Deforestation

Causes of deforestation in the Amazon
Cattle ranches 65-70%

Small-scale, subsistence agriculture 20-25%

Large-scale, commercial agriculture 5-10%

Logging, legal and illegal 2-3%

Fires, mining, urbanization, road construction, dams 1-2%

Selective logging and fires that burn under the forest canopy commonly result in forest degradation, not deforestation. Therefore these factor less in overall deforestation figures.

The pie chart above shows the percentages of the causes of deforestation in the Brazilian Amazon between the years of 2000 and 2005.

Between May 2002 and May 2003, Brazil [Map] lost more than 24,000 square kilometers of forest - an area larger than Israel and since 1978, over 500,000 square kilometers of Amazon rainforest have been destroyed. Why is Brazil losing so much forest? What can be done to slow deforestation?

Follow the link to learn more about what can be done to save the Amazon Rainforest in Brazil.

Although tropical forests cover only about 7 percent of the Earths dry land, they probably harbor about half of all species on Earth. Many species are so specialized to microhabitats within the forest that they can only be found in small areas. Their specialization makes them vulnerable to extinction. Cascading changes in the types of trees, plants, and insects that can survive in the fragments rapidly reduces biodiversity in the forest that remains. First, global markets consume rainforest products that depend on sustainable harvesting: latex, cork, fruit, nuts, timber, fibers, spices, natural oils and resins, and medicines. Finally, genetic diversity in the planetary gene pool is crucial for the resilience of all life on Earth to rare but catastrophic environmental events, such as meteor impacts or massive, sustained volcanism.

The graph shows the number of endemic species in the 14 different Biomes on the Planet. It emphasises the number of species in the tropical and sub-tropical zones.

With all the lushness and productivity that exist in tropical forests, it can be surprising to learn that tropical soils are actually very thin and poor in nutrients. The underlying parent rock weathers rapidly in the tropics’ high temperatures and heavy rains, and over time, most of the minerals have washed from the soil. Nearly all the nutrient content of a tropical forest is in the living plants and the decomposing litter on the forest floor. When an area is completely deforested for farming, the farmer typically burns the trees and vegetation to create a fertilizing layer of ash. After this slash-and-burn deforestation, the nutrient reservoir is lost, flooding and erosion rates are high, and soils often become unable to support crops in just a few years. If the area is then turned into cattle pasture, the ground may become compacted as well, slowing down or preventing forest recovery.

Up to thirty percent of the rain that falls in tropical forests is water that the rainforest has recycled into the atmosphere. Water evaporates from the soil and vegetation, condenses into clouds, and falls again as rain in a perpetual self-watering cycle. In addition to maintaining tropical rainfall, the evaporation cools the Earths surface. In many computer models of future climate, replacing tropical forests with a landscape of pasture and crops creates a drier, hotter climate in the tropics. Some models also predict that tropical deforestation will disrupt rainfall pattern far outside the tropics, including China, northern Mexico, and the south-central United States.

In the Amazon alone, scientists estimate that the trees contain more carbon than 10 years worth of human-produced greenhouse gases. When people clear the forests, usually with fire, carbon stored in the wood returns to the atmosphere, enhancing the greenhouse effect and global warming. Once the forest is cleared for crop or grazing land, the soils can become a large source of carbon emissions, depending on how farmers and ranchers manage the land. In places such as Indonesia, the soils of swampy lowland forests are rich in partially decayed organic matter, known as peat. During extended droughts, such as during El Nio events, the forests and the peat become flammable, especially if they have been degraded by logging or accidental fire. When they burn, they release huge volumes of carbon dioxide and other greenhouse gases.

Link between mining and deforestation in a good way!!