RAINFORESTS OF THE WORLD

For most of us, the word "rainforest" creates images of green forests, waterfalls, beautiful birds and flowers, and stunning animals such as gorillas and elephants. Rainforests do hold those things, but they receive a great deal of attention for many other qualities as well. Tropical rainforests provide homes for a large portion of all of the different types of plants and animals that we share the Earth with. Biologists describe this situation by saying that tropical rainforests have a high degree of biological diversity. These forests also provide tremendous amounts of fresh water, and have a strong positive influence on the climate of the entire world. Rainforest plants and animals are the source of many chemical compounds that are used as important drugs for treating disease and illness. Many of the medicinal uses of these plants and animals were first discovered by local peoples who live in the forests. Rainforests also hold tremendous natural resources that people need for food, shelter and to provide income and money. Some of the attention that rainforests receive come in the form of logging, dam building, mining, and forest clearing for growing crops and cattle. Because of these activities, rainforests are rapidly disappearing around the world, and many people are very upset about this. They worry that the entire balance of the world's ecosystem will be thrown out of kilter.

Rainforests are actually found in more places that just the warm, tropical parts of the world near the equator. Dense wet forests can also be found in temperate (mild) areas where the temperatures are much cooler. Such forests can be found along the west coast of North America from northern California through Canada to Alaska, and along the coast of Chile in South America. The biggest trees in the world such as Sequoias and Redwoods grow in these forests.

Tropical, warm rainforests grow in some the world's tropical regions near the equator. Tropical rainforests grow in areas with lots of rain at least part of the year, and warm temperatures above freezing year around. These forests share many things in common. Most of the soils in rainforests are very poor in nutrients. Soil nutrients are washed away by the heavy rainfall. Most of the energy and nutrients in tropical forests are found in the trees themselves. Any leaves or branches that fall quickly decompose and provide nourishment for living plants, animals and fungus. Insects reach their peak of diversity (there are more types of them than anywhere else) in tropical forests, and some species are colorful or large compared to their temperate relatives. Borneo is home for species of locusts that are more than 5 inches (12 cm) long. Ants are found everywhere in the rainforests, and are found by the millions from the ground to the tops of the highest trees. Many trees develop buttress roots, which look like thick wings that fan out from the base of the trees to support their great mass in the clay-rich soils (see photo at right). Fig trees are found in most tropical areas. They are an important food source for many types of rainforest birds and animals.

There are four great regions of tropical rainforests in the world. Each of them has many unique plants and animals that occur only in that region. Across these great regions tropical forests vary. In some areas the rains fall all year, while in other areas long dry seasons occur. Some forests are along flat lying riverbanks, while other rainforests grow in mountains on steep slopes. Some types of tropical forests grow near the ocean, while others only develop when a specific type of soil is present. All of these forest types have unique plants and animals associated with them. Tropical rainforests will not truly be protected until large representative areas of all of these types of forests are set aside as national parks or reserves.

The first great region of tropical forests is in Africa, and includes areas along the West Coast of the continent and in the basin of the mighty Congo River. African forests contain such unique animals as the African elephant, lowland gorillas, and chimpanzees. African forests are protected in a number of national parks and wildlife reserves including Lope Reserve in Gabon, Comoe National Park in Ivory Coast and the Salonga National Parks in Zaire.

Large areas of tropical forests can be found in South America in the huge basins of the Orinoco and Amazon Rivers. South American forests provide homes for many species of beautiful parrots and macaws, for numerous types of monkeys, and for jaguars and bears. South America contains the largest tracts of intact tropical forests in the world. In the countries of Brazil, Venezuela, Columbia, Peru and Bolivia are millions of acres of forest. However, these forests are rapidly being cut down to provide jobs, money and food for the people of these countries. Sometimes the deforestation occurs to provide quality wood, cheap beef, or corporate profits for people in rich Western Nations such as the United States. The populations of these countries are also growing rapidly adding to the rapid rate of deforestation. The South American forests stretch north into Central America through the countries of Panama, Costa Rica, Honduras, Nicaragua, Guatemala, Belize and Mexico.

The third type of forests are the Australian rainforests, which are found along that continent's north coast and in New Guinea. These forests include the world's most beautiful birds, called "Birds of Paradise". That group (the genus Paradisaea) includes 42 species of brightly colored, plumed birds. For more information and photos of these birds log onto the Birds of Paradise Species Interest Committee News. Australia and its forests have been isolated from the rest of the world for 100 million years. This is such a long period of time that most currently existing orders of mammals such as horses, rhinos, and hippos (Perissodactyla) and humans, apes and monkeys (Primates) had not yet evolved and come into being before Australia was isolated. As a result, Australian rainforests in general provide homes for only one group of mammals, the marsupials. Marsupials include kangaroos, koalas and opossums. These animals nurture their young inside a pouch. Originally marsupials were classified as one order of Mammals. Today biologists realize that marsupials are a much more diverse group of animals and thus the marsupials are classified in at least five separate orders including Dasyuromorphia, Permelemorphia, and Diprotodontia. For more information on the orders, families and species of mammals go to the Smithsonian Institution's web site on mammal diversity or the University of Berkeley's Hall of Mammals.

