- The Oak Creek Wildlife Area is located in Yakima County and Kittitas County and covers 67,100 acres. The topography is dominated by steep, rocky slopes, and a series of ridges and canyons. Open ridges and southern slopes at the lower elevations support sagebrush, bitterbrush and rabbitbrush. Bluebunch wheatgrass is the most prevalent native grass. In the early spring the area is full of color with wildflowers scattered across the rangeland. At higher elevations, the vegetation transitions to conifer forests. Ponderosa pine, Douglas fir, subalpine fir, Engelmann spruce and western white pine can all be found as elevations increase in the Rock Creek Unit.