Negative impacts are the extinction of animal and plant life, oil extraction, mining, logging, commercial agriculture, hydroelectric projects, pollution, poaching and hunting, road construction and fires.
It is a sad fact that while any forest has positive effects on all human life, unfortunately human life on Earth has mostly negative impacts on the forests. Almost 2 billion tons of timber will be cut out of the forests on a global scale each year. These losses mostly occur in developing countries where the trees will be cleared for farming and the wood will be used for energy fuel.
Rain forests are all disappearing at a rate of 70,000 sq km or 26,923 sq miles each year. Every week, over 100 animal and plant species become extinct because of this. Most of the animal species affected will be the insects. When land no longer supports crops, it will then be abandoned and another piece of forest will be cut down in another place. Because of this, many plants and animals are losing their different habitats. The human's capacity to harvest the trees for their wood is far greater than the ability of the forest to regenerate.
The water quality of the forests also suffers. With the trees gone, rain will no longer seep into the forest's soil and water reserves that are underground are not being replaced. This soil will then end up in rivers and streams and kill the fish. The quality of air is also being reduced by forest destruction from all the dust and soot in the air. With no trees, no oxygen is put back in the air. Gases are also building up in the Earth's atmosphere from pollution. With no trees, no carbon dioxide is removed from the atmosphere. This is raising the Earth's temperature, and could make further animal and plant species become extinct.