New research gives thumbs up to prescribed fires

A new study by Clemson University researchers lends further credence to the effectiveness of prescribed fire as a forest management tool that does not adversely impact ecosystem health by increasing sediment or nutrient runoff.

With the largest mountain wildfire in South Carolina history still fresh in the memories of many in the Upstate, that distinction is important because a primary reason for the use of prescribed fire is reducing the likelihood and severity of wildfires by reducing the amount of litter such as pine needles and fallen leaves available to — quite literally — add fuel to the fire.

In a review entitled “Prescribed fire effects on sediment and nutrient exports in forested environments,” Clemson researchers Kipling Klimas, Patrick Hiesl, Donald Hagan and Dara Park concluded that though sediment in runoff increases after prescribed fire in certain situations, these erosion events are associated with intense precipitation shortly after the fire and do not impair ecosystem function.

Klimas cited the wildfire that was ignited by an escaped campfire in November 2016 at Table Rock State Park as an example of the destruction wildfires can cause and evidence for the benefits of prescribed burning. After a dry fall season and with an ongoing drought in the Upstate, the Pinnacle Mountain Fire grew to 10,623 acres — making it the largest mountain wildfire on record in South Carolina — by the time it was controlled after burning for more than a month, according to the S.C. Forestry Commission.

Forestlands occupy approximately two-thirds of South Carolina’s land area and its $21 billion forestry industry represents the state’s top manufacturing industry. But while prescribed fire has long been considered a powerful and effective management tool, few previous studies had sought to quantify the impact of fire effects on forest health and water quality across varying environments and scales.

The assessment of nutrient and sediment runoff yields is important because while forests are an important source of clean water globally, and watersheds are often managed to provide clean water to urban populations, a primary concern associated with fire is elevated surface runoff and erosion caused by rainfall events following the fire, due to their ability to transport pollutants including sediment, macronutrients or other organic compounds into water systems.

“After fire, erosion and soil loss and soil mobility is the greatest concern associated with fire or any sort of forestry harvesting operation,” Klimas said. “So, that’s why we’re looking specifically at sediment. When you get sediment into streams — because we have trout waters up here in the Upstate, we’ve got streams that feed into municipal water supplies — it can reduce the productivity of the water body, it can kill off aquatic organisms and have other detrimental effects to that ecosystem. The streams coming out of the Blue Ridge Escarpment right here in the Upstate, around Table Rock Mountain and Caesar’s Head, they are all really important for downstream water quality.”