kinds of rain forests, too. Temperate rain
forests grow in cooler parts of the world,
such as the northwestern United States
and southern Australia. Monsoon rain
forests have a dry season and trees that
shed their leaves each year. They grow in
Southeast Asia. The rest of this article
will focus on tropical rain forests because
they are important to the health of the
entire planet.
Where Tropical Rain Forests
Are Found
Tropical rain forests grow around the
equator in the hot, wet region called
the tropics. They are found in parts of
the tropics that get more than 70 inches
(180 centimeters) of rain each year.
Parts of South and Central America,
western and central Africa, Southeast
Asia, and Australia have tropical rain
forests.
Features
Tropical rain forests can be divided into
several sections. At the top of the forest
is a thick layer called the canopy. It is
formed by the spreading branches and
thick leaves of tall trees. The canopy
blocks much of the sunlight from the
area below. The canopy can be between
100 and 170 feet (30 and 50 meters)
above the ground. A few very tall trees
stick up above the rest of the canopy.
They are called emergent trees. Many
Thick rain forest covers parts of the African
country of Cameroon.
BRITANNICA STUDENT ENCYCLOPEDIA Rain Forest 23
animals and insects live among the treetops
of the canopy.
The section below the canopy is called
the understory. It contains small trees,
shrubs, and plants. Many of these are
saplings (young trees). Their stems reach
up toward the light. However, these
smaller trees generally do not receive
enough sunlight to grow into adult trees.
On the forest floor, bacteria, fungi, and
insects help to break down dead plants
and animals. This process creates a thin,
rich top layer of soil that provides nutrients
to the roots of the plants and trees.
Because this layer of soil is thin, most of
the trees have shallow root systems.
Life in Tropical Rain Forests
The trees found in tropical rain forests
stay green all year, though they do shed
their leaves sometimes. Palms are among
the most common trees.
Below the thick canopy, other plants
have to compete with each other to get
enough light. As a result, many plants
use other plants to reach toward the
sunlight. For example, woody plants
called lianas attach to the stems of other
plants and climb from the ground to the
canopy. Mosses, ferns, and orchids may
also attach themselves to larger plants.
Each area of the rain forest has thousands
of species, or types, of animal.
Many plant-eating animals live in the
canopy—for example, monkeys, flying
squirrels, and sharp-clawed woodpeckers.
At the lower levels of the forest are
animals that run, flutter, hop, and climb
in the undergrowth. On the rain forest
floor are such animals as chimpanzees,
gorillas, elephants, pigs, deer, and
leopards.
Tropical Rain Forests in
Danger
Tropical rain forests grow in many poor
countries. Some poor countries sell the
wood and other resources of rain forests
to make much-needed money. This
often means that entire sections of the
forest are destroyed. The loss of rain
forests endangers many plants and animals
that live nowhere else in the world.
Some of these plants and animals may
become extinct if their rain forest habitat
is destroyed.
The destruction of tropical rain forests
also affects the environment of the rest
of the world. Through the process
Different kinds of plants grow at different
levels of a tropical rain forest.
24 Rain Forest BRITANNICA STUDENT ENCYCLOPEDIA
called photosynthesis, plants produce
oxygen and absorb carbon dioxide gas
from the atmosphere. Because the
number of plants in tropical rain forests
is so huge, the forests produce much of
the world’s oxygen, which all animals
need to live. When forests are burned,
massive amounts of carbon dioxide
escape into the atmosphere. This
carbon dioxide leads to a problem
called global warming.
..More to explore
Equator • Fern • GlobalWarming
• Palm
Raleigh
Population
(2000 census),
city, 276,093;
(2007 estimate)
375,806
Raleigh is the capital of the U.S. state
of North Carolina. It is one of three
cities—Raleigh, Durham, and Chapel
Hill—that make up an area called the
Research Triangle. Each of these cities
has a large university that conducts
scientific research. Raleigh is home to
North Carolina State University and
five other schools for higher education.
The area also has many companies that
conduct research and develop hightechnology
products. They are located
in a group of offices called Research
Triangle Park.
Most people in Raleigh work in government
or in research, education, health
care, and other service industries. Factories
in the city make such products as
paper, processed foods, electronics,
medicines, and computers.
Raleigh was created in 1792. It was built
to be the new capital of North Carolina.
In 1865, during the American Civil
War, the Union Army took control of
Raleigh. During the 20th century the
city grew greatly.
..More to explore
North Carolina
Ramadan
In the religion of Islam, the holy month
of Ramadan marks when the prophet
Muhammad received the words of the
