Land Clearing Consequences

Land clearing occurs in areas where development is planned and in areas designated for cattle grazing and plantations. Worldwide, the need for more food is a major reason for clearing land of trees, or deforestation. According to World Wildlife Fund, about half the forests that once grew around the world are gone, and forests are still disappearing at a rate 10 times higher than any possible level of regrowth. Nearly 36 million acres of forest disappear each year. Clearing tracts of forested land may seem necessary at the time, but the loss of forests can have long-term effects on the environment--and people.

Habitats

• Clearing forested land destroys the habitat of animals, plants, birds and insects that lived in the forest. Over time, as more land is cleared, the habitat that supports biodiversity shrinks. World Wildlife Fund notes that 80 percent of the world's species can be found in forests. Already various species are at risk of extinction because of habitat loss, which is the main threat to 85 percent of all species on the United Nations International Union for Conservation of Nature's threatened and endangered species list. Among these threatened and endangered species are those that hold economic and medicinal value for humans.

Soil Erosion

• Tree roots help hold topsoil in place. Once the trees are cut down, the land is vulnerable to erosion, especially in areas with heavy rainfall or windy conditions. A study of erosion in Africa's Ivory Coast found that forested slope areas lost 0.012 tons of soil per year per acre; cultivated slopes annually lost 36 tons per acre, while bare slopes lost 55 tons per acre. The loss of topsoil degrades the land's ability to produce food.

Trees and Water

• Trees perform as living pumps, drawing water from the soil and releasing it into the air. At the same time, the shade from trees slows evaporation of water in dry areas. Clearing land of trees can cause a variety of problems, from water-logged soil to soil that is too dry to be useful. Loss of trees can also affect the water table, causing increased soil salinity or changes in soil pH. Wells and springs may have less water or poorer quality water.

Greenhouse Gas Emissions

• Clearing land of trees and natural vegetation contributes to the rise in greenhouse gasses in the atmosphere because trees store carbon and release oxygen in the air. Studies suggest that deforestation leads to 15 to 30 percent of the world's greenhouse gas emissions. The Union of Concerned Scientists estimates that U.S. forests absorb between one million and three million metric tons of carbon dioxide each year. However, when the trees are burned, the carbon they stored is dumped back into the air.