Luther prairie burn preserves natural ecosystem

April 8, 2010

Faculty and students of the Luther College biology department conducted a prescribed burn in parts of the college’s Anderson Prairie and Hickory Ridge Woods on Wednesday, March 31, in an effort to maintain and restore the area’s natural ecosystems.

The prairie burn, which began about 6:15 p.m. and was completed and extinguished before 8:15 p.m., was supervised by Kirk Larsen, Luther professor of biology, who has planted and manages the college’s restored native tallgrass prairies.   

Planted in 1988, the 25-acre Anderson Prairie is divided into 19 plots that are burned or mowed on a three-year rotation to stimulate the beneficial effects that natural grass fires and grazing has on native prairies.

Unlike many ecosystems, prairie can survive under seemingly devastating circumstances. The presence of fire and large grazing animals are essential to the health and existence of native prairie plant species. Fire removes built up organic matter from the surface, destroys woody invaders and weeds, and allows for accelerated nutrient cycling.

Due to their extensive root systems, native plants have evolved to withstand fire. Once the plant litter has been cleared with fire, the sun can warm the soil and stimulate native plant growth.

The presence of the prairie provides numerous benefits that enhance soil quality. The extensive root systems provide a strong anchor to prevent erosion of top soil; nutrients and organic matter are recycled into the soil as plants die and decay; water quality is improved as the combination of roots and soil act as a filtration system for water absorption; and atmospheric carbon is sequestered by the new plant growth following fire. 

The clean water and rich soil provide optimal growth opportunities for a variety of plants, which in turn supply food and shelter for numerous animal species.

The controlled burns complement Luther’s efforts to restore the college’s Hickory Ridge Woods to an oak woodland ecosystem characteristic of region before the college was founded 150 years ago.

The initiative for the oak woodland restoration project came after the realization that decades of agricultural land use and benign neglect were causing Hickory Ridge Woods to be invaded by invasive species and lose much of its native biodiversity.            

The project began in 2006 when Professor Larsen and Jon Jensen, Luther associate professor of environmental studies, suggested that removing cedar trees to open up Hickory Ridge Woods would be a good service project for Luther students.

The woodland restoration program was initiated that year, and since then, each spring members of the biology faculty develop a list of restoration work projects to be done during the summer months.

The prescribed burns in prairie and oak woodlands such as the Hickory Ridge Woods restoration projects connect to Luther’s sustainability program and its goal of developing a greener campus.