Historically, wildfires were a commonly occurring phenomenon critical to maintaining the health of forests throughout much of the western U.S. However, the natural cycles of wildfire have been disrupted by modern attempts to control it. As a result, forests are now densely populated and have accumulated large stocks of dead vegetation. Combined with a warming climate and drier conditions, wildfires may have become more frequent and severe. This has the potential to alter the natural wildfire regime completely. The Utah Forest Institute – a Utah State University research group – is characterizing the “new” wildfire regimes in the state of Utah. The initial goal was to quantify >95% of the area burned from 1984 to present through field-calibrated remote-sensed techniques. The federal program that generates a dataset of large wildfires, Monitoring Trends in Burn Severity (MTBS), was leveraged and a dataset of smaller wildfires was added to it. Some of the primary objectives included 1) Determine the number, area burned, and burn severity of fires between 40 - 400 ha; 2) Determine the spatial pattern of burn severity within fires; 3) Generate a publicly available dataset of fires with their attributes – the Utah Fire Atlas; and 4) Determine how these attributes vary with each other as well as across fire types, ecosystem types, seasons, and years.
Results/Conclusions
In its current state, the Utah Fire Atlas is comprised of >600 wildfires and prescribed fires between 40 – 400 ha in size. Preliminary analyses show that while the frequency of small wildfires increased over time, there were no temporal trends in the area burned nor the burn severity. More, the frequency of small wildfires each year did not relate to the annual area burned nor the annual burn severity. Thus, even though small wildfires have become increasingly common, their overall ecological effect on the landscape has not changed. However, the burn severity of small wildfires did differ across years, ecosystem types, and seasons (though not consistently), and from prescribed fires. Further work that includes forest dynamics and climatic variability is needed to elucidate these patterns. Nonetheless, our Utah Fire Atlas dataset of small fires in conjunction with the dataset of larger fires generated by MTBS will not only increase the scientific understanding of fire in Utah but prove critical to informing land management and policy decision-making aimed at adapting ecological and social systems towards resilience to wildfire.