Chapter Two

What's Happening to Tropical Forests?

The Causes of Deforestation

As is the case with many complex environmental problems, the causes of deforestation cannot be summed up in a simple sentence. Deforestation of tropical rainforests is the result of several forces, all intricately interwoven. One thing is for certain: there is no "quick fix" for the problem of tropical deforestation.

At the root of the problem is people. In fact, one of the largest misconceptions about the tropical rainforests is that they are unpopulated wildernesses. In reality, people live in these forests. There, they try to meet their needs for food and shelter. Many have left rural or even urban areas in search of raw land to convert to cropland. They cut and slash trees and burn the fallen stems to prepare the ground for planting. This process is called slash-and-burn agriculture. Once the land is planted to crops, however, the thin soils of these areas quickly lose growth-supporting minerals through leaching. This leaves farmers no option but to cut more forest.

Slash-and-burn agriculture has been used for centuries in tropical areas. So why has it only recently become a problem? The difference is in the numbers. As populations surge, pressures on tropical rainforests increase. Years ago, land would rest between clearings, and within 30 or 40 years would regenerate to another tropical forest. Now, the rate of forest clearing has risen, and the time between forest cuttings has declined, sometimes to as little as four or five years.

Slash-and-burn agriculture, sometimes called shifting agriculture, oddly enough, gets a boost from some local governments. Officials consider forest land to be underdeveloped, and offer title to those who will improve it through clearing, and burning. Residents who try to use the forest in a sustainable manner, such as for collecting nuts, sometimes face eviction because they are not "improving" the land.

Other causes of deforestation include collecting firewood, cattle ranching, urbanization of forest areas, and logging.

Industrial logging is commonly perceived to be the primary cause of deforestation, but this isn't borne out in the statistics. Such activity is directly responsible for only 6 to 15 percent of tropical deforestation. The vast majority of wood harvested is used locally.

Commercial timber harvesting within the tropics does not result in landscapes cleared of trees. The reason for this is that there are thousands of plant species that reach tree size, but very few species that have commercial value. Fewer yet have value in international trade.

A cleared area is usually the result of agriculture or cattle ranching, not harvesting. But harvesting does often damage trees left in the forest, and may alter the mix of tree types. And although many trees remain after harvesting, roads built to remove logs from the forest are sometimes used by landless poor people to gain access.

Although logging is a relatively minor contributor to tropical deforestation globally, in parts of Asia and Africa, industrial logging does play a larger and sometimes major role in deforestation.

The Outlook for U.S. Forests

The population of the United States has greatly increased since the turn of the century, from 76 million in 1900 to more than 280 million people today. During the 1800s, three acres of cropland was needed to feed each new person. Had this continued, increases in the U.S. population would have required the clearing of almost all forest in the eastern U.S., and conversion to agriculture, just to feed our people.

Interestingly enough, deforestation isn't a problem in the United States. Increases in agricultural productivity mean that we've been able to feed our citizens, and those of other nations, with the same amount of cropland we used in the 1920s.

As our population increases, the demand for wood products increases, too. Laws protect forests from harvesting in certain areas (e.g., federally designated wilderness areas) and from over harvesting. With efficient management, our supply of timber is likely to be sufficient to meet our needs for a long time. The biggest challenge for forest managers in the future will be to figure out how to meet the nation's need for wood while retaining biological diversity and meeting demands for forest recreation, solitude, and historical preservation.