We created an enduring features (EF, ecological site type, geophysical setting) dataset for Oklahoma that is similar to the EF dataset we created for Texas (see Diamond et al. 2016, Diamond and Elliott 2015, Elliott et al. 2014), . Digital soil map unit polygons (MUs), variables derived from digital elevation models (e.g. percent slope), and landform models (e.g. low, gentle slopes and flats in the Ozark and Ouachita Mountains) were combined to form this dataset. Among these, the low flats of the Ozark and Ouachita Mountains were most complicated to model because the sites had a low slope but were occupied by dry-mesic forest (in contrast to the low slope of uplands, which tended to be drier). A combination of slope and landscape position were used to identify these sites and model appropriately. A total of 75 EFs were identified for Oklahoma.
