Question

why soil erosion and desertification are the consequences of deforestation?

Answer 1

deforestation causes soil erosion as the tree holds the soil tightly and not let it blow away with water or wind but when there will be no tress soil will blow out with water or wind.
Desertification occurs due to a deforestation. the plants bring rain and if there will be no rain soil will be infertile. The lack of plants can cause changes to the land. Plants help shade the soil, so when plants are removed, the soil will be exposed to the sun and will dry out more quickly.

Answer 2

Desertification is a type of land degradation in which a relatively dry land region becomes increasingly arid, typically losing its bodies of water as well as vegetation and wildlife. It is caused by a variety of factors, such as climate change and human activities.

Deforestation, clearance or clearing is the removal of a forest or stand of trees where the land is thereafter converted to a non-forest use.

Examples of deforestation include conversion of forestland to farms, ranches, or urban use.

The term deforestation is often misused to describe any activity where all trees in an area are removed.

trees' roots hold the soil together.once they are lost, the soil becomes loose.  

after that, if the soil becomes loose, then the top layer of the soil might get washed away or get blown with the wind.this top layer contains essential humus and nutrients for plants to grow.  

if there is no humus, the soil will become infertile, and also no plants will grow.