How Deforestation Works

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. Selective logging -- 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].

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].

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:

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, Carbonfund.org currently works on reforesting areas like Nicaragua and the state of Louisiana [source: Carbonfund.org].

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

[source: Forests.org]