Original sentence: After almost 20 years, much of the areas that burned have started to rejuvenate, and in many cases, are healthier, denser and more disease resistant.The Yellowstone Fire of 1988 was the largest forest fire known to affect  Yellowstone National Park in recorded history.The fires burned for several months and by the time the winter snows extinguished the flames, 793,880 acres (321,271 ha) or roughly 36 percent of the park had been impacted by the fires
Edited sentence: After almost 20 years, much of the area that burned has started to rejuvenate, and in many places the forest has regrown healthier, denser and more disease resistant.Because of man-made back fires and fire fighting efforts over 200 large mammals perished and two fire fighters persihed.If the fires had been allowed to burn naturally and freely scientists say that it would have burned the same amount of acreage but would have caused less devastation.Not only did the flames rejuvinate nature by getting rid of old growth and fallen trees, it released renewed nutrients back into the soil and air.The Yellowstone Fires of 1988 were the largest forest fires known to affect  Yellowstone National Park (and the surrounding area) in recorded history.The fires burned for several months and by the time the winter snows extinguished the flames, 793,880 acres (321,271 ha) or roughly 36 percent of the Greater Yellowstone Area, including the park, had been impacted by the fires.There was also an economic cost:  the price tag of the firefigthing efforts amounted to over 120 million USD