Fire-dependent ecosystems are those in which the health and even reproduction of many plant species depend upon periodic natural wildfires.

The US Forest Service has defined the forest of Pine Ridge, where Sowbelly Canyon is located, as being "Ponderosa Pine Forests of the Intermountain West". The region includes most of the forest land in the states shown in orange on this map from the US Forest Service website, as well as the portions of Nebraska that closely border that region. (The white star on the map below, which we added, shows the location of Sowbelly Ranch.)

According to the text that accompanies this Fire-Dependent Ecosystem Map on the USFS Smokey Bear site, forests in the ponderosa pine system in Sowbelly Canyon experience natural fires every five to 25 years, and such "fires tend to be low intensity ground fires that remove woody shrubs and favor grasses, creating open, park-like ponderosa stands."



Here is a picture of what this type of Ponderosa pine ecosystem looks like. This area of Sowbelly Canyon was high enough and rugged enough that it experienced little grazing or logging over the years, so the trees are still in a natural arrangement of size and spacing. Notice that the large trees did not catch on fire, even though the smaller trees were singed near the ground. In this area, the catastrophic wildfire of '06 wasn't catastrophic; it burned exactly the way it's supposed to burn in this type of ecosystem.

Fire stopped burning through Sowbelly Canyon every 5 to 25 years because it was suppressed. Meanwhile, most areas of the canyon were logged and grazed, which dramatically changed the forest density. In 2006, there had not been a forest fire in Sowbelly Canyon in over 80 years. This combination of factors caused the fire to be catastrophic in many areas of the canyon.