Administered by UC Irvine, the reserve is owned by the University of California and managed for teaching and research.

[2] Reserve lands form a transition zone, or ecotone, between the high-elevation ecosystems of the San Bernardino Mountains and the lower, hotter Mojave Desert.

Because the reserve lies in the rain shadow of the San Bernardino Mountains, millions of years of drying eroded the soils.

Habitats at the reserve include desert, a freshwater seep, and a wash. Vegetation typical of the high elevation Mojave, such as Joshua trees (Yucca brevifolia), nolina (Nolina parryi), and the reserve's namesake, the piñon pine (Pinus monophylla) grow atop the dry hills.

Perennially moist lower Railroad Wash sustains Muller's oak (Quercus cornelius-mulleri) and rushes (Juncus sp.)