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What Is Deforestation and What Are the Causes of Deforestation?

March 15, 2022

Deforestation is a major driver of climate change and biodiversity loss, but fortunately there are practical steps we can take to help prevent it.

Forests are some of the most biologically diverse and undisturbed ecosystems on the planet. The soil is often rich with nutrients as it has been nurtured for decades by natural cycles of growth and decay. Forests clean the air and hold the earth firm with their roots. Yet despite the vital importance of forests in providing the oxygen we breathe and sustaining ecosystems on which we rely,  every year we destroy millions of trees—whether for timber, to make room for cattle or crops, or to expand our settlements. 

What Is Deforestation? 

Deforestation is the conversion of naturally forested land to an alternative, permanent use that means the land is no longer forested. Alternate uses for land once it has been deforested include grazing animals, growing crops, and urban expansion.

Some other terms are useful for understanding the forms deforestation can take:

  • Tree Cover. Tree cover refers to any area that is covered by trees. This could include public parks, Christmas tree farms, or industrial plantations, none of which would typically be considered a forest. Researchers may analyze overall tree cover loss as an indicator of deforestation. 
  • Secondary Forest. Secondary forest is forested area that has been disturbed in some way. It could be forest that is recovering from prior use or forest in the process of being destroyed.
  • Primary Forest. A primary forest has reached maturity. These areas are some of the wildest in the world and often of great ecological significance. These are also called “old growth forests.”

Since 1990 it is estimated that over 400 million hectares of forest have been lost to other land uses. Per Global Forest Watch, in 2020 an astonishing 26 million hectares of tree cover was lost globally. That’s a larger area than Oregon.

What Are the Causes of Deforestation?

Recently, agricultural expansion was revealed to be an even larger driver of the destruction of forests than previously thought. At the COP26 Summit, the Food and Agricultural Organization of the United Nations (FAO) revealed that the growth of agriculture accounts for a whopping 89.9 percent of global deforestation. The other 10 percent of deforestation is split between urban and infrastructure development (5.6 percent) and other causes (4.6 percent). Agricultural expansion is the largest driver of deforestation in every region of the world save Europe, where development is responsible for a greater proportion of forest destruction. 

Commercial Agriculture

Commercial, industrialized agriculture is the greatest threat to forests. Between 2000 and 2010, large-scale agriculture (primarily cattle ranching and the cultivation of soy and palm oil) accounted for 40 percent of tropical deforestation. In South America and South East Asia particularly, deforestation is driven heavily by commercial agriculture. Once forests have been destroyed for this purpose, the change is typically a permanent one leaving little chance of reforestation. 

Subsistence Farming

Subsistence farming means the bulk of a farm’s produce is used by the farmer and their family with little left for sale or exchange. The techniques used by subsistence farms tend to be relatively low-yield, with lower use of chemicals such as pesticides and fertilizers. Despite this, subsistence farmers accounted for one-third of deforestation between 2000 and 2010. This is due to farmers clearing new land once the soil in one spot has been exhausted of nutrients. This type of farming is most common in Africa and has been increasing since 2000 because of population growth. Once subsistence farmers move on, the land is generally left fallow and is then able to recover over the course of several years making reforestation possible. 


The logging industry fells countless trees every year to supply companies that make products from wood, such as paper and timber for construction. Of particular concern is the vast illegal timber industry, which is estimated to be worth up to $152 billion annually. In addition to the damage dealt to the environment, illegal logging steals resources that local communities depend on for food and shelter. 

Fuel Wood Removals

Estimates suggest that the removal of wood for use as fuel makes up roughly 5 percent of deforestation. About three-quarters of wood fuel removals take place in Africa and Asia. 

Urban Expansion

Urban expansion drove the destruction of up to 35 million hectares of forest between 1992 and 2015. Of this, an estimated 3.3 million hectares were directly because of urban expansion, whereby forest was destroyed and converted into urban land. The remaining deforestation, between 17.8 and 32.4 million hectares, was indirectly driven by urban expansion as farmland was built on, causing farmers to seek more acreage. 

How Does Deforestation Happen? 

There is no single way that deforestation occurs. It can happen very quickly, as is the case when trees are cleared from the land to allow cattle to graze more easily or for the trees to be sold. It can also happen more slowly, for example following the construction of a road. The first inhabitants might make their home without clearing more than a couple of trees, but as more people come additional space is needed and trees are slowly removed until none remain. 

What Are the Effects of Deforestation? 

