Why Save the Rain Forests?

A CROWD is watching a soccer match and cheering wildly. They wish the game would last forever. But they keep shooting the players. One by one, the dead are carried off the field. The crowd becomes enraged when the game slows down.

Deforestation is much the same. Humans enjoy the forests, depend on them, in fact. But they keep killing off the equivalent of the players: the individual species of plants and animals, whose complex interplay is what keeps the forest alive. This is more than a game, though. Deforestation affects you. It touches the quality of your life, even if you have never seen a rain forest.

It is the tremendous variety of living things, what scientists call biodiversity, that some argue is the greatest asset of the rain forests. A fifth of a square mile [half a square km] of Malaysian rain forest may grow some 835 species of trees, more than in the United States and Canada combined.

But this lush complex of life is fragile. One scientist compared the individual species to the rivets on an airplane. The more rivets that pop loose, the more others begin to fail under increased stress. If that comparison is valid, our planet is one troubled “airplane.” As the rain forests shrink, some estimate that ten thousand species of plants and animals are lost every year, that the extinction rate is now some 400 times faster than it has ever been in the history of the planet.

Scientists bemoan the sheer loss of knowledge that comes from this drop in biodiversity. They say it is like burning a library before having read its books. But there are more tangible losses too. For example, some 25 percent of the medicines prescribed in the United States are based on tropical forest plants. One such medicine raised the remission rate for childhood leukemia from 20 percent in the 1960’s to 80 percent in 1985. So, according to the World Wildlife Fund, the rain forests “represent a vast pharmacy.” And countless plants are yet undiscovered, let alone examined for possible medical uses.

Furthermore, few of us realize how many of our food crops are derived from plants that were originally found in the rain forests. (See box on page 11.) To this day, scientists gather genes from the hardy, forest-​dwelling varieties of these plants and use them to bolster resistance to disease in their more fragile descendants, the domestic crops. Scientists have saved hundreds of millions of dollars in crop losses that way.

Furthermore, we do not know what rain forest foods may yet emerge as global favorites. Most North Americans do not know that just a hundred years ago, their forebears viewed the banana as a strange, exotic fruit and paid two dollars for one banana, individually wrapped.

The Global Picture

Man himself is the ultimate victim of deforestation. The effects on the global environment ripple outward until they circle the world. How? Let’s take another look at the typical rain forest. As the name implies, rain is its outstanding feature. Over 8 inches [20 cm] may fall in a day, over 30 feet [9 m] in a year! The rain forest is perfectly designed to cope with this torrential downpour.

The canopy breaks the force of the droplets so that they cannot scour the earth away. Many leaves are equipped with elongated ends, or drip tips, that break up the heavy droplets. Thus, the pelting rain is reduced to a steady dripping, which falls to the ground beneath with a softer impact. The tips also allow the leaves to shed water quickly so that they can get back to transpiration, returning moisture to the atmosphere. The root systems suck in 95 percent of the water that reaches the forest floor. As a whole, the forest absorbs rainfall like a gigantic sponge and then releases it slowly.

But with the forest gone, the rain falls straight and hard to the exposed soil and carries it off by the ton. For example, in Côte d’Ivoire, West Africa, two and a half acres [1 ha] of slightly sloped tropical rain forest loses only about three hundredths of a ton of soil per year. The same two and a half acres, as a deforested, cultivated plot, loses 90 tons of soil per year; as bare ground, 138 tons.

That kind of soil loss does more than ruin the ground for farming or grazing. Ironically, dams, which cause colossal amounts of deforestation, are themselves ruined by it. Overwhelmed by the silt carried by rivers from deforested areas, they swiftly clog up and are rendered useless. Coastal regions and spawning grounds are also fouled by the excess silt.

Effects on rain and weather patterns are even more disastrous. Rivers emerging from tropical rain forests are generally full year round. But without the forest to regulate the flow of water into the rivers, they overflow with sudden rains and then run dry. A cycle of floods and droughts emerges. Rain patterns may be affected for thousands of miles around, since a rain forest by transpiration contributes as much as half of the moisture in the local atmosphere. Thus, deforestation may have contributed to both the floods of Bangladesh and the droughts of Ethiopia that killed so many in this past decade.

But deforestation may also affect the climate of the entire planet. Rain forests have been called the earth’s green lung because they draw carbon dioxide from the air and use the carbon to build trunks and limbs and bark. When a forest is burned down, all that carbon is dumped into the atmosphere. The problem is, man is dumping so much carbon dioxide into the atmosphere (both by burning fossil fuels and by deforestation) that he may already have triggered a global warming trend called the greenhouse effect, which threatens to melt the planet’s polar ice caps and raise sea levels, inundating coastal regions.a

Little wonder, then, that people all over the world are getting involved in the crisis. Are they helping? Is any solution held out? What hope is there in this dismal situation?

[Footnotes]

[Box on page 11]

Bounty From the Rain Forests

Is there a piece of tropical rain forest near you right now? Consider some of the foods that were originally found in the rain forests around the world: rice, corn, sweet potatoes, manioc (cassava, or tapioca), sugarcane, bananas, oranges, coffee, tomatoes, chocolate, pineapples, avocados, vanilla, grapefruit, a variety of nuts, spices, and tea. Fully half of the world’s food crops are based on plants that came from rain forests! And those are just some of the foods.

Consider the medicines: Alkaloids from vines are used as muscle relaxants prior to surgery; the active ingredients of hydrocortisone to fight inflammation, quinine to fight malaria, digitalis to treat heart failure, diosgenin in birth control pills, and ipecac to induce vomiting all come from rain forest plants. Other plants have shown promise in fighting AIDS and cancer, as well as diarrhea, fever, snakebite, and conjunctivitis and other eye disorders. What other cures might still lie hidden is unknown. Less than 1 percent of rain forest plant species have been examined by scientists. Lamented one botanist: “We’re destroying things we don’t even know exist.”

Yet more products come from the vanishing forests: latex, resins, waxes, acids, alcohols, flavorings, sweeteners, dyes, fibers such as those used in life jackets, the gum used to make chewing gum, bamboo, and rattan​—in itself the basis for a vast, global industry.

[Diagram/​Picture on page 9]

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The Role of the Forest

[Picture on page 10]

Effects of Deforestation