You've probably noticed that if your neighbor stops mowing their lawn regularly, it doesn't take long for the weeds to spring up. And, if you've driven by an abandoned farm house, you may have seen shrubs growing up in what was once fertile pasture. In most parts of the world, if a plot of land is left alone long enough, it will naturally pass through a series of plant stages and eventually become covered with trees. This somewhat predictable pattern of changing communities of plants becoming more complex over time was formally described by H. C.