The effects of deforestation are numerous and far-reaching. They include economic loss, detrimental environmental impacts, biodiversity loss including species extinction, and human health implications. 

Economic Impacts

Deforestation undeniably does come with short-term economic gain for those who profit from the change in land use or who sell the harvested wood. The impacts on the surrounding communities, however, can be dire. Over 250 million people in poor rural areas live in forests, while about a billion people depend on forests for medicine, food, fuel, and even income. While the destruction of these forests may mean employment for some of the communities being impacted, the jobs offered are often low-wage and come with poor and dangerous working conditions. 

The value provided by the forests themselves should be enough to prove they’re worth saving on its own. One analysis of the Amazon Rainforest, for example, found that it was worth $8.2 billion if left standing. This number takes into account the sustainable industries the rainforest supports such as nut farming, as well as the environmental services the rainforest provides such as regulating local weather and sequestering carbon dioxide. This also does not take into account the value of these forests to the millions of species of nonhuman animals that live there.

Environmental Effects

One of the roles that trees and forests play is capturing and storing carbon dioxide, the most common greenhouse gas. When deforestation occurs, the overall amount of carbon stored by trees decreases. On top of this, the carbon dioxide that was stored by the cleared trees is often released back into the atmosphere, especially when forests are burned. Deforestation is responsible for the release of almost a billion tons of carbon every year.  Because trees help store carbon in soil, deforestation also leads to significant releases of carbon dioxide from soils.

Forests also play an important role in the water cycle, as they pull water from the ground and release it into the air during photosynthesis. When this cycle is disrupted by the destruction of forests, the land can become dry and barren leading to an increased risk of fire.

Food Insecurity 

Despite agriculture being the largest single driver of deforestation, the destruction of forests can increase food insecurity. Roughly one in six people depend upon forests for food and income. In addition to directly feeding so many people, forests also play a key role in agriculture by providing habitats for many crucial pollinators and helping to ensure that soil is healthy.  

Health Effects 

Deforestation has serious health consequences. The destruction of forests has caused an increase in hot, dry summers such as that experienced in North America in 2021, which led to the deaths of dozens of people. Wild animals displaced by deforestation also come into closer contact with humans, increasing the spread of zoonotic diseases (those which can spread between animals and people). 

What Animals Are Affected by Deforestation? 

The list of animals impacted by deforestation is seemingly endless and consists of species from insects to large mammals. Many, such as chimpanzees and monarch butterflies, are being threatened with extinction. Others, such as coyotes, bears, and puma are being drawn closer and closer to humans and are often forced to make their homes on the edges of urban areas, where fear and misunderstanding can prove fatal. 

How Can We Stop Deforestation? 

Consume Less, More Consciously

One of the best ways to help combat deforestation is to be more cognizant of our consumption and choose to consume less. Currently, humans are demanding too much from the planet. This is especially true of food, with the FAO estimating that one-third of the food produced around the world is wasted or lost. Being more cautious about the foods we purchase and making sure to use what we acquire can reduce the demand for food and the land necessary for production. 

Eat Less Meat

Meat consumption is incredibly inefficient. Animal agriculture takes up 83 percent of farmland but only provides 18 percent of calories consumed. When we choose to eat less meat, the amount of farmland required to produce food for individual consumption goes down considerably. 

Use Less Palm Oil

Palm oil can be found virtually everywhere: in food, cosmetics, even in our gas tanks. This is despite the negative environmental impact it causes. Palm oil-based biofuels have three times the environmental impact of traditional fossil fuels. The widespread use of palm oil, which can be found in half of all supermarket foods, is a major contributor to deforestation. Palm oil plantations, which lack the biodiversity or benefits of a forest, cover 27 million hectares of the earth’s surface. One way to reduce deforestation is to choose items that are free from palm oil or that use palm oil that is sustainably sourced. 

Spread Awareness

Humans are moving into more urban, densely populated areas and forests are becoming less visible and less entwined with peoples’ lives. Consider organizing a hike with friends and family at a national forest or state park to reconnect with nature. While there, you could share the story of forests and their importance to the continued health of people, animals, and the environment. Wherever you are you can spread awareness of the impact our consumption choices are having on forests and on the future of the planet.


Forests are essential ecosystems for wildlife and human livelihoods,  and are vital for regulating our climate. They provide a place for endangered species to survive, keep the water cycle flowing, and are depended upon by millions of people for food and income. Without forests, the air would be unbreathable and the weather unpredictable. Forests don’t just need our protection, we need theirs.