<P> Secondary succession is one of the two types of ecological succession of plant life . As opposed to the first, primary succession, secondary succession is a process started by an event (e.g. forest fire, harvesting, hurricane, etc .) that reduces an already established ecosystem (e.g. a forest or a wheat field) to a smaller population of species, and as such secondary succession occurs on preexisting soil whereas primary succession usually occurs in a place lacking soil . Many factors can affect secondary succession, such as trophic interaction, initial composition, and competition - colonization trade - offs . The factors that control the increase in abundance of a species during succession may be determined mainly by seed production and dispersal, micro climate; landscape structure (habitat patch size and distance to outside seed sources); bulk density, pH, and soil texture (sand and clay). </P> <P> Simply put, secondary succession is the ecological succession that occurs after the initial succession has been disrupted and some plants and animals still exist . It is usually faster than primary succession </P>

Which of the following is not an example of secondary succession