How Deforestation Works

By: Debra Ronca  | 

The destruction of forests can have long lasting negative effects on our world. See more pictures of trees.
Lester LefKowitz/Getty Images

To call attention to the issue of deforestation, Harrison Ford, star of the "Indiana Jones" movies, had his chest waxed on camera. "Every bit of rain forest that gets ripped out over there…really hurts us over here," he told viewers as hair was yanked from his pecs [source: AP]. Ford's public service announcement was in support of an environmental organization called Conservation International, which seeks to prevent deforestation.

Tree Image Gallery


So why would deforestation motivate a movie star to sacrifice chest hair?

Deforestation is the removal or destruction of large areas of forest or rainforest. Deforestation happens for many reasons, such as logging, agriculture, natural disasters, urbanization and mining. There are several ways to clear forest -- burning and clear-cutting the land are two methods. Although deforestation occurs worldwide, it's a particularly critical issue in the Amazon rainforests of Brazil. There, the tropical forests, and the species of plants and animals within them, are disappearing at an alarming rate. In December 2007, for example, experts measured Amazon destruction at more than 360 square miles (932 square kilometers) in just one month [source: BBC News].

The effects of deforestation are long lasting and devastating. Entire species of insects and animals have disappeared because of the destruction of their habitats. Deforestation can cause catastrophic flooding as well. And scientists see that deforestation has a significant effect on climate change, or global warming.


Causes of Deforestation

Nick Norman/National Geographic/Getty Images

For the most part, human activity is to blame for deforestation, though natural disasters do play a role. So let's take a look at how and why humans deforest areas.

Logging, or cutting down trees in a forest to harvest timber for wood, products or fuel, is a primary driver of deforestation. Logging affects the environment in several ways. Since trucks and large equipment need to get into the forest in order to access trees and transport timber, loggers must clear large areas for roadways. Selectivelogging -- where only the most valuable trees are felled -- doesn't help matters, as one falling tree can bring down dozens of surrounding trees and thin the forest's protective canopy [source: Butler]. The forest canopy is important to the forest's ecosystem because it houses and protects plant, animal and insect populations. It also protects the forest floor, which slows down soil erosion.


Agriculture also drives deforestaton. Farmers clear the land for crops or for cattle and often will clear acres of land using slash and burn techniques -- cutting down trees and then burning them. Migratory farmers clear a forest area and use it until the soil becomes too degraded for crops. Then they move on and clear a new patch of forest. The abandoned land, if left untouched, will eventually reforest, but it will take many, many years to return to its original state.

Hydroelectric dams are quite controversial because while they help to power communities, they also contribute to deforestation. Damming opponents believe that the building of such structures not only has a negative environmental impact, but it also opens up the area to loggers and more roads [source: Colitt]. To build a hydroelectric dam, acres of land must be flooded, which causes decomposition and release of greenhouse gases. Local people can also be displaced by dam projects, causing further deforestation when these people resettle elsewhere.

Fires, both accidental and intended, destroy acres of forest very quickly. Areas affected by logging are more susceptible to fires due to the number of dried, dead trees. Milder winters and extended warm seasons due to global warming also fuel fires. For example, certain species of beetle that usually die off each winter are now able to survive and continue feeding on trees. This feeding causes the trees to die and dry out, making them into kindling [source: Environmental Defense Fund].

Mining also results in deforestation. Digging a coal, diamond or gold mine requires the removal of all forest cover, not just for the mines but also for trucks and equipment. Recently, Venezuela denied a corporation called Crystallex permission to dig a mine because of environmental concerns [source: Walter and Bailey].

Palm oil has been receiving attention lately for its potential as a biofuel and is used in many packaged foods and beauty products. But palm oil is another cause of deforestation. Its rising prices make it more valuable, and, in response, Indonesian and Malaysian farmers destroy acres of trees to harvest it. For this reason, several countries are currently debating a ban on palm oil as a biofuel.

As cities grow larger to accommodate more people, trees are cut down to make more room for houses and roads. This urban sprawl deforestation is occurring worldwide, now that 50 percent of the world's population lives in cities [source: CNN].


