Bare rock, an empty lot, a burned prairie, a volcano. Watch living communities build themselves, get knocked down, and come back, and measure how long it takes.
These are models, and models leave things out. Real succession does not march through neat stages on a fixed timetable: it depends on climate, seeds nearby, animals, people and luck, and two plots next to each other can go different ways. Tab 1: the stage years, soil depths, species counts and heights are tuned to the typical pattern for the Great Lakes region and rounded; they are not measurements of one real place, and plant heights on the picture use a stretched scale so small plants show up. Tab 2: the grassland, temperate forest and rain forest numbers are made up to show the pattern your textbook describes (grasslands: low inertia, high resilience; rain forests: high inertia, low resilience). Tab 3 is real: the average plant cover, species counts and most common plants in Roger del Moral's permanent plots on Mount St. Helens, 1980 to 2009 (Ecological Archives E091-152, Ecology, 2010; Studebaker Ridge plots 1 to 10, Pine Creek A plots 1 to 4, Butte Camp B plots 1 to 6). Environmental Science, Chapter 5, Lesson 5.2: How Do Ecosystems Respond to Changing Conditions?