what is secondary succssion?

Answer 1

Wiki to the rescue:

"Secondary succession is one of the two types of ecological succession of plant life. As opposed to primary succession, secondary succession is a process started by an event (e.g. forest fire, harvesting, hurricane) 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. A harvested forest going back from being a cleared forest to its original state, the "climax community" (a term to use cautiously), is an example of secondary succession. Each stage a community goes through on its way to the climax community in succession can be referred to as a seral community."

Also:

"Secondary succession occurs when plants colonize ground
previously occupied by plants and still containing soil. Since
the soil is still intact, it contains propagules (seeds &
rhizomes) that are readily available for colonization.
Secondary succession occurs following treefalls, clearcutting,
fire, windstorms, agriculture, etc. Once soils are established, there is no fundamental difference between primary and secondary succession."

Answer 2

Secondary Succssion : the development of a new community in a previously occupied habitat.

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