Does succession run towards potential natural vegetation? An analysis across seres

Questions (1) Do 17 seres studied proceed towards corresponding potential natural vegetation; (2) what are the similarities between seral and potential natural vegetation, and is it possible to estimate how long it takes to reach potential natural vegetation; and (3) do primary and secondary seres differ? Location Extracted peatlands, corridors of the former iron curtain, artificial fishpond islands and barriers, sedimentary basins, various...