Restoring eastern redcedar encroached watersheds to prairie or switchgrass improves water quality and quantity

Eastern redcedar represents a modern-day challenge to Oklahoma as it has encroached approximately eight million acres of land. This conversion is detrimental to the ecological and economic value of the land, reducing ecosystem water provisioning in particular. Eastern redcedar trees consume more water such that less is available for municipal and agricultural uses as well as ecological stream flows. Currently, efforts to reduce eastern redcedar encroachment have been unsuccessful; however, studies have shown eastern redcedar biomass to be a potential ethanol feedstock for the state. The purpose of this study is to compare eastern redcedar removal and replacement with native prairie or planted switchgrass on surface runoff, sediment yield, and biomass production. More specifically, this study monitors surface runoff and sediment yield of encroached eastern redcedar, harvested eastern redcedar, cultivated switchgrass, and native prairie using experimental watersheds (5-10 acres in size). Preliminary analysis shows that removal of eastern redcedar increased water yield by 4-5 fold. Growing switchgrass produced more biomass than restoration to native prairie, but water yield did not differ between the two. Sediment concentrations from encroached eastern redcedar watersheds were higher compared to native prairie watersheds. After harvest, previously encroached watersheds initially experienced an increase in sediment yield due to soil disturbance. After switchgrass and native vegetation re-established, sediment yields declined. These results indicate that water yield and biomass production can be increased by converting eastern redcedar woodlands to switchgrass for use as dedicated biofuel feedstock.Robert E. McNair Post-Baccalaureate Achievement ProgramNational Institute of Food and Agriculture (U.S.)National Science Foundation (U.S.)Oklahoma Louis Stokes Alliance for Minority Participation ProgramNatural Resource Ecology and ManagementBiosystems and Agricultural Engineerin