26 August 2011

Logging and deforestation

Logging refers to the cutting down of trees, trimming of the cut trees into logs, and transportation of the logs to sawmills for processing. More broadly, logging may refer to the clearing of forested areas for subsistence farming, commercial farming, grazing, or other uses. Land clearance may be done in many ways, including slash-and-burn clearing, clearcutting (also called clearfelling) selective logging, and salvage logging.



Logging refers to the cutting down of trees, trimming of the cut trees into logs, and transportation of the logs to sawmills for processing. More broadly, logging may refer to the clearing of forested areas for subsistence farming, commercial farming, grazing, or other uses. Land clearance may be done in many ways, including slash-and-burn clearing, clearcutting (also called clearfelling) selective logging, and salvage logging.

Silviculture refers to the art and science of forest management. Many of the forest management concepts in use today were first developed in Germany in the 18th Century. One of the most important of these was the concept of sustained yield, which basically refers to managing the frequency and amount of tree harvesting in order to ensure that a reliable amount of timber may be cut indefinitely. In the last half of the 20th Century, silviculture expanded to include the concept of multiple uses, in recognition of the fact that forest management needed to address not only timber production but also forest uses such as recreation, hunting, watershed protection, and preservation of plant and animal habitat. More recently, the role of silviculture has expanded again to include the concept of the forest as an ecosystem interacting with human society, plant and animal environments, and climate.

The application of these concepts is a continuing subject of debate among groups with different and often conflicting opinions about forest management. The meaning of what a "sustainable" yield should be can be very different for timber companies, conservationists, ecologists, and local communities. Similarly, the concept of "multiple use" does not in itself provide an easy way to decide which uses are more or less important and deserve greater or lesser priority. These are essentially political issues that tend to be resolved or not resolved in the political arena, by legislative actions or local, national, or international agencies and regulatory bodies.

Deforestation commonly refers to the wholesale removal of forest cover by logging, natural events, or other human actions. Such actions include the use of herbicides both in war, as occurred in Vietnam, and in efforts to curb illegal drug production trafficking, as has occurred in Colombia and other areas of South America.

The process of deforestation by human activity is as old as civilization. Paleontologists have found indirect indications of widespread forest clearing dating back to the Stone Age. The development of culture in Minoan Crete in the Bronze Age was accompanied by severe deforestation The Gilgamesh Epic, written some 4,000 years ago, describes how the hero king Gilgamesh and his companion Enkidu defied the gods to cut down the cedar forests of Mesopotamia. Lebanon was famous for its cedar forests in antiquity, as mentioned in the Old Testament and other Near Eastern, Greek, and Roman sources, but today less than six percent of Lebanon is forested. Later, by the end of the Middle Ages, Western Europe faced actual shortages of fuel and wild game as a consequence of the systematic clearing of forest land in the previous centuries.

Currently, about 30% of the earth's land area is forested. However, an estimated 32,110,000 acres of forest disappear worldwide each year. According to the Food and Agriculture Organization of the United Nations, forestation is stable in the United States and has increased slightly in Western Europe. In particular, tropical forests in South America, Africa, and Asia are now suffering great harm from deforestation. The United Nations estimate that about 50,000 square miles of tropical forest are destroyed every 12 months.


Clearcutting refers to the complete clearance of forest areas. It was the most commonly practiced form of commercial logging in the first half of the 20th Century and is still widely practiced today. Conservationists and environmentalists argue that clearcutting results in deforestation, destruction of animal and plant habitats, and destruction of watersheds that protect against soil erosion and water pollution. However, the Society of American Foresters has argued that clearcutting is appropriate and even beneficial when properly used. They argue that forest re-growth occurs quickly after clearcuts, and that some forest-dwelling animals, including deer, bear, grouse, and quail, thrive in clearcut areas. The society also argues that it is the road building associated with logging, rather than tree harvesting itself, that is a cause of soil erosion and that this damage may be minimized by careful planning. It supports the use of clearcutting in defined forest areas, including those with trees damaged by natural causes or disasters, areas where the growth of shade-intolerant trees is desirable, and areas where it is desirable to increase the habitat of animals that do not do well in mature forests, such as songbirds, woodcocks, grouse, and deer.

