Rain forest

The world's rain forests are the richest ecosystems on Earth, containing an incredible variety of plant and animal life. These forests play an important role in maintaining the health and biodiversity of the planet. But rain forests throughout the world are rapidly being destroyed, threatening the survival of millions of species of plants and animals and disrupting climate and weather patterns. The rain forests of greatest concern are those located in tropical regions, particularly those found in Central and South America, and the ancient temperate rain forests along the northeastern coast of North America.

Tropical rain forests (TRFs) are amazingly rich and diverse biologically and may contain one-half to two-thirds of all species of plants and animals, though these forests cover only about 5–7% of the world's land surface. Tropical rain forests are found near the equatorial regions of Central and South America, Africa, Asia, and on Pacific Islands, with the largest remaining forest being the Amazon rain forest, which covers a third of South America.

TRFs remain warm, green, and humid throughout the year and receive at least 150 in (4 m) of rain annually, up to half of which may come from trees giving off water through the pores of their leaves in a process called transpiration . The tall, lush trees of the forest form a two- to three-layer closed canopy, allowing very little light to reach the ground. Although tropical forests are known for their lush, green vegetation, the soil stores very few nutrients. Dead and decomposing animals, trees, and leaves are quickly taken up by forest organisms, and very little is absorbed into the ground.

In 1989 World Resources Institute predicted that "between 1990 and 2020, species extinctions caused primarily by tropical deforestation may eliminate somewhere between 5–15% of the world's species...This would amount to a potential loss of 15,000 to 50,000 species per year, or 50 to 150 species per day." It is estimated that 30–80 million species of insects alone may exist in TRFs, at least 97% of which have never been identified or even discovered.

Tropical forests also provide essential winter habitat for many birds that breed and spend the rest of the year in the United States. Some 250 species found in the United States and Canada spend the winter in the tropics, but their population levels are decreasing alarmingly due to forest depletion.

Tropical rain forests have unique resources, many of which have yet to be utilized. Food, industrial products, and medicinal supplies are common examples. Among the many fruits, nuts, and vegetables that we use on a regular basis and which originated in tropical forests are citrus fruits, coffee, yams, nuts, chocolate, peppers, and cola. A variety of oils, lubricants, resins, dyes, and steroids are also products of the forests. Natural rubber , the fourth biggest agricultural export of southeast Asian nations, brings in over $3 billion a year to developing countries. The forests could also yield a sustainable supply of woods like teak, mahogany, bamboo, and others. Although only about 1% of known tropical plants have been studied for medicinal or pharmaceutical applications, these have produced 25–40% of all prescription drugs used in the United States. Some 2,000 tropical plants now being studied have shown potential as cancer-fighting agents.

Scientists studying ways to commercially utilize these forests in a sustainable, non-destructive way have determined that two to three times more money could be made from the long-term collection of such products as nuts, rubber, medicines, and food, as from cutting the trees for logging or cattle ranching. Perhaps the greatest value of tropical rain forests is the essential role they play in the earth's climate. By absorbing carbon dioxide and producing oxygen through photosynthesis , the forests help prevent global warming (the greenhouse effect ) and are important in generating oxygen for the planet. The forests help prevent droughts and flooding , soil erosion and stream sedimentation , maintain the hydrologic cycle , and keep streams and rivers flowing by absorbing rainfall and releasing moisture into the air.

Despite the worldwide outcry over deforestation, destruction is actually increasing. A 1990 study by the United Nations Food and Agriculture Organization found that tropical forests were disappearing at a rate exceeding 40 million acres (16.2 million ha) a year—an area the size of Washington state. This rate is almost twice that of the previous decade.

Timber companies in the United States and western Europe are responsible for most of this destruction, mainly through farming, cattle ranching, logging, and huge development projects. Japan, the world's largest hardwood importer, buys 40% of the timber produced, with the United States a close second. Ironically, much of the destruction of forests worldwide has been paid for by American taxpayers through such government-funded international lending and development agencies as the World Bank , the International Monetary Fund, and the Inter-American Development Bank, along with the United States Agency for International Development.

The release of the World Bank's new Operational Policy on Forests has been delayed since October 2001, and had not been released as of the first week in July 2002. The release has been delayed by a World Bank dispute over whether its new Forest Policy would apply to the World Bank's growing area of lending, which directly or indirectly finances logging activities. There has been widespread demand that the Forest Policy must apply to all World Bank operations that might have an impact on forests. It remains to be seen how the Operational Policy on Forests will handle this important question.

