Much of the central and eastern parts of the range are within Joshua Tree National Park. Big Morongo Canyon Preserve is located in the western end of the Little San Bernardino Mountains. The oasis here contains one of the ten largest cottonwood (Populus fremontii) and red willow (Salix laevigata) Riparian zone habitats in California. It was identified as an area of concern by the Bureau of Land Management in 1982. It also has the only native palm to California, Washingtonia filifera, or the Desert fan palm which is now common in artificial landscaping.