Slash-and-burn logging refers to clearcutting by cutting down trees and burning the trunks, debris, and remaining vegetation. It has been practiced for thousands of years, and is still used by millions of farmers in Central America, South America, Southeast Asia, and China. Selective logging refers to the logging of only mature, commercially valuable trees while leaving younger trees and other vegetation standing.

Salvage logging is the logging of forest areas that have been damaged by hurricanes, windstorms, fire, or other natural causes.

Plantation logging refers to logging of plantation forests grown for the specific purpose of harvesting and usually consisting of a single-tree species. Plantation forests comprise less than 10% of U.S. forest areas.

Modern commercial logging is usually carried out by crews of loggers hired by independent contractors. Loggers are divided in several different specialties. Among them are tree fallers who cut down trees with chain saws or moveable feller buncher machines (machines that combine the functions of cutting, segmenting, and splitting logs). Buckers trim the tops and branches and cut the logs into different lengths. Choke setters attach chains or cables around the logs so that they can be transported. Log sorters, markers, movers, and chippers sort, mark and move the logs, and operate the machines that chip up logs. Log graders and scalers inspect the logs, measuring them, checking for defects, and estimating their value. Equipment operators use skidding machines and grapple loaders to move the logs to designated points and load them onto trucks, as well as operating tractors and other heavy machinery.

Road building in forest areas is an important part of logging operations. In the United States, President George W. Bush's Administration defended road building in forest preserves as necessary for fighting against forest fires. However, environmentalists argue that road building not only destroys habitat but also may increase the danger of forest fires by letting in more light, which consequently helps dry out the forest floor, and by creating forest openings that serve as wind tunnels that fan flames once a fire begins. In Brazil, roads opened in the rainforest for selective logging paved the way for increased land clearing and settlement, and ultimately, for the deforestation of the affected forest areas.


There are about 750 million acres of forest area in the United States. More than 60% of forested land is privately owned. Oversight of privately-owned forest land is controlled by the states, not the federal government, and varies widely among the different states. Most commercial logging takes place on privately-owned land, mainly in the Pacific Northwest and Southeast. However, tree harvesting in privately owned forests outpaced new tree growth in the 1980s and 1990s, especially in the Pacific Northwest, and is expected to do so until 2020 or later. In part because of this trend, the issue of logging in the federal forest preserves has aroused increasing debate and political controversy.

The history of deforestation in the United States goes back for centuries. Native American cultures employed slash-and burn techniques (tree cutting and burning of stumps and vegetation) to clear land in the Eastern Woodlands. The later European settlement of America was accompanied by widespread clearing of land for agriculture and by the emergence of logging as a major industry that marched westward with the tide of exploration and immigration.

In the Northeast, by the 1830s, Bangor, Maine, was the largest lumber-exporting port in the world. Later in the 19th Century, Michigan and later Minnesota and Wisconsin became major logging centers. At the same time, the growth of rail transportation in Appalachia after the Civil War fostered the development of large-scale logging in this area, as well. By the end of the century, the Midwestern forests were depleted and the Northwestern states of Oregon and Washington, as well as Appalachia, emerged as major logging centers.

