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Deforestation: The Human Costs


"Of all the environmental impacts of the study projections, deforestation probably poses the most serious problems for the world, particularly for the developing world."

Global 2000

"It has been predicted that within the next 25-30 years, most of the humid tropical forest as we know it, will be transformed into unproductive land, and the deterioration of the savannah into desert will continue at ever-increasing speed."

As you read this sentence, 50 to 100 acres of primary tropical forests will be eliminated, disrupted, degraded or impoverished. Yearly, an area of tropical forest the size of Great Britain is "converted" from an area equal to the size of Europe.

If present trends continue, by the year 2000, all tropical forests, with the exception of two areas - the western Brazilian Amazon and Central Africa - will have been destroyed. Since 1950, according to the U.N. Food and Agriculture Organization (FAO), half of the world's forests have disappeared. Latin America has lost 37 percent of its tropical forests; Central America, 66 percent; Southeast Asia, 38 percent; Central Africa, 52 percent. Nearly 20 million acres are destroyed annually.

As areas of tropical forests are destroyed or degraded, tribal groups are forced to change their resource base. In some cases they move into areas occupied by other groups, straining the area's resources. In other cases they are forced to relocate outside of forests, permanently altering their way of life by converting to agriculture or to cash employment. Rarely are the rights of these groups to the lands they occupy recognized. Further, their intimate knowledge of the area's resources and how to manage them are nearly always ignored.

Millions of indigenous people live in tropical moist forests which cover some 3.6 million square miles in 70 countries. More than 80 percent of these forests are found in Bolivia, Brazil, Colombia, Gabon, Indonesia, Malaysia, Peru, Venezuela, and Zaire, while 30 additional countries contain sufficient tracts to have significant ecological and biotic values. If these areas are to be managed effectively into the next century, the indigenous peoples that inhabit them should be consulted.


Forests are vital to human existence in the tropics. In addition to providing habitats for hundreds of indigenous groups on five continents, they probably contain more than 3 million species of plants and animals. In Indonesia alone, 4000 species are thought to have been used by native peoples. The following are some of the valuable functions and products provided by tropical forests:

* Wood - Construction materials, fiber and manufactured products all depend on tropical forests. Most families and many industries in the tropics depend upon the forest for fuelwood. The export of wood provides some $4.7 billion annually.

* Indirect forest products. Latexes, resins, oils, nuts, arts and crafts are exported in increasing quantities.

* Agriculture - Some 40 percent of developing world farmers live in villages that depend upon the sponge-effect of forests to absorb and slowly release water. Many agricultural exports, some $36 billion a year, are dependent upon forest-generated soils and water. Yet, in Southeast Asia the green revolution is faltering in part because it is no longer possible to plant two or three crops per year. In some cases, water flow, due to rapid runoff, is deeper than .5 meters which kills many high-yielding rice varieties.

* Food - Aside from slash-and-burn agriculture and gathering, forests also provide meat. Some 70 percent of animal protein consumed by people in the forest areas of southern Nigeria is wildlife from the forests, worth $27 million a year. In Cambodia, fish yields of swamp forests can be 10 times higher than some of the best fishing grounds in the Atlantic.

* Fodder - In Nepal, tree leaves account for 25 percent of all cattle feed and 40 percent of all buffalo feed.

* Genetic diversity - There are millions of species in the tropical forests, many potentially useful to man, but only 15 percent have even been catalogued. One strain of annual corn recently discovered in Mexican forests would revolutionize corn production by eliminating the need to plow and replant.

* Climate - Forest cover. Essential for safe, reliable water supplies, forest cover also influences ground temperature, soil mixture and rainfall, regional weather patterns and global climate.

* Reduction of erosion/flooding - Forests benefit all who live downstream by reducing erosion and flooding. Floods and erosion will cause severe constraints on food production throughout the world before the end of the century by eroding topsoil, flooding rice fields, and filling in irrigation canals. Energy production has been reduced from many reservoirs because of siltation. For example the energy produced by the Mangla Reservoir Dam in Pakistan is reduced because of 100 million tons of silt each year, four-fifths coming from the deforested Jhelum River watershed. In Thailand, waterways that once provided energy efficient transportation are choked with silt and no longer navigable. In 1979, India suffered $2 billion in property damage and numerous lives in the Ganges Valley in part because of deforestation in northern India and Nepal.

