David Weldon, age 14, of Fairfield, Conn., for his question:
WHAT IS A TROPICAL RAIN FOREST?
A tropical rain forest is always green because most of its trees lose old leaves and grow new ones throughout the year. Also, various trees bear flowers and fruit at different times, and as a result, some kind of tree is in bloom or in fruit at any time of the year. Some trees grow fruit on low branches while others grow it on long, drooping, ropelike stalks.
A tropical rain forest is a large grove of tall trees in a region of year around warmth and plenty of rainfall. Almost all rain forests can be found near the equator.
Rain forests occupy large regions in Africa, Asia and Central and South America. They can also be found on Pacific islands. The largest in the world is the Amazonian rain forest that covers about a third of South America.
Rain forests have more kinds of trees in them than other wooded areas of the world. In South America, scientists counted 179 different species of trees on one eight and a half acre section of land. A forest of this size in the United States would rarely have more than seven species of trees.
Trees may grow to be 200 feet tall in a rain forest. The crowns or tops of tall trees form what is called an upper canopy. The crowns of shorter trees will form one or two lower canopies. All the canopies shade the forest floor so that, it receives less than one percent as much sunlight as does the upper canopy.
Because so little light reaches the floor of the forest, few bushes or flowering plants can grow. In areas where dense growth called jungles are formed within a rain forest, the tree canopies are not thick and much sunlight reaches the ground. Also, most jungles grow near broad rivers or in former clearings.
Temperatures in a rain forest are rarely above 93 degrees Fahrenheit and they do not generally fall below 68 degrees. At least 80 inches of rain falls each year in a tropical rain forest with thunderstorms usually occurring more than 200 davs annually. The air below the lower canopy is almost always humid.
The South American, the African and the Asian are the three largest rain forests in the world, and each has a different group of species of plants and animals. For example, each of the three forests has many species of monkeys, all of which differ from the species of the two other rain forests.
Lots of different kinds of animals can be found in tropical rain forests. Fruits and nuts provide food for bats, gibbons, monkeys, squirrels, parrots and toucans. Sloths and some monkeys feed on leaves while hummingbirds and sunbirds live on nectar from the flowers.
Frogs, lizards and lots of insects dwell on the branches of the trees while large birds and large snakes prey on the smaller animals.