Unbalancing Act

Deforestation: Easy Profits, Hard Problems

The Earth is losing a large percentage of its forests. Tearing down all those trees puts our planet's climate, its biodiversity—and our health—at risk.

Scientists have noticed a pattern: Outbreaks of deadly disease often erupt when people wipe out forests. Why?

• Workers go deep into the forest to cut trees. So people are exposed to zoonotic diseases that usually infect only forest animals. Lacking immunity, workers can contract a disease—then bring it home. This is the theory behind how the HIV/AIDS epidemic began.

• Puddles and even small ponds form where trees once stood. These pools make handy homes for mosquitoes and other disease vectors.

• Cattle grazing on deforested land can become a disease reservoir—a home to bacteria and viruses.

While forests die as part of a natural process, humans destroy about 27 hectares (67 acres) of forest every minute, according to the U.N.'s Food and Agriculture Organization. Those minutes and hectares add up fast. Over the course of a year, our planet loses some 14 million hectares (35 million acres) of forest. That's an area roughly the size of New York State. The World Resources Institute estimates that about 80 percent of the Earth's original forest cover has been destroyed or degraded.

Trees cut down. Source: USDA, Jeff Vanuga Source: USDA, Jeff Vanuga

Why do we tear down trees? The reasons are complex, of course, but they grow out of two simple facts: People need 1) space and 2) ways to support themselves. Historically, we lose forests when people decide to use the land for other purposes. A few centuries ago, for example, Europeans who settled in the eastern U.S. needed to grow food and raise animals. But the only way they could create the vast farmland they needed was to chop down huge forests. To them, the forests seemed endless, and no one worried about hurting the environment.


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Tree loss in 1995 and 2000. Source: UNEP
Compare the loss of trees (red areas) in Kenya's Immenti Forest Reserve. These satellite images reflect the changes that have occurred in just 5 years due to the illegal conversion of forested land to cropland (see diagram below).
Source: United Nations Environment Programme



Today's wealthy countries have huge appetites for lumber, paper, and other wood products. Not surprisingly, then, people in struggling nations race to turn their rainforests into cash. (The U.S. is the world's leading importer of forest products.) Clearing forests also opens up land on which swelling populations can live, farm, and raise livestock.


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Deforested land. Source: UNEP
In the 1990s, almost 70 percent of deforested land was changed to land for agriculture. In Latin America, the farms were large scale. In Africa, forest was converted mostly to small farms. (Pan tropical refers to overall data from satellite images.)
Source: United Nations Environment Programme


Everyone wins, right? That's the theory. Reality, though, serves up cruel ironies: Decisions about destroying forests are often made without taking the well being of local people into account. And profits frequently go to the local bigwigs or to foreign corporations.


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Illegal, uncontrolled logging in Burma. Source: UNEP
Illegal, uncontrolled logging in Burma leads to soil erosion, contributing to food shortages and malnutrition.
Source: UNEP


A further irony is that rainforests make poor farmland. Those lush jungles survived because their intricate ecosystems included organisms that could recycle the nutrients in dead animals and plants. But stripped of its green cover, the soil is thin and barren. Farmers often abandon the land after a few seasons. Ranchers tend to last about a decade. Then people move on to new places, where the cycle starts all over. And the former rainforest becomes a wasteland. Soil erodes. The original tree canopy never grows back. Everyone loses.

Does this need to happen? No. A recent study shows that if the rainforest were left standing, its resources would yield far more money than could ever be earned from lumber and agricultural products, if the forest were cut down.


Well, so what? Don't countries have the right to decide how to treat their own land, especially since the greatest impact-good and bad-is on local people?


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Deforestation often means walking long distances for firewood. Source: UNEP
Deforestation often means walking long distances for firewood.
Source: UNEP


The problem is, deforestation affects people all over the world. Here are four major ways:

  • Trees breathe in and store carbon dioxide, one of the major greenhouse gases. Fewer trees lead to more carbon dioxide in the atmosphere, boosting the likelihood of global warming.
  • Scientists estimate that 70 percent of all land-dwelling species live in rainforests. Wiping out such biodiversity also means wiping out irreplaceable sources of food and medicine. Did you know that more than 25 percent of Americans' prescription drugs come from plant substances—including species found only in the rainforest?
  • Trees release huge amounts of water vapor, a process called transpiration. This water vapor later condenses and returns to the surface as rain or snow. Destroying forests, then, cuts the amount of water vapor released into the atmosphere. That in turn can mean smaller amounts of rain and snow. Studies in Ghana and Nigeria, for example, reveal links between rainforest destruction and chronic drought. That's bad news for those who grow food—or eat it.
  • Clearing forests in some regions could spark outbreaks of infectious diseases. Pathogens, or organisms that cause illness, may spread more easily. And disease vectors might behave in new ways.

Click on the names below to learn more about how cutting down trees can give rise to disease.

Deforestation, you can see, really is everyone's problem. So what can we do about it? The key challenge is to help developing countries find Earth-friendly strategies for survival. How? Here are some ideas:

  • Join or contribute to groups that purchase and preserve forests, and educate the public.
  • Buy nuts, spices, oils, furniture and wood products, and other items that can be harvested responsibly from rainforests.
  • Boycott food raised on deforested land.
  • Encourage leaders to cooperate internationally.


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