In many regions of the American west, including the Front Range of Colorado, the vegetation has changed from more open conditions composed of fire adapted species to denser forests composed of species that are less fire tolerant.  The Front Range area was historically a mosaic landscape comprised of open grass/brush patches, ponderosa pine forests with a grass understory and a very open and park-like atmosphere, and some very dense forests not unlike the majority of the Front Range as it currently exists. 

Today, those open areas are reduced in number and size having been invaded by coniferous trees.  Those more open forests of the past may now have 10-30+ times the number of trees on the same acre and/or have a heavy brush understory component.  These tightly packed trees and brush are smaller, weaker, more disease prone, more susceptible to insect attack and storm damage than was the historical norm.  Typically, along the Front Range of Colorado, the succession of fire adapted ponderosa pine to less fire tolerant Douglas fir is changing the dominant tree species in much of the Montane/Foothills biotic zone communities.  Such forests provide large quantities of fuel awaiting ignition, are more susceptible to ignition, exhibit more intense fire behavior when they burn and pose a particularly significant threat when drought is also a factor.  Although such forest conditions are not without historical precedence, the current ubiquitous extent of these conditions is.

The result is an increased risk of large-scale, high-intensity wildfires that threaten altered forest ecosystems historically adapted to more frequent and lower intensity fires.  It is now more common to see sustained, high temperature, crown fires over larger areas than the historical norm.  This type of fire behavior results in the total destruction of vegetation and the supporting soils in areas that used to experience low-intensity ground fires.  The low-intensity fires of the past generally spared established, fire resistive species and served to enhance the overall forest health by eliminating accumulations of ground fuels, brush, small trees and returned nutrients to the soil. 

Water supplies and forest habitat are at risk due to the increasingly homogenous composition of forests and the compressed continuity of the fuels.  Also at risk are lives, property, and infrastructure where development intermixes with forest lands.  The threat is real and will not self-resolve in an acceptable manner.

The wildfire threat in ecological systems other than forested environments is all too real and needs to be addressed also.  In recent years, whole towns have been destroyed or threatened and many lives lost from grassland and brush fires in Texas, Oklahoma, Kansas and Colorado.  Grassland and shrub vegetation exhibit different types of fire behavior than forested terrain, but can be just as destructive to life and property.  The vast open country in which these fires typically occur is susceptible to powerful wind events that promote a fast rate of spread in these fine fuels.  This allows little time for notification and escape in advance of the flame front and puts lives at risk.  Different mitigation and response concerns exist within these environments compared to forested areas, but need to be addressed at the same level of urgency and concern.