Effects of Deforestation

Deforestation removes the forest canopy, which can result in soil erosion.
Troy Klebey/Getty Images

Scientists are finding more and more links between deforestation and global warming. The carbon footprint created by four years of deforestation is equal to the carbon footprint of every single air flight in the history of aviation up to the year 2025 [source: Kristof]. Let's break that down into simple logic: Trees absorb carbon dioxide. So fewer trees means more carbon dioxide is loose in the air. More carbon dioxide means an increased greenhouse effect, which leads to global warming. (You can read more about the greenhouse effect in What is the greenhouse effect?)

Reduced biodiversity is another deforestation concern. Rainforests, arguably the biggest victims of deforestation, cover only about 7 percent of the world's surface. However, within this 7 percent live almost half of all plant and animal species on earth. Some of these species only live in small specific areas, which makes them especially vulnerable to extinction. As the landscape changes, some plants and animals are simply unable to survive. Species from the tiniest flower to large orangutans are becoming endangered or even extinct. Biologists believe that the key to curing many diseases resides within the biology of these rare plants and animals, and preservation is crucial [source: Lindsey].


Soil erosion, while a natural process, accelerates with deforestation. Trees and plants act as a natural barrier to slow water as it runs off the land. Roots bind the soil and prevent it from washing away. The absence of vegetation causes the topsoil to erode more quickly. It's difficult for plants to grow in the less nutritious soil that remains.

Because trees release water vapor into the atmosphere, fewer trees means less rain, which disrupts the water table (or groundwater level). A lowered water table can be devastating for farmers who can't keep crops alive in such dry soil [source: USA Today].

On the other hand, deforestation can also cause flooding. Coastal vegetation lessens the impact of waves and winds associated with a storm surge. Without this vegetation, coastal villages are susceptible to damaging floods. The 2008 cyclone in Myanmar proved this fact to catastrophic effect. Scientists believe that the removal of coastal mangrove forests over the past decade caused the cyclone to hit with much more force [source: United Nations].

Deforestation also affects indigenous people, both physically and culturally. Because many indigenous people actually have no legal rights to the land on which they live, governments that want to use the forest for profit can actually "evict" them. As these populations leave the rainforest, they also leave their culture behind [source: Plotkin].


Ways to Reduce Deforestation and Repair the Damage

In December 2007, the United Nations Climate Change Conference took place in Bali, Indonesia. After 10 days of intense discussion, more than 180 countries agreed to the Bali Roadmap. The Bali Roadmap will guide participating countries in emissions reduction and intends to lead to a binding agreement at the 2009 United Nations summit in Denmark [source: Harris]. The United States and China initially did not agree to mandatory reductions, wanting countries to set their own goals, but they eventually conceded [source: USA Today].

The roadmap includes specific measures to reduce deforestation -- for tropical rainforests in particular. Many developing countries' economies rely on their forests, and they argue they should be able to use their land as they please. In response, the roadmap will investigate policies to financially reward countries who reduce their emissions by a certain percentage (the percentage has not yet been determined). Even this proposal faces controversy, however. Because those countries with the highest baseline rate of deforestation will receive the most reward credits, critics fear that many countries will rush to cut down trees in order to raise their own baseline [source: Tickell].


Besides the U.N., there also are dozens of nonprofits working to combat deforestation. A few well-known organizations include:

  • Conservation International -- teaches local farmers how to maximize their existing land, rather than clear new areas
  • The World Wildlife Fund -- works to shape policies and teams with communities to preserve forests
  • Rainforest Action Network -- uses in-your-face advertising campaigns to call attention to the rainforests
  • The Environmental Defense Fund -- champions government bills that provide financial incentive to private landowners (such as farmers) who practice land conservation
  • The Sierra Club -- works to protect and restore U.S. forests
  • Amazon Watch -- defends the rights of indigenous people and communities faced with industrial development
  • The Nature Conservancy -- has developed several initiatives to advance conservation

Can we really save the forests? Once the trees are gone, is it possible to restore the land? Most deforested areas, if left alone, will eventually regenerate to fertile landscape. We can certainly plant more trees -- a process called reforestation. In fact, many nonprofit organizations have popped up to support reforestation. For example, currently works on reforesting areas like Nicaragua and the state of Louisiana [source:].

