Rainforests are the most awesome natural ecosystems on Earth. The tropical rain forests are incredibly important to all of us who live on this planet. Among the many reasons why they remain crucial for our existence and survival are that they represent the lungs of the Earth. The rain forests are literally how the Earth breathes. With their millions of plants, trees, and flowers, there is a constant interchange of carbon dioxide and oxygen back into the Earth's atmosphere. The rain forests are also responsible for much of the Earth's weather patterns. With the abundance of rainfall, moisture evaporates back into the atmosphere to create clouds which in turn create weather patterns which affect us all wherever we live on the planet. But perhaps the most important aspect of rain forest life is the number of life forms we find there.

In every four square miles of tropical rain forest life, we can find over 1,500 species of flowering plants, 750 species of trees and 1,000 species of mammals, insects, birds, reptiles, and amphibians....and those are only the ones science knows about.

What is a rain forest?

The term rain forest describes forests that grow in constantly wet conditions. This can occur wherever annual rainfall is more than 80 inches. There are many kinds of rain forests. Among them are mangrove forests, high altitude cloud forests, temperate rain forests (like in the U.S. Pacific Northwest), and tropical rain forests that form large pockets of green along the earth's equator. Two hundred years ago, these green pockets circled the globe and encompassed Latin America, Africa, Southeast Asia, Indonesia, and Australia. Tropical rain forests once covered about 20% of the Earth's land surface. Today, they cover less than 6%. Every second an area of rain forest about twice the size of a football field is destroyed.

Where are tropical rain forests located?

Pockets of tropical rain forest lie in a broad belt both north and south of the equator, bordered on the north by the Tropic of Cancer and on the south by the Tropic of Capricorn. Rain forests today cover about 6% of the Earth's land surface in more than 50 countries. However, more than half of this total area of tropical rain forest is found in just three countries - Brazil (30%), Zaire (10%), and Indonesia (10%). Extensive tracts of rain forest are found in Latin America's vast Amazon region, central Africa's Zaire Basin, and the huge archipelago that stretches from Southeast Asia to Australia. Fifty million people make their home in the world's rain forests.

Why is tropical rain forest not a jungle?

"Jungle" is a term sometimes incorrectly used interchangeably with "tropical rain forest". Jungle is used to describe thick, impenetrable vegetation. Tropical rain forests are not impenetrable. In fact, the floor of a mature rain forest is relatively open and uncluttered. Tangled undergrowth is a rain forest myth.

What are the characteristics of tropical rain forests?

1. Tropical rain forests are characterized by hot, humid weather all year.
   
   • Abundant rainfall- more than 80 inches per year
   • Temperature- average temperature is over 75 degrees, with little variance
   • More sunlight- because of the location on or near the equator, these areas get 12 hour days all year and the sun's rays strike the equator at right angles, providing more direct and intense sunlight.
   • High humidity- average humidity is 70% by day, and 95% at night.
   

2. Tropical rain forests are luxuriant and diverse. The moist, hot conditions support an abundant diversity of plant life which in turn support a varied community of animals.
   
   • Some estimates are that up to 90% of all species may live in tropical rain forests.
   

3. Tropical rain forests are shallow, damp and infertile. Rain forest soil supports a large variety of plants, but the soil itself is not very fertile. Most of the nutrients used by the plants are stored in the plants themselves, not in the soil.

The four layers of rain forest life.

The Emergent Layer

Towering above all the other trees and plants in the rain forest are giant trees called emergents, which grow to heights of 115 to 250 feet. There are usually two or three of these per acre. Most have small leaves, umbrella shaped crowns and tall slender trunks.

The Canopy

The canopy is like a thick, green carpet formed by flat-topped trees that are between 65 and 100 feet tall. The canopy acts like a giant sun and rain umbrella, catching 98% of the sun's rays. Only 2% of the solar radiation actually reaches the forest floor. Also, the canopy absorbs much of the impact of the rain that falls on the forest floor. Canopy trees are the rain forest's photosynthetic powerhouse. They convert sunlight into energy that is used for growth, flowering and bearing fruit. This in turn attracts pollinating insects and certain nocturnal animals and amphibians, all of which form part of this vast ecosystem.

