GCSE Geography | Local Impacts of Deforestation (Tropical Rainforests 6)

There are also many local impacts of deforestation.

Local climate change

Deforestation has a huge impact on global climate change, but is also affects climate change on a local scale. The water cycle is disrupted by deforestation as the loss of trees means less evapotranspiration, so less moisture is returned to the atmosphere, meaning fewer clouds are formed, and making the local climate drier. Recycling water acts as a cooling system, so without this the climate gets warmer. A drier warmer climate is bad for local people and agriculture.

Soil erosion and fertility

Deforestation also has an impact on soil erosion and fertility. Chopping down trees leaves the thin top soil exposed, which is quicky removed by heavy rainfall (which is an issue in the rainforest!). Without the top soil layer it is very hard for any vegetation to grow. Soil erosion also leads to the silting up of river courses, which has an impact on marine ecosystems and increases the risk of flooding. Even if the soil is protected, it quickly loses the fertility it had when it was covered by trees.

Even more nutrients are removed when land is used for grazing or for crop plantations, so farmers have to abandon the patch of land they have been working on to move onto pastures new, which leads to further forest clearance and soil degradation.

River pollution

Another local impact is river pollution. Gold mining not only causes deforestation, but it also leads to polluted waterways as mercury is used to separate gold, which then seeps into the ground. This leaking mercury poisons fish, as well as inhabitants of nearby settlements, particularly through contaminated drinking water supplies. Rivers are also being polluted by silt from soil erosion, as described above.

Decline of indigenous tribes

Many people benefit from deforestation for economic reasons, however many do not because of the social and environmental impacts of forest loss. Indigenous tribes are affected more negatively than any other group as deforestation threatened their homes, food supply and traditional way of life. In the Amazon rainforest indigenous tribes have declined in number, from 330 to 240 tribes, as logging, the construction of roads, the creation of ranches, plantations and reservoirs, and the opening of mines, have all forced them off their land. Many displaced indigenous people have ended up in towns and cities, where life is difficult to adjust to as the way of life and environment is so different, and as a result many tribes people have ended with alcohol and drug addiction issues. Indigenous people have incredible knowledge about the medicinal value of many rainforest plants - the loss of tribes means that this valuable knowledge is also lost.

Today, there are still around 1 million people living in the Amazon rainforest, who make their living from subsistence farming or hunting and gathering, or from harvesting nuts or rubber. They are less easy to persuade to move out these days as they know that they have the right to remain in the forest, so often end up in conflict with developers.