Prescribed Burns Reduce Ticks While Wildfires Attract Fire Beetles

Wildfire-damaged forests in Washington state are attracting thousands of black fire beetles, while planned forest burns offer a potential way to reduce tick populations and encounters with disease-carrying pests. The U.S. Forest Service says repeated prescribed burns can alter forest conditions that ticks need to survive, although the results depend on how frequently and effectively the fires are conducted.

After the Spokane Complex fires swept through north Spokane earlier this year, thousands of black beetles from the genus Melanophila appeared in the ash. According to the U.S. Forest Service, specialized sensors allow these insects to detect infrared radiation from forest fires and locate recently scorched trees, where they lay their eggs.

Entomologists reported that the beetles can reach burned neighborhoods and cleanup areas while firefighters and other crews are still working or within days after a fire. The insects may crawl onto equipment or human skin and bite, mistaking warm bodies for charred wood. Their powerful mandibles can make the bites painful.

Prescribed fires differ from uncontrolled wildfires because land managers ignite them under predetermined conditions to achieve specific environmental goals. According to the U.S. Forest Service, these controlled burns can remove the shaded, damp vegetation that supports tick survival.

Dr. Michael Gallagher, a research ecologist at the Northern Research Station with the U.S. Forest Service, said the effectiveness of prescribed burning depends on its frequency and impact on the environment.

"Prescribed burning frequently and in an impactful way…can also reduce ticks, when it shapes that environment," Gallagher said.

Field studies have recorded tick mortality exceeding 75% after burns. Researchers at the University of Georgia also found that encounters with ticks carrying pathogenic bacteria fell by as much as 98% in southern pine forests maintained with frequent fire.

Those reductions required repeated burns over at least a decade, with fires conducted every two to four years. A single burn does not deliver the same results and can temporarily increase tick numbers.

Gallagher linked favorable conditions for ticks to the long-term reduction in forest burning and other management activities. According to U.S. Department of Agriculture Forest Service research, eastern forests historically burned at intervals ranging from 1 to 25 years, but fire suppression extended those intervals to 50 to 100 years across much of the region.

"Really, ticks have been able to thrive because of the byproduct of not burning; and not having as much cutting or work in the forest has enabled a really moderate environment for them," Gallagher said.

Tick exposure remains a significant public health concern. The Centers for Disease Control and Prevention reports that tick-related emergency room visits have increased since 2017. About 31 million Americans are bitten by ticks annually, and approximately 476,000 receive treatment for Lyme disease.

The CDC recommends using insect repellent, checking the body after spending time outdoors and removing attached ticks with tweezers. These measures help individuals reduce their risk of exposure but do not lower tick populations across an entire landscape.

The U.S. Forest Service identifies prescribed burning as one forest-management tool that can recycle nutrients, suppress certain pests and pathogens, support fire-dependent plants and reduce encounters with disease-carrying ticks when applied repeatedly under planned conditions.

Gallagher said changing environmental conditions could potentially reduce the public health burden associated with ticks.

"If you can minimize their interactions a bit through environmental changes…theoretically, that would reduce some of the disease burden," Gallagher said.

Gallagher also pointed to changing public attitudes toward fire as a factor in forest management. He said historical disasters contributed to perceptions of fire as a threat, particularly in the northeastern United States.

"Fire is a cultural thing, and I think our perceptions of fire have changed through time," Gallagher said.

"Some of the worst forest fires in national history happened in the Northeast a long time ago…I think that created this culture of thinking that fire is bad," Gallagher said.