Study finds prescribed fire often fails to eradicate invasive shrubs in eastern U.S. forests
A new investigation by Penn State scientists, published on 11 May 2026, shows that prescribed burning—intended to control invasive woody plants—frequently leaves the target shrubs alive, allowing them to resprout and continue dominating forest understories. The research focused on two aggressive colonizers, *Lonicera maackii* and *Ailanthus altissima*, across multiple sites in the Appalachian region.
Invasive woody species have reshaped eastern U.S. ecosystems for decades, outcompeting native flora, altering fire regimes, and reducing biodiversity. Land managers have turned to prescribed fire as a cost‑effective, low‑chemical method to suppress these invasives, hoping to restore native plant communities and improve wildlife habitat.
The authors, led by Dr. Emily Harris, measured post‑burn survival rates and resprouting vigor over three years, finding that up to 68 % of burned shrubs recovered within a single growing season. Phys.org notes that the authors attribute the failure to insufficient fire intensity and the deep root systems of the species. In contrast, a separate AP report on the same study emphasized that “soil moisture at the time of burn was a critical factor,” highlighting a minor discrepancy in emphasis.
Ecologists such as Dr. Luis Martínez of the University of Georgia argue that the findings underscore the need for integrated management—combining fire with mechanical removal or targeted herbicide applications—to achieve lasting control. Policy makers may need to revise state‑level burn guidelines to incorporate seasonality and fuel load assessments.
Future work will test combined treatments and develop decision‑support tools for land managers. The research team plans to release a field‑ready protocol by early 2027, while forest agencies are expected to reassess budget allocations for invasive‑species control programs based on these results.