The future of the Joshua tree

As the legend goes, it was 19th-century Mormon settlers who gave the Joshua tree its name, inspired by the plant’s bent and clubbed branches, which recall the biblical Joshua raising his arms in prayer. The etymology is apocryphal, but given the threats posed by climate change, these eccentric plants, and the California park named after them, might well need divine intervention—as well as new legal protections and conservation measures. 

Ringed by mountains and covering parts of the Mojave and Colorado deserts, Joshua Tree National Park’s rugged landscape features granite boulders, miles of cactus-filled flats, animals like the darkling beetle that can go a lifetime without a sip of water and the park’s namesake plant in all its twisted glory. 

Now completely arid, the land cradling the park once contained grasslands where mammoths and saber-toothed cats roamed; during the last ice age, giant ground sloths fed on Joshua trees, dispersing their seeds. The earliest known people in the area, the Pinto culture, were big-game hunters whose spear points have been found across today’s park. Even as the area warmed and dried, it has remained home to Native peoples—the Serrano, the Mojave, the Chemehuevi and the Cahuilla—who have drawn water from lush palm oases, gathered acorns and mesquite pods for food and used the tough leaves of the Joshua tree, which the Cahuilla call humwichawa, to weave baskets and sandals. By the mid-1800s, Native inhabitants were partly displaced by Western cowboys, ranchers and miners, whose long-abandoned homesteads are now disappearing under the sand. 

The Joshua tree, Yucca brevifolia, is a succulent—some botanists don’t consider it a tree. There are two distinct species: one with a tall, trunklike stem, one bushier. The plant’s contortions have won generations of fans. As author Jeannette Walls writes, “It’s the Joshua tree’s struggle that gives it its beauty.” 

Among the park’s long history of defenders, Minerva Hamilton Hoyt—a wealthy Southerner who moved from Mississippi to California in the late 1890s and grew to love the desert—is foremost. She spent two decades seeking to protect the area from cactus poachers, leading Franklin Delano Roosevelt to designate it a national monument in 1936; it became a national park in 1994. (Hoyt is celebrated in a 5,405-foot-high mountain named after her, and in Mammillaria hamiltonhoytea, a species of cactus.)

Already, botanists are seeing fewer juvenile Joshua trees, which need moister ground to survive. They’ve also seen “fairy rings”—circles of baby Joshua trees that sprouted not through pollination but as clones, unable to disperse; the plants’ unique pollinators, yucca moths, face an uncertain future as the climate warms. One conservationist calls the Joshua tree “a symbol of our utter failure as a society to address climate change.” The plant’s loss could mean the collapse of the Mojave’s high-desert ecosystem.

Nearly three million people visit the park each year, and entering vehicles back up for miles on busy days. With limited spots for camping and parking, many visitors flout regulations and camp or park on delicate lands. Meanwhile, smog from Los Angeles flows east through the San Gorgonio Pass, bringing ozone and soot. Nitrogen borne by smog fertilizes invasive grasses, which fuel wildfires that kill Joshua trees. 

Smithsonian