In the meantime, new movements in forest protection have sprung up over the years. They include:

  • Eco-forestry -- where only carefully selected trees are cut down and are transported with minimal damage to the area; the forest ecosystem is preserved while commercial timber extraction is still permitted
  • Green business -- focuses on recycled paper and wood products, wood alternatives and environmentally responsible consumerism
  • Land use planning -- advocates environmentally friendly development techniques, such as reduction of urban and suburban sprawl
  • Community forestry -- where concerned citizens come together to manage and participate in keeping their local forests viable and sustainable



Originally Published: Jun 10, 2008

Deforestation FAQS

What is deforestation?
Deforestation is the large-scale removal of trees to facilitate human activities. It has led to serious environmental concerns, including the loss of natural habitats for animals, soil erosion and a loss of biodiversity.
Why is deforestation a problem?
One of the major concerns of deforestation is the loss of valuable trees and plant life, which can lead to soil erosion, desertification, flooding and fewer crops.
What are the five main causes of deforestation?
Some of the most common causes of deforestation are unsustainable forest management, the mining industry, timber extraction, cattle breeding and cutting of trees for dam and infrastructure construction.
How can we stop deforestation?
Some of the ways to reverse the harmful effects of deforestation include planting a tree, using paperless products, buying recycled products, recycling materials and supporting certified wood products.
Is there any permanent solution for deforestation?
A permanent solution to deforestation is proper planning and forest management, planting more trees and stopping the excessive use of wood products.

Lots More Information

Related HowStuffWorks Articles

More Great Links


  • Associated Press. "Ouch! Harrison Ford Waxes Chest To Make a Point." May 20, 2008. (May 20, 2008)
  • BBC. "Brazil Amazon deforestation soars." Jan. 24, 2008. (May 20, 2008)
  • BBC. "Deforestation and the Greenhouse Effect." March 4, 2008. (May 27, 2008)
  • Butler, Rhett A. "An interview with ethnobotanist Dr. Mark Plotkin." Oct 31, 2006. (May 27, 2008)
  • Butler, Rhett A. "Logging." Tropical Rainforests: Imperiled Riches - Threatened Rainforests. Jan 9, 2006. (May 20, 2008)
  • "Reforestation." 2008. (May 28, 2008)
  • CNN. "Satellite images show effects of urban sprawl." Feb. 21, 2000. (May 21, 2008)
  • Colitt, Raymond. "Brazil Indians, activists protest over Amazon dam." Reuters. May 21, 2008. (May 20, 2008)
  • Dangerfield, Whitney. "The Mystery of Easter Island." April 1, 2007. (May 28, 2008)
  • Environmental Defense Fund. "Wildfires on the Rise with Global Warming." July 11, 2007. (May 21, 2008)
  • Food and Agriculture Organization of the United Nations. "Global Forest Resources Assessment 2005." 2005. (May 20, 2008)
  • Food and Agriculture Organization of the United Nations. "Intact mangroves could have reduced Nargis damage." May 15, 2008. (May 27, 2008)
  • Forest Protection Portal. "Ecological Science Based Forest Preservation & Conservation Advocacy." 2008. (May 28, 2008)
  • Harris, Richard. "Climate Roadmap Emerges from Grueling Bali Talks." NPR. Dec. 15, 2007. (May 28, 2008)
  • Kristof, Nicholas D. "Can We Be as Smart as Bats?" New York Times. May 1, 2008. (May 27, 2008)
  • Lindsey, Rebecca. "Tropical Deforestation." NASA. March 30, 2007. (May 27, 2008)
  • Matthew, Walter and Bailey, Stewart. "Crystallex's Planned Mine Won't Get Venezuela Permit." May 15, 2008. (May 21, 2008)
  • Pomeranz, Ken and Wong, Bin. "China and Europe: 1780-1937." Columbia University. 2004. (May 27, 2008)
  • Rosenthal, Elizabeth. "Once a Dream Fuel, Palm Oil May Be an Eco-Nightmare." New York Times. Jan. 31, 2007. (May 21, 2008)
  • Science Daily. "Tropical Reforestation Aided By Bats." April 28, 2008. (May 28, 2008)
  • Tickell, Oliver. "Bail - The Key Issues." The Bali Roadmap. Nov. 28, 2007. (May 28, 2008)
  • USA Today. "Deforestation exacerbates Haiti floods." Sept. 23, 2004. (May 27, 2008)
  • USA Today. "U.S., China resist caps on global gases." Dec. 17, 2007. (June 4, 2008)
  • World Wildlife Federation. "Climate change a threat to Amazon rainforest, warns WWF." March 22, 2006. (May 21, 2008)