Deforestation

Figure 1. A satellite image of a deforestation project in Bolivia.[1] (click to enlarge)

Deforestation is the temporary or permanent removal of large expanses of forest for agriculture or other uses. Harvesting materials like timber and fuelwood by chopping down forests yields many economic benefits, however it comes along with many harmful environmental impacts.[2]

Forests provide many ecological services such as air and water purification, storage of anthropogenic carbon, the supporting of diverse ecosystems, and much more. The clearing of forests can drastically reduce these beneficial services that forests provide.[2]

Many reforestation efforts are in place and have resulted in increasing areas of temperate forests in North America and Europe. As well, some of the cleared forests have seen natural regrowth in past years, although due to the lack of biodiversity present within them many experts do not believe they can be classified as the forests they once were.[2]

What is happening to the world's forests?

It is difficult to accurately determine how much deforestation is going on worldwide due to the lack of satellite and radar data, along with unmonitored land-use change. However studies indicate that over the past 8,000 years, human activities have reduced the Earth's original forest cover by 20-50%. On top of this, studies by the UN's Food and Agricultural Organization show that the world's forests are being cleared at a rate of 0.3-0.8% per year, with over four-fifths of these losses taking place in the tropics.[2]

The World Resources Institute estimates that if these rates continue, nearly 40% of the world's remaining forests will be logged or converted into other uses within 20 years.

Tropical deforestation

Figure 2. Removal of a forest in Rio de Janeiro, Brazil, for the use of clay.[3]

Tropical forests cover around 6% of the Earth's land area, yet data suggests that in the past they covered more than twice that amount. Most of this deforestation happened since the 1950's, and occurs dominantly in Brazil, Africa, and Asia.[4]

Brazil contains around 40% of the world's tropical rain forest, and sources say that without immediate action they may largely disappear within 40-50 years.[4] A decent portion (12%) of Brazil's land area was once covered in the Atlantic coast rain forest, however most of it has been cleared, leaving a major loss in biodiversity - a small area the size of two suburban house lots contains up to 450 unique species![4]

Tropical deforestation is a major problem, not just because it covers such a vast area, but because of the abundance of life that relies on it. More than half of the world's species of plants and animals live in tropical rain forests, and the removal of these forests can wipe out species reliant on them.

Impacts

There are a vast quantity of negative impacts associated with deforestation. The most dramatic impact is the loss of habitat for countless species, as 70% of all land animals and plants live in forests.[5]

Deforestation may also result in:[2]

  • Decreased soil fertility from erosion
  • Disruption of ecosystem processes
  • Premature extinction of specialized species
  • Regional climate change from extensive clearing
  • Releases of carbon dioxide into the atmosphere from tree decay

Deforestation can also drive climate change - trees contribute largely to the hydrologic cycle, and the absence of trees, along with their decay, releases carbon into the global carbon cycle. Trees also play a large role in local temperature control, as portions of the forest canopy block the sun's rays during the day and keeps heat trapped at night. Removal of trees can cause temperature swings harmful to the plants and animals living there.[5]

References

  1. Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/1/19/Bolivia-Deforestation-EO.JPG
  2. 2.0 2.1 2.2 2.3 2.4 G. Tyler Miller, Jr. and D. Hackett, "Managing and sustaining forests," in Living in the Environment, 2nd ed. USA: Nelson , 2011, ch.11, sec.4, pp.208-215
  3. Wikimedia Commons [Online], Available: https://upload.wikimedia.org/wikipedia/commons/1/11/Hillside_deforestation_in_Rio_de_Janeiro.jpg
  4. 4.0 4.1 4.2 G. Tyler Miller, Jr. and D. Hackett, "Tropical Deforestation," in Living in the Environment, 2nd ed. USA: Nelson , 2011, ch.11, sec.6, pp.219-222
  5. 5.0 5.1 National Geographic. (Accessed January 9, 2016). Deforestation [Online], Available: http://environment.nationalgeographic.com/environment/global-warming/deforestation-overview/

Authors and Editors

Jordan Hanania, Jason Donev