A recent study examining wildfire patterns in national forests across the western United States found that while roadless areas experience fewer fire ignitions, they are associated with significantly greater wildfire extent compared to roaded areas.
The study focused on national forests managed by the U.S. Forest Service, which are divided roughly in half between roadless areas managed for wilderness characteristics and roaded areas managed for multiple uses, including logging.
Despite roadless areas experiencing fewer fire ignitions, they exhibited a far greater wildfire extent than roaded areas. This finding was significant, with escaped fires originating in roadless areas growing to be one-third larger than those in roaded areas. Notably, over three-quarters of the largest wildfires on national forest land began in roadless areas, which account for less than half of the total area.
The influence of management regime on fire extent was observed to be substantial, even after considering biophysical differences between the two types of areas. Roadless areas, typically cooler, moister, and higher in elevation, were found to be more conducive to wildfire spread despite their less favorable conditions for ignition.
However, the study revealed that fire severity did not significantly differ between roadless and roaded areas. Statistical analyses indicated that variations in fire severity were primarily driven by environmental factors rather than land use designations.
The study emphasizes the importance of understanding and adapting to these differences in wildfire management and policy decisions.