Colorado Statewide Forest Resource Assessment

Analysis: Forest management, such as mechanical thinning of overly densestands and use of prescribed fi re, can reduce unwanted wildfi re impactsby increasing forest resilience and restoring fi re to a more natural role onthe landscape. As part of this assessment, two data layers were analyzedto identify areas where forest management could play a benefi cial role inrestoring fi re-adapted lands and reducing the risk of negative fi re impactsto both the environment and human values. These layers are focused on:1) wildfi re susceptibility, and 2) potential for wildfi re intensity. While theselayers are useful on their own, they also can provide valuable informationwhen combined with other data related to water supply, wildlife habitat,recreation and the wildland-urban interface.Wildfire SusceptibilityThe fi rst wildfi re-related layer is the product of a 2008 analysis done by theSanborn Map Company for the CSFS in order to identify forested areasacross the state with a high susceptibility to fi re starts. 25 To produce this layer,Sanborn developed a Wildfi re Susceptibility Index (WFSI) for the forestedareas of Colorado based on the probability of fi re occurrence and predictedrate of spread once a fi re started. Key inputs to this analysis included weather,historic fi re occurrences, topography, surface fuels and canopy closure. 26Sanborn worked with local fi re behavior specialists to update the underlyingdataset to account for changes in vegetative condition and structure due tolarge wildland fi res and mountain pine beetle, and other insect and diseaseepidemics that have occurred since the LANDFIRE data were collected. TheEastern Plains were not included in the assessment because LANDFIRE datawas not available at the time of the assessment.This layer shows more than 2 million acres with a high to very high WFSI inColorado. While all of the state’s forest types contain some acreage in thesecategories, the majority of the high rankings fall in piñon-juniper forests,followed by ponderosa pine forests and oak shrublands. Notably, privatelandowners control nearly 800,000 acres in the high to very high categories,followed by the BLM and then the USFS. Forest management in landscapesranked high to very high could be benefi cial for mitigating hazardousconditions in areas where fi re starts and rapid fi re spread are likely.25For more information on the Sanborn Map Company, Inc., please see their website at www.sanmap.com.26It is important to note that the output of this analysis is limited by the lack of consistent and complete fire reportingdata across all jurisdictions in the state.27