The first recognition that the country's forests were not simply a resource to be exploited but also a national asset that deserved protection came after the Civil War. New England writer and philosopher David Thoreau's The Maine Forest, the first book to call for the creation of preserves of virgin forest, was posthumously published in 1864. The same year saw the publication of George Perkins Marsh's Man and Nature, one of the first works to document the effect of human activity, including deforestation, on the environment. From 1877 to 1881, Secretary of the Interior Carl Schurz sought unsuccessfully to regulate unauthorized logging on federal lands. An effort to establish federal forest preserves through Congressional action in 1882 was also defeated. In 1891, passage of the Forest Reserve Act sanctioned the creation of forest preserves by the federal government and President Benjamin Harrison then established 13,000,000 acres of forest preserve, beginning with the creation of Yellowstone Park that same year. However, the Act did not specify the purposes or uses of the forest preserves. These issues were addressed in the Organic Act of 1897, which listed those purposes as watershed protection and securing a continuous supply of timber. This act also limited logging activities to the felling of dead, physically mature, large-growth trees specifically marked for cutting. The forest preserves were increased to 43,000,000 acres during the first 10 years following passage of the Forest Preserve Act. Early in the 20th Century, President Theodore Roosevelt established the U.S. Forest Service and increased the forest preserves to 194,000,000 acres.

However, within a few years these preserves were effectively opened to logging again. In 1922, the federal government initiated a policy of selling national forest land in exchange for land of equal value, which opened up portions of previously protected forest preserves to commercial exploitation.

The gradual exhaustion of private forest lands led to the enactment of the Sustained-Yield Forest Management Act in 1944, which authorized the Forestry Service to establish sustained yield units for private interests on federal land, and the Cooperative Forest Management Act of 1950, which mandated the Forestry Service to assist private industry in logging on federal land. This led to greatly increased tree cutting and road building in the forest preserves during the next 20 years.

Growing popular concern over environmental issues in the 1960s and 1970s led to a series of measures that directly or indirectly helped to protect the national forests. The National Environmental Policy Act of 1970 (NEPA) stated that all federal agencies must prepare environmental impact statements before they take any action that might significantly harm the environment. The Endangered Species Act of 1973 did not address forest preservation directly, but allowed environmentalists to oppose expanded road building and logging that might threaten endangered species or their habitats. In addition, because this law applied to both public and private land, it provided a legal weapon for taking action on privately-owned lands not covered by the National Environmental Policy Act or other federal regulations.

The Monongahela case of 1973 was another major turning point for forest management policy. In this case, a coalition of environmentalists and hunters won a court order banning clearcutting in the Monongahela National Forest in West Virginia, successfully arguing that clearcutting violated the 1997 Organic Act's provisions authorizing cutting of only dead, physically mature trees specifically marked for cutting. This case led to the passage of the National Forest Management Act of 1974 and the National Environmental Policy Act of 1976, which mandated development of management plans for every unit in the forest preserves by 1985, limited clearcutting, and, for the first time, listed diversity of plant an animal species as a goal in forest management.

President Ronald Reagan's Administration took steps to weaken these measures and allow the timber industry more freedom for logging activities in the national forests. It set up new requirements for the management plans that effectively held up their development. His Assistant Secretary of Agriculture John Crowell also sought to increase the quotas of timber that could be harvested in the national forests, despite resistance from Forest Service officials who argued the increases violated earlier federal legislation. Crowell was the former attorney of the Louisiana-Pacific Timber Company, which was the largest company involved in logging federal forest preserves.

In 1991, the U.S. Forest Service issued the Roadless Areas Conservation Rule, which placed about 33% of the of the national forest system out of bounds for most road building and logging. This measure protected 58.5 million acres of forest in 39 states.

In 2000, President George W. Bush's Administration revised the Roadless Rule to exempt the Tongass National Forest in Alaska, the largest forest preserve in the United States, from its restrictions. Then in 2005, the Bush Administration repealed the Roadless Rule entirely and replaced it with new regulations saying that governors had to petition the Department of Agriculture to protect the forests in their states. Currently, the fate of the Roadless Areas Conservation Rule is in the hands of the courts.

In 2006, a federal judge in California ruled that the Bush Administration's repeal was illegal because it violated federal legislation requiring environmental impact statements on the effects of road building and issued an injunction halting all activities inconsistent with the Roadless Rule. However, in August 2008 a federal judge in Wyoming issued an injunction against the Roadless Rule in response to a lawsuit by the State of Wyoming. He argued that the Forest Service had not allowed enough time for opponents of the rule to present alternative proposals, and the Forest Service had overstepped its authority in issuing the rule because it effectively created new federal wilderness areas, which only Congress had the right to do under existing law.


