Today this desert landscape looks as though it hasn’t changed in eons. But the story of
Joshua Tree is actually one of constant change, dating back not thousands or millions of years, but almost two billion years.
The present climate of the western deserts is relatively new. From approximately 25 million to 10,000 years ago, the Joshua Tree region received much greater precipitation than at present, with less evaporation and an average temperature that was several degrees cooler. The landscape, with scattered trees and shrubs and laced with streams, resembled an African grassland savanna, with large browsing mammals such as ancestral camels, horses, lions, and antelopes.
This former climate was critical in the development of today’s desert landscape. It’s hard to believe that it was water that shaped and sculpted these rocks but in fact, even today, water remains the primary agent eroding the landscape.