sadly, it has taken only a century of human [activity] to destroy what nature designed to last forever.”1

A rain forest has lots of rain. That is why it is called a rain forest. Mist and fog covers these thick green forests. And it rains every day. Downpours can dump 2 inches (5cm) of water in one hour. Up to 400 inches (1,016cm) of rain fall in a year in warm rain forests. Cool temperate rain forests get about 100 inches (254cm) of precipitation in a year.

A map showing the locations of the rain forests of the world.

A map showing the locations of the rain forests of the world.
Illustration by Kopp Illustration, Inc. The Gale Group.

Blankets of Green

Rain forests circle the Earth like a green belt. Most are found near the equator. They are called tropical rain forests. Over half of all tropical rain forests are found in Central and South America. About one-quarter are in Southeast Asia. The remaining rain forests are in Africa.

Temperate rain forests stretch along the coasts of temperate regions. These areas have mild climates. They are not as hot as tropical rain forests. The largest temperate rain forests grow along the western coast of North America. They stretch from Oregon to Alaska for 1,200 miles (1,931km). A few other temperate rain forests grow in northern Europe, Japan, New Zealand, and southern Australia. Tropical rain forests are always hot. But temperate rain forests have a change of seasons. The book Strange Worlds, Fantastic Places explains: “In certain places, heavy rainfall or thick mists throughout the year, and a cool, moderate [mild] climate with mild winters, will produce extraordinary [amazing] damp wonderlands, where plant growth is as abundant [plentiful] as any tropical forest.”2

Layers of Life

The rain forest is made up of four different layers: the forest floor, the understory, the upper canopy, and the emergent layer. At the top of the rain forest is the emergent layer. Emergent means “coming out from.” Emergent trees are 100 to 240 feet (30.5m to 73m) tall. They stick out above the lower forest plants. This layer is bright and breezy. It catches the sunlight and wind. Many of these trees have small, pointed leaves. They have straight, smooth trunks with few branches down below. Birds, small mammals, and any other sun-loving animals live here. It is the “penthouse” of the rain forest.

This illustration shows the four layers of the rain forest,

This illustration shows the four layers of the rain forest,
Illustration by Hans. Thomson Gale.

The next layer of a rain forest is the upper canopy. This is where trees grow to heights between 60 and 130 feet (18 and 40m). Some sunlight reaches the upper canopy. And most of the rain forest’s animals live here. Many animals live on the plentiful fruits and leaves here. They never go down to the forest floor. They have all the food they want in the upper canopy. They even get their daily supply of water without going to the ground. Monkeys, lemurs, and other tree climbers live here. Bright butterflies and colorful parrots fly among the branches of the upper canopy.

Below the upper canopy is the understory. This is a still, shady place. The upper canopy’s leaves block sunlight and wind from the understory. But they cannot keep out water. Rain slides down branches and trunks. The understory is made up of bushes, small trees, and the trunks of taller trees. This part of the rain forest is filled with reptiles and insects. Tiny rain frogs and lizards cling to branches and trunks. They wait silently for their next meal of ants or other insects to crawl past. Some of the world’s most dangerous snakes live in the understory. Two of them are the little fer-de-lance and the big bushmaster.

Finally, deep beneath the trees is the forest floor. Only a little sunlight ever reaches this hot, wet place. But the forest floor has its own inhabitants. These tiny creatures eat the litter of fallen leaves, twigs, and bark that cover the forest floor. They are called decomposers. They decompose, or break down, dead plants and animals. Termites, earthworms, and mushrooms are a few of the decomposers that thrive in the wet darkness.

The red uakari monkey is found in the Amazon rain forest region of South America and is considered a "near threatened" species by animal conservation groups.

The red uakari monkey is found in the Amazon rain forest region of South America and is considered a "near threatened" species by animal conservation groups.
Mattias Klum/National Geographic/Getty Images

Plants and Animals of the Rain Forest

The different layers of the rain forest have a warm climate, plentiful water, and lots of food. They are home to millions of plants and animals. These living things have adapted to living in a very wet environment. Some plants have leaves with “drip spouts” that let water run off easily. Others have slick, shiny leaves. Raindrops slide quickly off their smooth surface. These adaptations keep the leaves from drowning and stop mold or mildew from growing on them.

Plants need sunlight, water, and air to make food. In the rain forest there is plenty of water. But sunlight is scarce below the forest canopy. Tall trees catch the most light. Shorter trees and plants on the forest floor or in the understory have to live on less light. These plants often have large leaves that spread wide to catch as much sunlight as possible.

Animals have also adapted to the rain forest. High in the canopy animals like monkeys and sloths climb easily using their strong hands, feet, and tails. Large eyes help many animals see through the darkness of the forest floor and understory. Other floor-dwelling animals like tapirs and anteaters sniff and snuffle through the dead leaves hunting for grubs. Camouflage helps animals blend in with the branches and leaves of the rain forest trees. A vinesnake is thin and green. It hangs from branches waiting for an unsuspecting insect to crawl past. Some lizards can change colors to match their background. This helps them hide from hunters. It also keeps their prey from seeing them.