In the last half of the 20th Century, the forests of South America, Africa, and Asia became targets of large-scale commercial logging, with catastrophic effects; 20% of the world's tropical forests were destroyed between 1960 and 1990.

Although the United States and Western European countries have stable forest areas, they are also major importers of lumber. Asian countries with rapidly growing economies are also major lumber consumers. In the 1980s and 1990s, when its economy was booming, almost 30% of the world's total lumber exports were shipped to Japan. More recently, China has become a major importer of lumber from Asia and Africa.

In Brazil, the combined effects of commercial logging and land clearance for subsistence and commercial agriculture have reduced the tropical rainforest to 10% of its original size. It has been estimated that 20,000 acres of the Amazon Rainforest are being destroyed every year.

East Asia contains 17% of the world's forests but has lost almost 90% of its original forest area, much of it as a result of illegal logging over the past 20 years. In the Philippines alone, the total forest area has been reduced from 39.5 million acres to 1.72 million acres. In Cambodia, 40% of the land has been granted to Southeast Asian companies for large-scale, unregulated timber logging.

In China, the consequences of deforestation have included soil erosion and massive flooding. Between 1896 and 1986, forest cover in Heilongjiang province, the center of China's commercial logging industry, was reduced from 70% to 34%. To counter the effects of deforestation, the Chinese government instituted a replanting program in the 1980s. It also completely banned logging after disastrous flooding along the Yangtze River in 1998 was blamed on deforestation. As a result of these programs, forest cover in China, which had been reduced to 12% of land area in the 1980s, is now over 18%. However, to satisfy China's economic demand for wood, both for domestic and commercial use, China has become a major importer of lumber from both legal and illegal logging throughout Asia and Africa.

Russia contains more than 20% of the world's total forested land area. However, more than 20,000 square kilometers of forest in Russia is lost every year, including about one-third of the total being lost to illegal logging. Of particular concern is the fate of the Siberian Taiga, a vast expanse of 2,000,000 square miles of old-growth forest. Until recently, this area has been largely untouched, because the Siberian climate and severe environmental conditions make large-scale logging difficult.

In Ethiopia, 98% of native forest has been destroyed during the last 50 years. In Central Africa, industrial logging is now the main form of land exploitation, with 30% of forest land leased to the logging industry. Between 1990 and 2005, Nigeria lost 15 million acres of forest, about one-third of the country's forest area.

Illegal logging is defined as the harvest, transportation, or sale of timber products in violation of national laws. Although many countries around the world have passed laws creating forest preserves and banning or restricting logging in these preserves, they often lack the will or capability to enforce them. The European Union (EU) estimates that about 20% of timber exports entering the EU may come from illegal sources. In June 2008, the United States became the first country to ban the import and sale of wood or wood products from illegal logging.


Logging provides timber for use in construction, paper, and other wood products. It may also provide fuel for cooking and heating, and land for development, for people who lack alternative resources.

All forms of logging are destructive. In the case of slash-and-burn land clearance, the ashes serve as fertilizer for the cleared land in the short term. But once deprived of vegetation, the nutrients in the soil are quickly exhausted; the land no longer retains water, and the farmers or grazers soon need to move elsewhere and repeat the process. This repeated destruction of habitat has led some authorities to label slash-and-burn land clearance as the single greatest cause of deforestation. The consequences of clearcutting may include soil aridity caused by destruction of the forest canopy and increased exposure to light, and by the destruction of forest buffer zones that hold and absorb water. Clearcutting also contributes to an increase in the rate of global warming and the loss of plant and animal species because of soil erosion and loss of habitat.

