Most of the south metro area has a high desert and steppe climate where, over many centuries evolution, vegetation has adapted to a high altitude and dry climate. Native grasses were prominent in much of the area before the human population moved in. In some areas, Ponderosa Pines thrive as well.
In more recent times, as the human population has increased throughout the area, many non-native vegetation has been introduced. Many of these, such as Junipers, are highly flammable and should not be grown near a structure. Other trees and shrubs, such as Gambel (Scrub) Oak and Bristle Cone Pines should be avoided within 30 feet of a structure
See (link to Colorado Forest Service for more information)
Wildfires have always occurred in our area, long before the human population moved in. Native vegetation thrives, the wild fires strike and spread, and eventually burn out on their own, before starting the process all over again.
However, with the huge population growth, many factors have changed with the south metro area. Many homes are built very close together, non-native (and often more flammable vegetation) has been brought in, and often planted too close to homes.
In short, wildfires are inevitable. Letting them burn out on their own is typically not the best solution. While mitigation cannot stop wildfires from occurring, proper mitigation can often slow the spread of fires and help keep it from destroying property and lives.