The Understory

The understory is made up of the smaller trees and vines. Some of the trees in the understory are full-grown plants (up to 15 feet in height) able to survive in the shade of the taller canopy trees. Others are very young canopy trees. Many understory trees have elongated crowns and large leaves with pointed tips. These leaves help the trees absorb light and the tips allow excess moisture to drain off. Certain animals and numerous reptiles and amphibians spend much of their time in this middle level. The dim light and dense vegetation make it difficult for animals to see one another from a distance so many use sound to communicate and the understory is alive with the calls of birds and monkeys.

The Forest Floor

On the sheltered forest floor the air is still: humidity is 95-100% and the temperature remains around 75 degrees F. Although seedlings, herbs and ferns grow on the forest floor, the vegetation is sparse due mainly to the lack of sunlight. Many of the larger tropical rain forest animals can be found on the rain forest floor. Here tapirs, wild pigs, jaguars, and leopards hunt their prey. The floor is relatively free of decaying logs and dead leaves. This is because high temperatures, humidity, and billions of microorganisms living in the soil break down plant and animal debris very quickly. This fast and continual recycling of nutrients is what keeps tropical rain forests working so efficiently despite their shallow, relatively infertile soil. The rain forest is lush because nothing is wasted, everything is recycled!

 A Tropical Shopping TripTaking a trip to the grocery store is a mini-trip to the tropical forests of the world. Without the products from these equatorial areas, our shopping trip would be much shorter.

Among the hundreds of products that the rain forests of the world produce, we can see the results in our local neighborhood grocery store in the form of fruits, vegetables, spices, sugar, chocolate, vanilla, coffee, nuts, soft drinks, resins, oils, cookies, household plants, and chewing gum. Also cleaning supplies, cosmetics and health care and hygienic items such as shampoo, aloe vera cream, cough drops, suntan lotion, perfume, and insect spray all come from the tropics. So too does natural sponge, laundry soap, rubber gloves, disinfectant, and furniture polish. Of course, many paper items and wood used for our household furniture come from the rain forests as well. So do medicines of many varieties, from store bought prescriptions to more rare ones used in hospitals all over the world. Think about ways your life would change if these tropical habitats were to vanish.

Tropical Peoples

The human species has called the rain forests home for centuries. Many native peoples still inhabit this magical environment and have learned to live in it with perfect harmony. The following is a partial list of some of these indigenous peoples, their locale, and the kinds of homes they inhabit:

• Florida- Seminole Indians live in the swampy Everglades.

• Brazil- Yawalapiti Indians build large palm-thatched houses in forest clearings.

• Peru- Amahuaca people build houses of sticks thatched with palm leaves. These are built on stilts or rafts to protect them from floods.

• Venezuela- Yanomamo Indians live under great circular roofs made from palm leaves over a framework of poles.

• New Guinea- Asmat people get almost everything they need from the sago palm.

• Zaire- Along the Congo rain forest, Mbuti are nomadic hunters and food gatherers.

• Borneo- Dyaks live near the rivers in longhouses built on stilts.

• Malaysia- Villages, called Kampong, are built in forest clearings. Houses are built on stilts letting air blow around them keeping them cool and dry.

Major Threats to the Tropical Rain ForestsTropical rain forests are cut at the rate of about 57 acres per minute. Over 40% of all tropical rain forests have disappeared since the 1940's. The major threats are the following:

     Logging

Up to 10 million acres are destroyed yearly. Most of the wood is cut for firewood and charcoal, and habitats are destroyed not only by cutting but also by roads created to provide access to lumbering operations.

    Cattle Ranching

Cattle ranching is often carried out on lands abandoned by slash-and-burn farmers and loggers. Lands once grazed by cattle lose their nutrients after several years and no longer support growth of new forests, crops or grass.

    Illegal Wildlife Trade

Encouraged by the world’s demand for luxury items and exotic plants and pets, illegal wildlife trade is draining wildlife rapidly from the remaining forests. Examples of pets and plants threatened by this illegal wildlife trade include parrots and other exotic birds, reptiles, and orchids.