Selective logging has been thought to result in minimal damage to forest preserves. However, some recent studies have suggested that the damage caused by selective logging is more serious. A study by the Carnegie Institute of Washington's Department of Global Ecology found that three-fourths of selective logging activity in the Amazon caused canopy damage that left forests at increased risk of damage by drought and fire, so that about 16% of selectively logged forests were deforested within one year of logging, with deforestation continuing at a rate of 5.4% per year for the following four years.

Until recently, salvage logging was not considered as significantly damaging to forest preserves and was thought by some to decrease the risk of forest fires.

However, a 2006 study by researchers at Oregon State University who studied the effects of the Biscuit Fire of 2002, one of the largest forest fires in U.S. history, using satellite data, aerial photographs, and government records found that fire damage was greater in an area that had undergone salvage logging after a previous fire in 1987, than in areas that had been allowed to regenerate naturally after the 1987 fire.

Logging in any form threatens the preservation of old-growth forest areas (also referred to as virgin or untouched forest). Old-growth forests represent a unique environment defined by trees of many different ages and shapes, a thick upper canopy, with occasional breaks caused by fallen trees, fallen timber in different stages of decay, dense shrub layers and abundant ferns and lichens, and dead and fallen trees. The varied habitat in old-growth forests provides a home or temporary shelter for a wide variety of plants and animals, which depend on this unique habitat for food, shelter and nesting areas, as well as an aesthetic experience for human visitors. For instance, in the United States, the northern spotted owl uses old-growth forest areas for nesting sites; small animals and insects live in dead and/or fallen trees; and wolves, bald eagles, black-tailed deer and other animals depend on old growth forests for temporary or permanent shelter.

Moreover, most forms of logging also involve road building. Although it has been argued that road building in forest preserves may aid in fighting forest fires, U.S. Forest Service studies have found that such road building creates wind tunnels in forest area by drying out the forest floor and assisting the growth of underbrush, making it easier for fires to spread and increasing the risk of damage from windstorms.


Logging effects: Deforestation poses both short-term and long-term risks to the environment on both local and global levels.

On the local level, deforestation decreases the ability of forest land to retain water, which reduces soil cohesion and increases the risk of soil erosion, water quality, flash floods, and landslides.

On a global level, deforestation worsens the effects of global warming. Forests contribute to atmospheric stability by extracting carbon in the form of carbon dioxide (CO2) through photosynthesis and by collecting and storing carbon, a kind of storage referred to as a carbon trap. Deforestation not only reduces the amount of CO2 extracted but also releases vast quantities of CO2 into the atmosphere.

Deforestation also threatens the biodiversity of the planet. Biodiversity refers to the different kinds of plant, animal, and insect species in a specific area. Some scientists define biodiversity more broadly as including the varieties of all forms of life on earth and their interactions with each other and the environment. For some people, preservation of this variety of life is a value in and of itself. For others, biodiversity is important because the variety of plant and animal species and the interactions of these organisms with each other and with the physical environment in which they live have a significant impact on human life.

Estimates of the total number of species on earth vary wildly. To some extent, this is also true of estimates of biodiversity in tropical forest areas. It is well known that although tropical forests occupy only 6% of the world's land area, the variety of life in tropical forests is far higher than that found in more temperate areas such as Europe and North America. For instance, about 700 trees species were found in just 2.5 acres of Brazilian rainforest, compared to a total of 700 tree species in all of the United States and Canada. In Peru, 1,300 species of butterflies were found in a single rainforest, compared to 320 species in all of Europe, and 43 species of ants were found in a single tree, about the same number of ant species found in all of Great Britain.

Logging may lead to the extinction of both plant and animal species adapted to survival in a specific forest habitat. It may also endanger the survival of others that depend on the forest environment for food, shelter, and protection. Destruction of forest habitat may also lead to the destruction of plants and herbs with medical potential. Dr. Michael Balick, director of the Institute of Economic Botany at the New York Botanical Gardens, estimates that there could be as many as 328 drugs awaiting discovery in the tropical forests. However, other experts have cautioned that while many plants may contain cancer-fighting compounds, it may not be possible or economically practical to extract them successfully.

