Forests are cleared all around the world for a number of reasons, including:
- Harvesting of timber to produce wood and paper products
- Clearing land for farms, cash-crop plantations, and cattle ranching
- Clearing land for urban development, including homes and roads.
Forests are also being destroyed by acid rain resulting from our pollution-causing activities and through the introduction of disease and invasive species. Deforestation is a very real environmental threat. Our once vast forests are disappearing. All around the world, trees are being cut down too quickly for earth to regenerate new forests.
What happens when forests are cleared?
Floods and soil erosion
Erosion
The roots of a tree make gaps in the soil so that when it rains the water can sink in before being absorbed by the soil. These spaces also allow air and water to reach the roots of the plants. When trees removed using heavy machinery, the soil is pushed down and the gaps fill in. Because all plants and trees need that water and air to reach roots, the conditions become unfriendly for new growth.
Because the soil no longer can absorb the water, when it rains the water remains on the top of the soil and this can result in floods. The moving water also can completely wash away the top layer of the soil. This is called soil erosion. Without the top layer of soil, which is full nutrition, plants are not fed and find it hard to grow.
What we lose: About 24 billion tons of agricultural topsoil (the top layer of soil) wash or blow away each year.
Drought
Forests help produce rainfall. The more trees, the more water gets absorbed into clouds and the more rain falls. If the forests disappear, there will be less rain resulting in dryer conditions that eventually lead to drought. Once this happens, the damage is extensive making it difficult to plant more trees or plants later because the soil is so hard and dry.
Greenhouse gases and acid rain
Extra! Extra!
Read all about it!
Learn about how the polar bear's habitat is being affected by climate change and to learn more about acid rain, play the Acid Lake game.
Read all about it!
Learn about how the polar bear's habitat is being affected by climate change and to learn more about acid rain, play the Acid Lake game.
The earth's atmosphere contains a number of greenhouse gases. Greenhouse gases trap the heat from the sun inside the atmosphere. Some greenhouse gases are carbon dioxide (CO2), methane and water vapour. We need these gases in small amounts, but they can be harmful at high levels.
Forests help remove large amounts of CO2 from the air. They absorb the gas during photosynthesis. However, more CO2 is produced than all the trees can absorb when fossil fuels are burned, for example and when forests are cut down, even less CO2 is being absorbed leaving it trapped in the atmosphere.
As greenhouse gases build up, more of the sun’s heat gets trapped and that can lead to climate change (the disruption of the delicate balance of the earth's ecosystems). The added pollution in the atmosphere can also lead to acid rain when the gases mix with water in clouds. When this is deposited on forests it can damage the trees and the ecosystem as a whole.
Species extinction
The grizzly bear is at risk due to subalpine forest habitat loss.
Another harmful result of deforestation is the extinction of animal and plant species. They disappear because their environment and life cycles have been disturbed and they are unable to adapt to the changes. When species disappear, it is called extinction. Essential habitat is lost when forests are cut down; wildlife species lose their homes, their food sources and their place in the web of life. Even though extinction is part of life, it is happening far too quickly now.
It is estimated that as many as 150-200 species around the world go extinct every day!