A South American tapir looks for food on the forest floor.

A South American tapir looks for food on the forest floor.
© Michael and Patricia Fogden/Corbis

The South American green vinesnake hunts by hanging from branches and waiting for unsuspecting prey to crawl past.

The South American green vinesnake hunts by hanging from branches and waiting for unsuspecting prey to crawl past.
Mattias Klum/National Geographic/Getty Images

Some chameleon lizards change colors for hunting or protection, which makes them hard to see in the jungle.

Some chameleon lizards change colors for hunting or protection, which makes them hard to see in the jungle.
© Michael and Patricia Fogden/Corbis

Biodiversity

Tropical rain forests have the greatest biodiversity of life on Earth. This biome has more types of plants and animals than anywhere else on the planet. More than half of the world’s plant and animal species live in rain forests.

A small piece of rain forest can be home to thousands of different plants and animals. In 4 square miles (10 sq. km) of tropical rain forest, scientists discovered 750 different kinds of trees. This is four times the number of tree species found in all of North America’s forests. A rain forest may have over 1,000 different kinds of flowering plants. Many varieties of animals also live in the rain forest. One-third of all bird species live in the Amazon rain forest. The Amazon River and rain forest is in South America. Part of the Amazon rain forest lies in the country of Peru. In Peru, 43 different kinds of ants live on one tree trunk.

The rain forest in the Noel Kempff Mercado National Park is part of the Amazon basin.

The rain forest in the Noel Kempff Mercado National Park is part of the Amazon basin.
© Pablo Corral Vega/Corbis

Pieces of a Puzzle

The rain forest’s plants and animals depend on each other. For example, trees like mangos and figs depend on the fruit bat to spread their seeds. The bat eats the whole fruit. But the seeds pass through it. The seeds come out in its droppings as it flies along. The seeds have a better chance to sprout farther away from the parent tree. Without the fruit bats, the fruits would just fall off the tree and land close together. Fewer seeds would grow into new trees.

Franquet’s fruit bats live high in the rain forest canopy.

Franquet’s fruit bats live high in the rain forest canopy.
© DK Limited/Corbis

Each living thing in a rain forest is like the piece of a jigsaw puzzle. The extinction of even one species is like losing a puzzle piece. When a species disappears, the whole picture of the forest is changed. Yet each year, thousands of species are lost as the world’s rain forests are destroyed. Scientists are in a race against this destruction. They try to study all the new plants and animals that they can find. They know there is more to be discovered each time they trek through the forest.

Rain forests are more than homes to amazing plants and animals. The entire planet depends on the forests.

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Words to Know

adaptations:
Changes over time that help a living thing better survive where it lives.
biodiversity:
The number and variety of plants and animals found within a specified geographic region.
biome:
A large area where plants and animals have adapted to live in a certain climate.
conservation:
Preserving and protecting rivers, forests, and other natural resources through careful management.
carbon dioxide (CO2:
A gas that occurs naturally in the atmosphere. It is also produced when living things die and decay and when humans and other animals breathe it out.
deforestation:
The Cutting down or clearing of forests.
ecotourists:
Travelers who vacation in places where they can see, be with, and learn about nature.
extinction:
The disappearance forever of a species of plant or animal from the planet.
groundwater:
Water supplies that exist deep beneath Earth’s surface.
indigenous people:
Native people who first lived in a particular region.
photosynthesis:
The process by which plants use carbon dioxide, water and minerals from the soil, and sunlight to make their own food.
precipitation:
Rain, snow, sleet, or hail that falls to the ground.
sanctuary:
A place set aside for a special use only; the place might be for worship or a place where animals or people are safe from harm.
slash-and-burn:
A method of farming used in the tropics in which trees and bushes are cut down and then burned so that crops can be planted.
sustainability:
The practice of using natural resources without using them up or harming the environment.
temperate:
Having a mild climate that is not very hot or very cold.
water cycle:
The continuous movement of water on, above, and below the surface of the Earth.
Footnotes:1. Replanting the Rainforests, “The Importance of Rainforests,” April 7, 2009. http://replantingtherainforests.org/site/index.php/Benefits-to-the-Planet/the-importance-of-rainforests.html.
 
Source Citation   (MLA 8th Edition)
Jackson, Kay, and Peggy J. Parks. "Rain Forests: What Are Rain Forests?" Rain Forests, by Peggy J. Parks, Gale, 2012. Our Environment. Kids InfoBits, https%3A%2F%2Flink.gale.com%2Fapps%2Fdoc%2FFTGLRY405631511%2FITKE%3Fu%3Dpl3475%26sid%3DITKE%26xid%3D191bca31. Accessed 13 Dec. 2019.

Gale Document Number: GALE|FTGLRY405631511