Deforestation may also destroy the culture and endanger the lives of indigenous peoples who depend on the forest for their survival. It is estimated that up to 200 tribes in the Amazon rainforest are threatened by logging and land clearance.

However, the Society of American Foresters has argued that clearcutting is appropriate and even beneficial when properly used. They argue that forest re-growth occurs quickly after clearcuts and that some forest-dwelling animals, including deer, bear, grouse, and quail, thrive in clearcut areas. The society also argues that it is the road building associated with logging, rather than tree harvesting itself, that is a cause of soil erosion and that this damage may be minimized by careful planning. The society supports the use of clearcutting in defined forest areas, including those with trees damaged by natural causes or disasters; areas where the growth of shade-intolerant trees is desirable; and areas where it is desirable to increase the habitat of animals that do not do well in mature forests, such as songbirds, woodcocks, grouse, and deer.

Logging occupation: Logging is considered a dangerous occupation. In 2006, the fatality rate for logging workers was 85.6 deaths per 100,000 workers, the highest fatality rate for any employment category in the United States, and 20 times higher than the overall fatality rate in private industry.

The work is physically difficult, and mostly work is done outdoors, in all kinds of weather conditions. Injuries are most commonly caused by workers being struck by falling timber, branches, or other debris and equipment-related accidents. A 2002 study by the National Institute for Occupational Health and Safety (NIOHS) found that the use of feller bunchers may significantly reduce the injury rate among loggers. However, these machines are too large and cumbersome to be used in areas where the ground is steep or uneven.

In 2007, the mean hourly wage for loggers in the United States was $15.50. However, wages may vary widely according to skills and location. An experienced tree feller could earn more, while a beginner might earn little more than the federal minimum wage.


Reforestation refers to the restoration or recreation of forest land that was destroyed by natural causes or human activity. In some cases, reforestation may occur naturally if the deforested area is left undisturbed for a number of years. In other cases, reforestation takes place through the planting of new seedlings.

However, reforestation may often be difficult, particular in very dry areas. Forested land that once retained water may dry out quickly and even develop a hard crust, called a duripan or duricrust, once it is cleared. This crust prevents water from sinking into the soil and, thus, hampers root growth, making reforestation by any means more difficult. Deforestation often results in increased soil erosion that also hampers reforestation.

Some scientists argue that the way to conserve forest areas is to highlight the benefits to be gained by harvesting their resources rather than cutting them down. For instance, the Amazon rainforest is a source of nuts, fruits, latex, and herbs and plants with potentially valuable pharmaceutical applications.

The World Bank has suggested using carbon trading to preserve forest areas in developing countries. Carbon trading refers to payments made by industrialized countries to developing countries in return for reducing carbon dioxide emissions that contribute to global warming. The World Bank is looking into proposals that these payments go specifically to conserve forest areas that store carbon dioxide.

In Mexico, the concept of "community logging" has been encouraged in some areas to combine timber harvesting with ecological and environmental concerns and to protect the interests of local and indigenous peoples. A particularly successful example of such a program is the Union of Zapotec-Chinantec Forest Producer Communities, known as UZACHI. UZACHI controls 60,000 acres of land, of which 70% is forested, earns income from the forest through timber harvesting; harvesting of non-wood products such as mushrooms and ornamental plants; and also from tourism. The forest area itself is zoned into different areas to ensure biodiversity, conservation, and reforestation. Each of the local communities in UZACHI has its own sawmill, an important consideration since processed wood from sawmills is more valuable than raw timber. The communities also have furniture-making factories. Thirty percent of revenues are used for salaries and forest operations. The rest goes into community projects, including providing roads, clean water, and education. Management decisions are reviewed by the local councils in each of the communities, and the councils also decide how to use the revenues.


This information has been edited and peer-reviewed by contributors to the National Standard Research Collaboration (

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