If you leave something 20 years, trees will start growing pretty rapidly. They even mention deliberate tree planting, but in the pics there are few trees and th

If you leave something 20 years, trees will start growing pretty rapidly. They even mention deliberate tree planting, but in the pics there are few trees and those present look like they're struggling. Looks like it's mainly grass because that's what can cope, not because it's a plant eden of any sort. Arborists please chip in.