American, European, and Latin American demand for beef has contributed heavily to the conversion of rain forest to pasture land. It is estimated that one-fourth of all tropical forests destroyed each year are cut and cleared for cattle ranching. Between 1950 and 1980, two-thirds of Central America's primary forests were cut, mostly to supply the United States with beef for fast food outlets and pet food.

In Brazil and other parts of the Amazon Basin , cattle ranchers, plantation owners, and small landowners clear the forest by setting it on fire, which causes an estimated 23–43% increase in carbon dioxide levels worldwide and spreads smoke over millions of square miles, which interferes with air travel and causes respiratory difficulties.

Unfortunately, cleared forest that is turned into pasture land provides very poor quality soil, which can only be ranched for a few years before the land becomes infertile and has to be abandoned. Eventually desertification sets in, causing cattle ranchers to move on to new areas of the forest.

While huge timber and multi-national corporations have justifiably received much of the blame for the destruction of TRFs, local people also play a major role. Populations of the Third World gather wood for heating and cooking, and the demand brought about by their growing numbers has resulted in many deforested areas. The proliferation of coca farms, producing cocaine mainly for the American market, has also caused significant deforestation and pollution , as has gold prospecting in the Amazon.

The destruction of TRFs has already had devastating effects on indigenous peoples in tropical regions. Entire tribes, societies, and cultures have been displaced by environmental damage caused by deforestation. In Brazil fewer than 200,000 Indians remain, compared to a population of some six million about 400 years ago. Sometimes they are killed outright when they come into contact with settlers, loggers, or prospectors, either by disease or because they are shot. And those who are not killed are often herded into miserable reservations or become landless peasants working for slave labor wages.

Today, less than 5% of the world's remaining TRFs have some type of protective status, and there is often little or no enforcement of prohibitions against logging, hunting , and other destructive activities.

The ancient rain forests of North America are also important ecosystems, composed in large part of trees that are hundreds and even thousands of years old. Temperate rain forests (or evergreen forests) are usually composed of conifers (needle-leafed, cone-bearing plants) or broadleaf evergreen trees. They thrive in cool coastal climates with mild winters and heavy rainfall and are found along the coasts of the Pacific Northwest area of North America, southern Chile, western New Zealand, and southeast Australia , as well as on the lower mountain slopes of western North America, Europe, and Asia.

The rain forest of the Pacific Northwest, the largest coniferous forest in the world, stretches over 112,000 mi² (129,000 km²) of coast from Alaska to northern California, and parts extend east into mountain valleys. The forests of the Pacific Northwest consist of several species of coniferous trees, including varieties of spruce, cedar, pine, Douglas fir, Hemlock, and Pacific yew. Broadleaf trees, such as Oregon oak, tanoak, and madrone, are also found there. Redwood tree growth extends to central California. Further south are the giant sequoias, the largest living organisms on earth, some of which are over 3,000 years old.

In some ways, the temperate rain forests of the Pacific Northwest may be the most biologically rich in the world. Although TRFs contain many more species, temperate rain forests have far more plant matter per acre and contain the tallest and oldest trees on Earth. Over 210 species of fish and wildlife live in ancient forests, and a single tree can support over 100 different species of plants. One tree found in cool, moist forests is the slow-growing Pacific yew, whose bark and needles contain taxol, considered one of the most powerful anti-cancer drugs ever discovered.

Unfortunately, the clear-cutting of most of the ancient forests and their yew trees has caused a serious shortage of taxol. Some yew trees are unavailable for harvesting because they grow in forests protected as habitat for the endangered northern spotted owl . The logging of federal land under the jurisdiction of the Bureau of Land Management (BLM) and the U.S. Forest Service (USFS) has eliminated some of the last and best habitats for the Pacific yew.

The remaining ancient forest, almost all of which is now on BLM and USFS land, is being cut at a rate of 200,000 acres (81,000 ha) a year, as of 1992. At this rate it will be destroyed within less than two decades. The consequences of this destruction will include the disappearance of rare species dependent on this habitat, the silting of waterways and erosion of soil, and the decimation of salmon populations, which provide the world's richest salmon fishery, worth billions of dollars annually.

Although the timber industry claims that logging maintains jobs in the Pacific Northwest, logging national forest often makes no economic sense. Because of the expense of building logging roads, surveying the area to be cut, and the low price it charges for trees, the USFS often loses money on its timber sales. As a result of such "deficit" or "below cost" timber sales between 1989 and 1992, the USFS lost an average of almost $300 million a year by selling timber from national forests.

