How deforestation is responsible for landslide?

Answer 1

Trees and plants form root systems in the soil. These roots act like nets, helping to hold the soil in place. The roots, along with shade from the trees, also keep the soil moist and healthy so that it can absorb and drain lots of water. When trees and plants get cut down, those root systems die and decompose. The soil dries out and becomes very loose. Then, when a very heavy rain falls, the soil can wash away in a mudslide. This is most likely to happen where the ground is steep, like on the side of a hill or small mountain.
On a slope, tree roots help to hold the land together and pin it to the solid ground well below the surface.

Answer 2

Illegal logging can cause landslides of mud if there is a ban on clear cutting and the logger clearcuts a hillside.

Answer 3

Yes, it can. Trees and their roots bind and stabilize the soil, especially on a slope. Logging means that rains can undermine hill slopes and cause landslides.