The fourth area of tropical forest is the great Asian rainforests that stretch from India, in South Asia, to Java, an island in South East Asia. Borneo and the area around Gunung Buda are near Java on the eastern edge of this ecological province. The rainforests found on the islands of Sumatra, Borneo, Java, and on the Asian continent in West Malaysia, Thailand, Cambodia and Vietnam are similar. Much of the area, including Gunung Buda, receives steady rains throughout the year. Many of the trees found here are members of the Dipterocarp family. Dipterocarp means "two-winged seed" and many of these trees have two wings on their seeds. When trees are producing seeds, thousands on them will spin and twirl their way to the ground like children's toy helicopters. Other types of trees include Legumes, whose seeds form in pods, and many types of figs, particularly strangler figs. Strangler figs grow from tiny seeds that are carried by the wind up into the branches of large trees. From on high, the tiny fig sends down long roots that may eventually reach the forest floor. Once the roots reach soil, new branches and roots from the fig wrap around the existing tree and eventually strangle and kill it. Figs have adapted to killing other trees because of the support that they provide while the fig grows and because of the rareness of sunlight on the forest floor. Figs get around the problem of low light by taking the place of another tree that had already grown to the top of forest canopy and reached sunlight. The canopy in Southeast Asian Rainforests, including some forests near Gunung Buda, develops on two levels. Thirty to fifty meters above the forest floor (100 to 150 feet) a dense canopy composed of the crowns of smaller trees forms. Interspersed among the 1-meter (3 feet) diameter trunks of the smaller trees are the emergent species. These huge trees may have trunks that are 4 meters (13 feet) thick and they may reach heights of more than 75 meters (250 feet). Their crowns form a second higher and more open canopy.

Originally Sumatran and Indochinese tigers, Asian elephants, Sumatran and Javan rhinoceroses, and Sun Bears wandered the floors of the Southeast Asian forests. Today Sumatran tigers (Panthera tigris sumatrae) are seen in only a few National Park in Sumatra. Indochinese tigers (Panthera tigris corbetti) can still be found in one National Park, Taman Negara in west Malaysia, and in remote areas of Thailand, Cambodia and Vietnam. For more information on tigers try the Tiger Information Center. Asian Elephants (Elephas maximus) in South East Asia can be found in Southern Sumatra, Sabah in Borneo and in Northern Thailand, Cambodia, Vietnam and Laos. Information about elephants and other interesting animals can be found at a web site called Virtual Wildlife. Javan Rhinos (Rhinoceros sondaicus) are very rare and are limited to two areas, a national park in Western Java and a small mountainous area of Vietnam. Sumatran Rhinos (Dicerorhinus sumatrensis) can be found in several areas in Sumatra, in two National Parks in West Malaysia, and in eastern Sabah. For more information on the Sumatran and Javan Rhino visit the International Rhino Foundation. The status of the Sun Bear (Helarctos malaynus) is unknown. Other well-known residents of these forests are the orang-utans (Pongo pygmaeus), the great orange apes, and their cousins the gibbons, known for their long arms used for swinging through the trees. Orang-utans exist only on Borneo and in Northern Sumatra. They can be found in several Malaysian and Indonesian parks around Borneo and in one park in Northern Sumatra, Gunung Leuser National Park. Bornean and Agile Gibbons (Hylobates muelleri and Hylobates agilis) were once widespread throughout South East Asia, but hunting, habitat loss, and disease have severely reduced their numbers. For information on Gibbons and orang-utans, to to the web site of the Wisconsin Regional Primate Research Center.

There are many large birds in the forests of Borneo and Southeast Asia including hawks, eagles and owls. Another family of large birds is the Hornbills. They are found from Africa through Southern Asia. However, Sarawak, where Gunung Buda is located, is known as "the land of the Hornbills". Hornbills are often black with bold white markings. They have wingspans of up to four feet and huge, brightly colored bills. They are similar in appearance, though usually much larger than the Toucans of Central and South America. (For photos and information on Hornbills go to the World Hornbill Network).

Hornbills have a very unusual way of raising their young. They nest in hollows in large rainforest trees. When a female hornbill is ready to lay eggs, she will crawl into the hollow. Then together the male and female close up most of the hole through which she entered. They might use mud or feces to close the opening, leaving a small hole for air and feeding. In this protected space the female will lay her eggs and raise her young for up to three months. During this time, the male bird will feed the female and the new chicks through the small opening into the nest.