Does Human Accessibility Affect Lightning-Caused Wildfires? A Case Study of the Southern Rocky Mountains

A large portion of the Rocky Mountains consists of wildfire-prone public lands. Across various land management units, human accessibility and outdoor recreation are increasingly prevalent. This research analyzes the influence that outdoor recreation and human accessibility have on lightning wildfire occurrence and size because of the vegetation alteration that occurs during the creation of human accessibility infrastructure. Geographic and climate variables are also implemented to gain a more complete understanding. San Juan National Forest of the southern Rocky Mountains is the chosen study site for this analysis. Descriptive statistics, multivariate regression, and case–control logistic regression analysis are implemented in this analysis. Results demonstrate that designated outdoor recreation locations such as campsites and vehicle trails possess the ability to influence wildfire occurrence patterns, while locations of higher hiking trail density may be preventative of lightning wildfire. Results also demonstrate that areas closer to roadways and wildland-urban intermix are more lightning wildfire prone. Larger wildfires were associated with locations of lower road density and areas further away from the wildland-urban—interface. April—June precipitation averages and yearly minimum and maximum temperatures are significant to wildfire occurrences, while May and December precipitation averages are significant to wildfire size. Results of this analysis demonstrate a clear relationship between lightning wildfire and designated outdoor recreation locations. This relationship provides key insight into how locations become more fire prone, as a result of the vegetative effects that occur with the creation of designated human accessibility locations in San Juan National Forest.