Deforestation Process, Causes, Other Effects of Deforestation (For CBSE, ICSE, IAS, NET, NRA 2022)

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Deforestation

Deforestation can be defined as the large-scale removal of trees from forests (or other lands) for the facilitation of human activities.

Importance of Forests

  • Forests combat climate change by absorbing greenhouse gases (such as carbon dioxide) and acting as a carbon storehouse.
  • They are a source of oxygen, food, clean water, and medicine.
  • They play a vital role in the water cycle – they work to add water to the atmosphere via the process of transpiration.
  • Forests help mitigate the disastrous effects of floods by acting as a floodwater sink. Therefore, deforestation also increases the vulnerability of the landmass to certain natural calamities.
  • The large mass of trees in forest areas combats soil erosion by providing mechanical support to the soil.
  • Forests are home to over 50 % of all known species on the planet. They account for over 80 % of the land-based biodiversity. Globally, forests are home to approximately 30, 00,00, 000 human beings.
  • They are also a source of raw material for many commercially important products such as paper, wood, and fabric.
  • Approximately 1.6 billion jobs are forest-dependent. Forests also account for approximately 1 % of the world՚s GDP (gross domestic product) .

The Data Behind Deforestation

  • Forests cover approximately 31 % of the total land surface of the Earth.
  • Tropical forests harbor over half of all land-based animal and plant species in the world.
  • Between the years 2000 and 2012, over 568 million acres of forest has been claimed by deforestation.
  • Approximately 9 million acres of virgin tropical forest was cut down in the year 2018.
  • The Amazon rainforest, which is the source of 20 % of the world՚s oxygen supply, loses approximately 1.32 acres of its area every minute due to deforestation.

Causes of Deforestation

What Are the Human Activities That Cause Deforestation?

  • The primary anthropogenic activities (human activities) that contribute to deforestation include:
    • Agriculture – small-scale and large-scale farming
    • Logging – cutting of trees for use as raw material
    • Mining and urban expansion – clearing of forest area for the construction of infrastructure.
  • According to the secretariat of the UNFCCC (United Nations Framework Convention on Climate Change) , agriculture is the root cause of 80 % of deforestation. Logging accounts for another 14 % and the cutting of trees for use as wood fuel account for 5 % .
  • Slash-and-burn agriculture is one of the most destructive forms of agriculture that results in large-scale deforestation. It involves the burning of a large area of forest land and the subsequent plantation of crops in the same soil (which is now fertilized by the ashes of the burnt trees) . Despite the practice being abandoned by several developed countries, it is still followed in some Southeast Asian countries.

What Are the Secondary Factors That Contribute to Deforestation?

  • Illegal logging, which accounts for approximately 80 % of all logging activities, involves the harvesting and sale of timber in violation of the law. Corrupt government officials may accept bribes from illegal loggers and offer access to protected forest areas in return. Therefore, corruption can be viewed as an indirect cause of deforestation.
  • Overpopulation and population growth increase the requirement for several resources such as food and infrastructure. These requirements can, directly or indirectly, result in deforestation. For example, a huge explosion in the population of a city can result in the deforestation of the surrounding area for:
    • The construction of homes and other buildings.
    • Agriculture (to meet the increased demand for food) .
    • The construction of roads, dams, and other infrastructure.
  • Military conflicts among humans can also result in deforestation. For example, the U. S. military made extensive use of Agent Orange (a defoliant that causes the leaves of trees to wither and fall off) during the Vietnam War (1955 – 1975) .

Can Deforestation Occur Due to Natural Causes?

  • In some relatively rare cases, the deforestation of forest areas can be traced to natural causes. For example, volcanic eruptions can burn away the forest lands surrounding the volcano. Other examples of natural deforestation include:
    • Destruction of forests due to hurricanes, floods, and other natural calamities.
    • Invasion of the forest ecosystem by parasites that destroy trees.
    • Forest fires that are sparked by lightning and other natural phenomena.
  • It is important to note that natural factors have a very small stake in the overall deforestation of the Earth՚s land surface (anthropogenic factors account for almost all of it) .

How Does Deforestation Affect the Environment?

Increased Carbon Dioxide Levels in the Atmosphere

  • Forests serve as a carbon sink by absorbing atmospheric carbon dioxide during photosynthesis. Since carbon dioxide is a greenhouse gas, deforestation is a direct contributor to the greenhouse effect and (consequently) global warming.
  • Apart from being responsible for allowing gaseous carbon dioxide to linger in the atmosphere, deforestation also contributes towards increased carbon dioxide emissions. The CO2 emissions caused by deforestation account for approximately 12 % of all anthropogenic carbon dioxide emissions.

Deforestation and the Water Cycle

  • Since trees play a vital role in the water cycle, deforestation can contribute to significant disturbances in it.
  • Trees and plants regulate the moisture content in the atmosphere via the process of transpiration (they absorb groundwater through their roots and release it into the atmosphere from their leaves and flowers) .
  • Also, their roots burrow into the soil and create macropores in it. These macropores allow water to penetrate deeper into the soil, thereby increasing the water-holding capacity of the soil.
  • Dead plant material (such as leaves and twigs) that fall to the surface of the ground impart several properties to the soil, such as increased water-holding capacity.
  • Approximately 30 % of the world՚s fresh water supply can be sourced to tropical rainforests.
  • Deforestation is accompanied by reduced humidity, owing to the absence of transpiring trees. The water content in the soil and the groundwater levels also decline in the cleared land.
  • It is not uncommon for deforested land to experience extremely arid climates. In fact, deforestation has been linked to desertification and droughts.

Soil Erosion as a Consequence of Deforestation

  • Trees tend to bind their roots to the soil bedrock, thereby reinforcing the soil. Additionally, the plant litter generated by trees offers protection to the surface of the soil. In the absence of trees (as a consequence of deforestation) , the soil becomes vulnerable to erosion.
  • Deforestation of sloped lands is often accompanied by landslides, which can be explained by the loss of soil adhesion due to the absence of trees. The extent of erosion is amplified by certain natural calamities such as floods (note that the plant litter found on forest surfaces helps reduce the amount of soil washed away) .
  • Since soil erosion is a direct contributor to eutrophication, deforestation can be viewed as a contributor to other environmental concerns.

Effects of Deforestation on Biodiversity

  • Forests play host to a wide spectrum of wildlife. In fact, tropical rainforests are believed to be the most diverse ecosystems on the planet. Deforestation poses a grave threat to this biodiversity. On a local scale, the clearing of forest land can cause a decline in the population of certain species. On a global scale, however, deforestation can result in the extinction of several desirable species.
  • Approximately 50,000 species (consisting of plants, animals, and insects) are lost every year as a consequence of deforestation. Studies suggest that over 40 % of all plant and animal species in the Southeast Asian region will undergo extinction over the course of the 21st century.
  • The implications of large-scale biodiversity loss are difficult to predict, but it is highly probable that it would have an adverse effect on the food web. Also, the extinction of one species may play a leading role in the extinction of another via the phenomenon of coextinction.

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