The processes that are similar here are nudation and secondary succession. Nudation is the growing up of new plant species in an area completely devastated by big natural calamities like volcanic eruption and meteor impact. Secondary succession is the growing up of new plant species in an area that has its pre-existing stable ecosystem partially affected by calamities like hurricane, landslide, etc.
Answer to question 2: The formation of soil
Primary succession begins with the formation of soil due to weathering of rocks. This is followed by the development of vegetation where the organisms like lichen and algae act on the rocks and the soil to condition them for growth of new plant species.
