Humans can affect ecologicial succession in a number of ways.
1) Burning a forest could cause a primary/virgin forest to begin again as a secondary forest. The ecosystem does not “start over” at the beginning with just rock, as the soil and other organic matter remain after the fire, thus the first organisms to return are grasses and herbs:
2) Mining can allow for primary succession to occur, especially if the mining caused a great disturbance to the land and much the exposed terrain was rocky not cultivatable sediment. This primary succession would being with lichens and mosses, whose role will be to establish some organic matter for which other more advanced plant species can grow.
3) Disturbance succession is when an area is not allowed to progress in its succession, such as mowing the lawn. This is probably the most common way humans affect ecologic succession. The land may try to grow plants that should follow grasses in the natural succession, however, those new emergent species are cut back or removed, maintaining the “stunted” state of early succession (the grass).