Primary succession is the first stage of the ecological succession of plant life from abiotic land with no soil to fully support plant ecosystems (e.g., a forest). In primary succession, pioneer plants like mosses and lichen, start to “normalize” the habitat, creating rudimentary soil from their dead matter. These pioneer plants create conditions for the start of plant growth and so more complex plants like grasses and shrubs begin to colonise the area.
Over time the grass area is colonised by small woody plants, which give way to small trees and finally, after a few hundred years, large trees take over. The large trees represent the climax community because succession stops at this point.
A good example of primary succession takes place after a volcano has erupted. The barren land is first colonised by simple pioneer plants which pave the way for more complex plants, such as hardwood trees by creating soils and other necessities. Unlike secondary succession, which refers to succession after an environmental disaster (such as a forest fire) primary succession occurs on the geologic timescale, over thousands of years.