* Medicine - Half of the medications at your local drug store owe their origin to materials derived from tropical forests. Vincristine, made from a rainforest plant, now allows a child with leukemia an 80 percent chance of remission as compared with 20 percent in 1960. Tropical forests offer hope for other anti-cancer drugs, compounds for coronary disorders, and safer contraceptives.


The major cause of deforestation in the tropics is the need for food, fuel, shelter, and foreign exchange. The problems of converting forest areas for agriculture, fuelwood, and industrial logging are clues to more fundamental factors - problems of population pressure, unemployment, and inequitable land tenure.

Little can be done to slow global population growth for the next 50 to 70 years, by which time 12 to 16 billion people will inhabit the earth. In tropical countries, by the year 2000, more than 100 million people will be born annually.

Land ownership is tremendously inequitable in developing countries. In Latin America, 7 percent of the landowners own 93 percent of the arable land as compared to the U.S. where 7 percent of the landowners own 20 percent of the land.

During the last quarter of this century, annual, global wood needs are expected to double to just over 3 billion cubic meters. During the same period, demand for pulp is expected to increase from 265 million cubic meters to over 1000 million cubic meters.

Although tropical forests comprise 55 percent of global forest stocks, they contribute only 15 percent of the world trade in forest products. The Congo and Finland have land and forest areas roughly equivalent in size, yet in 1973 Finland exported forest products valued 60 times more. Amazonian countries have nearly three times more forest per person than the world average yet import more forest products by value than they export.

Between 1954 and 1976, the value of tropical wood exports increased from $272 million to $4.2 billion. Tropical wood exports are the fifth largest export earner, excluding oil, amounting to 4 percent of all exports from the developing world. The demand for tropical hardwood in developed countries has increased by 1500 percent since 1950 while in tropical regions it has only doubled.


Eighty percent of all wood harvested in the tropics is used for firewood and charcoal. For some 2 billion people in developing countries (80 percent of all households), it costs nearly as much to heat their cooking bowls as to fill them. Pressure on the forest will only mount while petroleum prices remain high and populations grow.

In parts of Latin America and West Africa, the urban poor often spend a quarter of their income on wood or charcoal for cooking. "Even if we produce enough food to feed the world's population," Erik Eckholm says, "there won't be enough firewood to cook it."

In Kwemzitu, Tanzania, Anne and Patrick Fleuret report that a woman with a household of five must gather 22.4 kgs of wood daily to meet the demands of her home. To keep pace with this consumption level 200 villagers would need to plant 1360 trees every year.

Shifting Cultivators

Small seminomadic groups of slash-and-burn agriculturalists in very large tracts of forest are probably beneficial to forest ecology. Small clearings open space, allow new growth and provide food for animals. However, population pressure has caused the number of shifting cultivators to become so numerous that normal fallow cycles are shortened.


Douglas Shane, in a report on deforestation in Latin America for the U.S. State Department, writes "cattle ranching is probably the single largest cause of deforestation in Latin America and to a large degree in Africa." It accounts for some 38 percent of Latin America's forest loss, but in Central America, between 1950 and 1975, pasturelands doubled while two-thirds of the forest were cut. Ninety percent of Latin America's beef exports come to the U.S. It has been estimated that for every million and a half pounds of beef exported, some 75,000 acres of rainforest are cleared. Originally planned to accommodate one steer per hectare, the pastures quickly deteriorate to one per 3 to 10 hectares. Since 1960 the consumption of beef in Central and South America has declined by 13.5 percent.


Tropical forests are increasingly destroyed by land-seeking rural poor. There are more than 600 million rural poor in the world without land or secure access to it, including some 85 percent of the households in Java and 70 percent in Brazil. Usually the poor migrate on their own; occasionally they are sponsored by government projects. Access roads into forest areas - aiding timber, mineral and oil extraction - frequently lead to spontaneous agricultural and livestock development.

The colonists move on after only two or three years as cleared areas are plagued by weeds, insects, and declining fertility. The land is often bought by cattle ranchers. Within 5 to 10 years, soil fertility continues to decline, pastures are invaded by weeds and the areas are abandoned. The effect is a moving frontier that results in waste and destruction.

