What is a rain forest?
Tropical rain forests are forests with tall trees, warm climates, and lots of rain. In some rain forests it rains more than one inch nearly every day of the year!
Where are rain forests located?
Rain forests are found in Africa, Asia, Australia, and Central and South America. The largest rain forest in the world is the Amazon rain forest in South America.
Rain forests are found in the tropics, the region between the Tropic of Cancer and the Tropic of Capricorn, just above and below the Equator. In this tropic zone the sun is very strong and shines about the same amount of time every day all year long, keeping the climate warm and relatively stable.
Many countries have tropical forests. The countries with the largest areas of tropical forest are (in order):
- Democratic Republic of Congo
Other countries that have large areas of rain forest include Bolivia, Cameroon, Central African Republic, Ecuador, Gabon, Guyana, India, Laos, Malaysia, Mexico, Myanmar, Papua New Guinea, Republic of Congo, Suriname, and Venezuela.
What makes a rain forest?
Each rain forest is unique, but there are certain features common to all tropical rain forests.
- Location: rain forests lie in the tropics.
- Rainfall: rain forests receive at least 80 inches (200 cm) of rain per year.
- Canopy: rain forests have a canopy, which is the layer of branches and leaves formed by closely spaced rain forest trees. Most of the plants and animals in the rain forest live in the canopy. The canopy may be 100 feet (30 m) above the ground.
- Biodiversity: rain forests have a high level of biological diversity or “biodiversity”. Biodiversity is the name for all living things—like plants, animals, and fungi—found in an ecosystem. Scientists believe that about half of the plants and animals found on Earth’s land surface live in rain forests.
- Symbiotic relationships between species: species in the rain forest often work together. In a symbiotic relationship, two different species benefit by helping each other—you can think of it as a partnership. For example, some plants produce small housing structures and sugar for ants. In return the ants protect the plants from other insects that want to feed on the plant’s leaves.
What is the canopy?
In the rain forest 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 rain forest trees. Scientists estimate that 60-90 percent of life in the rain forest is found in the trees, making this the richest habitat for plant and animal life. Many well-known animals such as monkeys, frogs, lizards, birds, snakes, sloths, and small cats are found in the canopy.
The conditions of the canopy are very 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 are specially adapted for life in the trees. 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.
Scientists have long been interested in studying the canopy, but the height of trees made research difficult until recently. Today there are special facilities with rope bridges, ladders, and towers to help scientists discover the secrets of the canopy.
The canopy is just one of several vertical layers in the rain forest. Take a look at the diagram on the left to see the other layers (the overstory, understory, shrub layer, and forest floor).
The rain forest floor
The rain forest floor is often dark and humid due to constant shade from the canopy’s leaves. Despite its shade, the rain forest floor is an important part of the forest ecosystem.
The forest floor is where decomposition takes place. Decomposition is the process by which fungi and microorganisms break down dead plants and animals and recycle essential materials and nutrients.
Also, many of the largest rain forest animals are found on the forest floor. Some of these are elephants (in Asia), the tapir (Southeast Asia and Central and South America), tigers (Asia), and the jaguar (Central and South America).
Rain forest rivers
Due to the tremendous amount of rainfall they receive, tropical rain forests have some of the largest rivers in the world, like the Amazon, Mekong, 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 (1,600 kilometers) long.