The World's Forests

Conventional wisdom holds that the world's forests, particularly the tropical forests, "are disappearing at alarming rates growing numbers of people seek land to cultivate, wood to burn, and raw materials for industry." But is some deforestation necessary to best meet the full range of social, environmental, and developmental goals? If existing rates of deforestation are alarming, what rates would be considered acceptable?

The search for answers is complicated by the fact that there is no single deforestation problem, but rather at least three sets of problems. The first concerns the role of the forests in meeting local economic and social needs, including commercial logging, forest amenities, and such environmental goals as watershed protection. The second set of problems encompasses global requirements for industrial wood and the part that local and regional forestlands play in meeting demand today and in the future. The third set relates to the environmental effects massive deforestation might have, particularly on global climate and on the global biological genetic pool. As these problems are highly interdependent, some recognition of the nature of the interdependencies is critical to any attempt to draw inferences about the future of forests and the extent to which deforestation is a serious problem regionally and globally.

The forest resource

Forests are renewable. Sometimes people must intervene to assure reforestation, but—absent external efforts to discourage it—some form of forest will regenerate naturally in a very large part of the world. Although the large volume of forests worldwide probably was more or less stable for many centuries, it was not stagnant. Natural processes, including fire, disease, insects, and storms continually swept over the world's forests destroying some—usually older, decadent stands—to make way for new vigorous forests.

To meet food needs, cropping and livestock raising gradually replaced hunting and gathering as the principal source of food. As this transition occurred, new institutions were developed to provide reasonable assurance that the individual or collective investor would be able to capture the fruits of the investments required in raising crops and animals. Generally, satisfactory institutions developed. When they did not, however, what economists call common property problems resulted. These have been characterized by Garrett Hardin as the "tragedy of the commons," in which a resource is used at a rate in excess of the social optimum and leads to environmental degradation.

While the transition from hunting and gathering to cropping and herding was well under way more than three thousand years ago, the forestry transition is of much more recent vintage. Forest management is reputed to have begun in Europe, perhaps as early as the thirteenth century, but for much of the world today forestry remains in the foraging and gathering stage. In the last half of this century, however, substantial progress has been made toward investment in planting, growing, and forest management, particularly in the establishment of public and private forest plantations. When the cost-minimizing investor—private or public—believes that the costs of obtaining wood resources will be lower if trees are grown and managed as a crop than if stands of decreasing quality are logged in areas of increasing inaccessibility, investments in forest management and forest plantations will be forthcoming. Of course, this is not an either/or proposition. The world's wood supplies now come from old-growth forests, second-growth naturally regenerated forests, and, increasingly, from artificially regenerated forest plantations. As the transition proceeds, plantations probably will increase while the other forest types, and particularly the old growth, will diminish in importance.

The precise extent to which forest plantations are being established is uncertain, but the areas are beginning to be large, even by global standards. Estimates are that plantation forests total some 90 million hectares or about 3 percent of the world's forestland. Furthermore, annual rates of plantation reforestation approached 10 million hectares in the late 1970s.

Deforestation problems

Supply availability, regional ecological, economic, and environmental problems, and world ecological implications are affected differently by differing rates and locations of deforestation.

Supply availability

Questions about the adequacy of the world's industrial wood supply do not differ fundamentally from those concerning the supply of other natural resources. Clearly, vast reserves of merchantable wood exist, but as these become more scarce and less accessible pressures will develop to push wood prices upward. In fact, this has been the experience with certain wood resources, such as sawlogs, over at least the past one hundred years. Perhaps the only possibility for this not to occur in a world of increasing demand is if technological change were to occur rapidly enough to offset the demand. At any rate, as prices increase, incentives are created for investments in forest management and particularly for the establishment of forest plantations. As noted, this indeed has been under way for some time and appears to be building momentum.

In principal, the world's industrial wood needs can be met using only a small fraction of land area already in forests. For example, assuming a net annual growth of 10 cubic meters per hectare per year—a growth rate attainable in many regions—the world's industrial wood consumption of 1979 could be met from the sustained-yield output of 140 million hectares of forest lands, or only about 3.5 percent of the current forestlands of the world.

An important side effect of the transition to industrial forest plantations is worth noting. To the extent that plantations assume a greater role in meeting the world's demand for wood, the pressure will be reduced on natural forests. Hence, one of the causes of the destruction of natural forests gradually should be reduced or eliminated.

Local and regional problems

Many of the local problems faced in forestry result from certain common property characteristics, as do such regional problems of deforestation as watershed deterioration. For example, the common property nature of a forest can lead to premature fuelwood gathering, which seriously reduces sustainable fuelwood production.

In the temperate climate forests of both the Northern and Southern Hemispheres, the creation of social institutions has checked many of these local problems by reducing or eliminating the common property features of the forest. Such institutional arrangements as the replacement of common property by private property, the development of governmental ownership and management, and the imposition of regulations to control external costs (damage to watersheds and so forth) have mitigated many of the most harmful external costs, although not always in the most efficient manner.

The same cannot be said for much of the tropics. Some positive signs are appearing, however. For example, efforts are beginning to limit deforestation in areas where adverse environmental effects are severe. And in many countries concerned about future environmental and wood resources, programs are being undertaken—often in the form of substantial incentives—for reforestation, forest plantation establishment, and the creation of forest reserves.