According to Peter H. Raven, Director, Missouri Botanical Garden,

The current Brazilian estimate is that .3 of 1 percent of the land in forest in the Amazon Basin can be put into sustainable agriculture using currently available technology. And our estimate would be that approximately 95 percent of all the land in the tropics that can be put into sustainable agriculture is already in cultivation.

Yet, colonization, funded both by national governments and international lending institutions, continues.

Industrial Logging

Industrial wood accounts for 20 percent of the total volume removed from tropical forests, but only a third is exported. While logging may not account for most global deforestation, in certain areas, it is the principal cause. Seventy percent of all tropical hardwood imports go to Japan; the Japanese consume more wood per capita than any other people on earth. Between 1950 and 1973 Southeast Asia increased exports of tropical hardwoods 24 times. In the same period, developed nations increased all tropical hardwood imports from 4.2 million cubic meters to 53.3 million cubic meters. Imports are expected to be 95 million cubic meters by the year 2000.

The process of industrial logging is highly selective, with only a few species and trees of a certain size harvested. Of the thousands of trees in the Amazon basin, some 400 with proven value, only about 50 species are harvested. Africa exports about 35 species, but 10 account for 70 percent of all exports. In Southeast Asia, logging of some 100 species occurs, but only a dozen or so account for most exports. Often less than five percent of the total number of trees are harvested in any area. Yet, logging operations can leave 30 to 65 percent of the residual trees damaged beyond recovery (even minor injuries allow pathogens to kill trees). Logging operations and roads - sometimes 10 km for each square kilometer of forest exploited - destroy 10 to 30 percent of the forest area. Roads often allow colonists to complete the deforestation process.

New harvesting techniques, including whole tree harvesting, the use of hundreds of species, and on-site chipping, make clear cutting more common. This allows for 200 to 300 percent greater yields per area. However, clear-cut forests do not regenerate easily if the area is too great or if it is not allowed to regrow immediately.


From 1950-1970, world consumption of paper products increased from 40 to 130 million tons. Today, developed countries use 160 million tons of pulp a year, the developing world a little over 20 million. In the former, per capita consumption is more than 155 kg of paper products per year (325 kg in the U.S.) while in the latter, it is no more than 5 kg (about 2.5 Sunday editions of The New York Times).

About 7 percent of the world's pulp needs come from tropical forests. Following increases in U.S. pulpwood prices, Japan, who imports half of its pulpwood, is now turning to Southeast Asia and Latin America for half its needs. If the U.S. recycled only 20 percent of the 46 million tons of wastepaper it discards each year (more than double the amount used by the developing world) no tropical rainforest would have to be converted for paper pulp.

Ironically developing countries import most of their pulp wood supplies. In 1975 the $2 billion price tag was almost two-thirds of the value of their timber exports. In 1977, Indonesia paid $92 million to import 85 percent of its pulp needs.

Thus far demand in developing countries is low. In 14 Asian countries, including the most populous (except China), newsprint used is less, combined, than in Canada. But population growth, and changing aspirations, will cause demand to soar. Paper shortages are already cited as contributing to setbacks in education. By 2000, Southeast Asia will probably need five times as much paper as it did in 1974.


The United States' effect on tropical forests is both positive and negative. On the negative side, wood and beef are imported in increasing quantities. Domestic policies restrict cutting in the U.S., encouraging imports from the 3rd World. Some 30 U.S. firms are involved in commercial forestry activities, mostly in Southeast Asia. American individuals and companies invest heavily in cattle ranching operations in tropical countries. The health of the U.S. economy is aided directly by inexpensive tropical forest products and indirectly by loans and trade with tropical countries. In 1978, the U.S. earned $16 billion from direct investments in the developing world. One-third of the U.S. export market is with non-oil-producing developing countries. Developing countries needing to pay these and other bills use forests to provide some of the foreign exchange.

On the positive side, the U.S. does have tariffs and quotas that apply to wood and meat imports. The U.S. requires social and environmental assessments of activities that might affect tropical moist forests and sponsors projects in tropical countries which modify, restore, or protect forests. The U.S. imports medicinal plants and various natural products which come from the forest but do not necessitate the destruction of it. And to offset the dangers the U.S. poses to tropical moist forests, the U.S. government has taken the lead in promoting rational forest use and management in the Third World.

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