In this case, the grass had been planted four years prior and was ready for a torch, according to Greden. In the pre-settlement era, naturally occurring fires rejuvenated the prairie on a fairly regular basis. These days, we have to kick-start the process. Yet, of course, a raging, out-of-control inferno is not an option. That's where pros like Greden enter the picture. Before he set this blaze, he lit several "backfires" to create a perimeter of burned out material. When the head-high flames in this photo reached the perimeter, they simply died out. It took two hours for Greden to complete the burn, and he had things under control the entire time.