Fire historically played a dominant role in shaping plant communities in the western United States. In many forests, prescribed fire is now being used in place of wildfire to reduce hazardous fuel accumulation, as well as create forest structures more resilient to disturbance. Although the majority of fires in the western United States historically occurred during the late summer or early fall, fire managers are often prevented from using prescription burning at this time due to air quality restrictions. One way of increasing the burning window is to burn earlier in the year. However, such fires are considered to be largely outside the historical fire regime, and ecosystem impacts of such early season fires are not well understood. USGS researchers Dr. Eric Knapp (now with the USFS Pacific Southwest Research Station), Dr. Dylan Schwilk, Jeffrey Kane, and Dr. Jon Keeley have added to our understanding of early season burning by comparing early summer burning with fall burning in mixed conifer forests in Sequoia National Park. This replicated experiment was part of a national network of sites funded by the Joint Fire Science Program for the Fire and Fire Surrogate Study, and was published in the Canadian Journal of Forest Research.