Vance Knoll

The Vance Knoll Research Natural Area (RNA) was established to represent grasslands common to the Biscuit scabland of Southwest Oregon. The topography within the RNA includes a broad ridge top and side slope. The soil is comprised of residual loess formed from Colombia River basalts and Mount Mazama ash. The two principal plant communities are Idaho fescue-prairie Junegrass (Festuca idahoensis /Koelena cristata) and Sandberg's bluegrass-onespike oatgrass (Poa sandbergii/Danthonia unispicata). The plant communities within the RNA have been influenced by livestock grazing, timber harvest, and road construction which have facilitated introduction of non-native plants.