Without downplaying the very real challenge of developing institutions to deal with local environmental problems, these problems in principal are easier to deal with than global problems. Both the forces generating the problem and the adverse effects that result roughly coincide in time and place, and usually only one or two sovereign states are involved. Thus, even if important local externalities and common property problems are concerned, understanding the nature and source of the problem offers at least a basis for introducing institutional arrangements and remedial actions that might rectify the problem.

Global problems

Forestry's relation to global externalities is more difficult. For example, the global atmosphere can be viewed as a common property that knows no international boundaries. Given that perspective and with no institutional arrangements to assure the "correct level" of use, the atmosphere might well be overused for the disposal of excessive carbon dioxide. The manifold problems of the so-called greenhouse effect—principally, shifting agricultural patterns and coastal flooding from melted polar ice—could result, many scientists believe.

The seriousness of the carbon dioxide threat is a matter of lively conjecture, however. And, in any event, the extent to which forests contribute to this problem is an open question. With net deforestation, the potential of increased carbon in the atmosphere is enhanced, but significant offsetting factors exist. Certainly much of the solid wood that is removed from the forest will not quickly find its way into the atmosphere since it is used in the building of structures and other items that often have very long lives; over 50 percent of the lumber in the United States is used in construction. In addition, large amounts of the carbon released into the atmosphere through deforestation subsequently are absorbed back into growing forests worldwide. Indeed, U.S. forests have experienced net additions to their volumes over the past fifty years and therefore can be viewed as a net carbon sink. Finally, the effect of the oceans is an important unknown in the carbon dioxide question. No one knows how much carbon dioxide—from forests or coal-fired power plants or other sources—is being absorbed by the oceans of the world. Doubtless it is vast, but one can only speculate how much so.

The problem of the world's genetic resources also involves common property difficulties. Some 25 to 50 percent of the world's species are estimated to be in the tropical forests. These genetic resources are like an unopened treasure chest in that their long-term value to humanity is quite uncertain. To the extent that the tropical forests are overcut, so too their genetic resources are threatened. Public and private actions aimed at reducing the lightest include the setting aside of tropical forest reserves to protect genetic diversity and the creation, by the timber industry, of an organization to systematically collect and preserve seed and establish growing reserves from a broad range of threatened sources of Central American tropical pines. These are important initiatives, but the momentum still is with the other side. As Harrington's article makes clear, the preservation of the world's genetic resources remains a source of serious concern.

What is happening to global forests?

Data from the Food and Agriculture Organization (FAO) Yearbook of forest products indicate that the four economically developed regions—North America, Europe, the USSR, and Oceania, which have about 50 percent of global forests—have had stable or growing areas of forestland since 1950. In addition, the Peoples Republic of China shows significant deforestation during that period. In summary, forest area in the temperate climates is stable or increasing slightly.

For the tropical world, the most recent and perhaps the most thorough analysis of deforestation data was undertaken by Lanley, who finds deforestation is occurring in the closed broadleaf forests at a rate of 7.1 million hectares, or 0.60 percent, per year. The rate of deforestation is almost identical for Latin America, Africa, and Asia, but because of the larger area of tropical closed broadleaf forest in Latin America, this region accounts for about 56 percent of the total tropical area deforested. When other forest types in the tropics are included, that is, open and coniferous forest, the total area deforested annually is estimated to be 11.3 million hectares, with the percentage decline in all tropical forests falling slightly to 0.58 percent per annum. Furthermore, Lanley indicates that the undisturbed or virgin broadleaf closed forests have a far lower rate of deforestation than the total—only 0.27 percent annually. This suggests that the pressure is relatively low on the more pristine tropical forests.

Myers takes a somewhat different approach in a study published by the National Academy of Sciences in 1980. Myers measured deforestation as the conversion of moist tropical forest to any other use, even naturally regenerated forests, in several countries with a wide range of deforestation rates. To take only two of his findings: Myers estimates the Ivory Coast rate of deforestation at —5.3 percent, and Brazil is at just —0.342 percent. At these rates, by about the end of this century the Ivory Coast forests would disappear altogether, whereas Brazilian forests would be reduced by only 6 percent.

While there has been a net decline in natural tropical forests, it should be noted that the data do not account for the establishment of plantation forests which, for many purposes, replace the natural forests. The level of such replacement is well below the level of deforestation, but it does offset some of the decline What may we conclude about the state of global deforestation? First, the rate and level of deforestation depend on one's definition. When natural and artificial reforestation are included, the extent of global deforestation surely is much more modest than sometimes is alleged. Second, in terms of total forested land, little basis exists for serious concern about the imminent demise of the world's forests. Of the eight major regions of the world, five—North America, Europe, the USSR, China, and Oceania—have stable or growing areas of forestland. Three regions—Africa, Asia (excluding China), and Latin America—are experiencing modest declines in their forested land area. Third, the tropical forests of the world are undergoing net deforestation. While the overall rate is modest (0.58 percent), in certain regions it is cause for concern. However, the rate of deforestation appears to be quite low for the important undisturbed broadleaf closed forests.

The data suggest to us little possibility of the world running out of forests, or even of major regions being dramatically denuded in any reasonable time. But this is not to suggest that excessive rates of deforestation do not occur in certain regions, particularly in tropical areas. These excesses have created regional environmental and fuelwood problems and could destroy some of the world's genetic resources. Alarm may be an inappropriate response to what actually is occurring in the world's forests, but so would be neglect.