Reducing fuel loads in forested environments through mechanical thinning and prescribed burning can be effective strategies to reduce the future risk of extreme wildfire behavior. But other environmental factors may lead to unintended wildfire behavior in areas where fuel loading has been reduced.

Forest managers use tools such as mechanical thinning of stands and prescribed fires to reduce fuel loads and the likelihood of future severe wildfires in fire-prone ecosystems. However, the reduction of midstory and understory vegetation does not drive fire behavior in isolation. A Northern Research Station scientist partnered with scientists from the University of California Irvine, the Southern Research Station, Tall Timbers Research Station, and Los Alamos National Laboratory in a study using the FIRETEC fire-behavior model to investigate how the factors of mid-canopy fuel loading, fuel moisture, and wind interact to ultimately affect how fires spread through a forest stand containing longleaf pines, common persimmon, and turkey oak. The study showed that the desired outcome of lower fire intensities via the application of fuel-load reduction strategies is highly sensitive to fine-scale changes in local wind conditions and fuel moisture. In dry conditions, too much thinning can introduce more windy and turbulent conditions, which can increase fire intensity. But doing no thinning can also lead to an increase in fire intensity when fuels are dry. When fuels are moist and windy conditions are present, reduced mid-canopy fuel loads via thinning can also increase fire spread rates. This study and other fire-behavior modeling studies provide valuable information to forest managers that can guide them as they develop fuel reduction strategies to mitigate wildfire risk.