Several private conservation groups, such as the Wilderness Society and the Sierra Club , are working to preserve the remaining ancient forests on BLM and USFS land through federal legislation, lawsuits, and other actions. In April 1993, President Bill Clinton attended a "timber sum mit" in Portland, Oregon, to discuss the ancient forests, endangered species , and timber jobs. But the cutting of old growth forests and "below cost" timber sales have continued much as before. The Bush administration has not supported environmental issues. In 2001, President Bush triggered international outrage when he refused to agree to the Kyoto Protocol, a United Nations approved plan to preserve the environment .

Two of the largest remaining temperate rainforests are Alaska's 16.9 million-acre (6.8 million ha) Tongass National Forest and the Russian Taiga . Tongass is the last large, relatively undisturbed, temperate rain forest in the United States, stretching over 600 mi (966 km) of coast along the Alaska Panhandle. It has the highest concentration of bald eagles and grizzly bears anywhere on Earth. In addition to reducing habitat for wildlife and salmon hatching, scenic areas are being destroyed, reducing tourism and recreation in the area.

The huge forests in the Russian Far East and Siberia are called the Taiga. The Siberian portion is the world's largest forest. Comprising some two million mi² (5.1 million km²), the Taiga is much larger than the Brazilian Amazon and would cover the entire American lower 48 states. With Russia becoming more market-oriented and in desperate need of money, some have discussed selling the logging rights to some of these forests to American, Japanese, and Korean logging companies.

Pressure from environmentalists and increasing public concern for rain forests has encouraged world leaders to consider more environmental laws. In June 1992, at the United Nations Earth Summit conference in Rio de Janeiro, Brazil, a set of voluntary principles to conserve the world's threatened forests were agreed upon. The document affirms the right of countries to economically exploit forests but states that this should be done "on a sustainable basis," recognizing the value of forests in absorbing carbon dioxide and slowing climate change. Initial hope that the agreement on principles might eventually be turned into a binding international convention has evaporated, and throughout the world, forests continue to be destroyed. Some of the last remaining untouched forests are being opened up to poaching , logging, and other exploitation, such as the one million acre (405,000 ha) virgin Ndoke rainforest of the northern Congo Republic, a wildlife paradise full of thousand-yearold trees, along with elephants , leopards, gorillas, and other endangered species.

There is a small but positive sign of a much-needed change. In October 2001 Brazil suspended all trade in mahogany. The government's decision followed a two-year investigation by Greenpeace using ground, air, and satellite surveillance to document rampant illegal logging on Indian reservations and other protected wildlife areas. In addition, a report released in June 2002 showed that the rate of forest destruction of Brazil's Amazon jungle fell 13.4% from a five-year peak in 2000. However, the rate of destruction still deeply troubles environmentalists.

See also Compaction; Deciduous forest; Decomposition; Migration; Old-growth forest

[Bill Asenjo Ph.D. ]

RESOURCES

BOOKS

Caufield, C. In the Rainforest: Report From a Strange, Beautiful, Imperiled World. Chicago: University of Chicago Press, 1986.

Mitchell, G. J. World on Fire: Saving an Endangered Earth. New York: Charles Scribner's Sons, 1991.

Myers, N. The Sinking Ark: A New Look at Disappearing Species. Oxford: Pergamon Press, 1979.

Porritt, J. Save the Earth. Atlanta: Turner Publishing, 1991.

Raven, P. H. "The Cause and Impact of Deforestation." In Earth 88: Changing Geographic Perspectives. Washington, DC: National Geographic Society, 1988.

Repetto, R. The Forest for the Trees? Government Policies and the Misuse of Resources. Washington, DC: World Resources Institute, 1988.

Zuckerman, S. Saving Our Ancient Forest. Los Angeles: Living Planet Press, 1991.

PERIODICALS

Bugge, A. "Brazil's Amazon Destruction Down but Still Alarming." Reuters June 12, 2002.

Jordan, M. "Brazilian Mahogany: Too Much In Demand—Illegal Logging, Exports Are Lucrative for Criminals, Disastrous for Rain Forest." Wall Street Journal, November 14, 2001.

"United States Government Report Blames Humans for Global Warming." Reuters [cited July 2002]. <http://www.enn.com/news/wirestories/2002/06/06042002>.

"World Bank Forest Policy." World Rainforest Movement Bulletin 55 [cited February 2002]. <http://www.wrm.org.uy>.