砍伐森林的危害

Forests contribute to the survival of human beings. But the phenomenon of deforestation is becoming more and more serious. Here are some specific explanations about the environmental impacts associated with deforestation.

Forests do good to air. They can not only produce oxygen via photosynthesis but also weaken strong wind and clean the air in several ways. When the airflow is heavy with dust, passing through forests can decelerate the wind and drop the large particles onto ground at the same time. Some cortexes can secrete olein to stick dusts and can produce a substance to kill pathogenic bacteria in the air (Encyclopedia of China).

Moreover, forests can change climate. Trees store large amounts of carbon in the woody branches and roots by photosynthesis. When trees are burned or cut and left to decay, the carbon in the branches and roots is released into the atmosphere as carbon dioxide, which leads to an increased carbon dioxide concentration. Carbon dioxide is the major contributor to the green house effect. It is estimated that deforestation contributes 1/3 of all carbon dioxide release caused by people (Encyclopedia of China).

Forests also reduce the risk of landslides, mud-rock flow, floods and desertification. Deforestation can speed up soil erosion and make landslides and mud-rock flow much more possible, because when there are less trees, the decrease of frictional drag and tensile stress between

tree root and soil can lead to landslides and then cause mud-rock flow. What’s more, trees can absorb rains, and a clear-cut will probably bring on floods.

In addition, forests can reduce the loss of soil nutrition. Deforestation aggravates wind erosion and water erosion of soil, resulting in losing essential minerals. Eventually, the soil will become barren for crops.

Last but not least, forests can protect animals and plants. Nearly two thirds of plants and animals and 60million people live in forests (from Chinese Information Center).When the habitat of plants and animals is destroyed, they have no choice but to die. It is said that more than 100 kinds of animals become extinct per day (China Daily). To be or not to be, this is not what animals and plants can decide, but we human beings